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Bass, Adam Stuart, Anand Chandra Singh, Scott Paulson und Viola Ingrid Birss. „Minimizing Coke Formation at La0.3Ca0.7Fe0.7Cr0.3O3-δ Perovskite Anodes in a Syngas Fed-SOFC“. ECS Meeting Abstracts MA2023-02, Nr. 46 (22.12.2023): 2238. http://dx.doi.org/10.1149/ma2023-02462238mtgabs.
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As the world moves to decarbonize the fossil fuel sector, transition technologies are needed that bridge the gap between natural gas power plants and more sustainable low-carbon energy sources. These newer technologies often still rely on fossil fuels but have improved energy conversion efficiencies and lower net carbon dioxide (CO2) outputs over conventional fossil fuel based electric power generation systems. In this work, we are exploring one such technology, namely the use of a syngas-fed solid oxide fuel cell (SOFC) to generate heat, electricity, steam, and captured CO2. Core to this technology is the mixed ion electron conductor deployed at the anode and cathode that catalyzes all of the relevant reactions, namely electrochemical oxidation of hydrogen (H2) and carbon monoxide (CO) at the anode, producing steam and CO2, and reduction of oxygen at the cathode. Carbon formation (coking) is normally a significant problem affecting SOFCs operating on carbon-based fuels, as it leads to a rapid decline in electrochemical performance by blocking catalytically active sites and pores with various carbon species, e.g., amorphous, graphitic, or nanotubular carbon.1 The formation of carbon species from syngas is known to occur through various mechanisms, with the Boudouard reaction (∆H= -172 kJ/mol) and the reduction of CO (∆H= -131 kJ/mol) being the most prominent.2 As such, temperature is a key parameter to optimize as it determines the propensity for carbon formation at equilibrium. In addition, the kinetics of carbon formation can be significantly reduced by introducing oxygen to the fuel gas stream in the form of O2, CO2, or H2O.3 The catalyst materials investigated here are mixed conducting perovskite oxides (La0.3Ca0.7Fe0.7Cr0.3O3- δ, LCFCr) that have been optimized and modified recently by our group, both in the as-prepared undoped form and after B-site doping with variable quantities of transition metals (M), e.g., Ni,4 forming nanoparticle (NP)-decorated ABO3-Mx surfaces. Our catalyst is highly active for H2 and CO oxidation, CO2 reduction, and O2 reduction, where it was demonstrated that the un-doped parent material can deliver a stable power density of 0.2 W/cm2 for several hundred hours with negligible performance degradation in 3% humidified H2.5 In more recent work, excellent resilience to carbon deposition for exsolved Fe-Ni@LCFCr up to 70:30 CO:CO2 was demonstrated.4 Herein, we show that minimal coke forms during exposure of these materials to dry syngas at 600oC, even under open circuit conditions. The catalysts were prepared using combustion synthesis and were characterized by XRD, SEM EDX, and TPO-MS in order to confirm morphology, crystal structure, and composition as a function of temperature and gas environment.4 Symmetrical electrolyte-supported SOFCs were constructed using our catalyst as both the anode and cathode. Catalyst layers of 1 cm2 were screen printed to a thickness of 25 µm on both sides of commercially available 130 µm thick samaria-doped ceria (SDC)-buffered scandia-stabilized zirconia (ScSZ) electrolyte, followed by sintering at 1100°C for 2 h,4 with porous metal current collectors used. The cells were mounted and tested in a Fiaxel SOFC test station with gas flow controlled by mass flow controllers. Preliminary electrochemistry experiments were conducted in 5:95 H2:N2, or 1:1 H2:CO (syngas) balanced by CO2 in a 1:2 ratio of fuel to oxidant into the anode chamber, and air into the cathode chamber at 600 oC, with performance evaluation carried out using CV, EIS and chronopotentiometry. The power density was found to be ca. 2x higher in dry H2 vs. in syngas, as expected, considering that H2 is a more active fuel vs. CO. Additionally, EIS exhibited ca. 2x higher resistance in the low frequency arc in syngas, which can be attributed to sluggish CO oxidation kinetics.4 Chronopotentiometry was performed for 20 h at 10 mA cm-2, showing a degradation rate of only 0.08 mV h-1, suspected to be primarily due to current collector delamination. Coking studies were also conducted on button cells at 600 oC in 1:1 H2:CO for 25 h at open circuit, comparing to a NiO standard that was painted on the electrolyte just next to the LCFCr-Ni working electrode. Imaging by SEM showed negligible carbon formation on the perovskite surface, supported by EDX analysis, compared to the extensive degree of coking observed at the standard. Further quantification was conducted by TPO-MS, also confirming minimal carbon formation. References Bengaard et al., Journal of Catalysis, 2002, 209, 365–384. Farshchi Tabrizi et al., Energy Conversion and Management, 2015, 103, 1065–1077. Sasaki et al., Journal of The Electrochemical Society, 2003, 150. Ansari et al., Journal of Materials Chemistry A, 2022, 10, 2280–2294. Addo et al., ECS Transactions, 2015, 66, 219–228.
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Mezza, Alessio, Angelo Pettigiani, Nicolò B. D. Monti, Sergio Bocchini, M. Amin Farkhondehfal, Juqin Zeng, Angelica Chiodoni, Candido F. Pirri und Adriano Sacco. „An Electrochemical Platform for the Carbon Dioxide Capture and Conversion to Syngas“. Energies 14, Nr. 23 (24.11.2021): 7869. http://dx.doi.org/10.3390/en14237869.
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We report on a simple electrochemical system able to capture gaseous carbon dioxide from a gas mixture and convert it into syngas. The capture/release module is implemented via regeneration of NaOH and acidification of NaHCO3 inside a four-chamber electrochemical flow cell employing Pt foils as catalysts, while the conversion is carried out by a coupled reactor that performs electrochemical reduction of carbon dioxide using ZnO as a catalyst and KHCO3 as an electrolyte. The capture module is optimized such that, powered by a current density of 100 mA/cm2, from a mixture of the CO2–N2 gas stream, a pure and stable CO2 outlet flow of 4–5 mL/min is obtained. The conversion module is able to convert the carbon dioxide into a mixture of gaseous CO and H2 (syngas) with a selectivity for the carbon monoxide of 56%. This represents the first all-electrochemical system for carbon dioxide capture and conversion.
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HASAN, A. T., und T. J. GRAY. „EXPERIMENTAL STUDY OF SINGLE-ELECTRON-CAPTURE CROSS SECTIONS BY LOW-ENERGY $N^+_2$ AND N+ IONS IN N2 MOLECULAR GAS“. International Journal of Modern Physics E 11, Nr. 06 (Dezember 2002): 567–72. http://dx.doi.org/10.1142/s0218301302001113.
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Absolute total cross sections for single-electron-capture are measured for [Formula: see text] and N+ ions traversing N2 molecular gas of collision energies in the range of 0.60 to 1.5 keV. These cross sections are found to be in the range of 3.97 - 6.25 Å2 for [Formula: see text] ions, and in the range of 0.46 - 1.67 Å2 for N+ ions. A comparison is made between the present measurements of the total cross sections of the N+ + N2 system and all the experimental results, which are represented by B. G. Lindsay et al.,1 for the O+ + N2 system. The present measurements of the total cross section of the N+ + N2 system are in partial agreement with measurements of B. G. Lindsay et al.,1 and in an excellent agreement with the measurements of Moran et al.,2 The present measurements of the total cross sections of the [Formula: see text] system are compared to the theoretical calculations and the experimental results of the same system.23 The results are in disagreement with each other.
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Mekbuntoon, Pongsakorn, Sirima Kongpet, Walailak Kaeochana, Pawonpart Luechar, Prasit Thongbai, Artit Chingsungnoen, Kodchaporn Chinnarat, Suninad Kaewnisai und Viyada Harnchana. „The Modification of Activated Carbon for the Performance Enhancement of a Natural-Rubber-Based Triboelectric Nanogenerator“. Polymers 15, Nr. 23 (28.11.2023): 4562. http://dx.doi.org/10.3390/polym15234562.
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Increasing energy demands and growing environmental concerns regarding the consumption of fossil fuels are important motivations for the development of clean and sustainable energy sources. A triboelectric nanogenerator (TENG) is a promising energy technology that harnesses mechanical energy from the ambient environment by converting it into electrical energy. In this work, the enhancement of the energy conversion performance of a natural rubber (NR)-based TENG has been proposed by using modified activated carbon (AC). The effect of surface modification techniques, including acid treatments and plasma treatment for AC material on TENG performance, are investigated. The TENG fabricated from the NR incorporated with the modified AC using N2 plasma showed superior electrical output performance, which was attributed to the modification by N2 plasma introducing changes in the surface chemistry of AC, leading to the improved dielectric property of the NR-AC composite, which contributes to the enhanced triboelectric charge density. The highest power density of 2.65 mW/m2 was obtained from the NR-AC (N2 plasma-treated) TENG. This research provides a key insight into the modification of AC for the development of TENG with high energy conversion performance that could be useful for other future applications such as PM2.5 removal or CO2 capture.
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Snoeckx, R., S. Heijkers, K. Van Wesenbeeck, S. Lenaerts und A. Bogaerts. „Correction: CO2 conversion in a dielectric barrier discharge plasma: N2 in the mix as a helping hand or problematic impurity?“ Energy & Environmental Science 15, Nr. 2 (2022): 866. http://dx.doi.org/10.1039/d2ee90005j.
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Correction for ‘CO2 conversion in a dielectric barrier discharge plasma: N2 in the mix as a helping hand or problematic impurity?’ by R. Snoeckx et al., Energy Environ. Sci., 2016, 9, 999–1011, DOI: 10.1039/C5EE03304G.
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Gong, Dehong, Zhongxiao Zhang und Ting Zhao. „Decay on Cyclic CO2 Capture Performance of Calcium-Based Sorbents Derived from Wasted Precursors in Multicycles“. Energies 15, Nr. 9 (03.05.2022): 3335. http://dx.doi.org/10.3390/en15093335.
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In order to obtain the cheap waste calcium-based sorbent, three wasted CaCO3 precursors, namely carbide slag, chicken eggshells, and analytical reagent-grade calcium carbonate, were selected and prepared at 700 °C to form calcium-based sorbents for CO2 capture. TGA was used to test the CO2 uptake performance of each calcium-based sorbent in 20 cycles. To identify the decay mechanism of CO2 uptake with an increasing number of cycles, all calcium-based sorbents were characterized by using XRF, XRD, and N2 adsorption. The specific surface area of calcium-based sorbents was used to redefine the formula of cyclic carbonation reactivity decay. The carbonation conversion rate of three calcium-based sorbents exhibited a decreasing trend as the cycle number increased. Chicken eggshells exhibited the most significant decrease rate (over 50% compared with Cycle 1), while carbide slag and analytical reagent-grade calcium carbonate showed a flat linear decline trend. The specific surface area of the samples was used to calculate carbonation conversion for an infinite number of cycles. The carbonation conversion rates of three calcium-based sorbents were estimated to decrease to 0.2898, 0.1455, and 0.3438 mol/mol, respectively, after 100 cycles.
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Donskoy, I. G. „Thermodynamic modeling of solid fuel gasification in mixtures of oxygen and carbon dioxide“. Journal of Physics: Conference Series 2119, Nr. 1 (01.12.2021): 012101. http://dx.doi.org/10.1088/1742-6596/2119/1/012101.
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Abstract One of the main problems in the use of solid fuels is inevitable formation of significant amounts of carbon dioxide. The prospects for reducing CO2 emissions (carbon capture and storage, CCS) are opening up with the use of new coal technologies, such as thermal power plants with integrated gasification (IGCC) and transition to oxygen-enriched combustion (oxyfuel). In order to study the efficiency of solid fuel conversion processes using carbon dioxide, thermodynamic modeling was carried out. Results show that difference between efficiency of fuel conversion in O2/N2 and O2/CO2 mixtures increases with an increase in the volatile content and a decrease in the carbon content. The effect of using CO2 as a gasification agent depends on the oxygen concentration: at low oxygen concentrations, the process temperature turns out to be low due to dilution; at high oxygen concentrations, the CO2 concentration is not high enough for efficient carbon conversion.
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Moreira-Coello, Víctor, Beatriz Mouriño-Carballido, Emilio Marañón, Ana Fernández-Carrera, María PÉrez-Lorenzo und Antonio Bode. „Quantifying the overestimation of planktonic N2 fixation due to contamination of 15N2 gas stocks“. Journal of Plankton Research 41, Nr. 4 (Juli 2019): 567–70. http://dx.doi.org/10.1093/plankt/fbz034.
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AbstractThe 15N2-tracer assay [Montoya et al. (1996) A simple, high-precision, high-sensitivity tracer assay for N2 fixation. Appl. Environ. Microbiol., 62, 986–993.] is the most used method for measuring biological N2 fixation in terrestrial and aquatic environments. The reliability of this technique depends on the purity of the commercial 15N2 gas stocks used. However, Dabundo et al. [(2014) PLoS One, 9, e110335.] reported the contamination of some of these stocks with labile 15N-labeled compounds (ammonium, nitrate and/or nitrite). The contamination of commercial 15N2 gas stocks with 15N-labeled nitrate and 142 ammonium and consequences for nitrogen fixation measurements. Considering that the tracer assay relies on the conversion of isotopically labeled 15N2 into organic nitrogen, this contamination may have led to overestimated N2 fixation rates. We conducted laboratory and field experiments in order to (i) test the susceptibility of 15N contaminants to assimilation by non-diazotroph organisms and (ii) determine the potential overestimation of the N2 fixation rates estimated in the field. Our findings indicate that the contaminant 15N-compounds are assimilated by non-diazotrophs organisms, leading to an overestimation of N2 fixation rates in the field up to 16-fold under hydrographic conditions of winter mixing.
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Àlvares, Cristina. „Narration et prédation: Pascal Quignard et la théorie cynégétique du récit“. Semiotica 2021, Nr. 239 (04.02.2021): 81–97. http://dx.doi.org/10.1515/sem-2018-0055.
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Résumé Notre propos est de réunir quelques réflexions de Pascal Quignard sur le récit afin d’en dégager les coordonnées ou les prémisses d’une théorie narrative chez cet écrivain qui, n’étant pas un théoricien, est sans doute quelqu’un qui fait œuvre de pensée. Notre hypothèse est que, situées dans le cadre d’une épistémologie naturaliste et d’un récit anthropogénétique au sein duquel la prédation joue un rôle majeur, en particulier celui de condition de possibilité de la narration, les spéculations de Quignard s’élaborent sur fond de la théorie sémio-narrative laquelle subit ainsi une reformulation. Nous soutenons que la réinterprétation quignardienne fait partie des théories, comme celles de Petitot et de Thom, qui proposent une solution morphogénétique au problème de la conversion (de la substance sémique en forme narrative) tel qu’il se présente chez Greimas. Au sein de cette convergence avec le structuralisme naturaliste et morphodynamique, la spécificité de Quignard réside dans la configuration de la conversion comme capture. Cette figure dynamique devient alors un opérateur de narrativité différent des modèles logiques (carré sémiotique) ou topologiques (catastrophes) qui formalisent rationnellement la conversion. Elle est au cœur de la pensée de l’écrivain sur le phénomène narratif.
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Piccirilli, Luca, Danielle Lobo Justo Pinheiro und Martin Nielsen. „Recent Progress with Pincer Transition Metal Catalysts for Sustainability“. Catalysts 10, Nr. 7 (11.07.2020): 773. http://dx.doi.org/10.3390/catal10070773.
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Our planet urgently needs sustainable solutions to alleviate the anthropogenic global warming and climate change. Homogeneous catalysis has the potential to play a fundamental role in this process, providing novel, efficient, and at the same time eco-friendly routes for both chemicals and energy production. In particular, pincer-type ligation shows promising properties in terms of long-term stability and selectivity, as well as allowing for mild reaction conditions and low catalyst loading. Indeed, pincer complexes have been applied to a plethora of sustainable chemical processes, such as hydrogen release, CO2 capture and conversion, N2 fixation, and biomass valorization for the synthesis of high-value chemicals and fuels. In this work, we show the main advances of the last five years in the use of pincer transition metal complexes in key catalytic processes aiming for a more sustainable chemical and energy production.
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Yin, Huayi, und Dihua Wang. „(Invited) Electrochemical Conversion of CO2 Into Oxygen/ and C/CO in Molten Carbonate“. ECS Meeting Abstracts MA2023-01, Nr. 56 (28.08.2023): 2737. http://dx.doi.org/10.1149/ma2023-01562737mtgabs.
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The molten salt CO2 capture and electrochemical transformation (MSCC-ET) process has been demonstrated as an effective approach to capturing and converting CO2 into oxygen and C/CO [1-2]. The effective CO2 capture and electrochemical conversion rely on the high-temperature molten carbonate electrolytes and the cost-effective inert oxygen-evolution anode. In recent years, we have focused on the electrolyte engineering to modulate the reactions at both the cathode and anode as well as the CO2 capture efficiency [3-4]. Besides, we insist on developing iron- and nickel-base oxygen-evolution inert anodes in terms of revealing the fundamental principles and basic guidelines for choosing proper materials and fabrication processes [5]. By doing so, we can prepare functional carbon materials or CO at the cathode with a high current efficiency of over 90%, and produce oxygen at the inert anode. In addition, the kilo-ampere scale electrolyzer was built to produce oxygen, carbon or CO with an energy efficiency of over 50%. Therefore, the molten carbonate CO2 electrolyzer shows its potential to convert CO2 on the Mars to produce oxygen and fuels to support the future exploration of outer space. References [1] H. Y. Yin, D. H. Wang*, et al., Capture and electrochemical conversion of CO2 to value-added carbon and oxygen by molten salt electrolysis. Energy & Environmental Science, 2013, 6: 1538-1545. [2] R. Jiang, M. X. Gao, X. H. Mao, D. H. Wang*. Advancements and potentials of molten salt CO2 capture and electrochemical transformation (MSCC-ET) process, Current Opinion in Electrochemistry, 2019, 17: 38-46. [3] B. W. Deng, J. J. Tang, X. H. Mao, Y. Q. Song, H. Zhu, W. Xiao, D. H. Wang*. Kinetic and Thermodynamic Characterization of Enhanced Carbon Dioxide Absorption Process with Lithium Oxide-Containing Ternary Molten Carbonate, Environmental Science & Technology, 2016, 50(19): 10588-10595. [4] Z. S Yang, B. W. Deng, K. F. Du, H. Y. Yin*, D. H. Wang*, A general descriptor for guiding the electrolysis of CO2 in molten carbonate, 2022, in press. [5] P. L. Wang, K. F. Du, Y. P. Dou, H. Zhu, D. H. Wang*, Corrosion behaviour and mechanism of nickel anode in SO42- containing molten Li2CO3-Na2CO3-K2CO3. Corrosion Science 2022, 166. Figure 1
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Wang, Lei, Wu Qin, Ling Nan Wu, Xue Qing Hu, Ming Zhong Gao, Jun Jiao Zhang, Chang Qing Dong und Yong Ping Yang. „Experimental Study on Coal Chemical Looping Combustion Using CuFe2O4 as Oxygen Carrier“. Advanced Materials Research 805-806 (September 2013): 1387–90. http://dx.doi.org/10.4028/www.scientific.net/amr.805-806.1387.
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Chemical-looping combustion (CLC) has been proposed as an efficient and clean technology that could contribute to achieve carbon dioxide capture with negligible cost. The technology uses a metal oxide as oxygen carrier that indirectly transfer oxygen from air to fuels to oxidize the fuels. CuFe2O4 was prepared as a novel oxygen carrier to decrease the cost of raw material and increase the reactivity of iron-based oxygen carrier. The structure of the prepared oxygen carrier was characterized by scanning electron microscope (SEM) and an X-ray diffractometer (XRD). The reaction of CuFe2O4 with coal was tested in a thermogravimetric analyzer (TGA). Results showed that the pyrolysis of coal under CO2 was more complete than that under N2, and the final conversion of CuFe2O4 during CLC of coal reached 66.6%. SEM images and BET surface area of the fresh and the used oxygen carrier show little agglomeration during the process.
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Du, Yapeng, Yu Chai, Xiaoping Zheng und Yanzhen Zheng. „Theoretical Study on the Multiple Free Radical Scavenging Reactions of Pyranoanthocyanins“. Antioxidants 13, Nr. 1 (22.12.2023): 33. http://dx.doi.org/10.3390/antiox13010033.
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The free radical trapping capacities of multiple pyranoanthocyanins in wine storage and ageing were theoretically explored by density functional theory (DFT) methods. Intramolecular hydrogen bonds were detected in all pyranoanthocyanins, and the planarity of the compounds worsened with an increasing dielectric constant in the environment. Solvents significantly influenced the reaction enthalpies; thus, the preferred thermodynamic mechanisms of the free radical scavenging reactions were modified in different phases. This study incorporates hydrogen atom transfer (HAT), proton loss (PL), electron transfer (ET) reactions, and demethylation (De) of methoxy group mechanisms. The three pyranoanthocyanins have the capacity to capture n1+1 free radicals, where n1 represents the number of methoxy groups. In the gas phase, they prefer employing the n1-De-HAT mechanism on the guaiacyl moiety of the B ring, resulting in the formation of a stable quinone or a quinone radical to scavenge free radicals. In the benzene phase, pyranoanthocyanins trap free radicals via a PL−n1−De−HAT mechanism. In the water phase, the targeted pyranoanthocyanins may dissociate in the form of carboxylate and tend to utilize the n2−PL−n1−De−ET mechanism, where n2 and n1 represent the number of phenolic groups and methoxy groups, respectively, facilitating multiple H+/e− reactions.
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Reisner, Erwin. „(Invited) Solar Panel Technologies for Light-to-Chemical Conversion“. ECS Meeting Abstracts MA2023-02, Nr. 47 (22.12.2023): 2370. http://dx.doi.org/10.1149/ma2023-02472370mtgabs.
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Solar panels are well known to produce electricity, but they are also in early-stage development for the production of sustainable fuels and chemicals. These panels mimic plant leaves in shape and function as demonstrated for overall solar water splitting to produce green H2 by the laboratories of Nocera and Domen.1,2 This presentation will give an overview of our recent progress to construct prototype solar panel devices for the conversion of carbon dioxide and solid waste streams into fuels and higher-value chemicals through molecular surface-engineering of solar panels with suitable catalysts. Specifically, a standalone ‘photoelectrochemical leaf’ based on an integrated lead halide perovskite-BiVO4 tandem light absorber architecture has been built for the solar CO2 reduction to produce syngas.3 Syngas is an energy-rich gas mixture containing CO and H2 and currently produced from fossil fuels. The renewable production of syngas may allow for the synthesis of renewable liquid oxygenates and hydrocarbon fuels. Recent advances in the manufacturing have enabled the reduction of material requirements to fabricate such devices and make the leaves sufficiently light weight to even float on water, thereby enabling application on open water sources.4 The tandem design also allows for the integration of biocatalysts and the selective and bias-free conversion of CO2-to-formate has been demonstrated using enzymes.5 The versatility of the integrated leaf architecture has been demonstrated by replacing the perovskite light absorber by BiOI for solar water and CO2 splitting to demonstrate week-long stability.6 An alternative solar carbon capture and utilisation technology is based on co-deposited semiconductor powders on a conducting substrate.2 Modification of these immobilized powders with a molecular catalyst provides us with a photocatalyst sheet that can cleanly produce formic acid from aqueous CO2.7 CO2-fixing bacteria grown on such a ‘photocatalyst sheet’ enable the production of multicarbon products through clean CO2-to-acetate conversion.8 The deposition of a single semiconductor material on glass gives panels for the sunlight-powered conversion plastic and biomass waste into H2 and organic products, thereby allowing for simultaneous waste remediation and fuel production.9 The concept and prospect behind these integrated systems for solar energy conversion,10 related approaches,11 and their relevance to secure and harness sustainable energy supplies in a fossil-fuel free economy will be discussed. References (1) Reece et al., Science, 2011, 334, 645–648. (2) Wang et al., Nat. Mater., 2016, 15, 611–615. (3) Andrei et al., Nat. Mater., 2020, 19, 189–194. (4) Andrei et al., Nature, 2022, 608, 518–522. (5) Moore et al., Angew. Chem. Int. Ed., 2021, 60, 26303–26307. (6) Andrei et al., Nat. Mater., 2022, 21, 864–868. (7) Wang et al., Nat. Energy, 2020, 5, 703–710. (8) Wang et al., Nat. Catal., 2022, 5, 633–641. (9) Uekert et al., Nat. Sustain., 2021, 4, 383–391. (10) Andrei et al., Acc. Chem. Res., 2022, 55, 3376–3386. (11) Wang et al., Nat. Energy, 2022, 7, 13-24.
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Micheli, Francesca, Enrica Mattucci, Claire Courson und Katia Gallucci. „Bi-Functional Catalyst/Sorbent for a H2-Rich Gas from Biomass Gasification“. Processes 9, Nr. 7 (19.07.2021): 1249. http://dx.doi.org/10.3390/pr9071249.
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The aim of this work is to identify the effect of the CaO phase as a CO2 sorbent and mayenite (Ca12Al14O33) as a stabilizing phase in a bi-functional material for CO2 capture in biomass syngas conditioning and cleaning at high temperature. The effect of different CaO weight contents is studied (0, 56, 85, 100 wt%) in sorbents synthesized by the wet mixing method. These high temperature solid sorbents are upgraded to bi-functional compounds by the addition of 3 or 6 wt% of nickel chosen as the metal active phase. N2 adsorption, X-ray diffraction, scanning electronic microscopy, temperature-programmed reduction analyses and CO2 sorption study were performed to characterize structural, textural, reducibility and sorption properties of bi-functional materials. Finally, sorption-enhanced reforming of toluene (chosen as tar model), of methane then of methane and toluene with bi-functional compounds were performed to study the best material to improve H2 content in a syngas, provided by steam biomass gasification. If the catalytic activity on the sorption enhanced reforming of methane exhibits a fast fall-down after 10–15 min of experimental test, the reforming of toluene reaches a constant conversion of 99.9% by using bi-functional materials.
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Hsieh, Chu-Chin, Jyong-Sian Tsai und Jen-Ray Chang. „Effects of Moisture on NH3 Capture Using Activated Carbon and Acidic Porous Polymer Modified by Impregnation with H3PO4: Sorbent Material Characterized by Synchrotron XRPD and FT-IR“. Materials 15, Nr. 3 (20.01.2022): 784. http://dx.doi.org/10.3390/ma15030784.
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The performances of reactive adsorbents, H3PO4/C (activated carbon) and H3PO4/A (Amberlyst 35), in removing NH3 from a waste-gas stream were investigated using a breakthrough column. Accelerated aging tests investigated the effects of the water content on the performance of the adsorbents. Results of breakthrough tests show that the adsorption capacity greatly decreased with the drying time of H3PO4/C preparation. Synchrotron XRPD indicated increased amorphous phosphorus species formation with drying time. Nitrogen adsorption-desorption isotherms results further suggested that the evaporation of water accommodated in macropores decreases adsorption capacity besides the formation of the amorphous species. Introducing water moisture to the NH3 stream increases the adsorption capacity concomitant with the conversion of some NH4H2PO4 to (NH4)2HPO4. Due to the larger pore of cylindrical type and more hydrophilic for acidic porous polymer support, as opposed to slit-type for the activated carbon, the adsorption capacity of H3PO4/A is about 3.4 times that of H3PO4/C. XRPD results suggested that NH3 reacts with aqueous H3PO4 to form NH4H2PO4, and no significant macropore-water evaporation was observed when acidic porous polymer support was used, as evidenced by N2 isotherms characterizing used H3PO4/A.
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Di Lauro, Enrico, Maria Maza, Javier L. Lara, Inigo J. Losada und Diego Vicinanza. „NUMERICAL MODELING OF WAVE INTERACTION WITH A NON-CONVENTIONAL BREAKWATER FOR WAVE ENERGY CONVERSION“. Coastal Engineering Proceedings, Nr. 36 (30.12.2018): 64. http://dx.doi.org/10.9753/icce.v36.structures.64.
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The hybrid non-conventional breakwaters are innovative coastal structures, which have as a primary function the coastal and harbours protection, but with the important benefit of electricity production, due to their combination with Wave Energy Converters. The most recent example of a non-conventional breakwater is called OBREC, standing for Overtopping Breakwater for Energy Conversion (Vicinanza et al., 2014). The device consists of a traditional rubble mound breakwater, in which the seaward armour layer in the upper part is replaced with a frontal sloping ramp and a reservoir. The structure is designed to capture and gather the water that overtops the crest ramp. The potential energy of the water stored in the reservoir is converted into kinetic energy and then into electrical energy by flowing through low head hydraulic turbines coupled with generators, exploiting the different water levels between the reservoir and the sea level.
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Bohlen, Barbara, Nick Daems und Tom Breugelmans. „Electrochemical Production of Formate Directly from Amine-Based CO2 Capture Media“. ECS Meeting Abstracts MA2023-01, Nr. 26 (28.08.2023): 1722. http://dx.doi.org/10.1149/ma2023-01261722mtgabs.
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Introduction There is an urgency for the development and establishment of technologies to deal with the effects of climate change and increasing temperature of the planet.1 The decrease in the CO2 emissions is a possible path, and the capture of CO2 from the atmosphere is another alternative to try and tackle the effects of climate change.2 The combination of capture and conversion of CO2 is a potential approach to achieve the net-zero emission goals and a circular economy for the future.3 Amine scrubbing is an industrially established capture technology that utilizes mainly monoethanolamine (MEA) as the capture solution to capture CO2 from post-combustion flue gases. The process has the disadvantage of a high energy demand, which prevents its wider application.2 This study proposes a novel capture and utilization (CCU) combination: the use of the MEA capture solution as electrolyte for the electrochemical CO2 reduction (eCO2R). In that way, the CO2 capture and conversion will be combined in the same medium, avoiding the energy-intensive regeneration step, thus saving energy, as well as generating products of industrial interest. Sn-based catalysts were primarily chosen due to their selectivity towards formate, one of the most straightforward reduction products from CO2. Results The eCO2R from the capture media (30 wt% MEA solutions, saturated with CO2) was promoted in a zero-gap type reactor, composed of an Sn-based cathode, a Ni foam anode and a bipolar membrane (BPM) separating the cathode and anode compartments. The BPM is responsible for providing protons to the cathode side of the electrolyzer, which promote the hydrolysis of the carbamate on the surface of the catalyst and thus enhances the CO2 availability and consequently the eCO2R. Figure 1 presents a scheme of the zero-gap electrolyzer, highlighting the hydrolysis of the carbamate in contact with the catalyst, and compares the faradaic efficiencies (FE) towards formate obtained by different setups of the zero-gap electrolyzer, at -50 mA cm-2. The Sn nanoparticle (SnNP)-based catalysts show a low efficiency for the eCO2R from the capture media (up to 5%). As published in the literature, surfactants are capable to inhibit the hydrogen evolution reaction (HER) in electrochemical systems and thus promote the eCO2R.4 The surfactant cetyltrimethylammonium bromide (CTAB) was therefore added to the system and the FE towards formate increased, although merely up to 6.43%. To further increase the surface area available for the eCO2R, a metal gauze was introduced as support for the working electrode (WE). Here, a Cu gauze with electrodeposited Sn (SnED) was used as WE and the obtained FE was 70% higher than for the carbon supported SnNP catalysts, up to 8.49%, without the addition of the surfactant. The hydrophilic nature of the metal surface (in comparison to the carbon paper substrate of the NPs) and a bigger surface area could be the reasons behind this enhancement in the FE using metal WE. Future studies will focus on the further enhancement of the FE towards formate. Conclusion This study shows the feasibility of a novel CCU technology: the electrochemical reduction of CO2 to formate from an amine-based capture medium. Sn-based catalysts lead to an FE of up to 8.49%. The use of a metallic electrode lead to a larger enhancement of the FE, in comparison to the addition of a surfactant to the electrolyte for the SnNP-based catalyst. There is yet room for further improvement of the faradaic efficiency by the combination of the metal electrode and the use of surfactants to inhibit the HER, as well as the use of catalysts with higher selectivity towards the product, such as Bi. The use of a zero-gap electrolyzer shows the feasibility of scaling up the system to industrially relevant dimensions and the easiness of incorporating the electrochemical system to the end of pre-existing capture plants. References Ghiat, I., & Al-Ansari, T. (2021). Journal of CO2 Utilization, 45. Gutiérrez-Sánchez, O., Bohlen, B., et al. (2022). ChemElectroChem, 9(5), e202101540. Li, M., Irtem, E., et al. (2022). Nature Communications 2022 13:1, 13(1), 1–11. Chen, L., Li, F., et al. (2017). ChemSusChem, 10(20), 4109–4118. Figure 1
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Jiang, Z., T. Xiao, V. L. Kuznetsov und P. P. Edwards. „Turning carbon dioxide into fuel“. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 368, Nr. 1923 (28.07.2010): 3343–64. http://dx.doi.org/10.1098/rsta.2010.0119.
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Our present dependence on fossil fuels means that, as our demand for energy inevitably increases, so do emissions of greenhouse gases, most notably carbon dioxide (CO 2 ). To avoid the obvious consequences on climate change, the concentration of such greenhouse gases in the atmosphere must be stabilized. But, as populations grow and economies develop, future demands now ensure that energy will be one of the defining issues of this century. This unique set of (coupled) challenges also means that science and engineering have a unique opportunity—and a burgeoning challenge—to apply their understanding to provide sustainable energy solutions. Integrated carbon capture and subsequent sequestration is generally advanced as the most promising option to tackle greenhouse gases in the short to medium term. Here, we provide a brief overview of an alternative mid- to long-term option, namely, the capture and conversion of CO 2 , to produce sustainable, synthetic hydrocarbon or carbonaceous fuels, most notably for transportation purposes. Basically, the approach centres on the concept of the large-scale re-use of CO 2 released by human activity to produce synthetic fuels, and how this challenging approach could assume an important role in tackling the issue of global CO 2 emissions. We highlight three possible strategies involving CO 2 conversion by physico-chemical approaches: sustainable (or renewable) synthetic methanol, syngas production derived from flue gases from coal-, gas- or oil-fired electric power stations, and photochemical production of synthetic fuels. The use of CO 2 to synthesize commodity chemicals is covered elsewhere ( Arakawa et al. 2001 Chem. Rev. 101 , 953–996); this review is focused on the possibilities for the conversion of CO 2 to fuels. Although these three prototypical areas differ in their ultimate applications, the underpinning thermodynamic considerations centre on the conversion—and hence the utilization—of CO 2 . Here, we hope to illustrate that advances in the science and engineering of materials are critical for these new energy technologies, and specific examples are given for all three examples. With sufficient advances, and institutional and political support, such scientific and technological innovations could help to regulate/stabilize the CO 2 levels in the atmosphere and thereby extend the use of fossil-fuel-derived feedstocks.
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Shibata, Setsuko, Eiko Kawano und Takeshige Nakabayashi. „Research Center of Radioisotopes at University of Osaka Prefecture Radiocarbon Dates I“. Radiocarbon 39, Nr. 1 (1997): 79–87. http://dx.doi.org/10.1017/s0033822200040935.
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The radiocarbon dating laboratory has been in operation since 1984 at the Radiation Center of Osaka Prefecture (OR), predecessor of the Research Center of Radioisotopes, University of Osaka Prefecture. We use liquid scintillation counting (LSC), following sample conversion to methanol through combustion and LiAlH4 reduction. This method was developed by Yamada et al. (Yamada, Higashimura and Shidei 1966; Yamada and Kobashigawa 1986). In cooperation with Yamada, we somewhat modified their procedure: 1) sample charcoal is burned at 700° in the presence of CuO needles and Sulfix grains to remove sulfur and halogen compounds produced during the combustion; 2) the combustion is carried out by using N2-O2 mixed gas of minimized O2 content and stopped when a small amount of the charcoal still remains unchanged, because precise investigation of methanol preparation revealed that O2 gas stimulates byproduct formation during LiAlH4 reduction (Shibata et al. 1985; Shibata et al. 1993). Usually, methanol is prepared directly from sample charcoal in a reaction apparatus (“direct method”). When the sample quantity is insufficient, generated CO2 is isolated as CaCO3 and diluted with inactive commercial CaCO3 if necessary (< 40 g of CaCO3 yield). Then CaCO3 is hydrolyzed with HCl to CO2 for methanol preparation in the usual way (“separate method”). We use standard oxalic acid SRM 4990C (HOxII) for determination of modern 14C (Stuiver 1983). The acid is oxidized to CO2 using the wet method of Valastro, Land and Valera (1977) followed by methanol preparation in the same manner as for unknown samples.
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Ghodake, Pravinkumar. „The complexity of harmonically scattered nonlinear waves from triangular, circular, and rectangular corners of the 2-D domain“. Journal of the Acoustical Society of America 154, Nr. 4_supplement (01.10.2023): A262. http://dx.doi.org/10.1121/10.0023468.
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Considering recent advancements in the nonlinear pulse-echo technique, understanding reflected nonlinear waves from inaccessible edges and surfaces becomes important. A unique geometrical model solved numerically using the finite element method is proposed and studied via extensive numerical experiments to gain insight into harmonically scattered waves from different shapes of the 2-D spaced corners considering the challenges of theoretical solutions that can capture the interplay between multiple phenomena. Tang et al. (2012), Kube (2017-18), and Achenbach and Wang (2017-18) studied the harmonic scattering of waves from nonlinear inclusions using analytical techniques. Linear longitudinal waves scattered from the triangular, circular, and rectangular-shaped free and fixed edges of the 2-D spaced corner show mode conversion and energy transfer between bulk wave modes at fundamental frequencies. The interaction of nonlinear ultrasonic waves with the edges makes things complex due to an interplay between harmonic generation, linear scattering, harmonic scattering, bulk wave mode conversion, and harmonic energy redistribution between all harmonics of the scattered longitudinal and transverse waves. This results in non-intuitive interesting responses. These studies are extended to explore one-way and two-way two-wave mixing of longitudinal waves and their interesting nonlinear effects. Phase difference introduced during harmonic scattering distinguishes the sensitivity of fundamental harmonics.
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Kim, Seon Il, Yong Jae Kim, JaeHyoung Yun und Wonhyoung Ryu. „MnO2-Modified 3D-Printed Lattice Photo-Bioelectrode for Photosynthetic Energy Conversion from Spinach Thylakoids“. ECS Meeting Abstracts MA2022-01, Nr. 45 (07.07.2022): 1884. http://dx.doi.org/10.1149/ma2022-01451884mtgabs.
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Photosynthetic bio-solar energy conversion has been widely investigated as a promising potential in the field of renewable energy due to its high internal quantum efficiency. Thylakoid membranes (TMs) are organelles in chloroplasts where photosynthesis occurs. Once photosynthesis begins photosynthetic electrons (PEs) were generated, and they were transferred via proteins embedded in TMs by sequential redox reactions. To efficiently collect PEs, several approaches were reported to improve electrical connections such as carbon nanotube modified electrode [1], graphene oxide (GO)/TMs composites [2], or ruthenium oxide (RuO2) modified electrode [3]. As another approach, TM-alginate films were electrosprayed on SU-8 micro-pillar electrode to enlarge the electrochemical surface area between TMs and electrode [4]. However, the previous works were still limited in using two-dimensional electrodes with a marginal increase of electrode surface area. In this study, we aimed to maximize the electrochemically-active surface of TM-decorated bioelectrodes using 3D-printed polymeric lattices. We designed an octet-truss lattice structure with a high specific surface area. For the large surface area of the electrode with a high volume fraction, a strut diameter of the lattice was set to be 0.4 mm in the unit cell of an octet-truss lattice with a total length of 2.5 mm. To maximize light transmission, the octet-truss lattice was 3D-printed with a clear resin using stereolithography (SLA). To grant electrical conductivity on the hydrophobic nature of poly(urethane dimethacrylate) resin, poly(dopamine) (PDA) was polymerized as a binder on SLA-printed lattices followed by immersion in the 1.3 wt% of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) solution for 30 min. After immersion in PEDOT:PSS solution, PEDOT:PSS coated lattice was gently dried to remove the remaining solution with N2 gun and annealed in a vacuum oven at 120 ℃ for 15 min. On the other hand, the intrinsic electrical conductivity of PEDOT:PSS is lower than 1 S/cm. Therefore, to enhance the conductivity of annealed PEDOT:PSS layer, PEDOT:PSS coated lattice was immersed 5 wt% of ethylene glycol (EG) solution. Then, EG-treated PEDOT:PSS coated lattice was annealed in a vacuum oven as above described. Due to the removal of surplus insulating PSS chains and reorientation of PEDOT chains, the resistance of EG-treated PEDOT:PSS coated lattice was measured thousands of times lower than no treated lattice. A manganese oxide (MnO2) was electrochemically deposited for improved attachment to TMs at 0.5 V vs Ag/AgCl for 2 min. Then, TMs of 1 mg chl/ml were drop-cast on MnO2/PEDOT:PSS/PDA octet-truss lattice electrode. Each intermediate product was carefully analyzed using SEM, optical microscopy, and fluorescence spectroscopy. The PE currents from TM/MnO2/PEDOT:PSS/PDA octet-truss lattice electrode were measured and compared to a flat electrode and with different layers of lattice structures. With 2 layers of TM/MnO2/PEDOT:PSS/PDA octet-truss lattice electrode, the PE currents were increased 4 times compared to PE currents of the flat electrode. Acknowledgement This work was supported by the National Research Foundation of Korea(NRF) Grant funded by the Korean Government(MSIT) (No. 2020R1A2C3013158), and the Human Resources Development program (No.20204030200110) of the Korea Institute of Energy Technology Evaluation and Planning(KETEP) grant funded by the Korea government Ministry of Trade, Industry and Energy. References [1] Dmitry Pankratov, et al, Electrochimica Acta, 2019, 310, 20-25 [2] HyeIn Shin, et al, Applied Surface Science, 2019, 481, 1 [3] Hyeonaug Hong, et al, Advanced Sciences, 2021, 7, 20 [4] Seon Il Kim, et al, ACS Applied Materials & Interfaces, 2020, 12, 54683-546934
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Owhoso, Fiki V., und David G. Kwabi. „Effect of Covalent Modification on Proton-Coupled Electron Transfer at Quinone-Functionalized Carbon Electrodes“. ECS Meeting Abstracts MA2022-02, Nr. 57 (09.10.2022): 2171. http://dx.doi.org/10.1149/ma2022-02572171mtgabs.
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Electrodes functionalized with molecularly well-defined reactive/catalytic species have become attractive for promoting a wide variety of electrochemical energy conversion processes or systems, such as electrocatalytic CO2 and O2 reduction, as well as metal-sulfur and redox-flow batteries.1-3 Critical to the performance of these electrodes is the interaction between the electric field, and the molecular species at the electrical double layer. Nevertheless, elucidating the potential/electric field experienced at the functionalized interface is challenging. We show in this work that the acid-base thermochemical (i.e. Pourbaix) behavior of molecular quinones can vary depending on their mode of covalent attachment to a carbon electrode and ionic strength of the electrolyte, in a manner that sheds light on the experienced interfacial electric field. This work can inform strategies for effective pH modulation at electrified interfaces in ways that can enhance the electrocatalytic processes and systems mentioned above, and enable newer applications such as pH-swing-based electrochemical CO2 capture using appropriately chemically modified electrodes.4 References 1 Ren, G. et al. Porous Core–Shell Fe3C Embedded N-doped Carbon Nanofibers as an Effective Electrocatalysts for Oxygen Reduction Reaction. ACS Applied Materials & Interfaces 8, 4118-4125, doi:10.1021/acsami.5b11786 (2016). 2 Zhang, S., Fan, Q., Xia, R. & Meyer, T. J. CO2 Reduction: From Homogeneous to Heterogeneous Electrocatalysis. Accounts of Chemical Research 53, 255-264, doi:10.1021/acs.accounts.9b00496 (2020). 3 Zhao, C.-X. et al. Semi-Immobilized Molecular Electrocatalysts for High-Performance Lithium–Sulfur Batteries. Journal of the American Chemical Society 143, 19865-19872, doi:10.1021/jacs.1c09107 (2021). 4 Jin, S., Wu, M., Gordon, R. G., Aziz, M. J. & Kwabi, D. G. pH swing cycle for CO2 capture electrochemically driven through proton-coupled electron transfer. Energy & Environmental Science, doi:10.1039/D0EE01834A (2020).
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Fasolini, Andrea, Silvia Ruggieri, Cristina Femoni und Francesco Basile. „Highly Active Catalysts Based on the Rh4(CO)12 Cluster Supported on Ce0.5Zr0.5 and Zr Oxides for Low-Temperature Methane Steam Reforming“. Catalysts 9, Nr. 10 (25.09.2019): 800. http://dx.doi.org/10.3390/catal9100800.
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Syngas and Hydrogen productions from methane are industrially carried out at high temperatures (900 °C). Nevertheless, low-temperature steam reforming can be an alternative for small-scale plants. In these conditions, the process can also be coupled with systems that increase the overall efficiency such as hydrogen purification with membranes, microreactors or enhanced reforming with CO2 capture. However, at low temperature, in order to get conversion values close to the equilibrium ones, very active catalysts are needed. For this purpose, the Rh4(CO)12 cluster was synthetized and deposited over Ce0.5Zr0.5O2 and ZrO2 supports, prepared by microemulsion, and tested in low-temperature steam methane reforming reactions under different conditions. The catalysts were active at 750 °C at low Rh loadings (0.05%) and outperformed an analogous Rh-impregnated catalyst. At higher Rh concentrations (0.6%), the Rh cluster deposited on Ce0.5Zr0.5 oxide reached conversions close to the equilibrium values and good stability over long reaction time, demonstrating that active phases derived from Rh carbonyl clusters can be used to catalyze steam reforming reactions. Conversely, the same catalyst suffered from a fast deactivation at 500 °C, likely related to the oxidation of the Rh phase due to the oxygen-mobility properties of Ce. Indeed, at 500 °C the Rh-based ZrO2-supported catalyst was able to provide stable results with higher conversions. The effects of different pretreatments were also investigated: at 500 °C, the catalysts subjected to thermal treatment, both under N2 and H2, proved to be more active than those without the H2 treatment. In general, this work highlights the possibility of using Rh carbonyl-cluster-derived supported catalysts in methane reforming reactions and, at low temperature, it showed deactivation phenomena related to the presence of reducible supports.
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Harvey, S. P., und H. J. Richter. „Gas Turbine Cycles With Solid Oxide Fuel Cells—Part I: Improved Gas Turbine Power Plant Efficiency by Use of Recycled Exhaust Gases and Fuel Cell Technology“. Journal of Energy Resources Technology 116, Nr. 4 (01.12.1994): 305–11. http://dx.doi.org/10.1115/1.2906458.
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In conventional energy conversion processes, the fuel combustion is usually highly irreversible, and is thus responsible for the low overall efficiency of the power generation process. The energy conversion efficiency of the combustion process can be improved if immediate contact of fuel and oxygen is prevented and an oxygen carrier is used. In a previous paper (Harvey et al., 1992), a gas turbine cycle was investigated in which part of the exhaust gases—consisting mainly of CO2, H2O, and N2—are recycled and used as oxygen-carrying components. For the optimized process, a theoretical thermal efficiency of 66.3 percent was achieved, based on the lower heating value (LHV) of the methane fuel. A detailed second-law analysis of the cycle revealed that, although the exergy losses associated with the fuel oxidation were significantly less than those associated with conventional direct fuel combustion methods, these losses were still a major contributor to the overall losses of the system. One means to further improve the exergetic efficiency of a power cycle is to utilize fuel cell technology. Significant research is currently being undertaken to develop fuel cells for large-scale power production. High-efficiency fuel cells currently being investigated use high-temperature electrolytes, such as molten carbonates (~ 650°C) and solid oxides (usually doped zirconia, ~1000°C). Solid oxide fuel cells (SOFC) have many features that make them attractive for utility and industrial applications. In this paper, we will therefore consider SOFC technology. In view of their high operating temperatures and the incomplete nature of the fuel oxidation process, fuel cells must be combined with conventional power generation technology to develop power plant configurations that are both functional and efficient. In this paper, we will show how monolithic SOFC (MSOFC) technology may be integrated into the previously described gas turbine cycle using recycled exhaust gases as oxygen carriers. An optimized cycle configuration will be presented based upon a detailed cycle analysis performed using Aspen Plus™ process simulation software (Aspen Technology, 1991) and a MSOFC fuel cell simulator developed by Argonne National Labs (Ahmed et al., 1991). The optimized cycle achieves a theoretical thermal efficiency of 77.7 percent, based on the LHV of the fuel.
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Song, Jun Tae, Yuta Takaoka, Atsushi Takagaki, Motonori Watanabe und Tatsumi Ishihara. „Synergistic Integration of Zr-MOF (UiO-66) and Bi Electrocatalysts for Enhanced CO2 Conversion to Formate“. ECS Meeting Abstracts MA2023-02, Nr. 47 (22.12.2023): 2382. http://dx.doi.org/10.1149/ma2023-02472382mtgabs.
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The utilization of renewable energy-driven CO2 conversion technology has garnered considerable attention as a potential remedy for both the energy crisis and climate change. Among various methods, the electrocatalytic CO2 reduction reaction (CO2RR) has received particular focus due to its mild reaction conditions and its ability to produce various valuable products. Specifically, formic acid holds great promise for CO2 electrolysis due to its potential for energy storage and transportation, as well as its commercial viability as indicated by techno-economic assessments. Bi, In, and Sn are several metal catalysts that have been reported for formic acid production, with Bi catalysts demonstrating favorable properties in terms of both cost-effectiveness and selective production of formic acid. However, despite efforts to enhance the intrinsic catalytic activity of Bi through methods such as nanostructuring and alloying, it has yet to achieve the desired level of performance. In light of recent findings by Nam et al. on the ability of a metal-organic framework (MOF) to regulate reaction intermediates for Ag catalyst, resulting in higher CO production, we draw inspiration from MOF's versatility and demonstrate the successful coupling of Bi with UiO-66, a Zr-MOF, to achieve higher CO2 reduction rates and thus increase formic acid production [1]. We synthesized MOF materials, UiO-66 and NH2-functionalized UiO-66 (UiO-66-NH2), and deposited Bi catalysts on the MOF structures using the NaBH4 reduction method, resulting in Bi/UiO-66 and Bi/UiO-66-NH2 samples. To compare the catalytic activity, we also synthesized Bi particle samples using the same method (Bi). Prior to CO2 reduction examination, all electrocatalysts were pre-treated in a 1.0 M KOH solution for 5 minutes, and then CO2 electrolysis was performed in a flow-cell reactor. Among the synthesized samples, Bi/UiO-66 demonstrated excellent CO2 reduction properties, exhibiting about 5 times higher current density (-220 mA/cm2) at an applied potential of -0.7 V vs. the reversible hydrogen electrode (RHE) than Bi alone (-44 mA/cm2), despite the identical electrochemically active surface area (ECSA) for both samples. On the other hand, Bi/UiO-66-NH2 showed an almost identical ECSA-normalized current density compared to Bi/UiO-66, indicating the negligible effect of NH2 functionalization on UiO-66 for CO2RR. Nevertheless, it is evident that the utilization of Zr-MOF (UiO-66) is beneficial in increasing the CO2 conversion rate of metallic Bi catalyst. To comprehend the reason behind the superior catalytic activity exhibited by the Bi/UiO-66 sample, we conducted various characterizations, such as SEM, TEM, FTIR, Raman, and XPS. Our results revealed that the structural evolution of UiO-66 occurs by the formation of carbonate-coordinated Zr-hydroxide during CO2 electrolysis, contributing to the high CO2 reduction current density. Moreover, the disappearance of the carbonate-relevant peak in the C 1s from XPS analysis after the decline in catalytic activity suggests that the carbonate species formed at Zr-MOF site, which is the captured form of CO2 molecules, play a crucial role in efficient CO2 capture and conversion. These findings suggest that Zr-MOF can be used for CO2 capture and conversion with high efficiency. [1] Nam et al., J. Am. Chem. Soc. 2020, 142, 51, 21513–21521.
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Dubadi, Rabindra, Ewelina Weidner, Bogdan Samojeden, Teofil Jesionowski, Filip Ciesielczyk, Songping Huang und Mietek Jaroniec. „Exploring the Multifunctionality of Mechanochemically Synthesized γ-Alumina with Incorporated Selected Metal Oxide Species“. Molecules 28, Nr. 5 (21.02.2023): 2002. http://dx.doi.org/10.3390/molecules28052002.
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γ-Alumina with incorporated metal oxide species (including Fe, Cu, Zn, Bi, and Ga) was synthesized by liquid-assisted grinding—mechanochemical synthesis, applying boehmite as the alumina precursor and suitable metal salts. Various contents of metal elements (5 wt.%, 10 wt.%, and 20 wt.%) were used to tune the composition of the resulting hybrid materials. The different milling time was tested to find the most suitable procedure that allowed the preparation of porous alumina incorporated with selected metal oxide species. The block copolymer, Pluronic P123, was used as a pore-generating agent. Commercial γ−alumina (SBET = 96 m2·g−1), and the sample fabricated after two hours of initial grinding of boehmite (SBET = 266 m2·g−1), were used as references. Analysis of another sample of γ-alumina prepared within 3 h of one-pot milling revealed a higher surface area (SBET = 320 m2·g−1) that did not increase with a further increase in the milling time. So, three hours of grinding time were set as optimal for this material. The synthesized samples were characterized by low-temperature N2 sorption, TGA/DTG, XRD, TEM, EDX, elemental mapping, and XRF techniques. The higher loading of metal oxide into the alumina structure was confirmed by the higher intensity of the XRF peaks. Samples synthesized with the lowest metal oxide content (5 wt.%) were tested for selective catalytic reduction of NO with NH3 (NH3-SCR). Among all tested samples, besides pristine Al2O3 and alumina incorporated with gallium oxide, the increase in reaction temperature accelerated the NO conversion. The highest NO conversion rate was observed for Fe2O3-incorporated alumina (70%) at 450 °C and CuO-incorporated alumina (71%) at 300 °C. The CO2 capture was also studied for synthesized samples and the sample of alumina with incorporated Bi2O3 (10 wt.%) gave the best result (1.16 mmol·g−1) at 25 °C, while alumina alone could adsorb only 0.85 mmol·g−1 of CO2. Furthermore, the synthesized samples were tested for antimicrobial properties and found to be quite active against Gram-negative bacteria, P. aeruginosa (PA). The measured Minimum Inhibitory Concentration (MIC) values for the alumina samples with incorporated Fe, Cu, and Bi oxide (10 wt.%) were found to be 4 µg·mL−1, while 8 µg·mL−1 was obtained for pure alumina.
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Ustarroz, Jon, Miguel Bernal Lopez, Daniel Torres, Sajid Hussain und Leonardo Bertolucci Coelho. „(Invited) High-Throughput Nanoscale Resolved Electrochemistry to Study Electrochemical Nucleation, Growth and Dissolution“. ECS Meeting Abstracts MA2022-01, Nr. 23 (07.07.2022): 1148. http://dx.doi.org/10.1149/ma2022-01231148mtgabs.
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Electrochemical nucleation and growth (EN&G) is the cornerstone for many (nano)material growth routes and the main factor limiting battery durability. At the same time electrochemical dissolution (ED) is the main cause of material degradation in exposed environments (corrosion) or energy conversion and storage devices. The in-depth experimental assessment of both processes is very challenging. The reasons are the random nature of initiation events (nucleation), the heterogeneity of surfaces and the (very) fast kinetics of these processes across several length scales. For all that, our current understanding of the mechanisms involved is inaccurate and incomplete [1]. During the last years, we have developed an approach based on using carbon-coated TEM grids as electrodes to combine ex-situ atomic-scale TEM characterization with electron tomography and macroscale electrochemical measurements [2,3]. This approach has brought valuable evidence of non-classical growth pathways such as growth mediated by nanocluster aggregation. Yet, it does not capture the influence of the heterogeneous nature of the surface where EN&G proceeds, nor the dynamics before, during and after nucleation [4,5]. In this contribution, we present our recent work in which we combine high-throughput nanoscale resolved electrochemistry by Scanning Electrochemical Cell Microscopy (SECCM), with ex-situ and in-situ high resolution characterization, including electrochemical transmission electron microscopy (EC-TEM), to study the electrochemical nucleation, growth, and dissolution of metal (Cu, Au, Ag and Pt) nanoparticles (NPs) [6,7]. The spatially resolved electrochemical characterization enables a one-to-one correlation between the electrochemical data and the local surface properties, which can be evaluated by different surface analytical tools. Moreover, the confinement of the electrochemical cell to the SECCM meniscus enables us to resolve a diversity of events during the electrochemical dissolution of electrodeposited NPs. EC-TEM experiments advocate that the nature of these events corresponds to the dissolution of individual NPs spanning a wide range of time [6]. The combination of SECCM and EC-TEM opens up new opportunities for the rational design of functional nanostructured materials by electrodeposition, and for the evaluation of their durability under electrochemical polarization. The ability to study these taking into account the heterogeneous nature of the supports and the differences within nanomaterial ensembles is essential for applications in electrochemical conversion and storage. References: [1] Ustarroz, J. Current Opinion in Electrochemistry. 19 (2020) 144–152. [2] Ustarroz, J et al. Journal of the American Chemical Society (2013), 135, 11550–11561. [3] Ustarroz, J et al. The Journal of Physical Chemistry C (2012), 116, 2322–2329. [4] Hussein H. E. M. et al., ACS Nano. 12, 7388–7396 (2018). [5] Harniman R. L. et al., Nat. Commun. 8, 971 (2017). [6] Bernal, M. et al. In revision (2022). [7] Torres, D. et al. To be submitted (2022).
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Carpenter, Chris. „Natural-Gas-Foam Fluid Reduces Water Needed for Fracture Stimulations“. Journal of Petroleum Technology 73, Nr. 06 (01.06.2021): 56–57. http://dx.doi.org/10.2118/0621-0056-jpt.
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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 201450, “Reducing the Volume of Water Needed For Hydraulic Fracturing by Using Natural-Gas-Foamed Stimulation Fluid,” by Raj Malpani, SPE, Chris Daeffler, and Sandeep Verma, SPE, Schlumberger, et al., prepared for the 2020 SPE Annual Technical Conference and Exhibition, originally scheduled to be held in Denver, Colorado, 5–7 October. The paper has not been peer reviewed. Using natural-gas (NG) -foam fracturing fluids reduces the enormous water requirements for stimulation by as much as 60 to 80% and poses benefits for productivity in water-sensitive formations. The study outlined in the complete paper aims to characterize hydraulic-fracture geometry and quantify the expected production when using an NG-foam fracturing fluid. Using validated models, the authors provide a comparative analysis to determine the advantages of using NG foams relative to conventionally used slickwater, linear gel, and crosslinked fluid. NG-Foam Fluids Although foamed fluids were first used in the 1960s, the use of nitrogen (N2) and carbon dioxide (CO2) foams has not been widely practiced because of cost, complexity, and unproven production benefits. The use of NG-foam fracturing fluid is not widespread either, but this study attempts to identify specific regions and reservoirs where the use of these fluids may lead to economic and long-term production benefits. The authors write that using NG foams is likely to provide long-term sustainable benefits in areas where water procurement and disposal costs are high, where natural gas may be available from a central processing facility through pipelines, and where the reservoir is relatively shallow and contains clay-bearing minerals. This work is inspired by a program sponsored by the US Department of Energy to investigate NG as an alternative to N2 and CO2 in foamed fracturing fluids. Initially, the project focused on identifying a thermodynamic path-way to use NG obtained from producing wells and processing plants. The study later extended into laboratory-scale experiments to measure NG-foam-fluid rheology, which was found to be comparable to foams based on N2 and CO2. The first step in the work flow is to build a static geological model to capture the reservoir description. The subsequent step is to use the rock characterization to simulate the induced hydraulic fractures. The hydraulic-fracture simulator also predicts the proppant distribution and its conductivity and treating pressure. The simulated treating pressure is matched with observed pressure during stimulation treatment to calibrate the hydraulic-fracture model. The hydraulic fractures are then gridded in the static geological model to generate the reservoir model for flow modeling. This is a critical step in the process because the static model is linked to the dynamic simulator without losing the details of the hydraulic fractures. The reservoir simulator is used to match the historical production performance to calibrate the reservoir model and forecast future production profiles. This hydraulic-fracture modeling, followed by the flow-modeling process, is repeated for various pumping schedules and recipes to perform a sensitivity analysis, which is detailed in the complete paper.
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Harada, Yuya, Daiki Kono, Dai Xinjie und Tsukasa Yoshida. „Hydrogen Evolution Reaction By Metal-Free Poly-Neutral Red Electrocatalyst“. ECS Meeting Abstracts MA2022-02, Nr. 22 (09.10.2022): 925. http://dx.doi.org/10.1149/ma2022-0222925mtgabs.
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While electric power supply by renewable sources such as solar and wind has become viable for their significant cost reduction, its intermittency demands urgent development of large scale storage technologies. Although conversion of electrical energy into storable hydrogen via electrolysis of water is ideal, noble metals and their oxides are used as electrocatalysts for their activities and stabilities. Alternative electrocatalysts out of abundant elements are needed for sustainable technological development. Recently, some metal-free organic conductive polymers with hydrogen-bonding capabilities were found to exhibit high electrocatalytic activities towards hydrogen evolution reaction (HER) [1,2]. We have succeeded electropolymerization of neutral red (NR) resulting in a formation of conductive poly-NR (PNR) that shows a relatively high HER catalytic activity [3]. PNR possesses hydrogen-bonding N atoms as annelated in the phenazine aromatic system as well as those in the amino substituents. Electrochemical analysis combined with in situ spectroscopy as well as DFT calculation was performed to clarify the mechanism and kinetics of HER electrocatalysis by PNR. This films of PNR were obtained by electropolymerization on F-doped SnO2 coated conductive glass (FTO, Asahi Glass) and SIGRATHERM® GFA5 Carbon felt with potential cycling between -0.2 and 1.2 V (vs. Ag/AgCl) at 50 mV s-1 for 50 times in a 5 mM NR - 0.1 M H2SO4 aqueous solution under N2. Polyaniline (PANI) was also obtained by the same method for comparison. The HER catalysis was evaluated by linear sweep voltammetry (LSV) in a 1 M trifluoromethanesulfonic acid (TfOH) under N2. The film samples were characterized by Fourier transform infrared spectroscopy (FT-IR), UV-visible spectroscopy. In-situ UV-visible spectroelectrochemical monitoring of the reaction intermediate was carried out to determine the rate of HER. PNR undergoes a pseudo-reversible reduction that shifts -61.8 mV/pH under acidic conditions and HER takes off right at this point (Fig. 1, a). Coupling of the same number of protons / electrons is expected as the electrochemical stoichometry from the observed Nernstian relationship, namely, resulting in a singly reduced PNR-H or doubly reduced PNR-H2 as depicted in Fig. 1 b. Protonation of N atoms was reasonably expected and also supported by the DFT calculation. The hydrogen atoms stabilized in the reaction intermediate can be associated to release H2 (Tafel mechanism) to complete the cycle of electrocatalysis of HER. Reduction of PNR in fact is associated with a color change. The broad reddish absorption of PNR peaking at around 500 nm attenuates to change the color to a pale yellow by constantly applying -0.15 V vs. RHE to produce PNR-H and/or PNR-H2 state as shown in Fig. 1c. Gradual recovery of the original red PNR was observed under open circuit under N2, associated with the H2 release. Thus, the rate of the spectral change is analyzed to determine the rate of the Tafel process. Pseudo-first order reaction rate law can be applied as proton is abundant and its concentration is constant, so that the rate of HER (r H2) is simply described as the rate of consumption of PNR-H and/or PNR-H2 as, r H2=-dC PNR-H2/dt =-kt (1) The ratio of PNR-H and PNR-H2 as compared to their initial amount (x PNR-red) was defined from the absorbance at 545 nm before and after reduction as, x PNR-red = C PNR-red/C 0-PNR-red = exp (-kt) (2) Good fitting of the experimental data was obtained to yield a pseudo-first order reaction rate constant of 9.98×10-4 s-1 for this rate-limiting step. References [1] H. Coskun et al. Advanced Materials 32, 1902177 (2020). [2] H. Coskun et al. Advanced Materials Interfaces 7, 1901364 (2020). Figure 1
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Novoselova, Inessa, Sergiy Kuleshov und Anatoliy Omel'chuk. „(Digital Presentation) Electrochemical Conversion of CO2 into Tungsten Carbides in Molten Salts“. ECS Meeting Abstracts MA2023-01, Nr. 26 (28.08.2023): 1744. http://dx.doi.org/10.1149/ma2023-01261744mtgabs.
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Huge amounts of anthropogenic emissions of the greenhouse gas carbon dioxide into the Earth's atmosphere are one of the key factors causing global warming. To mitigate the consequences of the severe climate changes caused by this phenomenon, over the last two decades great efforts of researchers have been directed towards the development of sustainable, environmentally friendly, carbon neutral and, if possible, not very expensive (in terms of used energy and inexpensive consumables) technologies for capture, conversion and storage (CCS) of CO2. Electrochemical conversion of CO2 using molten salts can rightfully be classified as CCS technology. In this case, carbon dioxide from various sources of its generation (fossil fuel power plants, industrial enterprises with a high carbon footprint) can be captured by molten salt (as a result of its physical dissolution, or chemical absorption by molten salt), and then electrochemically be converted into high value-added carbon-containing compounds: (a) carbon monoxide [1]; (b) carbon allotropes of various structures and modifications [2]; (c) refractory metal carbides [3], and various composites based on them. The reaction path and composition of the cathode products will depend on the electrolysis conditions. Elemental carbon synthesis precursor can be – carbon dioxide, directly dissolved in the molten salt mixture (direct reduction of CO2), as well as the carbonate anion, formed as a result of carbon dioxide interaction with oxide ions which are presented in the electrolyte bath (indirect reduction of CO2). This work presents the result of research concerning the electrochemical synthesis of the powders of tungsten carbides (WC and W2C) in chloride melt NaCl-KCl (1:1) under carbon dioxide pressure at the temperature range 700 – 800 оС. Refractory metal precursors are its oxy-anions (WО3; W2O7 2-; Меn x[WO4]nx-2; WO3F3 3- where Me – Na; K; Li; Mg; Ca; n – valance of metal Me). The formation of the new forms of tungsten electrochemical active particles in electrolyte is realized by the changing (control) of acidity of the melt. Carbon source is CO2, which was introduced into the electrolyzer under the excessive pressure of 0.1 – 1.7 MPa. The creation of excessive gas pressure is necessary condition for the increasing of the rate of electrolytic process (current densities) throw the rise of CO2 solubility in chloride melt. The general scheme of the high-temperature synthesis of tungsten carbides by the method of Molten Salt Carbon Electrochemical Transformation (MS-CCT) is presented in Fig. 1. The electrochemical investigations of partial and joint electroreduction of tungsten carbide precursors were carried out by the method of cyclic voltammetry. The areas of potentials and current densities, where the joint electrochemical discharge of tungsten carbide precursors (a narrow range of deposition potentials) occurs up to refractory metal and carbon takes place were found. Electrolytical synthesis of nano-sized (10 – 30 nm) powders of tungsten carbides (WC, W2C) and composites WC-C (up to 5 wt % of free carbon); W2C-WC; WC-C-Pt was carried out from the melts of different chemical composition; and the characterization of obtained products was fulfilled by the methods of chemical analysis, X-ray diffraction, DTG, BET adsorption, scanning and transmission electron microscopy. Synthesized composite materials based on tungsten carbides of various compositions were investigated as a cathode material in the reaction of electrolytic splitting of water for hydrogen production in a sulfuric acid solution [4]. The obtained results showed that the best activity has a composite of tungsten monocarbide WC with a content of free carbon up to 5 wt.%. The hydrogen onset potential for this electrode is -0.02 V, the overvoltage of hydrogen release at ik = 10 mA/cm2 is -110 mV, the exchange current is 7.0×10-4 A/cm2, the Tafel slope – -85 mV/dec. The presence of free carbon on the surface of tungsten carbides electrode improves its catalytic activity, increasing the area of the active surface. The catalytic activity of electrodes made of tungsten monocarbide increases with the introduction of platinum (up to 10 wt %) into the composite. References Kaplan V, Wachtel E, Gartsman K et al (2010) Conversion of CO2 to CO by electrolysis of molten lithium carbonate. J Electrochem Soc 157:B552–B556. Novoselova I.A., Kushkhov Kh.B., Malyshev V.V., Shapoval V.I. (2001) Theoretical foundations and implementation of high-temperature electrochemical synthesis of tungsten carbides in ionic melts. Theor. Found. Chem. Eng. 35:175–187. Novoselova I.A., Kuleshov S.V., Volkov S.V. et al (2016) Electrochemical synthesis, morphological and structural characteristics of carbon nanomaterials produced in molten salts. Electrochim Acta 211:343–355. Novoselova I, Kuleshov S, Fedoryshena E et al (2018) Electrochemical synthesis of tungsten carbide in molten salts, its properties and applications. ECS Trans 86:81–94. Figure 1
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Noudari, Abhinav, Shailesh Pathak, William Mcginley, Gautam Gupta, Sreedevi Upadhyayula und Mahendra Sunkara. „Plasma-Catalytic Methane Pyrolysis for Hydrogen and Valuable Carbons“. ECS Meeting Abstracts MA2023-01, Nr. 20 (28.08.2023): 1497. http://dx.doi.org/10.1149/ma2023-01201497mtgabs.
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Current technologies for hydrogen production are based primarily on reforming of fossil fuels using steam, which produces large amount of carbon dioxide emissions (> 9 tons of CO2 per ton of hydrogen produced). Majority of refineries, ammonia producers, and fuel cell power plants utilize steam methane reforming for production of hydrogen at scale. In this paper, we discuss an approach for activating methane and pyrolyzing using molten metal based alloys that includes Gallium. Sunkara’s group had developed this process earlier for making carbon micro-tubes with tunable morphology.[1, 2] Here, experiments were performed using pure methane, acetylene suggests a potential pathway for complete pyrolysis through recycle to produce hydrogen and carbons. The carbons produced are high surface area and are also do not contain any impurities. Majority of the carbons produced contain graphene sheets in random manner along with onion morphologies. The mechanism of methane pyrolysis involves a similar mechanism as that of silicon dissolution from silanes into molten Gallium. The activated species dissolve into molten Ga [3] and then undergo dehydrogenation reactions resulting in carbon nucleation and growth on molten Ga surface. The immiscibility of carbon and molten Ga allows for easier separation of resulting carbons through simple scraping from the surface. Techno-economic analysis suggests that the cost of hydrogen produced using the proposed catalytic technology could be less than $1/kg if the carbon by-product has value > $3/kg. Such low cost of hydrogen production is only possible if the following technical specifications are met: methane conversion is greater than 90%; scalable to 100 tons per year; and reduced loss and re-use of catalyst. Bhimarasetti, G., J.M. Cowley, and M.K. Sunkara, Carbon microtubes: tuning internal diameters and conical angles. Nanotechnology, 2005. 16(7): p. S362. Bhimarasetti, G., et al., Morphological Control of Tapered and Multi‐Junctioned Carbon Tubular Structures.Advanced Materials, 2003. 15(19): p. 1629-1632. Carreon, M.L., et al., Synergistic interactions of H2 and N2 with molten gallium in the presence of plasma. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2018. 36(2): p. 021303.
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Tekin, Serdar B., Saeed Almalki, Andrea Vezzoli, Liam O’Brien, Steve Hall, Paul R. Chalker und Ivona Z. Mitrovic. „(Digital Presentation) Optimization of MIM Rectifiers for Terahertz Rectennas“. ECS Meeting Abstracts MA2022-01, Nr. 19 (07.07.2022): 1076. http://dx.doi.org/10.1149/ma2022-01191076mtgabs.
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There is a significant demand for harvesting renewable infrared (IR) energy from unused heat sources. The rectifying antenna (rectenna) device has the ability to capture alternating current (AC) IR radiation and rectify it into usable direct current (DC) electricity. Metal-Insulator-Metal (MIM) diodes have shown to be the most prominent contenders for rectenna applications. This is due to their ultra-fast current transport mechanism in the femtosecond range by means of quantum mechanical tunnelling. Optical rectification at 28.3 THz has recently been demonstrated by rectenna devices based on MInM diodes using Au/Al2O3/Ti [1] and Ti/TiO2/ZnO/Al [2] configurations. Although the results are promising, the overall conversion efficiency is quite low, 2.05 × 10-14 [1], mainly due to the poor rectification properties of the diodes. Other recent research [3-5] has focused on the combination of stoichiometric and non-stoichiometric oxides with the aim of engineering the barrier heights to achieve low dynamic resistance (R0 ), high responsivity (β0 ) and asymmetry (η0 ) at zero-bias where the results are very promising for self-biased rectennas. The most recent experimental breakthrough was achieved by Ni/NiO/AlOx/CrAu bowtie rectennas that feature a device area of 0.035 µm2, low R0 of 13 kΩ and high β0 of 0.5 A/W. The results show that 5.1% coupling efficiency and 1.7 × 10−8% power conversion efficiency can be achieved with correct optimization of oxide stack. Furthermore, the most recent theoretical study [6] shows that the β0 of the MI2M diodes can be further improved to ~ 5 A/W by keeping the impedance match between the diode and the antenna at around 100 Ω. The proposed Ti/1 nm TiO2/1 nm Nb2O5/Ti rectenna design can achieve diode cut-off frequency (fc ) of 17 THz and resistance × capacitance (RC) time constant of 9 fs assuming the diode area of 0.01 µm2. Liverpool group has demonstrated recently [7,8] the effect of resonant tunnelling in non-cascaded (Al/Ta2O5/Nb2O5/Al2O3/Al) and cascaded (Al/Nb2O5/Al2O3/Ta2O5/Al) triple insulator diode structures with an oxide thickness ratio of 1:3:1 (in nm) deposited by atomic layer deposition (ALD). The diodes exhibit superior β = 5 A/W at 0.2 V and η = 12 at 0.1 V, with a drawback of high R0 due to high barrier heights between the metal/oxide layers. In this paper, we further optimize the MInM diode configurations so that the metal/oxide barrier is significantly lowered to ~ 0.1 eV. This is achieved by using the combinations of rectenna contender oxides such as Al2O3, NiO and ZnO that have high electron affinity and low dynamic permittivity [9]. Ultra-thin (≤ 5 nm) insulating layers were fabricated using radio frequency (RF) magnetron sputtering and ALD. Metal electrodes were deposited by thermal evaporation and RF sputtering using shadow mask, photolithography and nanolithography processes. The device areas range from 100 µm × 100 µm, 1 µm × 1 µm and 100 nm × 100 nm depending on the patterning process to observe the effect of device scaling on the conduction mechanisms and direct current (DC) rectification properties. The deposited oxide layers were measured by variable angle spectroscopic ellipsometry (VASE) to ascertain their thickness, uniformity and optical constants. DC current voltage measurements were performed on fabricated diodes to evaluate key rectification parameters such as R0 , β0 , η and non-linearity (fNL ) around zero-bias. Complementary theoretical calculations were performed to substantiate the experimental results and allow comparison of different MInM diode configurations such as NiO/Al2O3, ZnO/Al2O3, NiO/ZnO and NiO/ZnO/Al2O3. This work shows that the coupling efficiency at IR cut-off frequencies can be improved by optimizing the barriers in MInM rectifiers. References. [1] Jayaswal et al.,Materials Today Energy, 7, 1-9 (2018); [2] Elsharabasy et al., IEEE J. Photovoltaics, 9, 1232, (2019); [3] Matsuura et al., Sci. Rep. 9, 1-7 (2019); [4] Weerakkody et al., ACS Appl. Nano Mater. 4, 2470–2475 (2021); [5] Belkadi et al., Nat. Commun., 12, 1–6 (2021); [6] Elsharabasy et al., Results Mater. 11, 100204 (2021); [7] Mitrovic et al., ECS Trans. 72, 287 (2016); [8] Tekin et al., Solid State Electron. 185, 108096 (2021); [9] Mitrovic et al., Materials, 14, 5218 (2021).
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Dominguez-Benetton, Xochitl. „Synthesis of Nanostructures Using Gas-Diffusion Electrodes“. ECS Meeting Abstracts MA2022-02, Nr. 24 (09.10.2022): 994. http://dx.doi.org/10.1149/ma2022-0224994mtgabs.
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Gas diffusion electrodes (GDEs) intertwine an ionically conducting liquid and a gas with an electrically conducting solid, supporting electrochemical reactions involving constituents linked to the three phases (i.e., chemical species, electrons). GDEs are broadly used in electrochemical energy-conversion devices, such as fuel cells and metal-air batteries, as well as in electrolyzers aiming at chemical synthesis, like in the chlor-alkali industry, hydrogen peroxide production, CO2 conversions to fuels and fine chemicals, or N2 reduction to ammonia. Recently, the use of GDEs was pioneered for metal recovery and the synthesis of nanostructures, in a process named gas-diffusion electrocrystallization (GDEx).[1–4] A liquid solution containing dissolved metal or metalloid ions (e.g., Cu2+, Fe3+, As3+, PtCl2 −6) flows through an electrochemical cell equipped with a GDE, filling in its porosity. The gas (e.g., O2, O2 in air, CO2, etc.) percolates through a hydrophobic backing (e.g., PTFE) on the GDE. After the gas diffuses to the electrically conducting layer acting as an electrocatalyst (e.g., hydrophilic porous activated carbon), the gas is electrochemically reduced. For instance, by imposing specific cathodic polarization conditions (e.g., at −0.145 VSHE O2 is reduced producing H2O2, H2O and OH–). As the highly abundant hydroxyl ions accompanied by redox reactive species spread to the bulk electrolyte, a reaction front develops throughout the hydrodynamic boundary layer. This creates local saturation conditions at the electrochemical interface, where metal ions precipitate in metastable or stable phases, depending on the operational variables. When O2 is the oxidizing gas, GDEx has been explained with an oxidation-assisted alkaline precipitation mechanism.[4] Conversely, when CO2 is used, the reaction front, rich in reducing species, yields elemental nanoparticles. This centennial celebration talk will explain the underlying principles of GDEx, portray reflections on its design and scale-up, and substantiate some of the experimental merits achieved. It will include the GDEx: (a) synthesis of iron oxide nanoparticles with high control of their magnetic susceptibility[1]; (b) recovery and immobilization of arsenic into crystalline scorodite[2]; (c) synthesis of nanoparticles with novel magnetic ground states (e.g., spin liquids and spin glasses)[3]; (d) synthesis of libraries of electrochemically-active materials[5] and (e) formation of elemental nanoparticles of platinum group metals (PGMs). References: [1] Prato et al. (2019) Sci Rep https://doi.org/10.1038/s41598-019-51185-x [2] Pozo et al. (2020) React Chem Eng https://doi.org/10.1039/D0RE00054J [3] Pozo et al. (2020) Nanoscale https://doi.org/10.1039/C9NR09884D [4] Eggermont et al. (2021) React Chem Eng https://doi.org/10.1039/D0RE00463D [5] Prato et al. (2020) J Mat Chem A https://doi.org/ 10.1039/D0TA00633E Acknowledgements: This research has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreements No 958302 (PEACOC project), No 730224 (Platirus project), No 796320 (MAGDEx project), and No 654100 (CHPM2030 project). Support from the Flemish SIM MaRes programme, under grant agreement No 150626 (Get-A-Met project) is also acknowledged. The author thanks Rafael Prato, Sam Eggermont, Guillermo Pozo, Luis Fernando Leon Fernandez, Omar Martinez Mora, Ramin Rabani, Kudakwashe Chayambuka, Elisabet Andres Garcia, Katrijn Gijbels, Yolanda Alvarez Gallego, and Jan Fransaer for their valuable contributions to the development of the GDEx process.
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Dominguez-Benetton, Xochitl. „(Invited) Lithium Recovery from Geothermal Brines“. ECS Meeting Abstracts MA2022-02, Nr. 27 (09.10.2022): 1040. http://dx.doi.org/10.1149/ma2022-02271040mtgabs.
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Lithium is a critical raw material for developing current lithium-ion batteries and prospective next-generation batteries. Its reserves are concentrated in a handful of countries. It is primarily extracted from continental brines, wherein Li+ is relatively concentrated (0.3 –1.5 wt%) in a complex mixture of many more components with relatively large water solubilities. Current practices to extract lithium from continental brines involve evaporation, i.e., >90% of water. Eventually, the concentration of Li+ intensifies up to 6–7%, in a brine which follows numerous chemical processing steps, to ultimately produce battery-grade lithium chemicals. Despite being the easiest and currently most cost-effective practices, these are inefficient and unsustainable (chemical-intensive, requires extensive land use and time, and delivers large volumes of waste), especially in the context of the sharp increase in the demand for lithium that is already happening and is expected to endure in the coming decades. To sustainably meet the future demand for lithium, it is imperative to develop more efficient extraction methods, which are faster, less climate/weather reliant, minimize waste production, and especially deal with water differently than current industrial processing (i.e., circumventing evaporation). Besides being applicable to concentrated lithium brines, characteristic of primary extraction, these methods should especially be applicable to dilute brines (i.e., geothermal, oilfield, seawater, wastewater,—which contain 0.01–0.3 mg of Li+ per L of brine), as these have more recently prospected for Li recovery. Together with lithium recycling from spent batteries, these hold the promise of delocalizing raw lithium sourcing. New extraction technologies have emerged within the past decade, including adsorption and the use of membranes. In addition to being insufficient for an effective recovery, some alternatives seem to imply a harsher environmental impact than current practices, whereas others would be disadvantageous to treat the large volumes of fluid associated with lithium extraction. Especially, electrochemical methods for Li+ recovery are (re)surging.[1] The use of Li+ insertion electrodes coupled to membranes and membrane electrolysis are notoriously thriving.[1,2] However, the first approach bears the limitation of requiring extremely thin and large area electrodes to process large brine volumes, and the second one suffers from being energy-intensive, plus current investigations show the constant addition of chemicals for pH adjustment, and produce chloride- and hypochlorite-anions rich solutions which are neither economic nor sustainable.[2] Furthermore, in membrane electrolysis swelling of the ion exchange membrane could be an issue[3] that has not been addressed in Li+ recovery studies; if excessive, this could lead to membrane deformations and ultimately to the blockage of the flow channels within the reactor. Despite the aforementioned limitations, electrochemical methods are a more sustainable and versatile option, with latent competitiveness vs. current industrial practices. Thus, ideal solutions should have the added value of circumventing the limitations of the state-of-the-art electrochemical approaches mentioned above. This aim was pursued in the present work. Gas diffusion electrodes (GDEs) are broadly used in electrochemical energy-conversion devices, such as fuel cells and metal-air batteries, as well as in electrolyzers aiming at chemical synthesis, like in the chlor-alkali industry, hydrogen peroxide production, CO2 conversions to fuels and fine chemicals, or N2 reduction to ammonia. Recently, the use of GDEs was pioneered for metal recovery in a process named gas-diffusion electrocrystallization (GDEx).[4–7] This talk will explain the underlying principles of GDEx and its successful application in the recovery of highly dilute lithium (<300 mg L-1) in synthetic brines containing up to 150 mg L-1 NaCl, as well as in real geothermal brines with Li+ concentrations below 50 mg L-1. Up to 50% of direct lithium extraction from the brine can be achieved, selectively, forming solid materials with lithium concentrations >0.5%, which are promising as a starting material for the direct conversion into battery-grade lithium hydroxide or carbonate. References: [1] Battistel A., et al. (2020) Adv Mater 32, 1905440. [2] Torres W.R., et al. (2020) J Membrane Sci, 615, 118416. [3] Paidar, M., Faleev V., Bouzek K. (2016) Electrochim Acta, 209, 737. [4] Prato et al. (2019) Sci Rep https://doi.org/10.1038/s41598-019-51185-x [5] Prato et al. (2020) J Mat Chem A https://doi.org/ 10.1039/D0TA00633E [6] Pozo et al. (2020) Nanoscale https://doi.org/10.1039/C9NR09884D [7] Eggermont et al. (2021) React Chem Eng https://doi.org/10.1039/D0RE00463D Acknowledgements: This research has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 654100 (CHPM2030 project). Support from the Flemish SIM MaRes programme, under grant agreement No 150626 (Get-A-Met project) is also acknowledged. The author thanks Elisabet Andres Garcia, Luis Fernando Leon Fernandez and Erwin Maes for their valuable contributions to this work.
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Cobb, Samuel J., Azim M. Dharani, Ana Rita Oliveira, Inês A. C. Pereira und Erwin Reisner. „Using Enzymes to Understand and Control the Local Environment of Catalysis“. ECS Meeting Abstracts MA2023-02, Nr. 52 (22.12.2023): 2530. http://dx.doi.org/10.1149/ma2023-02522530mtgabs.
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Local environments within porous electrodes are an inherent, but often neglected component of catalysis as the local conversion of reactants to products means catalysis occurs in a very different environment to bulk solution. By understanding and modifying these local environments using a combination of experimental and computational techniques, we show how to improve the performance of electrocatalytic reactions to address the climate crisis by efficiently converting renewable energy to chemical fuels. The selectivity and activity of enzymes means they are ideal model catalysts that can guide the design of synthetic systems. However, they must be in an environment that is close to their optimal to operate efficiently, with small changes in properties such as pH drastically affecting their activity. By optimising their local environment, the rates of fuel formation can be drastically (>18×) increased.[1] We also demonstrate the crucial role of CO2 hydration kinetics on the local pH and CO2 concentration using the enzyme Carbonic Anhydrase co-immobilised with Formate Dehydrogenase.[2] Carbonic Anhydrase catalyses CO2 hydration, causing CO2 to act as a better buffer to mitigate changes in the local pH environment allowing the system to operate closer to its optimal and how this contrasts with heterogeneous CO2 reduction. (fig. 1a) We extend this approach to low CO2 concentrations, taking inspiration from the natural carboxysome to develop a system where Formate Dehydrogenase and Carbonic Anhydrase are co-immobilised in a nanoconfined structure to improve low CO2 concentration utilisation. (fig. 1b).[3] The electrolysis of dilute CO2 streams suffers from low concentrations of dissolved substrate and its rapid depletion at the electrolyte-electrocatalyst interface. These limitations require first energy-intensive CO2 capture and concentration, before electrolyzers can achieve acceptable performances. For direct electrocatalytic CO2 reduction from low-concentration sources, we introduce a strategy that mimics the carboxysome in cyanobacteria by utilizing microcompartments with nanoconfined enzymes in a porous electrode. Carbonic Anhydrase accelerates CO2 hydration kinetics and minimizes substrate depletion by making all dissolved carbon available for utilization, while a highly efficient formate dehydrogenase reduces CO2 cleanly to formate; down to even atmospheric concentrations of CO2. This bio-inspired concept demonstrates that the carboxysome provides a viable blueprint for the reduction of low-concentration CO2 streams to chemicals by using all forms of dissolved carbon. References [1] E. E. Moore, S. J. Cobb et al., Proc. Natl. Acad. Sci. USA 2022,119, e2114097119 [2] S. J. Cobb et al., Nat. Chem. 2022, 14, 417 – 424 [3] S. J. Cobb et al., Angew. Chem. Int. Ed.,2023 Just Accepted, DOI: 10.1002/anie.202218782 Figure 1
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Roberts, James M., Chelsea E. Stockwell, Robert J. Yokelson, Joost de Gouw, Yong Liu, Vanessa Selimovic, Abigail R. Koss et al. „The nitrogen budget of laboratory-simulated western US wildfires during the FIREX 2016 Fire Lab study“. Atmospheric Chemistry and Physics 20, Nr. 14 (24.07.2020): 8807–26. http://dx.doi.org/10.5194/acp-20-8807-2020.
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Abstract. Reactive nitrogen (Nr, defined as all nitrogen-containing compounds except for N2 and N2O) is one of the most important classes of compounds emitted from wildfire, as Nr impacts both atmospheric oxidation processes and particle formation chemistry. In addition, several Nr compounds can contribute to health impacts from wildfires. Understanding the impacts of wildfire on the atmosphere requires a thorough description of Nr emissions. Total reactive nitrogen was measured by catalytic conversion to NO and detection by NO–O3 chemiluminescence together with individual Nr species during a series of laboratory fires of fuels characteristic of western US wildfires, conducted as part of the FIREX Fire Lab 2016 study. Data from 75 stack fires were analyzed to examine the systematics of nitrogen emissions. The measured Nr ∕ total-carbon ratios averaged 0.37 % for fuels characteristic of western North America, and these gas-phase emissions were compared with fuel and residue N∕C ratios and mass to estimate that a mean (±SD) of 0.68 (±0.14) of fuel nitrogen was emitted as N2 and N2O. The Nr detected as speciated individual compounds included the following: nitric oxide (NO), nitrogen dioxide (NO2), nitrous acid (HONO), isocyanic acid (HNCO), hydrogen cyanide (HCN), ammonia (NH3), and 44 nitrogen-containing volatile organic compounds (NVOCs). The sum of these measured individual Nr compounds averaged 84.8 (±9.8) % relative to the total Nr, and much of the 15.2 % “unaccounted” Nr is expected to be particle-bound species, not included in this analysis. A number of key species, e.g., HNCO, HCN, and HONO, were confirmed not to correlate with only flaming or with only smoldering combustion when using modified combustion efficiency, MCE=CO2/(CO+CO2), as a rough indicator. However, the systematic variations in the abundance of these species relative to other nitrogen-containing species were successfully modeled using positive matrix factorization (PMF). Three distinct factors were found for the emissions from combined coniferous fuels: a combustion factor (Comb-N) (800–1200 ∘C) with emissions of the inorganic compounds NO, NO2, and HONO, and a minor contribution from organic nitro compounds (R-NO2); a high-temperature pyrolysis factor (HT-N) (500–800 ∘C) with emissions of HNCO, HCN, and nitriles; and a low-temperature pyrolysis factor (LT-N) (<500 ∘C) with mostly ammonia and NVOCs. The temperature ranges specified are based on known combustion and pyrolysis chemistry considerations. The mix of emissions in the PMF factors from chaparral fuels (manzanita and chamise) had a slightly different composition: the Comb-N factor was also mostly NO, with small amounts of HNCO, HONO, and NH3; the HT-N factor was dominated by NO2 and had HONO, HCN, and HNCO; and the LT-N factor was mostly NH3 with a slight amount of NO contributing. In both cases, the Comb-N factor correlated best with CO2 emission, while the HT-N factors from coniferous fuels correlated closely with the high-temperature VOC factors recently reported by Sekimoto et al. (2018), and the LT-N had some correspondence to the LT-VOC factors. As a consequence, CO2 is recommended as a marker for combustion Nr emissions, HCN is recommended as a marker for HT-N emissions, and the family NH3 ∕ particle ammonium is recommended as a marker for LT-N emissions.
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Gupta, Subodh. „Technology Focus: Decarbonization (July 2023)“. Journal of Petroleum Technology 75, Nr. 07 (01.07.2023): 96–97. http://dx.doi.org/10.2118/0723-0096-jpt.
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With several applications under its belt, carbon capture and sequestration (CCS) is a proven technology. Costs are a concern, however, when it is not accompanied with CO2 enhanced oil recovery. Naturally, the effort is now to bring down costs by understanding various aspects of the process. This is reflected amply in the overwhelming majority of the approximately 300 papers on emissions reduction produced since late 2021 at various SPE conferences. These cover a range of CCS-related topics, such as onshore to offshore applications, drilling operations, well metallurgy, well-flow modeling, repurposing wells, storage capacity, and reservoir suitability. Because the basics of CCS and carbon capture, use, and storage (CCUS) are mostly familiar to a large part of the readership, I am choosing to bring to your attention the summary of those articles that are devoted to approaches other than or beyond CCS, even if they have to climb further on the development ladder. These include bio-based approaches, geothermal, and use of hydrogen as a substitute fuel. The first of these papers discusses the generation of biomethane and hydrogen from palm oil mill effluent and using hyperthermophile bacteria. The second deals with making use of seaweeds such as Macrocystis pyrifera, commonly found in desertic or semidesertic climates though thermal conversion to hydrogen. The third deals with mangrove restoration for biomass growth and carbon fixation. For further reading and interest I have two topics to suggest: geothermal and hydrogen. Geothermal is not a new technology, but selecting and targeting the right reservoir can make a huge difference to its commercial viability. In this respect, the readers will find the included paper to be a good atlas. While I have been skeptical about hydrogen’s capacity to play an immediate role in decarbonization, the recommended paper focused on hydrogen challenges my preconceptions to an extent, and I think is therefore worthy of mention. In a 2019 International Energy Agency report, the cost of blue hydrogen from natural gas was mentioned to be approximately $1.50/kg in a few favorable jurisdictions, including the US. Can the cost of producing clean hydrogen from noncommercial gas pools be in the same range? The recommended-reading paper on this subject estimates the calculation-based cost of green hydrogen to be even 5–10 times more favorable. Although it may be premature to celebrate, given that this is still based on paper estimates and that other challenges in hydrogen storage and transport exist, it still bodes well for the commerce of clean hydrogen. While it causes optimism, caution is warranted, given significant challenges (not dwelled upon in the paper) in purification and sustainability of a subsurface hydrogen-production process. I am confident you will find these papers to be interesting and stimulating reads. Recommended additional reading at OnePetro: www.onepetro.org. OTC 32035 A Fully Integrated and Updated Geothermal Gradient Atlas of the World by Susan Smith Nash, American Association of Petroleum Geologists, et al. SPE 209558 Subsurface Hydrogen Generation: Low-Cost and Low-Footprint Method of Hydrogen Production by Roman Berenblyum, Hydrogen Source, et al.
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He, Wanru, Xuecao Li, Yuyu Zhou, Zitong Shi, Guojiang Yu, Tengyun Hu, Yixuan Wang et al. „Global urban fractional changes at a 1 km resolution throughout 2100 under eight scenarios of Shared Socioeconomic Pathways (SSPs) and Representative Concentration Pathways (RCPs)“. Earth System Science Data 15, Nr. 8 (11.08.2023): 3623–39. http://dx.doi.org/10.5194/essd-15-3623-2023.
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Abstract. The information of global spatially explicit urban extents under scenarios is important to mitigate future environmental risks caused by global urbanization and climate change. Although future dynamics of urban extent were commonly modeled with conversion from non-urban to urban extent using cellular-automata (CA)-based models, gradual changes of impervious surface area (ISA) at the pixel level were limitedly explored in previous studies. In this paper, we developed a global dataset of urban fractional changes at a 1 km resolution from 2020 to 2100 (5-year interval), under eight scenarios of socioeconomic pathways and climate change. First, to quantify the gradual change of ISA within the pixel, we characterized ISA growth patterns over the past decades (i.e., 1985–2015) using a sigmoid growth model and annual global artificial impervious area (GAIA) data. Then, by incorporating the ISA-based growth mechanism with the CA model, we calibrated the state-specific urban CA model with quantitative evaluation at the global scale. Finally, we projected future urban fractional changes at 1 km resolution under eight development pathways based on the harmonized urban growth demand from Land Use Harmonization2 (LUH2). The evaluation results show that the ISA-based urban CA model performs well globally, with an overall R2 of 0.9 and a root mean square error (RMSE) of 0.08 between modeled and observed ISAs in 2015. With the inclusion of temporal contexts of urban sprawl gained from GAIA, the dataset of global urban fractional change shows good agreement with 30-year historical observations from satellites. The dataset can capture spatially explicit variations of ISA and gradual ISA change within pixels. The dataset of global urban fractional change is of great use in supporting quantitative analysis of urbanization-induced ecological and environmental change at a fine scale, such as urban heat islands, energy consumption, and human–nature interactions in the urban system. The developed dataset of global urban fractional change is available at https://doi.org/10.6084/m9.figshare.20391117.v4 (He et al., 2022).
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Hu, Shu. „(Invited) A Coating Strategy for Heterogeneous Photocatalysis Producing Renewable Fuels“. ECS Meeting Abstracts MA2022-01, Nr. 36 (07.07.2022): 1554. http://dx.doi.org/10.1149/ma2022-01361554mtgabs.
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Photocatalysts coevolve reductive and oxidative reactions in close proximity. Due to simplified reactor implementation, photocatalysis promises solar fuels production at scale. Despite decades of study, their rates and selectivity were often improved by trial and error, and their solar-to-fuel conversion efficiencies remain much lower than the theoretical limit. I will discuss an emerging coating strategy to stabilize particulate photocatalysts in a photo-reactor that promises solar energy utilization at scale. Those photocatalysts coevolve reductive and oxidative reactions in close proximity, and they potentially overcome the scale-up challenge by photoelectrochemical panels. I will first introduce the Hu-lab invented oxide coatings to protect semiconductors, such as silicon and gallium indium phosphide, and achieve efficient and durable photocatalysis. We elucidate the coupled multi-phase processes, including charge separation, charge transfer, and chemical transport across multiple scales. We will show that the local electrochemical potentials of conduction-band electrons and the branching ratios of local charge transfer kinetics under multiple pathways are mutually dependent, and how charge transfer kinetics and surface energetics sensitively determine the charge separation behavior.[1] Based on the holistic understanding of the photophysical, electrocatalytic, and transport processes coupled at the nanoscale, we employ stabilization coatings to coevolve H2 at a record rate of 48.5 mmol∙h-1∙g-1 or 2.5 mL H2∙h-1∙cm-2 under 1-sun solar illumination in ambient air.[2] Additionally, the discovery of new coatings offers the opportunity to tune the local energetics, kinetics, and reaction environments of supported co-catalysts. Manipulation of the electronic defect energetics enables the semiconductor photoabsorbers of 1.1 – 2.3 eV with sufficient band energetics. Coated photocatalysts can perform H2 evolution, water oxidation, and can further achieve CO2 reduction reactions combining with CO2 capture.[3] Recently, Berlinguette and others showed a CO2 electrolyzer for directly converting dissolved bicarbonates into CO2-reduction products.[4] The analogy in photocatalysis is to locally drive pH swing to release CO2 at the oxidative sites, whereas the nearby reductive sites reduce in-situ generated CO2 into CO2R products. We show that in the presence of quinone redox couples in a bicarbonate solution, CO is produced with a 1-atm CO2-free headspace where the only source of CO2 is the (bi)carbonate anions.[6] We envision the direct solar fuels production from natural resources such as sunlight, bicarbonates from the ocean, or moisture in the air in a durable particle reactor.[5] References: [1] Zhenhua Pan, Yanagi Rito, Q. Wang, X. Shen, Q. Zhu, Y. Xue, J. A. Rohr, Takashi Hisatomi, Kazunari Domen, and Shu Hu, “Mutually-dependent kinetics and energetics of photocatalyst/ co-catalyst/two-redox liquid junctions”, Energy & Environmental Science , 13, 162–173 (2020). doi: 10.1039/C9EE02910A [2] T. Zhao, R. Yanagi, Y. Xu, Y. He, Y. Song, M. Yang, and S. Hu, “A Coating Strategy to Achieve Effective Local Charge Separation for Photocatalytic Coevolution”, Proceedings of National Academy of Sciences , 16, 119(7) e2023552118 (2021). doi: 10.1073/pnas.2023552118 [3] J. Tang, D. Solanki, T. Zhao, and S. Hu, “Selective Two-Electron Hydrogen Peroxide Conversion Tailored by Surface, Interface, and Device Engineering,”, Joule , 6, 1432 – 1461 (2021). doi: 10.1016/j.joule.2021.04.012. [4] Li, T.; Lees, E. W.; Zhang, Z.; Berlinguette, C. P. Conversion of bicarbonate to formate in an electrochemical flow reactor. ACS Energy Lett 2020, 5 (8), 2624-2630. doi: 10.1021/acsenergylett.0c01291 [5] X. Shen, S. Hu, et al., “Comprehensive Evaluation For Protective Coatings: Optical, Electrical, Photoelectrochemical, and Spectroscopic Characterization”, Frontier in Energy Research .
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AIB, Ekejiuba. „Universal “Plug and Play” Real-Time Entire Automotive Exhaust Effluents, Industry Vents and Flue Gas Emissions Liquefiers: The Game Changer Approach-Phase Two Category“. Petroleum & Petrochemical Engineering Journal 7, Nr. 2 (04.04.2023): 1–56. http://dx.doi.org/10.23880/ppej-16000349.
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The first in the series of Azuberths Game Changer publications “Synergy of the Conventional Crude Oil and the FT-GTL Processes for Sustainable Synfuels Production: The Game Changer Approach-Phase One Category” a.k.a. (DOI: 10.23880/ppej16000330) is targeted at reducing 80 per cent CO2 emissions from the internal combustion engines by upgrading from the conventional crude oil refinery products to the synthetic fuels products (ultra-low-carbon fuels). This paper will focus on the complete elimination of the remaining 20 per cent CO2 emissions (i.e. to achieve zero- CO2 emissions) in transportation and power generating internal combustion engines as well as in the other centralized emissions/emitters such as petroleum industry flare lines, industrial process and big technology industries scrubber flue gas, et cetera. This invention stems from similar biblical quote {Isaiah 6:8-New International Version (NIV)} which states, and then I heard the voice of the Lord saying, “Whom shall I send? And who will go for us?” And I (Isaiah) said, “Here am I. Send me!” Laterally, in this case I (Azunna) said, “Here am I. Please use me”. Hence the aftermath, IJN-Universal Emissions Liquefiers is a plug and play units for all categories of pollutants discharge into the atmosphere. The work is motivated by the scientific facts that (i) The release of CO2 from automotive exhaust effluents, industry vents and flue gas emissions into the atmosphere contributes to greenhouse gas (GHG) accumulation causing global warming hence climate changes issues such as flooding of coastlines/sea-rising, melting of the glaciers, disrupted weather patterns, bushburning/wildfire, depletion of Ozone layer, smog and air pollution, acidification of water bodies, runaway greenhouse effect, etc. (ii) Every gas stream (e.g., flue gas) can be made liquid by e.g. a series of compression, cooling and expansion steps and once in liquid form, the components of the gas can be separated in a distillation column. (iii) Captured liquefied gases can be put to various uses, especially carbon dioxide (CO2 ), which can be used for the production of renewable energy via Synfuels such as the e-fuel/solar fuel. The natural atmosphere is composed of 78% nitrogen, 21% oxygen, 0.9% argon, and only about 0.1% natural greenhouse gases, which include carbon dioxide, organic chemicals called chlorofluorocarbons (CFCs), methane, nitrous oxide, ozone, and many others. Although a small amount, these greenhouse gases make a big difference - they are the gases that allow the greenhouse effect to exist by trapping in some heat that would otherwise escape to space. Carbon dioxide, although not the most potent of the greenhouse gases, is the most important because of the huge volumes emitted into the air by combustion of fossil fuels (e.g., gasoline, diesel, fuel oil, coal, natural gas). In general, the major contributors to the greenhouse effect are: Burning of fossil fuels in automobiles, deforestation, farming processing and manufacturing factories, industrial waste and landfills, increasing animal and human respiration, etc. The increased number of factories, automobiles, and population increases the amount of these gases in the atmosphere. The greenhouse gases never let the radiations to escape from the earth atmosphere and increase the surface temperature of the earth. This then leads to global warming. The petroleum industry well sites vent/flare gases (methane, ethane, propane, butanes, H2 O (g), O2 , N2 , etc.). Internal combustion engines (automobiles-cars, vehicles, ships, trains, planes, etc.) release exhaust effluents (containing H2 O (g), CO2 , O2 , and N2 ); steam generators in large power plants and the process furnaces in large refineries, petrochemical and chemical plants, and incinerators burn considerable amounts of fossil fuels and therefore emit large amounts of flue gas to the ambient atmosphere. In general, Flue gas is the gas exiting to the atmosphere via a “flue”, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler or steam generator. The emitted flue gas contains carbon dioxide CO2 , carbon monoxide CO, sulphur oxide SO2 , nitrous oxide NO and particulates. Furthermore, GTL plants produce CO2 , H2 O and waste heat, while both pyrolysis and gasification plant generate gaseous products consisting of (a mixture of non-condensable gases such as H2 , CO2 , and CO and light hydrocarbons “e.g. CH4 ” at room temperature, as well as H2 O (g), O2 and complex hydrocarbons e.g. C2 H2 , C2 H4 , etc.). In general, all combustion is as a result of air-fuel mixture burning (i.e. air or oxygen mixing directly with biomass/ coal or with liquid/gaseous hydrocarbon inside internal combustion engines), releases carbon dioxide and steam (H2 O) back into the atmosphere as well as producing energy for work. Specifically, during combustion, carbon combines with oxygen to produce carbon dioxide (CO2 ). The principal emission from transportation and power generating internal combustion engines is carbon dioxide (CO2 ). The level of CO2 emission is linked to the amount of fuel consumed and the type of fuel used as well as the individual engine’s operating characteristics. For instance, diesel-powered engines have higher emission than petrol/gasoline-powered engines. Although emphasis is places more on CO2 , this investigation is ultimately concerned with the real-time liquefaction of all the components of gaseous release/emissions -related to air pollution/health problem. It is believed that the mortality rate from air pollution is eight times larger than the mortality caused by car accidents each year. Pollutants with the strongest evidence for public health concern include particulate matter (PM), ozone (O3 ), nitrogen dioxide (NO2 ) and sulphur dioxide (SO2 ). All the exhaust effluents gases/flue gas and vent/flare gases are captured by liquefying them and then put to various uses, to achieve “Net zero” emissions. Fundamentally, the objective of the present invention is to develop a compact device (Universal Emissions Liquefiers) that can be retro-fitted onto the exhaust tailpipe-end of the internal combustion engines (diesel-powered, gasoline-powered, and hybrid automobiles-cars, vehicles, SUV’s, trucks, motor cycles, tri-cycles, portable electric generators, sea and cargo ships/ boats, trains, planes, rockets, etc.) and outlet of industrial machines that release flue gases through exhaust/scrubber channels, as well as crude oil, refined products storage tanks that vent greenhouse gases into the atmosphere, coal processing units/ plants and turn them into liquid { CO2 (l), N2 (l), O2 (l), etc.} or powdered components or chemically transform them in realtime with selective catalysts to any other specific compound, e.g. treating CO2 with hydrogen gas (H2) can produce methanol (CH3 OH), methane (CH4 ), or formic acid (HCOOH), while reaction of CO2 with alkali (e.g. NaOH) can give carbonates (NaHCO3 ) and bicarbonates (Na2 CO3 ). Nitrogen (N2 ) to ammonia (NH3 ) or Hydrazine (N2 H4 ), and molecular oxygen (O2 ) to hydrogen peroxide (H2 O2 ), et cetera. Alternatively, in new automobiles designs, the universal emissions liquefiers’ device can be directly net-worked on the floor alongside the catalytic converters and may eliminate the need for muffler/silencer/resonator. This is achieved by the application of any of the five main gas capture/separation technologies: Liquid absorption, Solid adsorption, Membrane separation (with and without solvent- organic or inorganic), Cryogenic refrigeration/distillation, and Electrochemical pH-swing separation or their combination to selectively trap and liquefy the individual pollutants. According to the fact from CarBuster, almost 0.009 metric tons of carbon dioxide is produced from every gallon of gasoline burned, which means that the average car user makes about 11.7 tons of carbon dioxide each year from their cars alone
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Bhattacharyya, Paramita, Brahim Ahammou, Fahmida Azmi, Rafael Kleiman und Peter Mascher. „Design and Fabrication of Multiple-Color-Generating Thin-Film Optical Filters for Photovoltaic Applications“. ECS Meeting Abstracts MA2022-01, Nr. 19 (07.07.2022): 1064. http://dx.doi.org/10.1149/ma2022-01191064mtgabs.
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The use of electric vehicles (EVs) can reduce greenhouse gas emissions, air pollution, dependency on fossil fuels, and their adverse health effects on humans. But, we can only utilize the full environmental benefits of EVs when they are charged with renewable energy sources with zero or low carbon emissions. As a solution, Mobarak et al. [1] suggested integrating low-cost, flexible, and thin-film copper indium gallium selenide (CIGS) solar cells directly onto the steel of all the upward-facing body parts of the vehicles. But, this integration of solar cells comes with an aesthetic drawback. Previously, colorful photovoltaics (PVs) have been designed with one-dimensional (1D) photonic crystals or various 1D and 2D metallic nanostructures for aesthetic building-integrated photovoltaics (BIPVs) [2, 3]. However, the functionality of our application differs from that of BIPV as we need maximum absorption of the solar spectrum to obtain maximum conversion efficiency. Thus, we propose replacing the anti-reflective coating (ARC) present in the solar cells with a notch filter (a narrow high-reflection region in the visible range along with high transmission for the rest of the solar spectrum) to obtain colors. High-performance notch filters with a narrow and ultra-steep notch are well known in literature [4, 5]. Generally, high-performance notch filters are designed with a minimum of 45 layers. It is challenging to use filters with many layers on solar cells due to fabrication and thickness complexities. Thus, we created designs with a maximum of 27 layers for possible integration with photovoltaics. We used OptiLayer [6] to simulate our designs and the gradual evolution technique was used to optimize the designs. We performed our simulations with a multilayer structure of alternating high and low refractive indices of 2.09 and 1.45, respectively, on top of a silicon substrate. We optimized this multilayer structure for three reference wavelengths (400 nm, 550 nm, and 700 nm) resembling three colors. Our designs have notch widths of less than 100 nm for all the reference wavelengths with an average of 70% reflection in the high-reflection region and less than 20% reflection in the high-transmission area. To fabricate our designs, we need materials that are transparent to the solar spectrum targeted by the active material of the solar cells. The materials also need to have refractive indices closer to our simulation. Thus, we chose the combination of silicon nitride and silicon dioxide as our high and low refractive index material, respectively [7, 8]. To better understand our designs’ optical characteristics, we fabricated a scaled-down version of our structure with 5-10 layers. We used electron cyclotron resonance plasma-enhanced chemical vapor deposition (ECR-PECVD) to deposit the multilayer structure on silicon wafers. To obtain the silicon nitride and silicon dioxide layers, we used a SiH4/N2/O2/Ar precursor mixture. By tuning the gas flow rate in the reactor chamber, we tuned the stoichiometry and obtained the required refractive index for each layer. To characterize the refractive index and thickness for each layer, we used variable angle spectroscopic ellipsometry (VASE). We made a detailed comparison of our simulation and fabrication results. References [1] M. H. Mobarak, R. N. Kleiman, J. Bauman, Solar-charged electric vehicles: A comprehensive analysis of grid, driver, and environmental benefits, IEEE Transactions on Transportation Electrification 7 (2021) 579–603. doi:10.1109/TTE.2020.2996363. [2] G. Y. Yoo, et al., Multiple-color-generating cu(in,ga)(s,se)2 thin-film solar cells via dichroic film incorporation for power-generating window applications, ACS Applied Materials & Interfaces 9 (2017) 14817–14826. doi:10.1021/acsami.7b01416, pMID: 28406026. [3] K. T. Lee, et al., Colored dual-functional photovoltaic cells, Journal of Optics 18 (2016) 064003. [4] U. Schallenberg, et al., Design and manufacturing of high-performance notch filters, volume 7739, International Society for Optics and Photonics, SPIE, 2010, pp. 720 – 728. doi:10.1117/12.856580. [5] J. Zhang, et al., Design and fabrication of ultra-steep notch filters, Opt. Express 21 (2013) 21523–21529. doi:10.1364/OE.21.021523. [6] OptiLayer, 1994. URL: https://www.optilayer.com/support/faq, accessed: 2021-12-06. [7] A. Z. Subramanian, et al., Low-loss singlemode pecvd silicon nitride photonic wire waveguides for 532–900 nm wavelength window fabricated within a cmos pilot line, IEEE Photonics Journal 5 (2013) 2202809–2202809. doi:10.1109/JPHOT.2013.2292698. [8] W. D. Sacher, et al., Visible-light silicon nitride waveguide devices and implantable neurophotonic probes on thinned 200 mm silicon wafers, Opt. Express 27 (2019) 37400–37418. doi:10.1364/OE.27.037400
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Liu, Matthew Junjie, Huaxin Gong, Kindle Shea Williams, Jesse E. Matthews, Michael J. Zachman, Adam S. Hoffman, Simon R. Bare et al. „Electrocatalytic Nitrate Reduction to Ammonia at Atomically Dispersed Titanium Sites on Carbon Nanoflowers“. ECS Meeting Abstracts MA2023-01, Nr. 39 (28.08.2023): 2299. http://dx.doi.org/10.1149/ma2023-01392299mtgabs.
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Active nitrogen species are widely acknowledged as pollutants that are both harmful to the environment as well as human health. Emissions from wastewater and agricultural applications contain nitrogen in many forms, but in soils and waterways nitrate (NO3 -) predominates due to the presence of nitrifying bacteria. In comparison to more reduced forms of nitrogen such as total ammonia (NH3/NH4 +), nitrate is not only a less versatile species from a chemical manufacturing and energy standpoint; it is also more difficult to selectively separate from wastewater streams. For instance, we have conducted considerable work on electrochemical ammonia stripping, achieving high selectivities and even enabling concentration of ammonia in the form of strong ammonium salt solutions.1 Moreover, it is estimated that recovery of active nitrogen species from municipal and agricultural wastewaters could offset the need for ~30% of Haber-Bosch ammonia synthesis. From this perspective, it is desirable to develop catalysts that are active and selective for the conversion of nitrate to ammonia. Titanium metal has been demonstrated as a relatively active and selective catalyst for nitrate reduction to ammonia in acid;2 however, similarly active and selective catalysts under neutral-to-alkaline conditions are a subject of active research.3–6 Here we report on the performance of atomically dispersed titanium sites on carbon nanoflowers7 for the reduction of nitrate to ammonia under alkaline conditions. The dispersity of these catalysts was supported by XAS (little/negligible Ti-Ti scattering, putative Ti-N and Ti-N-C scattering), STEM (visual confirmation of atoms), and XRD (no crystalline Ti phases observed). We contrast the performance of these atomically dispersed catalysts with that of bulk titanium foil, which shows comparably low activity and selectivity for nitrate reduction at similar pHs and potentials. In addition, we compare the atomically dispersed titanium catalysts with titanium nanoparticles, as a first-order check for catalyst aggregation under reductive reaction conditions. Moreover, the performances of all of these catalysts are compared with the baseline/controls of bare carbon paper, as well as carbon nanoflowers supported on carbon paper without titanium dopant. Additional control experiments include tests conducted in the absence of nitrate. These lines of evidence, together with the relatively high rate of ammonia production (>0.01 mmol / cmgeo 2 / h, >10 mmol / mg Ti / h), support the notion that atomically dispersed titanium is uniquely active and selective for NO3RR under alkaline conditions. Further, for the above catalysts at pH ~13, we show the impacts of potential on the product distribution, including nitrogen mass balance and Faradaic efficiency. As a best practice, we demonstrate consistent closure of both metrics. Potential was varied between -0.4 V and -0.85 V vs. RHE. Partial current toward NO3RR increases with increasing overpotential, as another sanity check supporting the findings. Notably, in addition to observing ammonia and nitrite as products of NO3RR, we also checked for other stable intermediates (in addition to N2) along the 8-electron reaction pathway – and as a result, we are able to report small amounts (FE ~5-10%) of hydroxylamine (NH2OH) product. In the specific case of atomically dispersed titanium on carbon nanoflowers, we also report on certain observed electrolyte effects, such as the incorporation of perchlorate vs. sulfate as a supporting electrolyte. We demonstrate the role of supporting salt both in modifying selectivity – e.g. sulfate suppressing HER, possibly via site-blocking – as well as in altering the carbon support itself. These observations contribute to a growing body of work that will enable the engineering of these catalysts for high-rate reduction of nitrate to ammonia, aiding both wastewater remediation and the decarbonization of ammonia synthesis. References: (1) Liu, M. J., et al. Water Res. 2020, 169, 115226. https://doi.org/10.1016/j.watres.2019.115226. (2) McEnaney, J. M., et al. ACS Sustain. Chem. Eng. 2020, 8 (7), 2672–2681. https://doi.org/10.1021/acssuschemeng.9b05983. (3) Wu, Z.-Y., et al. Nat. Commun. 2021, 12 (1), 2870. https://doi.org/10.1038/s41467-021-23115-x. (4) Liu, H., et al. Angew. Chem. Int. Ed. 2022, 61 (23). https://doi.org/10.1002/anie.202202556. (5) Chen, F.-Y., et al. Nat. Nanotechnol. 2022, 17 (7), 759–767. https://doi.org/10.1038/s41565-022-01121-4. (6) Murphy, E., et al. ACS Catal. 2022, 12 (11), 6651–6662. https://doi.org/10.1021/acscatal.2c01367. (7) Chen, S., et al. J. Am. Chem. Soc. 2018, 140 (32), 10297–10304. https://doi.org/10.1021/jacs.8b05825.
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Nowell, W. B., J. Curtis, F. Xie, H. Zhao, D. Curtis, K. Gavigan, S. Venkatachalam et al. „THU0564 PARTICIPANT ENGAGEMENT IN AN ARTHRITISPOWER REAL-WORLD STUDY TO CAPTURE SMARTWATCH AND PATIENT-REPORTED OUTCOME DATA AMONG RHEUMATOID ARTHRITIS PATIENTS“. Annals of the Rheumatic Diseases 79, Suppl 1 (Juni 2020): 523–24. http://dx.doi.org/10.1136/annrheumdis-2020-eular.2355.
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Background:Clear characterization of how different types of patient-generated data reflect patient experience is needed to guide integration of electronic patient-reported outcome (ePRO) measures and biometrics in generating real-word evidence (RWE) related to rheumatoid arthritis (RA).Objectives:To characterize the level of participant (pt) engagement/adherence and data completeness in an ongoing study of 250 RA pts enrolled in the Digital Tracking of Arthritis Longitudinally (DIGITAL) study1of the ArthritisPower real-world registry.Methods:ArthritisPower pts with RA were invited to join a digital RWE study with 14-day lead-in and 12-week main study period. In the lead-in, pts were required to electronically complete: a) two daily single-item Pain and Fatigue numeric rating scales and b) longer weekly sets of ePROs. Successful completers of the lead-in were mailed a smartwatch (Fitbit Versa) and study materials. The smartwatch collected activity, heart rate, and sleep duration/quality biosensor data; a study-specific customization of the ArthritisPower mobile application collected ePROs. The main study period included automated and manual reminders/prompts about completing ePROs, wearing the smartwatch and regularly syncing it. Study coordinators monitored pt data and contacted pts via email, text and/or phone to resolve adherence issues during the conduct of the study based on pre-determined rules triggering pt contact. Rules were based chiefly on consecutive spans of missing data. Pts were considered adherent in giving complete data for each week if providing (1) daily ePROs for ≥5 of 7 days/week, (2) weekly ePROs and (3) ≥80% of synced activity data for ≥5 of 7 days/week. Composite adherence for the first month of the main study period required meeting >70% weekly adherence parameters during the first 30 days, ie completing daily ePROs for ≥5 of 7 days/week, weekly ePROs ≥3 of 4 weeks and ≥80% of synced activity data for ≥5 of 7 days/week.Results:As of December 2019, 170 ArthritisPower members enrolled and completed at least 30 days of the main study period; 92.9% female with mean (SD) age 52.5 (10.7) and 10.5 (10.4) years since diagnosis. The overall conversion rate from initial interest to successful completion of the lead-in period was 49.0%. Pts who advanced to the main study were significantly more likely than those who did not to be currently employed (52.9% vs. 41.8%, p=0.038) and be on biologic DMARD monotherapy (64.7% vs. 47.5%, p=0.001). Overall, daily ePRO data had the lowest adherence with 70.0% of pts providing >70% of the requested data consistently across the first 30 days of the main study period (Figure 1). Composite adherence was met by 66.5% of pts. The most common time of day to provide ePRO data was morning, in the hours around scheduled app and email notifications at 10 a.m. in pt’s local time zone. Activity data had the highest adherence and persistence, with 92.9% of pts providing 80% or more of activity data for each 24-hour period in the first 30 days (Figures 1 & 2). Observed weekly adherence did not decline over time. Of 5100 possible person days in the study at day 30, we observed 643 days (91.0% of actual to maximum possible total patient days) where activity data was provided for at least 80% of the 24-hour period.Conclusion:RWE studies involving passive data collection in RA require pt-centric implementation and design to minimize pt burden, promote longitudinal engagement and maximize adherence. Passive data capture via activity trackers such as smartwatches, along with regular contact such as automated reminders, may facilitate greater pt adherence in providing longitudinal data for clinical trials.References:[1]Nowell WB, et al. JMIR Res Protoc. 2019;8(9):e14665.Disclosure of Interests:W. Benjamin Nowell: None declared, Jeffrey Curtis Grant/research support from: AbbVie, Amgen, Bristol-Myers Squibb, Corrona, Janssen, Lilly, Myriad, Pfizer, Regeneron, Roche, UCB, Consultant of: AbbVie, Amgen, Bristol-Myers Squibb, Corrona, Janssen, Lilly, Myriad, Pfizer, Regeneron, Roche, UCB, Fenglong Xie: None declared, Hong Zhao: None declared, David Curtis: None declared, Kelly Gavigan: None declared, Shilpa Venkatachalam: None declared, Laura Stradford: None declared, Jessica Boles: None declared, Justin Owensby: None declared, Cassie Clinton: None declared, Ilya Lipkovich Shareholder of: Eli Lilly and Company, Employee of: Eli Lilly and Company, Amy Calvin Shareholder of: Eli Lilly and Company, Employee of: Eli Lilly and Company, Virginia S. Haynes Shareholder of: Eli Lilly and Company, Employee of: Eli Lilly and Company
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Nagel, A., M. Radziszewski, B. Khatri, M. M. Wiley, A. M. Stolarczyk, M. L. Joachims, Q. Sun et al. „POS0456 AUTOPHAGY-RELATED RISK LOCI IN SLE AND THEIR ROLE IN NEUTROPHILS“. Annals of the Rheumatic Diseases 81, Suppl 1 (23.05.2022): 482.1–482. http://dx.doi.org/10.1136/annrheumdis-2022-eular.2496.
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BackgroundSystemic lupus erythematous (SLE) is an autoimmune disease with ~150 established susceptibility risk loci. Genome wide-association (GWA) studies in SLE cases and controls of Korean ancestry identified the SLE risk locus ATG16L2-P2RY2, and rs11235604 as a SLE-associated missense variant (R220W) of Autophagy Related 16 Like 2 (ATG16L2) [1]. PRDM1-ATG5 is also an SLE risk locus in European populations that is implicated in autophagy. Autophagy plays a crucial role in neutrophil extracellular trap (NET) formation, degranulation, and limiting autoantigens in blood. Dysregulated autophagy has been implicated in SLE pathology and poor disease outcomes. The function of ATG16L2 is unknown, but evidence suggests it may function as a negative regulator of autophagosome formation [2].ObjectivesTo identify autophagy-related SLE risk variants shared across different ancestry populations and define the role of ATG16L2 in SLE and autophagy.MethodsSLE case-control GWA scans from European (7568 cases; 1082 controls), African American (4336 cases; 935 controls), Hispanic (3752 cases; 1840 controls), and Korean (1173 cases; 4213 controls) populations were imputed and SNP associations tested. Meta-analysis was performed, then Bayesian statistics were used to define a credible SNP set. Bioinformatic analyses (RegulomeDB, promoter capture Hi-C, eQTLs, etc.) further prioritized SNPs based on predicted functionality. The functional significance of autophagy SLE risk genes, ATG16L1, ATG16L,2 and ATG5, were tested by CRISPR knockout (KO) in PLB-985 cell line. CRISPR-targeted single cell clones were screened for ATG16L1, ATG16L2 or ATG5 deletion using qPCR, NanoPore sequencing, and Western blotting. Changes in autophagy were assessed by Western blotting and confocal microscopy.ResultsTransracial fine-mapping of PRDM1-ATG5 locus identified two SNP associations shared across the credible sets in all populations: rs56886418 (p=1.38x10-5) located in the intron of PRDM1 and rs77791277 (p=1.38x10-5) that tagged a group of SNPs in strong linkage disequilibrium. Cross comparison of the credible SNP sets and bioinformatic analyses of shared SNPs identified rs533733 and rs9373843 as additional likely functional variants. Bioinformatic analyses prioritized rs56886418, an eQTL for ATG5 (p=0.05) and PRDM1 (p=4.75x10-7) in blood cells positioned in a topologically associated domain (TAD) that may interact with ATG5 and PRDM1 promoters in EBV-transformed B cells. SNP rs533733 is an eQTL for ATG5 in neutrophils (p=0.006) and is in a TAD 6.4kb 3’ of PRDM1 that interacts with the ATG5 promoter region where rs9373843 (eQTL of ATG5 in neutrophils (p=0.04)) is positioned. These data suggest that risk SNPs on the PRDM1-ATG5 locus may modulate ATG5 expression and autophagy in specific cell types by modulating the local chromatin regulatory network.To assess the roles of ATG5, ATG16L1 and ATG16L2 in autophagy, PMA/I-induced hallmarks of autophagy, LC3-I and LC3-II conversion and p62 protein aggregation, were assessed in homozygous and heterozygous ATG5, ATG16L1, or ATG16L2 CRISPR KO PLB-985 cells by Western blotting and confocal microscopy. Loss of ATG5 or ATG16L1 impaired PMA/I-induced autophagosome formation in myeloid-like and differentiated neutrophil-like PLB-985 cells. In contrast, loss of ATG16L2 elevated the conversion of LC3-I to LC3-II and p62 protein aggregation in both cell types, suggesting that ATG16L2 may inhibit autophagy.ConclusionFunctional characterization of SNPs on the PRDM1-ATG5 and ATG16L2-P2RY2 loci, and the functional characterization of ATG16L2 in myeloid and neutrophil cell lines, provide new insights into the mechanisms that regulate autophagy in health and disease. Ongoing studies will focus on in vitro validation of predicted functional SNPs and will introduce ATG16L2 rs11235604 risk variant in PLB-985 cells to assess its importance in autophagy.References[1]Lessard CJ, et al. Arthritis Rheumatol. 2016; 68(5):1197-1209.[2]Wible DJ, et al. Cell Discov. 2019; 5:42.Disclosure of InterestsNone declared.
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Gado, Alanna M., Deniz Ipekçi, Stoyan Bliznakov, Leonard J. Bonville, Jeffrey McCutcheon und Radenka Maric. „Investigation of the Performance and Durability of Reactive Spray Deposition Fabricated Electrodes on a Bifunctional Membrane for Alkaline Water Electrolysis and CO2 Reduction Reaction“. ECS Meeting Abstracts MA2023-01, Nr. 38 (28.08.2023): 2250. http://dx.doi.org/10.1149/ma2023-01382250mtgabs.
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Alkaline water electrolysis (AWE) is a promising technology for carbon capture [1]. Anion exchange membrane water electrolyzers (AEMWEs) utilize low-cost, non-precious metal materials, providing an economically viable alternative to more expensive proton exchange membrane water electrolyzers (PEMWEs). While PEMWEs can operate at much higher current densities, they require noble metal catalysts and titanium components for the high potential environment anode [1]. The implementation of a bipolar membrane (BPM) will allow both HER and OER to occur under kinetically favorable conditions [2, 3] by combining both thin AEM and thin PEM layers within a single membrane. AEMs, PEMs, and BPMs have been tested in CO2RR electrolyzers [4]. The BPM may provide a pathway to combine the advantages of both AEMs and PEMs for CO2 reduction. Altering both the membrane and CCM is a focus in the research and development in CO2RR electrolyzers. Lee et al. [5] explored the use of a porous membrane for CO2 reduction. While work can be done to improve performance and crossover, the porous membrane provided excellent mechanical properties and good economic potential. There has been some work done on developing bifunctional membranes for water electrolysis and CO2 reduction [3, 6, 7]. Two key issues with operation of a CO2RR electrolyzer with a BPM is the reactant CO2 that is lost to the AEM and PEM membrane layer interface and the instability of the cell. Both issues contribute to a significant decrease in performance and faradaic efficiency in product conversion. Development of the BPM, both on the membrane’s fabrication and configuration, and electrode layers, needs to be explored to reach higher performances and longer lifespans. In this work, reactive spray deposition technology (RSDT) was used to fabricate electrodes on a UConn fabricated bipolar membrane. Testing of each configuration was conducted as both an AEM water electrolyzer and CO2RR electrolyzer. Polarization, electrochemical impedance spectroscopy, electrochemical equivalent circuits, and distribution of relaxation times were used to investigate cell performance and durability. References [1] B. Mayerhofer, D. McLaughlin, T. Bohm, M. Hegelheimer, D. Seeberger, and S. Thiele, “Bipolar membrane electrode assemblies for water electrolysis,” ACS applied energy materials, vol. 3, no. 10, pp. 9635–9644, 2020. [2] J. Xu, I. Amorim, Y. Li, J. Li, Z. Yu, B. Zhang, A. Araujo, N. Zhang, and L. Liu, “Stable overall water splitting in an asymmetric acid/alkaline electrolyzer comprising a bipolar membrane sandwiched by bifunctional cobalt-nickel phosphide nanowire electrodes,” Carbon Energy, vol. 2, no. 4, pp. 646–655, 2020. [3] Q. Lei, B. Wang, P. Wang, and S. Liu, “Hydrogen generation with acid/alkaline amphoteric water electrolysis,” Journal of Energy Chemistry, vol. 38, pp. 162–169, 2019. [13] W. H. Lee, K. Kim, C. Lim, Y. J. Ko, Y. J. Hwang, B. K. Min, U. Lee, and H. S. Oh, “New strategies for economically feasible CO2 electroreduction using a porous membrane in zero-gap configuration,” Journal of Materials Chemistry A, vol. 9, pp. 16169–16177, 8 2021 [4] D. A. Salvatore, C. M. Gabardo, A. Reyes, C. P. O’Brien, S. Holdcroft, P. Pintauro, B. Bahar, M. Hickner, C. Bae, D. Sinton, E. H. Sargent, and C. P. Berlinguette, “Designing anion exchange membranes forCO2 electrolysers,” Nature Energy, vol. 6, pp. 339–348, 4 202 [5] W. H. Lee, K. Kim, C. Lim, Y. J. Ko, Y. J. Hwang, B. K. Min, U. Lee, and H. S. Oh, “New strategies for economically feasible CO2 electroreduction using a porous membrane in zero-gap configuration,” Journal of Materials Chemistry A, vol. 9, pp. 16169–16177, 8 2021 [6] W. Li, Z. Yin, Z. Gao, G. Wang, Z. Li, F. Wei, X. Wei, H. Peng, X. Hu, L. Xiao, J. Lu, and L. Zhuang, “Bifunctional ionomers for efficient CO electrolysis of CO2 and pure water towards ethylene production at industrialscale current densities,” Nature Energy, 2022 [7] C. P. O’Brien, R. K. Miao, S. Liu, Y. Xu, G. Lee, A. Robb, J. E. Huang, K. Xie, K. Bertens, C. M. Gabardo, et al., “Single pass CO2 conversion exceeding 85% in the electrosynthesis of multicarbon products via local CO2 regeneration,” ACS Energy Letters, vol. 6, no. 8, pp. 2952–2959, 2021.
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Rocha, N. A. S., B. C. S. Leão, M. F. Accorsi und G. Z. Mingoti. „90 INTRACELLULAR REACTIVE OXYGEN SPECIES IN BOVINE EMBRYOS CULTURED IN VITRO WITH CATALASE UNDER VARIOUS OXYGEN TENSIONS“. Reproduction, Fertility and Development 24, Nr. 1 (2012): 157. http://dx.doi.org/10.1071/rdv24n1ab90.
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The production of reactive oxygen species (ROS), such as superoxide anion (O2–), hydroxyl radical (OH–) hydrogen peroxide (H2O2) and organic peroxides, is a normal process that occurs in the cellular mitochondrial respiratory chain. The high oxygen tension in in vitro culture (IVC) conditions is believed to induce oxidative stress, as a result of increase in ROS intracellular production, that can be correlated with embryonic developmental failure. Supplementation with antioxidants during IVC appears to increase the resistance of bovine embryos to the oxidative stress and consequently improve embryo development. The aim of this study was to evaluate the effects of antioxidant (catalase) and oxygen tensions during IVC on the embryonic development and quantification of intracellular ROS. Cumulus–oocyte complexes (COC; n = 337) were in vitro matured (IVM) in TCM-199 supplemented with 0.2 mM pyruvate, 25 mM sodium bicarbonate, 75 μg mL–1 gentamicin, 10% FCS and hormones for 24 h at 38.5°C and 5% CO2 in air. Then they were fertilized and the presumptive zygotes were cultured in SOFaa medium without (control) or with 100 UI catalase (CAT) for 7 days at 38.5°C in one of 2 types of humified atmosphere: 5% CO2 in air (≈20% O2) or in gaseous mixture (7% O2, 5% CO2 and 88% N2). The cleavage rate was evaluated at 72 hours post-insemination (hpi) and the embryonic development at 168 hpi. At this time, the level of intracellular ROS was measured using the fluorescent probe 6-carboxy-2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA; Molecular Probes, Invitrogen, Oakville, Canada), at 5 μM (Bain et al. 2011 Reprod. Fertil. Dev. 23, 561–575). Stained embryos were imaged immediately using an inverted microscope and analysed by Q-Capture Pro image software (QImaging, Surrey, BC, Canada). The signal intensity values of embryos were subtracted by the average of backgrounds in the images. Embryo development was analysed by chi-squared test and means of the intensity of fluorescence were compared by ANOVA followed by Tukey's test (P < 0.05). The cleavage rates were 84.04%a (control 20% O2), 77.55%a (CAT 20% O2), 77.03%a (control 7% O2) and 71.83%a (CAT 7% O2). The embryonic development rates were 40.43%a (control 20% O2), 33.67%a (CAT 20% O2), 20.27%b (control 7% O2) and 16.90%b (CAT 7% O2). The fluorescent intensity were 3.9 ± 0.4a (control 20% O2), 1.8 ± 0.2b (CAT 20% O2), 2.7 ± 0.2ab (control 7% O2) and 2.8 ± 0.2ab (CAT 7% O2). Although catalase did not significantly affect blastocyst frequencies (P > 0.05), embryo development was adversely affected by reduced O2 tension (P < 0.05). H2DCFDA staining indicated a significant (P < 0.05) reduction in the levels of intracellular ROS within embryos cultured with catalase under 20% O2 compared with the control group in the same O2 tension. Additionally, a consistent but insignificant reduction in intracellular ROS within embryos cultured under 7% O2 was found. We can conclude that supplementation with catalase to IVC medium at 20% O2 is suitable for lowering intracellular ROS levels in IVP bovine embryos, without lowering the rates of blastocysts production. This finding corroborates with theory that antioxidants are beneficial to embryo quality. Alta Genetics Brazil, Deoxi Biotecnologia.
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Sachs, Michael, Benjamin Poulter, Zhaoyuan Yang, Niranjan Govind, Robert Schoenlein, Munira Khalil und Elisa Biasin. „Impact of Solvent-Solute Hydrogen Bonding on Ultrafast Electron Transfer in a Trimetallic Iron-Ruthenium Complex“. ECS Meeting Abstracts MA2022-02, Nr. 48 (09.10.2022): 1807. http://dx.doi.org/10.1149/ma2022-02481807mtgabs.
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Transition metal complexes (TMCs) are widely used as light absorbers and catalysts for photochemical energy conversion processes such as photocatalytic reactions in liquid environments. Of particular interest are TMCs which incorporate multiple bridged metal centres because they represent a step towards more complex supramolecular assemblies that can ultimately enable control of the charge flow in solution-based photo-redox processes. However, the development of design guidelines for such molecular assemblies is impeded by an incomplete understanding of the coupling between their electronic and nuclear dynamics, including the interplay of TMCs with their liquid environment upon photoexcitation. Probing the involved processes requires high spatial sensitivity towards electronic motion and the ability to capture atomic motion on ultrafast timescales – a combination which is not readily available for optical transient spectroscopic techniques. X-ray free electron lasers (XFELs) have revolutionized the field of ultrafast science in recent years. XFELs generate tuneable and extremely bright X-ray pulses with a typical pulse duration of <30 fs, which are well-suited as an element-specific probe of ultrafast electronic and atomic motion in molecules and materials.1,2 Applied to TMCs, XFEL probes are sensitive to the local electronic structure in such molecular systems as well as to intra- and inter-molecular structural reorganization at an atomic level.3 In this talk, I will present work on the interaction of a linear trimetallic cyanide-bridged iron-ruthenium complex (FeRuFe) with its solvent environment, carried out using the LCLS XFEL facility at SLAC National Accelerator Laboratory. The focus of this study lies on elucidating how photoinduced intramolecular electron transfer processes in FeRuFe are affected by hydrogen bonding interactions between its cyanide ligands and the surrounding solvent molecules. In water, such solvent-solute hydrogen bonding interactions are stronger for Fe(II) than Fe(III), leading to substantial changes in solute-solvent interactions upon photoinduced electron transfer between metal centres. The experiment is performed in a pump-probe geometry on a liquid jet, where a visible/near-infrared pump induces a metal-to-metal charge transfer (MMCT) between Ru and Fe which is followed by an ultrafast back-electron transfer (BET). The excited state dynamics are monitored using hard X-ray pulses as a function of time delay between the laser pump and the X-ray probe pulses. To resolve and correlate electronic and structural dynamics upon MMCT excitation, we simultaneously perform ultrafast Fe Kβ X-ray emission spectroscopy (XES) and X-ray solution scattering (XSS) measurements, where XES is sensitive to the oxidation and spin state of the Fe centres and XSS provides information on atomic motion in solute and solvent, as demonstrated in previous work on a similar system.4 To evaluate the effect of solute-solvent hydrogen bonding interactions on the electron transfer dynamics, we perform measurements in a series of solvents with different hydrogen bonding properties, including water, methanol, and acetonitrile. We find that the BET increases as a function of decreasing hydrogen bonding ability of the solvent, and that distinct signatures of solvation dynamics are present in the scattering data. The resulting molecular level understanding of solvent reorganization coupled to electron transfer demonstrates that the strength and type of solute-solvent interactions are a central factor in determining the outcome of photoinduced charge transfer processes in TMCs. References Bergmann, U. et al. Using X-ray free-electron lasers for spectroscopy of molecular catalysts and metalloenzymes. Nat. Rev. Phys. 3, 264–282 (2021). Schoenlein, R. et al. Recent advances in ultrafast X-ray sources. Philos. Trans. R. Soc. Math. Phys. Eng. Sci. 377, 20180384 (2019). Gaffney, K. J. Capturing photochemical and photophysical transformations in iron complexes with ultrafast X-ray spectroscopy and scattering. Chem. Sci. 12, 8010–8025 (2021). Biasin, E. et al. Direct observation of coherent femtosecond solvent reorganization coupled to intramolecular electron transfer. Nat. Chem. 13, 343–349 (2021).
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Carpenter, Chris. „Well-Integrity Risk-Assessment Strategy Applied to CO2 Sequestration Project“. Journal of Petroleum Technology 75, Nr. 01 (01.01.2023): 78–80. http://dx.doi.org/10.2118/0123-0078-jpt.
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_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 22348, “Scrutinizing Well Integrity for Determining Long-Term Fate of a CO2 Sequestration Project: An Improved and Rigorous Risk-Assessment Strategy,” by Parimal A. Patil, SPE, Asyraf M. Hamimi, and M. Azuan B. Abu Bakar, Petronas, et al. The paper has not been peer reviewed. Copyright 2022 International Petroleum Technology Conference. Reproduced by permission. _ Depleted hydrocarbon reservoirs are considered inherently safe for carbon sequestration, but a high density of wells penetrating the carbon dioxide (CO2) storage reservoir could compromise containment performance in a carbon capture and sequestration (CCS) project. A risk-management methodology can be incorporated to evaluate primary and secondary barriers in existing plugged and abandoned (P&A) and development wells to ensure long-term viability of CO2 sequestration projects. The complete paper evaluates well-integrity and CO2 leakage risks along the wells in a depleted field that penetrates the CO2 storage reservoir. Background The identified CO2 storage site offshore Malaysia is a depleted hydrocarbon field discovered in the early 1980s. Subsequently, two appraisal wells were drilled to further assess the field’s development potential. The structure is a north/south anticline with an aerial extent of approximately 35 km2 and a vertical closure of 100 m on top of the reservoirs. Eighteen major and minor gas-bearing reservoirs exist in the field. The hydrocarbons from deeply buried reservoirs were produced over a period of approximately 15 to 25 years through deviated wellbores. In total, 24 wells are in the targeted field; of these, three are abandoned exploration and appraisal wells and 21 are development wells drilled from the platform. All exploration and appraisal wells are P&A, while 21 development wells are still accessible from the platform. High uncertainties are associated with the P&A wells because the well sites were restored per a regulatory requirement in which the casings were cut below mudline and a surface cement plug was placed with no intention of re-entering these wells. Development wells, on the other hand, were assessed and screened for reuse by conversion into CO2 injectors. Understanding Well Integrity for CO2 Storage Potential leakages that may occur through various mechanisms during geological storage of CO2 in the storage field include failed caprock and trap integrity and leakage along existing wellbores. Parameters that could cause leakage of CO2 because of failed caprock include existing faults or fractures, reactivation of faults, development of new fractures during injection, and caprock failure caused by pressures exceeding fracture pressure during or after injection. The geological analysis of the depleted field for potential development as a future CO2 storage site must understand and mitigate associated risks by integrating information from various databases. However, the integrity of wells in the storage project must be ensured over very long time scales, in the thousands of years.
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Ashok Choppadandi. „Enhancing Customer Experience in E-Commerce Through AI-Powered Personalization: A Case Study“. Tuijin Jishu/Journal of Propulsion Technology 43, Nr. 4 (24.07.2023): 516–24. http://dx.doi.org/10.52783/tjjpt.v43.i4.6018.
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Aim: This study is intended to engage in the in-depth study of AI-enabled personalization tactics on the quality of customer experience as competition informs the e-commerce environment. The research employs a case study assessment of a prominent world-wide retailer with the primary aim of revealing the dominant influence of cutting-edge AI personalisation technology in actual applications. Methods: The study applied the mixed-methods research, which was made up of quantitative as well as qualitative research techniques such as sound data analysis and field research approaches to arrive at a comprehensive apprehension of the phenomenon. Data science system features such as studying key customer behaviour metrics, conversions, average order, customer value, and satisfaction, appreciate the company's case from superior data systems. The qualitative side of this study was indicated through the revelation of in-depth interviews that were done with a group of educated customers and an extensive online survey that was designed to capture their preferences, opinions, and perceptions in relation to the personalized shopping experience(Gao & Liu, 2022b). Results: The result shown a superlative boost in a lot of customer experience metrics, such as loyalty, proactivity, predictability, and automation, after the execution of the advanced AI personalization engine. What need to be prominently mentioned is an increase of conversion rate which saw a hike by 25% endorsing the fact that now, more customers on the site would complete their purchase process. Also, there was a remarkable 17% increase in the average order value, showing that personalized suggestions and tailor-made experiences had an impact on how customers would spend more per time they place an order. Customer’s life-time value (CLV) was extended by 12%. User stayed loyal and engaged for the longer time period. This probably was the most impressive outcome of the brand's satisfaction scores, as the jumps of them by 22% show the improvement of the customer experience overall. The analysis of qualitative data reveals that consumers experience genuine appreciation of the personalized shopping experience they get from being offered items that match their personal attributes such as the in-depth interpretations of customer likes and dislikes which the algorithm platform uses, quick discovery of products with minimal scrolling, saving of the time used in the search phase, and emotional closeness to freedom/ your identity, in the case of fashion (Raji et al., 2021). Conclusion: This comprehensive case study provides compelling evidence of the transformative potential of AI-powered personalization in enhancing customer experience within the e-commerce landscape. By leveraging advanced machine learning algorithms and vast customer data repositories, businesses can deliver highly tailored content, product recommendations, and optimized search results that resonate deeply with individual customer preferences and needs. The findings demonstrate that implementing AI personalization strategies can drive improved customer engagement, increased sales, and foster long-term loyalty, ultimately conferring a significant competitive advantage in the rapidly evolving e-commerce industry.