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Journal articles on the topic 'K-Fe catalysts'
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1
Xiang, Minglin, and Juan Zou. "CO Hydrogenation over Transition Metals (Fe, Co, or Ni) Modified K/Mo2C Catalysts." Journal of Catalysts 2013 (September 3, 2013): 1–5. http://dx.doi.org/10.1155/2013/195920.
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Transition metals (Fe, Co, or Ni) modified K/Mo2C catalysts were prepared and investigated as catalysts for CO hydrogenation. The addition of Fe, Co, or Ni to K/Mo2C catalyst led to a sharp increase in both the activity and selectivity of C2+OH, but the promotion effects were quite different and followed the sequence: Ni > Co > Fe for the activity and Fe > Co > Ni for the alcohol selectivity. For the products distributions, it also displayed some differences; Co promoter showed much higher C5+ hydrocarbon selectivity than Fe or Ni promoter, but Fe or Co promoter gave lower methane selectivity than Ni promoter, and Fe promoter showed the highest C2=-C4= selectivity.
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Aluha, James, Stéphane Gutierrez, François Gitzhofer, and Nicolas Abatzoglou. "Use of Plasma-Synthesized Nano-Catalysts for CO Hydrogenation in Low-Temperature Fischer–Tropsch Synthesis: Effect of Catalyst Pre-Treatment." Nanomaterials 8, no. 10 (October 12, 2018): 822. http://dx.doi.org/10.3390/nano8100822.
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A study was done on the effect of temperature and catalyst pre-treatment on CO hydrogenation over plasma-synthesized catalysts during the Fischer–Tropsch synthesis (FTS). Nanometric Co/C, Fe/C, and 50%Co-50%Fe/C catalysts with BET specific surface area of ~80 m2 g–1 were tested at a 2 MPa pressure and a gas hourly space velocity (GHSV) of 2000 cm3 h−1 g−1 of a catalyst (at STP) in hydrogen-rich FTS feed gas (H2:CO = 2.2). After pre-treatment in both H2 and CO, transmission electron microscopy (TEM) showed that the used catalysts shifted from a mono-modal particle-size distribution (mean ~11 nm) to a multi-modal distribution with a substantial increase in the smaller nanoparticles (~5 nm), which was statistically significant. Further characterization was conducted by scanning electron microscopy (SEM with EDX elemental mapping), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The average CO conversion at 500 K was 18% (Co/C), 17% (Fe/C), and 16% (Co-Fe/C); 46%, 37%, and 57% at 520 K; and 85%, 86% and 71% at 540 K respectively. The selectivity of Co/C for C5+ was ~98% with 8% gasoline, 61%, diesel and 28% wax (fractions) at 500 K; 22% gasoline, 50% diesel, and 19% wax at 520 K; and 24% gasoline, 34% diesel, and 11% wax at 540 K, besides CO2 and CH4 as by-products. Fe-containing catalysts manifested similar trends, with a poor conformity to the Anderson–Schulz–Flory (ASF) product distribution.
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Kim, ChoHwe, and YoungChul Kim. "Promotional Effect of Iron on Nickel-Based Catalyst for Combined Steam-Carbon Dioxide Reformation of Methane." Journal of Nanoscience and Nanotechnology 20, no. 9 (September 1, 2020): 5506–9. http://dx.doi.org/10.1166/jnn.2020.17632.
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In this study, the effect by Iron with nickel-based catalyst for the combined steam and carbon dioxide reforming of methane was investigated. Fe-promoted and un-promoted Ni–Mg–Ce/γ-Al2O3 catalysts were prepared by co-impregnation and evaluated in a quartz fixed-bed reactor at H2O:CO2:CH4 ratios of 0.9:1:1 and a temperature of 1073 K under atmospheric pressure. The physicochemical properties of the catalysts were investigated by N2 adsorption–desorption, XRD, H2-TPR, CO2-TPD, TGA and FE-SEM. The iron-supported catalysts showed improved resistance to carbon deposition and suppressed sintering of nickel. As a result, NMC-Fe(5) showed the lowest coke and high stability over 70 h among all other catalysts.
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Ribeiro, Mirtha Z. Leguizamón León, Joice C. Souza, Muthu Kumaran Gnanamani, Michela Martinelli, Gabriel F. Upton, Gary Jacobs, and Mauro C. Ribeiro. "Fischer–Tropsch Synthesis: Effect of the Promoter’s Ionic Charge and Valence Level Energy on Activity." Reactions 2, no. 4 (October 10, 2021): 408–26. http://dx.doi.org/10.3390/reactions2040026.
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In this contribution, we examine the effect of the promoter´s ionic charge and valence orbital energy on the catalytic activity of Fe-based catalysts, based on in situ synchrotron X-ray powder diffraction (SXRPD), temperature-programmed-based techniques (TPR, TPD, CO-TP carburization), and Fischer–Tropsch synthesis catalytic testing studies. We compared the promoting effects of K (a known promoter for longer-chained products) with Ba, which has a similar ionic radius but has double the ionic charge. Despite being partially “buried” in a crystalline BaCO3 phase, the carburization of the Ba-promoted catalyst was more effective than that of K; this was primarily due to its higher (2+) ionic charge. With Ba2+, higher selectivity to methane and lighter products were obtained compared to the K-promoted catalysts; this is likely due to Ba´s lesser capability of suppressing H adsorption on the catalyst surface. An explanation is provided in terms of a more limited mixing between electron-filled Ba2+ 5p and partially filled Fe 3d orbitals, which are expected to be important for the chemical promotion, as they are further apart in energy compared to the K+ 3p and Fe 3d orbitals.
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Gujjar, Soumya J., Avinashkumar V. Karre, Alaa Kababji, and Dady B. Dadyburjor. "Effect of Changing Amounts of Promoters and Base Fe Metal in a Multicomponent Catalyst Supported on Coal-Based Activated Carbon for Fischer–Tropsch Synthesis." Reactions 2, no. 1 (February 1, 2021): 11–29. http://dx.doi.org/10.3390/reactions2010003.
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The effect of varying the amounts of metals Fe, Cu, K, and Mo was studied on a catalyst supported on activated carbon (AC), which is an item of novelty of this paper. The base-case catalyst contains 16% Fe, 0.9% K, 6% Mo, and 0.8% Cu relative to the AC support. For all of the catalysts used, alcohol production is small. The production of hydrocarbons depends upon the amount of Fe and other promoters used. The amount of Fe was increased from 0% to 32% on the catalyst containing base-case amounts of the other materials. While 0% Fe shows no activity towards Fischer–Tropsch synthesis (FTS), 32% Fe shows a marginal increase in FTS activity when compared with 16% Fe. Furthermore, the amount of K was increased from 0% to 1.8%, with the other metals in their base-case amounts. The selectivity of C1–C4 decreases with the addition of K, while the selectivity of C5+ increases. Analogously, the amount of Mo was increased from 0% to 12%. A small amount of Mo results in an increase in FTS activity but decreases with the addition of more Mo. Cu on the catalyst was increased from 0% to 1.6%, with 0.8% Cu proving optimum for FTS.
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Ku, YuPing, Konrad Ehelebe, Markus Bierling, Florian Dominik Speck, Dominik Seeberger, Karl J. J. Mayrhofer, Simon Thiele, and Serhiy Cherevko. "The Interplay of Oxygen Reduction Reaction and Iron Dissolution from Fe-N-C Electrocatalysts." ECS Meeting Abstracts MA2022-01, no. 35 (July 7, 2022): 1486. http://dx.doi.org/10.1149/ma2022-01351486mtgabs.
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Fe-N-C catalysts are regularly proposed as promising earth-abundant and cheap catalysts replacing platinum group metal catalysts for fuel cells (FCs). Besides the activity, especially the stability of those materials remains challenging. It was found that the electrochemical activity and durability of Fe-N-C catalysts are superior in alkaline compared to acidic media, [1-3] yet most of their degradation studies are done in acidic media. [4-9] Moreover, although these are systematic works, discrepancies in these results from aqueous model systems (AMS) [5,6] and FC testing [7-9] remain puzzling. For example, the origin of the dissolved Fe species was found to be from poorly active sites in AMS [5] yet from highly active sites in operating FCs. [7,8] Additionally, the harmful effects of reactive oxygen species (ROS) on Fe-N-C catalysts are proven in AMS [6] but not directly correlated to the durability in FCs. [9] To bridge this gap, a gas diffusion electrode (GDE) half-cell coupled with inductively coupled plasma mass spectrometry (ICP-MS) has been developed to study on-line dissolution in realistic catalyst layers. [10] In this work, using a GDE-ICP-MS, we investigate the impacts of oxygen reduction reaction (ORR) on Fe leaching from realistic Fe-N-C alkaline catalyst layers. [11] For the first time, Fe dissolution is measured online at current densities above -100 mA·cm-2. The novel results show that compared to the model Ar-saturated environment, the Fe dissolution is dramatically higher during ORR. Furthermore, between 0.6 and 1.0 VRHE, we unveil an interesting correlation between Fe dissolution and charge transfer events. This subsequently leads to our hypothesis that the instability of the coordinated Fe during Fe3+/Fe2+ redox transitions is responsible for Fe leaching from Fe-N-C catalysts in alkaline media in this potential region. The novel insights into Fe-N-C catalyst degradation in realistic conditions can lead to rational design of this promising platinum group metal free catalyst for efficient, durable, and affordable FCs. References: [1] Santori, P. G. et al. Effect of pyrolysis atmosphere and electrolyte pH on the oxygen reduction activity, stability and spectroscopic signature of FeNx moieties in Fe-N-C catalysts. J. Electrochem. Soc. 2019, 166: F3311. [2] Holby, E. F. et al. Acid stability and demetalation of PGM-Free ORR electrocatalyst structures from density functional theory: a model for “single-atom catalyst” dissolution. ACS Catal. 2020, 10: 14527-14539. [3] Bae, G. et al. PH effect on the H2O2-induced deactivation of Fe-N-C catalysts. ACS Catal. 2020, 10: 8485-8495. [4] Kumar, K. et al. On the influence of oxygen on the degradation of Fe‐N‐C catalysts. Angew. Chem. 2020, 132: 3261-3269. [5] Choi, C. H. et al. Stability of Fe‐N‐C catalysts in acidic medium studied by operando spectroscopy. Angew. Chem. Int. Ed. 2015, 54: 12753-12757. [6] Choi, C. H. et al. The Achilles' heel of iron-based catalysts during oxygen reduction in an acidic medium. Energy Environ. Sci. 2018, 11: 3176-3182. [7] Li, J. et al. Identification of durable and non-durable FeNx sites in Fe–N–C materials for proton exchange membrane fuel cells. Nat. Catal. 2021, 4: 10-19. [8] Chenitz, R. et al. A specific demetalation of Fe–N4 catalytic sites in the micropores of NC_Ar + NH3 is at the origin of the initial activity loss of the highly active Fe/N/C catalyst used for the reduction of oxygen in PEM fuel cells. Energy Environ. Sci. 2018, 11: 365-382. [9] Zhang, Gaixia, et al. Is iron involved in the lack of stability of Fe/N/C electrocatalysts used to reduce oxygen at the cathode of PEM fuel cells? Nano Energy, 2016, 29: 111-125. [10] Ehelebe, K. et al. Platinum dissolution in realistic fuel cell catalyst layers. Angew. Chem. Int. Ed. 2021, 60: 8882-8888. [11] Ku, Y.-P. et al. Oxygen reduction reaction causes iron leaching from Fe-N-C electrocatalysts. 2021 Submitted, DOI: 10.21203/rs.3.rs-1171081/v1.
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Calizzi, Marco, Robin Mutschler, Nicola Patelli, Andrea Migliori, Kun Zhao, Luca Pasquini, and Andreas Züttel. "CO2 Hydrogenation over Unsupported Fe-Co Nanoalloy Catalysts." Nanomaterials 10, no. 7 (July 11, 2020): 1360. http://dx.doi.org/10.3390/nano10071360.
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The thermo-catalytic synthesis of hydrocarbons from CO2 and H2 is of great interest for the conversion of CO2 into valuable chemicals and fuels. In this work, we aim to contribute to the fundamental understanding of the effect of alloying on the reaction yield and selectivity to a specific product. For this purpose, Fe-Co alloy nanoparticles (nanoalloys) with 30, 50 and 76 wt% Co content are synthesized via the Inert Gas Condensation method. The nanoalloys show a uniform composition and a size distribution between 10 and 25 nm, determined by means of X-ray diffraction and electron microscopy. The catalytic activity for CO2 hydrogenation is investigated in a plug flow reactor coupled with a mass spectrometer, carrying out the reaction as a function of temperature (393–823 K) at ambient pressure. The Fe-Co nanoalloys prove to be more active and more selective to CO than elemental Fe and Co nanoparticles prepared by the same method. Furthermore, the Fe-Co nanoalloys catalyze the formation of C2-C5 hydrocarbon products, while Co and Fe nanoparticles yield only CH4 and CO, respectively. We explain this synergistic effect by the simultaneous variation in CO2 binding energy and decomposition barrier as the Fe/Co ratio in the nanoalloy changes. With increasing Fe content, increased activation temperatures for the formation of CH4 (from 440 K to 560 K) and C2-C5 hydrocarbons (from 460 K to 560 K) are observed.
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Fidelis, Michel, Eduardo Abreu, Onélia Dos Santos, Eduardo Chaves, Rodrigo Brackmann, Daniele Dias, and Giane Lenzi. "Experimental Design and Optimization of Triclosan and 2.8-Diclorodibenzeno-p-dioxina Degradation by the Fe/Nb2O5/UV System." Catalysts 9, no. 4 (April 8, 2019): 343. http://dx.doi.org/10.3390/catal9040343.
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This study describes the experimental design and optimization of the photocatalytic reaction using the immobilized catalyst Fe/Nb2O5 in the degradation of Triclosan and 2.8-DCDD. The techniques employed to characterize the photocatalysts were: specific surface area, average pore volume, average pore diameter, photo-acoustic spectroscopy (PAS), X-ray diffraction (XRD), and scanning electron microscopy (SEM/EDS). The reaction parameters studied were pH, catalyst concentration, catalyst calcination temperature, and nominal metallic charge. The results indicated that the immobilized Fe/Nb2O5 catalysts were efficient in the degradation of Triclosan and 2.8-dichlorodibenzene-p-dioxin. The catalysts with nominal metal loading of 1.5% Fe calcined at 873 K showed the highest constant reaction rate and the lowest half-life 0.069 min−1 and 10.04 min. Tests in different matrices indicated that the photocatalytic reaction using aqueous solution containing Cl− is faster when compared with the ultrapure water matrix.
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Nam, Sang-Sung, Gurram Kishan, Myung-Woo Lee, Myoung-Jae Choi, and Kyu-Wan Lee. "Selective Synthesis of C2–C4 Olefins and C5+ Hydrocarbons over Unpromoted and Cerium-promoted Iron Catalysts Supported on Ion Exchanged (H, K) Zeolite-Y." Journal of Chemical Research 23, no. 5 (May 1999): 344–45. http://dx.doi.org/10.1177/174751989902300524.
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Hydrogenation of CO2 to hydrocarbons is carried out on unpromoted and Ce-promoted iron catalysts supported on ion exchanged (H, K) zeolite-Y; the results suggest that the Fe–Ce/KY catalyst has significant advantages being highly selective for C2–C4 olefins and C5+ hydrocarbons.
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Cai, Binxiang, Huazhang Liu, and Wenfeng Han. "Solution Combustion Synthesis of Fe2O3-Based Catalyst for Ammonia Synthesis." Catalysts 10, no. 9 (September 7, 2020): 1027. http://dx.doi.org/10.3390/catal10091027.
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Fe2O3-based catalysts were prepared by solution combustion synthesis (SCS) with metal nitrates (Fe, K, Al, Ca) as the precursors and glycine as the fuel. The activities of catalysts were evaluated in terms of ammonia synthesis reaction rate in a fixed bed reactor similar to the industrial reactors. The results indicate that the precursor of catalyst prepared by SCS is Fe2O3 which facilitates the high dispersion of promoters to provide high activity. The catalysts exhibit higher activity for ammonia synthesis than that of traditional catalysts, and the reaction rate reaches 138.5 mmol g−1 h−1. Fe2O3 prepared by SCS could be favorable precursor for ammonia synthesis catalyst. The present study provides a pathway to prepare catalyst for ammonia synthesis.
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Liu, Yuanchao, Eamonn Murphy, Divija Nitin Mamania, Kaustubh Khedekar, Tristan Asset, Frederic Jaouen, Iryna V. Zenyuk, and Plamen Atanassov. "(Invited) Impact of Pore Morphology and Surface Hydrophobicity of the Carbon Matrix on the Macrokinetics of the Oxygen Reduction Reaction Performance for Atomically Dispersed Fe-N-C Catalysts." ECS Meeting Abstracts MA2022-01, no. 7 (July 7, 2022): 633. http://dx.doi.org/10.1149/ma2022-017633mtgabs.
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Atomically dispersed transition metal catalysts are an important family of non-precious metal electrocatalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells. The iron-nitrogen-carbon (Fe-N-C) catalyst, wherein the iron metal centers are coordinated by nitrogen atoms (FeNx) on carbonaceous supports, exhibits outstanding ORR activity in both rotating disk electrode (RDE) and membrane electrode assembly (MEA) configurations.[1] The pore structure[2] and surface hydrophobicity[3] of the carbon matrix are of particular significance to the MEA performance, where the high current throughput requires good mass transport capability and controlled water flooding on the electrodes. In this work, we employed two widely used Fe-N-C catalysts – one pyrolyzed from metal organic framework (MOF-derived)[4] and the other produced by using the sacrificial support method (sacrificial templated)[1]. Specifically, nitrogen physisorption and water vapor physisorption were used to study the pore morphology and the specific surface hydrophobicity, respectively. As shown in Figure 1, the sacrificial templated Fe-N-C catalyst showed a significant mesoporosity as compared to the MOF-derived counterpart, while its surface was much more hydrophobic, as indicated by the less water uptake through whole pressure range (Figure 1f). Such difference of carbon morphology was further correlated to their macrokinetic performance in a MEA configuration, to reveal the impact of the morphological and hydrophilic/hydrophobic balance on these two types of Fe-N-C catalysts. Reference [1] T. Asset and P. Atanassov, Joule, 2020, 4, 33. [2] Y. Huang, Y. Chen, M. Xu, T. Asset, P. Tieu, A. Gili, D. Kulkarni, V. de Andrade, F. de Carlo, H. S. Barnard, A. Doran, D. Y. Parkinson, X. Pan, P. Atanassov, and I. Zenyuk, Materials Today, 2021, 47, 53. [3] L. Liu, S. J. Tan, T. Horikawa, D. D. Do, D. Nicholson and J. Liu, Adv Colloid Interface Sci, 2017, 250, 64. [4] K. Kumar, T. Asset, X. Li, Y. Liu, X. Yan, Y. Chen, M. Mermoux, X. Pan, P. Atanassov, F. Maillard and L. Dubau, ACS Catalysis, 11, 484. Figure 1. XRD (a) and AC-STEM (b-d) images of the Fe-N-C catalyst produced by the sacrificial support method. Nitrogen (e) and water vapor (f) physisorption isotherms of MOF-derived and sacrificial templated Fe-N-C catalysts. (g) Pore size distribution of the two catalysts by the BJH method based on the N2 adsorption branch. Figure 1
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van den Berg, F. R., M. W. J. Crajé, A. M. van der Kraan, and J. W. Geus. "Reduction behaviour of Fe/ZrO2 and Fe/K/ZrO2 Fischer–Tropsch catalysts." Applied Catalysis A: General 242, no. 2 (March 2003): 403–16. http://dx.doi.org/10.1016/s0926-860x(02)00532-x.
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Sánchez-López, Perla, Yulia Kotolevich, Evgeny Khramov, Ramesh Kumar Chowdari, Miguel Angel Estrada, Gloria Berlier, Yan Zubavichus, Sergio Fuentes, Vitalii Petranovskii, and Fernando Chávez-Rivas. "Properties of Iron-Modified-by-Silver Supported on Mordenite as Catalysts for NOx Reduction." Catalysts 10, no. 10 (October 9, 2020): 1156. http://dx.doi.org/10.3390/catal10101156.
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A series of mono and bimetallic catalysts based on a Fe-Ag mixture deposited on mordenite was prepared by ion-exchange and evaluated in the catalytic activity test of the de-NOx reaction in the presence of CO/C3H6. The activity results showed that the most active samples were the Fe-containing ones, and at high temperatures, a co-promoter effect of Ag on the activity of Fe catalysts was also observed. The influence of the order of cation deposition on catalysts formation and their physicochemical properties was studied by FTIR (Fourier Transform Infrared Spectroscopy) of adsorbed NO, XANES (X-ray Absorption Near-Edge Structure), and EXAFS (Extended X-ray Absorption Fine Structure) and discussed in terms of the state of iron. Results of Fe K-edge XANES oscillations showed that, in FeMOR catalysts, iron was present in a disordered state as Fe3+ and Fe2+. In FeAgMOR, the prevailing species was Fe3+, while in the AgFeMOR catalyst, the state of iron was intermediate or mixed between FeMOR and FeAgMOR. The Fe K-edge EXAFS results were characteristic of a disordered phase, the first coordination sphere being asymmetric with two different Fe-O distances. In FeAgMOR and AgFeMOR, coordination of Fe-O was similar to Fe2O3 with a few amount of Fe2+ species. We may conclude that, in the bimetallic FeAgMOR and AgFeMOR samples, a certain amount of tetrahedral Al3+ ions in the mordenite framework is replaced by Fe3+ ions, confirming the previous reports that these species are active sites for the de-NOx reaction. Based on the thermodynamic analysis and experimental data, also, it was confirmed that the order of deposition of the components influenced the mechanism of active sites’ formation during the two steps ion-exchange synthesis.
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Stoyanova, Maria, and Stoyanka Christoskova. "Novel Ni−Fe-oxide systems for catalytic oxidation of cyanide in an aqueous phase." Open Chemistry 3, no. 2 (June 1, 2005): 295–310. http://dx.doi.org/10.2478/bf02475998.
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AbstractCatalytic activity of mixed Ni−Fe oxide systems with respect to air oxidation of aqueous cyanide solution at 308 K was investigated. The catalysts employed were prepared by an oxidation-precipitation method at room temperature and were characterized by powder X-ray diffraction (XRD), Mössbauer spectroscopy, and chemical analysis. The cyanide oxidation rate was found to be dependent on the catalyst's calcination temperature, pH of the medium, and catalyst loading. Results revealed that the catalyst calcined at 120°C is the most active where up to 90% of free cyanide (4 mM) was removed after oxidation for 30 minutes in the presence of 2.5 g/L catalyst at pH 9.5. The cyanide conversion becomes less favorable as the pH of the solution increases (with other constant parameters). The selectivity data showed that carbon dioxide is the main oxidation product, regardless of pH of the solution.
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Su, Chun Yan, Jian Qun Tan, and Cheng Xue Wang. "Study on CO2 Hydrogenation to Ethylene with Iron-Based Catalyst." Advanced Materials Research 791-793 (September 2013): 112–15. http://dx.doi.org/10.4028/www.scientific.net/amr.791-793.112.
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Carbon dioxide hydrogenation to ethylene was investigated on Fe-Cu-K-Ce loading catalysts. These catalysts were prepared by impregnation method, and studied on the CO2conversion and the selectivity of ethylene. The proper carrier was obtained comparing with their catalytic activity. The loading contents of active components on carriers and reaction conditions were studied. Results show that the MgO-ZSM-5 are the best carrier, the content of Fe at 15% and the molar ratio of Fe: Cu: K: Ce with 100: 20: 8: 8 is better under the condition of reaction temperature and reaction pressure are 623K and 1.0Mpa respectively with CO2conversion of more than 60% and the selectivity of ethylene of more than 20%. The catalysts were characterized by CO2temperature-programmed desorption (CO2-TPD).
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Shahroudbari, Isa, Yaghoub Sarrafi, and Yahya Zamani. "Study of carbon dioxide hydrogenation to hydrocarbons over iron-based Catalysts: Synergistic effect." Kataliz v promyshlennosti 21, no. 3 (May 17, 2021): 182. http://dx.doi.org/10.18412/1816-0387-2021-3-182.
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The full article will be published in the English version of the journal "Catalysis in Industry" No. 4, 2021.Hydrogenation of CO2 to CO and hydrocarbons is carried out over a wide range of catalysts. Group of VIIIB transition metals have proved high conversion and selectively for CO and methane. Meanwhile, low cost and effective catalysts are preferable in an industrial scale. In this work, the synergistic effect of iron content on the catalytic performance were investigated in carbon dioxide hydrogenation reaction. Incipient wetness impregnation procedure was used for the preparation of four γ-Al2O3 supported iron-based catalysts. BET, XRD, H2-TPR and TEM techniques were employed for the catalyst characterization. The evaluation of catalysts were carried out in a fixed bed reactor at the process conditions of temperature of 300 °C, pressure of 20 atm, H2 to CO2 ratio of 3 and GHSV of 3 nl.h–1·gCat–1. It was found that the promoter addition improves the activity of Fe catalyst for both Fischer – Tropsch synthesis (FTS) and Reverse Water Gas Shift (RWGS) reactions. The results showed that conversion of CO2 was from 15.6 to 35.6 % with major products of methane, C2 to C4, C5+ and CO. It was also found that impact of K and Ce promoters into iron catalyst showed the highest conversion and hydrocarbon yield due to the synergistic effect.
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Lin, Quan, Meng Cheng, Kui Zhang, Weizhen Li, Peng Wu, Hai Chang, Yijun Lv, and Zhuowu Men. "Development of an Iron-Based Fischer—Tropsch Catalyst with High Attrition Resistance and Stability for Industrial Application." Catalysts 11, no. 8 (July 27, 2021): 908. http://dx.doi.org/10.3390/catal11080908.
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In order to develop an iron-based catalyst with high attrition resistance and stability for Fischer–Tropsch synthesis (FTS), a series of experiments were carried out to investigate the effects of SiO2 and its hydroxyl content and a boron promoter on the attrition resistance and catalytic behavior of spray-dried precipitated Fe/Cu/K/SiO2 catalysts. The catalysts were characterized by means of N2 physisorption, nuclear magnetic resonance (NMR), X-ray diffraction (XRD), Raman spectrum, X-ray photoelectron spectroscopy (XPS), H2-thermogravimetric analysis (H2-TGA), temperature-programmed reduction and hydrogenation (TPR and TPH), and scanning and transmission electron microscopy (SEM and TEM). The FTS performance of the catalysts was tested in a slurry-phase continuously stirred tank reactor (CSTR), while the attrition resistance study included a physical test with the standard method and a chemical attrition test under simulated reaction conditions. The results indicated that the increase in SiO2 content enhances catalysts’ attrition resistance and FTS stability, but decreases activity due to the suppression of further reduction of the catalysts. Moreover, the attrition resistance of the catalysts with the same silica content was greatly improved with an increase in hydroxyl number within silica sources, as well as the FTS activity and stability to some degree. Furthermore, the boron element was found to show remarkable promotion of FTS stability, and the promotion mechanism was discussed with regard to probable interactions between Fe and B, K and B, and SiO2 and B, etc. An optimized catalyst based on the results of this study was finalized, scaled up, and successfully applied in a megaton industrial slurry bubble FTS unit, exhibiting excellent FTS performance.
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Elsaesser, Patrick, Philipp Veh, Severin Vierrath, Matthias Breitwieser, and Anna Fischer. "MOF-Derived Fe-Zn-N-C Catalysts for Precious Metal Free Cathodes Showing High Performance in Anion-Exchange Membrane Fuel Cells." ECS Meeting Abstracts MA2022-01, no. 35 (July 7, 2022): 1482. http://dx.doi.org/10.1149/ma2022-01351482mtgabs.
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Hydrogen technologies such as low-temperature fuel cells are, besides batteries, the most promising technologies for mobility and transport applications. Currently, Proton Exchange Membrane Fuel Cells (PEMFCs) are, in terms of low-temperature fuel cells, the state-of-the-art technology achieving high power densities and reasonable stabilities. With the recent development and increasing availability of stable and performant hydroxide conductive ionomers, Anion Exchange Membrane Fuel Cells (AEMFCs) have gained increasing interest in recent years as they combine the advantages of PEMFCs, like low-temperature operation and high-power density with the low component costs of alkaline fuel cells.1,2 Especially the possibility of replacing the expensive Pt-based electrocatalysts used in PEMFCs with cheaper electrocatalysts like nickel-based materials for the anode and iron-based materials for the cathode could significantly decrease the fuel cell costs.1,3,4 Although the oxygen reduction reaction (ORR) at the cathode is favored in alkaline media compared to acidic media, the ORR is still a challenging reaction in AEMFCs.5,6 Over the last decades, various materials were investigated in order to replace the expensive Pt electrocatalysts at the cathode. Among these materials, iron- and nitrogen-doped carbons (Fe-N-C) with molecular iron sites (Fe-Nx) show comparable catalytic activities to Pt and decent stabilities.7–9 Fe-N-C catalysts can be obtained by co-pyrolysis of Fe- N-, and C-sources and subsequential acid leaching. One way to achieve Fe-N-C catalysts with high dispersion of Fe-Nx sites is by using Fe-doped metal-organic frameworks (Fe-MOFs) as precursors. These combine the presence of pre-coordinated Fe-Nx motives as well as high porosity and high specific surface area.10 To produce Fe-N-C catalysts, we synthesized Fe-, and Zn-doped MOFs (Fe-Zn-MOF) as multicomponent Fe-, Zn-, N-, and C-precursors and pyrolyzed them in the presence of additional nitrogen sources at high temperatures. The resulting Fe-Zn-N-C catalysts revealed high dispersion of Fe and Zn, high specific surface areas (400-600 m2/g), and high porosity as revealed by XRD, EDX, HAADF STEM, and N2 physisorption. Depending on the pre-treatment of the Fe-Zn-MOF, the Fe content of the resulting Fe-N-C catalyst could be varied. Benefiting from the high Fe-dispersion and the high specific surface areas, the best performing Fe-Zn-N-C catalyst with high Fe content shows high activity towards the ORR in alkaline media (0.1 mol/L KOH) as demonstrated by RDE measurements featuring a high half-wave potential (0.87 V vs. RHE) and high mass activity (47 mA/mgcat) and thereby outperforming a commercial 50 wt.% Pt/C catalyst in terms of half-wave potential (0.83 V vs. RHE). To investigate the performance of the Fe-Zn-N-C catalysts in AEMFCs, membrane electrode assemblies (MEAs) were prepared with the synthesized Fe-Zn-N-C catalysts at the cathode, a commercial PtRu/C catalyst (40 wt.% Pt, 20 wt.% Ru on carbon black, AlfaAesar) at the anode, and a commercial ionomer as membrane and catalyst layer ionomer. The AEMFC with the best performing Fe-Zn-N-C catalyst revealed a high peak power density of 850 mW/cm², which is among the highest reported peak power densities for non-precious metal cathode catalysts in combination with a commercially available anion exchange ionomer. 1 D. R. Dekel, J. Power Sources, 2018, 375, 158–169. 2 R. O’Hayre, S.-W. Cha, W. Colella and F. B. Prinz, Fuel Cell Fundamentals, John Wiley & Sons, Inc, Hoboken, NJ, USA, 2016. 3 X. Ge, A. Sumboja, D. Wuu, T. An, B. Li, F. W. T. Goh, T. S. A. Hor, Y. Zong and Z. Liu, ACS Catal., 2015, 5, 4643–4667. 4 E. S. Davydova, S. Mukerjee, F. Jaouen and D. R. Dekel, ACS Catal., 2018, 8, 6665–6690. 5 M. Hren, M. Božič, D. Fakin, K. S. Kleinschek and S. Gorgieva, Sustain. Energy Fuels, 2021, 5, 604–637. 6 N. Ramaswamy and S. Mukerjee, Adv. Phys. Chem., 2012, 2012, 1–17. 7 X. Ren, B. Liu, X. Liang, Y. Wang, Q. Lv and A. Liu, J. Electrochem. Soc., 2021, 168, 044521. 8 L. Osmieri, L. Pezzolato and S. Specchia, Curr. Opin. Electrochem., 2018, 9, 240–256. 9 M. M. Hossen, K. Artyushkova, P. Atanassov and A. Serov, J. Power Sources, 2018, 375, 214–221. 10 C. Li, D. H. Zhao, H. L. Long and M. Li, Rare Met., 2021, 40, 2657–2689.
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Loiland, Jason A., Matthew J. Wulfers, Nebojsa S. Marinkovic, and Raul F. Lobo. "Fe/γ-Al2O3 and Fe–K/γ-Al2O3 as reverse water-gas shift catalysts." Catalysis Science & Technology 6, no. 14 (2016): 5267–79. http://dx.doi.org/10.1039/c5cy02111a.
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Wang, Tao Tao, Xian Yong Wei, Jian Jun Zhao, Xing Zhen Qi, and Zhi Min Zong. "Effect of Microwave on Iron Potassium Catalyst Fischer-Tropsch Synthesis." Advanced Materials Research 236-238 (May 2011): 795–98. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.795.
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Fe-K/SiO2 catalysts were prepared by microwave irradiation or by the steep and calcine conventional method. They were then tested by analyzing the products on-line with a gas chromatograph (GC 508) equipped with thermal conductivity detector (TCD) and in-series of packed columns Porapak-Q. The structure and morphology of the catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) as well as N2 physisorption with the BET method. The result show that microwave radiation of the catalyst led to an increase in the surface area, mesopores pore volume, the catalyst proved to have more reaction activity than that prepared by conventional method.
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Takagiwa, Shota, Osamu Kanasugi, Kentaro Nakamura, and Masahito Kushida. "Synthesis of Vertically-Aligned Carbon Nanotubes from Langmuir-Blodgett Films Deposited Fe Nanoparticles on Al2O3/Al/SiO2/Si Substrate." Journal of Nanoscience and Nanotechnology 16, no. 4 (April 1, 2016): 3289–94. http://dx.doi.org/10.1166/jnn.2016.12312.
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In order to apply vertically-aligned carbon nanotubes (VA-CNTs) to a new Pt supporting material of polymer electrolyte fuel cell (PEFC), number density and outer diameter of CNTs must be controlled independently. So, we employed Langmuir-Blodgett (LB) technique for depositing CNT growth catalysts. A Fe nanoparticle (NP) was used as a CNT growth catalyst. In this study, we tried to thicken VA-CNT carpet height and inhibit thermal aggregation of Fe NPs by using Al2O3/Al/SiO2/Si substrate. Fe NP LB films were deposited on three typed of substrates, SiO2/Si, as-deposited Al2O3/Al/SiO2/Si and annealed Al2O3/Al/SiO2/Si at 923 K in Ar atmosphere of 16 Pa. It is known that Al2O3/Al catalyzes hydrocarbon reforming, inhibits thermal aggregation of CNT growth catalysts and reduces CNT growth catalysts. It was found that annealed Al2O3/Al/SiO2/Si exerted three effects more strongly than as-deposited Al2O3/Al/SiO2/Si. VA-CNTs were synthesized from Fe NPs-C16 LB films by thermal chemical vapor deposition (CVD) method. As a result, at the distance between two nearest CNTs 28 nm or less, VA-CNT carpet height on annealed Al2O3/Al/SiO2/Si was about twice and ten times thicker than that on SiO2/Si and that on as-deposited Al2O3/Al/SiO2/Si, respectively. Moreover, distribution of CNT outer diameter on annealed Al2O3/Al/SiO2/Si was inhibited compared to that on SiO2/Si. These results suggest that since thermal aggregation of Fe NPs is inhibited, catalyst activity increases and distribution of Fe NP size is inhibited.
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Khattab, Mohammed A., Heba A. El-Deeb, and Azza El-Maghraby. "Influence of the Catalyst Supporting Material on the Growth of Carbon Nanotubes." Advanced Materials Research 1163 (April 2021): 117–27. http://dx.doi.org/10.4028/www.scientific.net/amr.1163.117.
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Catalytic chemical vapor deposition (CCVD) is considered as the most suitable technique for the large scale and low-cost production of carbon nanotubes (CNTs). Catalytic activity of Fe-Co, Fe-Ni and Co-Ni mixture supported on Al2O3 has been investigated in the production of carbon nanotubes (CNTs). Absolute ethanol was used as a source of carbon and nitrogen as the carrier gas. The Carbon nanotubes prepared by the catalytic decomposition of ethanol at 1173°K over iron supported alumina or silica catalysts with 5Wt% iron loading in a horizontal tube furnace under flow of nitrogen. The morphological structure of deposits CNTs were investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that the alumina supported catalysts more active towards CNTs formation than silica supported catalysts even with changing the percentage of metal loading (2.5% - 10%). Further investigation for alumina support with other metals and their binary metals heve been done to see for how far the alumina is suitable as a support. The yield of the carbon deposit obtained varied from 11.2 to 34.9% of the initial weight of the catalyst. The results revealed that CNTs prepared by Fe-Ni/Al2O3 catalyst has high length/diameter ratio and small tube diameter ≈ 17 nm.
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Möller, P., and H. Papp. "Heats of Adsorption and Reaction of CO on Iron/Manganese Oxide Catalysts." Adsorption Science & Technology 4, no. 3 (September 1987): 176–84. http://dx.doi.org/10.1177/026361748700400303.
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The heats of adsorption and reaction of CO have been measured on reduced Fe/Mn oxide catalysts of different compositions at temperatures between 263 and 543 K. The heats of adsorption depend only to a small extent on the manganese content of the catalyst and are independent of the temperature of reduction. The former fact points to a more structural than electronic effect of the manganese oxide addition. The heats of adsorption are, however, strongly dependent on measurement temperature, increasing from about 60 kJ mol-1 at 263 K to about 200 kJ mol-1 at 493 K and then decreasing again to about 180 kJ mol-1 at 543 K. This temperature dependence can be explained by consecutive reactions following CO adsorption, i.e. the Boudouard reaction, dissociation of CO and diffusion of carbon into the bulk of iron. The amount of CO adsorbed is correlated to the metallic iron content in the surfaces of the catalysts.
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Wang, Xiaoping, Magali Ferrandon, Jaehyung Park, Evan C. Wegener, A. Jeremy Kropf, and Deborah J. Myers. "Optimization of Synthesis Variables Towards Improved Activity and Stability of Fe-N-C PGM-Free Catalysts." ECS Meeting Abstracts MA2022-01, no. 35 (July 7, 2022): 1447. http://dx.doi.org/10.1149/ma2022-01351447mtgabs.
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Materials in the Fe-N-C family are the most promising platinum group metal-free (PGM-free) catalysts for the oxygen reduction reaction (ORR) in polymer electrolyte fuel cells (PEFCs).1-3 Although significant progress has been made in recent years in improving both the ORR activity and durability of the Fe-N-C catalysts, further improvements are needed, especially in long-term performance durability in hydrogen-air PEFCs, to enable their use in applications such as propulsion power for light-duty vehicles.3 The most active ORR catalysts in the Fe-N-C family were synthesized by heat treating iron salts or other iron-containing compounds with zinc-based zeolitic imidazolate frameworks (ZIFs) and/or phenanthroline (as carbon and nitrogen sources), or by heat treating iron-substituted ZIFs. For this family of PGM-free materials, it has been shown that many synthesis variables, such as the metal and carbon-nitrogen macrocycle content, the heat treatment temperature, atmosphere, and temperature profile all affect the activity and durability of the resulting catalysts.4-7 Optimization of these variables and testing the resulting catalyst properties is not a trivial task, and only a limited portion of the composite composition and temperature space has been explored for this family of catalysts. To accelerate optimization of the synthesis variables to obtain improved ORR activity and stability for the Fe-N-C catalysts, high-throughput synthesis and characterization methods were developed and utilized. An automation platform, a multi-port ball-mill, and parallel fixed bed reactors in Argonne’s High-throughput Research Laboratory were used to rapidly synthesize the PGM-free catalysts with systematically-varied synthesis conditions. A multi-channel flow double electrode (m-CFDE) cell and other cells were designed and constructed for the simultaneous testing the ORR activity and stability of the multiple catalysts synthesized. The ORR activity and stability of the catalysts were correlated with their Fe speciation, as determined using Fe K-edge X-ray absorption spectroscopy (XAFS), electrochemically-determined surface areas, and other variables, which is beneficial for the further improved catalyst activity and stability. References B. Pivovar, Nature Catalysis, 2 (2019) 562. S. Thompson and D. Papageorgopoulos, Nature Catalysis, 2 (2019) 558. L. Osmieri, J. Park, D.A. Cullen, P. Zelenay, D.J. Myers, and K.C. Neyerlin, Curr. Opin. Electrochem., 25 (2021) 100627. X. Wang, H. Zhang, H. Lin, S. Gupta, C. Wang, Z. Tao, H. Fu, T. Wang, J. Zheng, G. Wu, and X. Li, Nano Energy, 25 (2016) 110. H. Zhang, S. Hwang, M. Wang, Z. Feng, S. Karakalos, L. Luo, Z. Qiao, X. Xie, C. Wang, D. Su, Y. Shao, and G. Wu, J. Am. Chem. Soc., 139 (2017) 14143-14149. E. Proietti, F. Jaouen, M. Lefevre, N. Larouche, J. Tian, J. Herranz, and J.-P. Dodelet, Nature Comm. 2 (2011) 1. A. Zitolo, V. Goellner, V. Armel, M.-T. Sougrati, T. Mineva, L. Stievano, E. Fonda, and F. Jaouen, Nature Materials, 14 (2015) 937. This work was supported by the U.S. Department of Energy (DOE), Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office (HFTO) under the auspices of the Electrocatalysis Consortium (ElectroCat). This work utilized the resources of the Advanced Photon Source, a U.S. DOE Office of Science user facility operated by Argonne National Laboratory for DOE Office and was authored by Argonne, a U.S. Department of Energy (DOE) Office of Science laboratory operated for DOE by UChicago Argonne, LLC under contract no. DE-AC02-06CH11357.
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Choi, Pyoung Ho, Ki-Won Jun, Soo-Jae Lee, Myuong-Jae Choi, and Kyu-Wan Lee. "Hydrogenation of carbon dioxide over alumina supported Fe-K catalysts." Catalysis Letters 40, no. 1-2 (1996): 115–18. http://dx.doi.org/10.1007/bf00807467.
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Zheng, Yuhao, Chenghua Xu, Xia Zhang, Qiong Wu, and Jie Liu. "Synergistic Effect of Alkali Na and K Promoter on Fe-Co-Cu-Al Catalysts for CO2 Hydrogenation to Light Hydrocarbons." Catalysts 11, no. 6 (June 15, 2021): 735. http://dx.doi.org/10.3390/catal11060735.
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Alkali metal K- and/or Na-promoted FeCoCuAl catalysts were synthesized by precipitation and impregnation, and their physicochemical and catalytic performance for CO2 hydrogenation to light hydrocarbons was also investigated in the present work. The results indicate that Na and/or K introduction leads to the formation of active phase metallic Fe and Fe-Co crystals in the order Na < K < K-Na. The simultaneous introduction of Na and K causes a synergistic effect on increasing the basicity and electron-rich property, promoting the formation of active sites Fe@Cu and Fe-Co@Cu with Cu0 as a crystal core. These effects are advantageous to H2 dissociative adsorption and CO2 activation, giving a high CO2 conversion with hydrogenation. Moreover, electron-rich Fe@Cu (110) and Fe-Co@Cu (200) provide active centers for further H2 dissociative adsorption and O-C-Fe intermediate formation after adsorption of CO produced by RWGS. It is beneficial for carbon chain growth in C2+ hydrocarbons, including olefins and alkanes. FeCoCuAl simultaneously modified by K-Na exhibits the highest CO2 conversion and C2+ selectivity of 52.87 mol% and 89.70 mol%, respectively.
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Ichikuni, N., Y. Wakai, T. Hara, and S. Shimazu. "Nb and Fe K-edges XAFS study on the structure of supported Fe-NbN catalysts." Journal of Physics: Conference Series 190 (November 1, 2009): 012169. http://dx.doi.org/10.1088/1742-6596/190/1/012169.
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Xiong, Yi Na, Xiao Hua Chen, Zhi Yang, and Long Shan Xu. "A Facile Synthesis of Carbon Nanobelts over Mo/Fe/MgO Catalysts." Advanced Materials Research 430-432 (January 2012): 1361–64. http://dx.doi.org/10.4028/www.scientific.net/amr.430-432.1361.
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Carbon nanobelts(CNBs) with high purities (over 90%) have been successfully synthesized by catalytic decomposition of CH4 over Mo/Fe/MgO catalysts at 1173 K. The CNBs have thickness of about 8.0nm, width of about 50-200nm.with few defects and amorphous. It has been found that the addition of component Mo in catalysts plays a key role to synthesize the carbon nanobelts at high yields. The graphitic sheets increased with the increase of Mo content in catalysts.
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Nasser, AL Hassan Mohammed, Haitham M. Elbery, Hasan N. Anwar, Islam K. Basha, Hamada A. Elnaggar, Koichi Nakamura, and Ahmed A. El-Moneim. "A Study of Promoters Effect on Fe on Reduced Graphene Oxide Catalyst Performance in Fischer-Tropsch Synthesis System." Key Engineering Materials 735 (May 2017): 143–47. http://dx.doi.org/10.4028/www.scientific.net/kem.735.143.
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In this work the Fischer-Tropsch synthesis reaction was catalyzed by reduced graphene oxide supported Fe nanoparticles catalysts in a fixed bed reactor. Also the influence of promotion by K and Mn on the catalytic activity of Fe nanoparticles was investigated. The systems showed acceptable CO conversions reaching as high as 96.2%. The selectivities of the C1-5 ranged from 38 to 62%. There was a very high CO2 selectivity which was explained by incomplete reduction of the catalysts. The Anderson-Schultz-Flory parameter was calculated and varied between 0.25 and 0.3. The strongest promoting effect was achieved by the K promoter which tended to reduce light product selectivities and CO2 production the most.
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Barrio, Jesus, Angus Pedersen, Jingyu Feng, Magda Titirici, and Ifan Erfyl Lester Stephens. "Targeted Synthesis of Metal Dual Atom Electrocatalysts." ECS Meeting Abstracts MA2022-01, no. 7 (July 7, 2022): 629. http://dx.doi.org/10.1149/ma2022-017629mtgabs.
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Natural enzymes present within their structure active centres composed of earth-abundant metals in atomic proximity. Such active sites, dual atom catalysts, display a unique efficiency in catalytic processes such as the nitrogen conversion to ammonia, the production of ethylene through C-C coupling, or the oxygen reduction reaction in fuel cells amongst others.1,2 Theoretical calculations suggest that the high catalytic activity of dual atom catalysts arises from the different binding mode of reactant molecules to that of metal foils and single atom catalysts, which allows to break transition scaling relationships.3 Nevertheless, the experimental synthesis and characterisation of this class of materials is highly challenging.4 It is particularly difficult to avoid the formation of single atom catalysts or nanoparticles. In this work we show a general approach to fabricate bioinspired Fe dual atom catalysts in a nitrogen doped carbon support; we test the catalyst for the oxygen reduction reaction under acidic conditions. The catalyst exhibited an activity of 2.4 ± 0.3 A g-1 carbon at 0.8 V versus a reversible hydrogen electrode in acidic media, comparable to the most active in the literature. The two-step procedure leads to well defined Fe-based dimers. We characterised these materials by means of X-ray absorption spectroscopy (XAS) and scanning transmission electron microscopy. Our general approach providing a new towards targeted synthesis of dual atom electrocatalysts for energy-critical reactions. References (1) Chen, J. G.; Crooks, R. M.; Seefeldt, L. C.; Bren, K. L.; Bullock, R. M.; Darensbourg, M. Y.; Holland, P. L.; Hoffman, B.; Janik, M. J.; Jones, A. K.; Kanatzidis, M. G.; King, P.; Lancaster, K. M.; Lymar, S. V; Pfromm, P.; Schneider, W. F.; Schrock, R. R. Beyond Fossil Fuel–Driven Nitrogen Transformations. Science 2018, 360, eaar6611 (2) Lee, C. C.; Hu, Y.; Ribbe, M. W. Vanadium Nitrogenase Reduces CO. Science 2010, 329, 642 (3) Singh, A. R.; Montoya, J. H.; Rohr, B. A.; Tsai, C.; Vojvodic, A.; Nørskov, J. K. Computational Design of Active Site Structures with Improved Transition-State Scaling for Ammonia Synthesis. ACS Catal. 2018, 8, 4017–4024 (4) Pedersen, A.; Barrio, J.; Li, A.; Jervis, R.; Brett, D. J. L.; Titirici, M. M.; Stephens, I. E. L. Dual-Metal Atom Electrocatalysts: Theory, Synthesis, Characterization, and Applications. Adv. Energy Mater. 2021, 2102715 Figure 1
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Martinelli, Michela, Carlo Giorgio Visconti, Luca Lietti, Pio Forzatti, Claudia Bassano, and Paolo Deiana. "CO2 reactivity on Fe–Zn–Cu–K Fischer–Tropsch synthesis catalysts with different K-loadings." Catalysis Today 228 (June 2014): 77–88. http://dx.doi.org/10.1016/j.cattod.2013.11.018.
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Zhu, Baozhong, Zhaohui Zi, Yunlan Sun, Qilong Fang, Junchao Xu, Weiyi Song, Hailong Yu, and Enhai Liu. "Enhancing low-temperature SCR de-NOx and alkali metal poisoning resistance of a 3Mn10Fe/Ni catalyst by adding Co." Catalysis Science & Technology 9, no. 12 (2019): 3214–25. http://dx.doi.org/10.1039/c9cy00599d.
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Beall, Casey Elizabeth, Emiliana Fabbri, Nataša Diklić, Dino Aegerter, Sena Yüzbasi, Adam Hugh Clark, Thomas Graule, Maarten Nachtegaal, and Thomas J. Schmidt. "Investigating Perovskite Oxide Catalysts As Bifunctional Oxygen Electrodes Using Operando XAS." ECS Meeting Abstracts MA2022-01, no. 34 (July 7, 2022): 1377. http://dx.doi.org/10.1149/ma2022-01341377mtgabs.
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With the increase in renewable energy usage comes the need for energy storage systems due to intermittency issues. Hydrogen storage systems have been identified as one solution. Unitized regenerative fuel cells (URFC) combine electrolyzers and fuel cells in one device, allowing electricity to be stored and used easily. However, the oxygen electrodes are still affected by high overpotentials and slow kinetics. Perovskite oxides have been identified as a class of materials, which are low-cost, tunable, and active for the oxygen reduction (ORR) and evolution (OER) reactions. Here, we investigate perovskites as bifunctional catalysts for ORR and OER in alkaline solution. We examine and compare two strategies for bifunctional catalysts: using one catalyst, which is able to perform OER and ORR vs. a combination of two catalysts, one active for ORR and one active for OER. Frequently, the catalysts’ performances for these two reactions are measured separately.1,2,3 Here, we investigate how these bifunctional catalysts respond to cycling between the OER and ORR regions. Ba0.5Sr0.5Co0.8Fe0.2O3 (BSCF) is known to be a promising OER catalyst.4,5,6 However, without carbon, it lacks ORR activity.4 La(1-x)SrxMnO3 (LSM) is a promising ORR catalyst.3,7 However, without modification, it has been shown to have limited OER activity.3 Separately, these catalysts lack high performance for both reactions. Here, we combine the two catalysts into a BSCF/LSM/Carbon composite electrode and compare to electrodes prepared from the constituent single material components. In addition, we have synthesized single material perovskites containing both Co and Mn that to the best of our knowledge have never been tested as electrodes for ORR/OER. In order to understand the catalysts’ behaviors under OER and ORR conditions, X-ray adsorption spectroscopy (XAS) was measured continuously while performing cyclic voltammetry. We were able to monitor the continuous changes of the Co, Mn, and Fe oxidation states and local environment during OER and ORR with remarkably high time/applied potential resolution. Our findings illustrate the reversible and irreversible changes that can occur during OER and ORR and provide strategies for future bifunctional catalyst design. References Kirsanova, M. A.; Okatenko, V. D.; Aksyonov, D. A.; Forslund, R. P.; Mefford, J. T.; Stevenson, K. J.; Abakumov, A. M. Bifunctional OER/ORR Catalytic Activity in the Tetrahedral YBaCo 4 O 7.3 Oxide. Mater. Chem. A 2019, 7 (1), 330–341. Elumeeva, K.; Masa, J.; Sierau, J.; Tietz, F.; Muhler, M.; Schuhmann, W. Perovskite-Based Bifunctional Electrocatalysts for Oxygen Evolution and Oxygen Reduction in Alkaline Electrolytes. Acta 2016, 208, 25–32. Xu, W.; Apodaca, N.; Wang, H.; Yan, L.; Chen, G.; Zhou, M.; Ding, D.; Choudhury, P.; Luo, H. A-Site Excessive (La0.8Sr0.2)1+ XMnO3 Perovskite Oxides for Bifunctional Oxygen Catalyst in Alkaline Media. ACS Catal. 2019, 9 (6), 5074–5083. Fabbri, E.; Nachtegaal, M.; Cheng, X.; Schmidt, T. J. Superior Bifunctional Electrocatalytic Activity of Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ /Carbon Composite Electrodes: Insight into the Local Electronic Structure. Energy Mater. 2015, 5 (17), 1402033. Fabbri, E.; Nachtegaal, M.; Binninger, T.; Cheng, X.; Kim, B.-J.; Durst, J.; Bozza, F.; Graule, T.; Schäublin, R.; Wiles, L.; Pertoso, M.; Danilovic, N.; Ayers, K. E.; Schmidt, T. J. Dynamic Surface Self-Reconstruction Is the Key of Highly Active Perovskite Nano-Electrocatalysts for Water Splitting. Mater. 2017, 16 (9), 925–931. Kim, B. J.; Fabbri, E.; Abbott, D. F.; Cheng, X.; Clark, A. H.; Nachtegaal, M.; Borlaf, M.; Castelli, I. E.; Graule, T.; Schmidt, T. J. Functional Role of Fe-Doping in Co-Based Perovskite Oxide Catalysts for Oxygen Evolution Reaction. Am. Chem. Soc. 2019, 141 (13), 5231–5240. Tulloch, J.; Donne, S. W. Activity of Perovskite La1−xSrxMnO3 Catalysts towards Oxygen Reduction in Alkaline Electrolytes. Power Sources 2009, 188 (2), 359–366.
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García-Hurtado, Elisa, Aída Rodríguez-Fernández, Manuel Moliner, and Cristina Martínez. "CO2 hydrogenation using bifunctional catalysts based on K-promoted iron oxide and zeolite: influence of the zeolite structure and crystal size." Catalysis Science & Technology 10, no. 16 (2020): 5648–58. http://dx.doi.org/10.1039/d0cy00712a.
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The influence of the zeolite structure and crystal size on bifunctional tandem catalysts combining K-promoted iron oxide (K/Fe3O4) with different zeolites has been studied for the CO2 hydrogenation reaction at 320 °C and 25 bar.
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Kumar, Kavita, Tristan Asset, Plamen Atanassov, Frederic Jaouen, Laetitia Dubau, and Frederic Maillard. "Unravelling the Influence of Oxygen on the Degradation Mechanisms of Fe-N-C Oxygen Reduction Reaction Catalysts." ECS Meeting Abstracts MA2022-01, no. 49 (July 7, 2022): 2070. http://dx.doi.org/10.1149/ma2022-01492070mtgabs.
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Pyrolyzed iron-nitrogen-carbon materials (Fe-N-C) comprising mostly atomic Fe-Nx moieties are the most mature class of noble metal free catalysts for the oxygen reduction reaction (ORR) in acidic media. Such catalysts show excellent performance in proton exchange membrane fuel cell (PEMFC), approaching that of platinum-based catalysts. [1] However, an important performance loss is observed during operation, in conditions mimicking those of a PEMFC. [2] To shed fundamental light onto the degradation mechanisms at stake, two different Fe-N-C materials were prepared, one using a metal organic framework (MOF) and the other a sacrificial support method (SSM), and are labelled Fe-N-C_MOF and Fe-N-C_SSM, respectively. These materials were characterized before and after two different accelerated stress tests (ASTs: 10 k cycles, 0.6-1.0 V vs. RHE, 3s-3s, 0.1 M H2SO4, 80°C) under Ar or O2 atmosphere. Stronger degradation and higher ORR mass activity loss were observed when the AST is performed in O2 vs. Ar-saturated acidic electrolyte. For AST under Ar condition, physicochemical characterisations revealed a demetallation process and the eventual occurrence of a clustering mechanism whereas for AST performed in O2 atmosphere, a decrease of the Fe content and the formation of Fe oxide particles was observed (Figure 1). Keywords: Electrocatalysis, Fe-N-C, Oxygen Reduction Reaction, Durability, PEMFC Acknowledgements These studies were financed by the French National Research Agency in the frame of the CAT2CAT (grant number n°ANR-16-CE05-0007) and the ANIMA (grant number n°ANR-19-CE05-0039) projects. References [1] E. Proietti, F. Jaouen, M. Lefèvre, N. Larouche, J. Tian, J. Herranz, J. P. Dodelet, Nat. Commun. 2011, 2, 416. [2] Y. Shao, J. P. Dodelet, G. Wu, P. Zelenay, Adv. Mater. 2019, 21, 1807615. [3] K. Kumar, T. Asset, X. Li, Y. Liu, X. Yan, Y. Chen, M. Mermoux, X. Pan, P. Atanassov, F. Maillard, L. Dubau, ACS Catal. 2021, 11, 484-494. [4] K. Kumar, P. Gairola, M. Lions, N. Ranjbar-Sahraie, M. Mermoux, L. Dubau, A. Zitolo, F. Jaouen, F. Maillard, ACS Catal. 2018, 8, 11264-11276. [5] K. Kumar, L. Dubau, M. Mermoux, J. Li, A. Zitolo, J. Nelayah, F. Jaouen, F. Maillard, Angew. Chem. 2020, 132, 3261-3269. Figure 1
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Chen, Ning, Jianli Zhang, Qingxiang Ma, Subing Fan, and Tian-Sheng Zhao. "Hydrothermal preparation of Fe–Zr catalysts for the direct conversion of syngas to light olefins." RSC Advances 6, no. 41 (2016): 34204–11. http://dx.doi.org/10.1039/c5ra27712d.
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Two-step hydrothermal preparation of Fe/Zr–K catalysts could improve the olefin selectivity and product distribution by reducing the secondary hydrogenation ability and suppressing the formation of heavy hydrocarbons during CO hydrogenation.
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Guo, Hai Jun, Lian Xiong, Cai Rong Luo, Jie Li, Fei Ding, Xin De Chen, and Yong Chen. "Study of Cu-Fe-Co-M/SiO2 (M = Unpromoted, Li, Na, K and Cs) Catalysts for Mixed Alcohols Synthesis from CO Hydrogenation." Advanced Materials Research 347-353 (October 2011): 3691–94. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.3691.
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A series of Cu-Fe-Co based catalysts prepared by co-impregnation method using different alkali additives was characterized by BET, XRD and FESEM-EDX and investigated under MAS from CO hydrogenation. The results showed that the catalyst Cu25Fe22Co3-Na3/SiO2 has the highest catalytic activity and selectivity of total alcohol and C5+OH. XRD and FESEM-EDX demonstrated the Na3 catalyst exhibited homogeneous distribution of elements and effective synergy effect between Cu and Fe components, thereby performed good catalytic performances for MAS from CO hydrogenation. The presence of a suitable content of alkali promoter was necessary for mixed alcohols synthesis from syngas.
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Razmara, Zohreh, and Jan Janczak. "Synthesis and crystal structure of a new heteronuclear complex of Fe(iii)–K designed to produce effective catalysts for CO hydrogenation." Dalton Transactions 49, no. 30 (2020): 10498–508. http://dx.doi.org/10.1039/d0dt01230k.
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Matsuzawa, Koichi, Momo Obata, Yuu Takeuchi, Yoshiro Ohgi, Kaoru Ikegami, Takaaki Nagai, Ryuji Monden, and Akimitsu Ishihara. "(Digital Presentation) Effects of Foreign Elements Added Oxide-Based Electrocatalyst for Oxygen Reduction Reaction as Non-Precious Metel Cathodes." ECS Meeting Abstracts MA2022-01, no. 35 (July 7, 2022): 1544. http://dx.doi.org/10.1149/ma2022-01351544mtgabs.
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On Dec. 2020, new MIRAI of fuel cell vehicle (FCV) from Toyota started to sell in Japan. However, the price of new model is almost same as previous model. For wide commercialization of FCV, it should be required for more development. One of the barriers of innovative system for the FCV is conventional platinum-based electrocatalyst. The cost of Pt is very expensive due to its very poor resources. Moreover, the conventional Pt-based electrocatalyst cannot reach enough performance for next generation FCV that is proposed in new roadmap released from NEDO, Japan. From this point of view, the non-precious metal electrocatalyst should be required for the breakthrough against above issue. We have focused and studied group 4 and 5 metal oxide-based electrocatalyst as non-platinum catalysts for the oxygen reduction reaction (ORR) because of low-cost, abundant reserves, and high stability in acidic electrolytes [1-2]. We found that titanium oxide prepared from TiOTPyzPz supported on multi-walled carbon nanotubes had superior ORR activity [3]. On the other hand, it was published as an international patent that the addition of other elements such as Fe and Ni is affected to enhance the ORR activity of Ti oxide-based electrocatalyst [4]. In this study, we have investigated to apply for the TiOTPyzPz as a starting material with and without Fe, Ni, and Zn addition to enhance the ORR activity of Ti oxide-based electrocatalyst. 2,3-Dicyanopyrazine, urea, and Ti isopropoxide were dissolved in quinoline and refluxed to synthesize TiOTPyzPz. Iron acetate, Nickel acetate, and Zinc acetate were also added to dissolve in quinoline to obtain the Fe, Ni, and Zn-added TiOTPyzPz as a starting material. The molar ratio of Ti:Fe:Ni:Zn was set to constant. These starting materials were mixed with carbon nanotube by ball-milling to prepare the precursors. These precursors were heat-treated under low oxygen partial pressure for 3 h to obtain titanium oxide-based catalysts. The catalyst powder was dispersed into 1-propanol with Nafion solution to prepare a catalyst ink. The ink was dropped on a glassy carbon rod, and dried for an hour to use as a working electrode in electrochemical measurement. Electrochemical measurements were performed in 0.5 mol dm-3 H2SO4 at 30 oC with a conventional 3-electrode cell. A reversible hydrogen electrode (RHE) and a glassy carbon plate were used as used as a reference and counter electrode, respectively. Slow scan voltammetry (SSV) was performed at a scan rate of 5 mV s-1 from 0.2 V to 1.2 V vs. RHE under O2 and N2. The ORR current (i ORR) was determined by calculating the difference between the current under O2 and N2. Figure 1 shows the effect of Fe, Ni, and Zn addition to TiOTPyzPz as a starting material on the ORR polarization curves of the titanium oxide-based catalysts. The vertical axis is based on catalyst weight. Ti oxid-based electrocatalyst prepared from Fe, Ni, and Zn addition to TiOTPyzPz (TiOx-Fe, Ni, Zn) resulted in the increase in the onset potential for the ORR and ORR current compared to that without addition (TiOx), revealing that the addition of Fe, Ni, and Zn was found to be effective in improving the ORR activity. XRD pattern of TiOx shows several peaks identified TiO2-Rutile, TiO2-Anatanse and TiO2-Brookite while the XRD pattern of TiOx-Fe, Ni, Zn also shows several peaks identified similar to TiOx. In the case of XRD pattern of TiOx-Fe, Ni, Zn, the peak identified compounds relating to additional elements such as Fe, Ni and Zn does not detect strongly. It is suggested that the addition of Fe, Ni and Zn to TiOTPyzPz conduce to the distortion of crystal phase of TiO2 [5] and it affected to suppress the crystal growth of Ti oxide-based electrocatalyst. These facts are possibly contributed to enhance the ORR activity of TiOx-Fe, Ni, Zn compared to that of TiOx. Acknowledgement: The authors thank New Energy and Industrial Technology Development Organization (NEDO) and ENEOS Tonen General Research / Development Encouragement & Scholarship Foundation for financial support. Reference [1] A. Ishihara, Y. Ohgi, K. Matsuzawa, S. Mitsushima, and K. Ota, Electrochim. Acta, 55, 8005 (2010). [2] A. Ishihara, S. Tominaka, S. Mitsushima, H. Imai, H. Imai, O. Sugino, and K. Ota, Curr. Opin. Electrochem., 21 , 234 (2020). [3] S. Tominaka, A. Ishihara, T. Nagai, and K. Ota, ACS Omega, 2, 5209 (2017). [4] K. Takahashi, T. Imai, R. Monden, Y. Wakisaka, and S. Sato, Oxygen Reduction Catalyst, Process for Producing Same, and Polymer Electrolyte Membrane Fuel Cell, WO/2013/008501. [5] Y. Yamamoto, S. Kasamatsu, and O. Sugino, J. Phys. Chem. C, 123, 19486 (2019). Figure 1
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Chang, Hai, Quan Lin, Meng Cheng, Kui Zhang, Bo Feng, Jiachun Chai, Yijun Lv, and Zhuowu Men. "Effects of Potassium Loading over Iron–Silica Interaction, Phase Evolution and Catalytic Behavior of Precipitated Iron-Based Catalysts for Fischer-Tropsch Synthesis." Catalysts 12, no. 8 (August 19, 2022): 916. http://dx.doi.org/10.3390/catal12080916.
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Potassium (K) promoter and its loading contents were shown to have remarkable effects on the Fe–O–Si interaction of precipitated Fe/Cu/K/SiO2 catalysts for low-temperature Fischer-Tropsch synthesis (FTS). With the increase in K content from 2.3% (100 g Fe based) up to 7% in the calcined precursors, Fe–O–Si interaction was weakened, as reflected by ATR/FTIR, H2-TPR and XPS investigations. XRD results confirmed that the diffraction peak intensity from (510) facet of χ-Fe5C2 phase strengthened with increasing K loading, which indicates the crystallite size of χ-Fe5C2 increased with the increase in K contents either during the syngas reduction/carburization procedure or after FTS reaction. H2-TPH results indicated that more reactive surface carbon (alpha-carbon) was obtained over the higher K samples pre-carburized by syngas. Raman spectra illustrated that a greater proportion of graphitic carbon was accumulated over the surface of spent samples with higher K loading. At the same time, ATR-FTIR, XRD and Mössbauer spectra (MES) characterization results showed that a relatively higher level of bulk phase Fayalite (Fe2SiO4) species was observed discernibly in the lowest K loading sample (2.3 K%) in this work. The catalytic evaluation results showed that the CO conversion, CO2 selectivity and O/P (C2–C4) ratio increased progressively with the increasing K loading, whereas a monotonic decline in both CO conversion and O/P (C2–C4) ratio was observed on the highest K loading sample during c.a. 280 h of TOS.
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Szymanski, R., P. Sarrazin, P. Ruterana, E. Merlen, and J. P. Boitiaux. "Genesis of Pd-Fe particles by Fe carbonyl surface reaction on Pd/Al2O3: Influence of the precursor activation." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (August 1990): 300–301. http://dx.doi.org/10.1017/s0424820100174631.
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Bimetallic Pd-Fe catalysts supported on a transition alumina have been synthetised by reacting Fe carbonyl with the metal surface of a Pd/Al2O3 precursor under mild conditions. The genesis of bimetallic particles was characterized by STEM (VG HB5) and HREM (Jeol 120 CX and Philips EM 430).The monometallic Pd/Al2O3 was prepared by impregnation with nitrate precursor, drying, calcination at 773 K in air and reduction at 723 K in H2. A solution of Fe (CO)5 in toluene was then reacted with the reduced precursor at 298 K under flowing hydrogen (procedure 1). An alternative consisted in reacting the carbonyl directly with the calcined precursor (Procedure 2). Alloy formation was achieved in both cases by a subsequent reduction at 723 K.The general Pd-Fe particle morphology is close to that of the reduced Pd precursor. An amorphous layer at the periphery of a number of particles indicates a surface segregation which has probably occured during the transfer to the microscope of the sample kept in air, due to the high reactivity of Fe towards oxygen (Figure 1).
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de Albuquerque Fragoso, Danielle Munick, Henrique Fonseca Goulart, Antonio Euzebio Goulart Santana, and Samuel David Jackson. "Targeted Substituted-Phenol Production by Strategic Hydrogenolysis of Sugar-Cane Lignin." Biomass 1, no. 1 (June 18, 2021): 11–28. http://dx.doi.org/10.3390/biomass1010002.
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In this work, a waste-derived lignin with abundant uncondensed linkages, using accessible solvents (acetone/water mixture) and low-cost catalysts showed successful depolymerization for the production of target molecules 4-ethylphenol, 4-propyl-2,6-dimethoxyphenol and 4-propyl-2-methoxyphenol. Lignin samples were obtained from sugar-cane bagasse residue by an organosolv process. Four alumina-based catalysts (Pt/Al2O3, Rh/Al2O3, Ni/Al2O3 and Fe/Al2O3) were used to depolymerize the sugar cane lignin (SCL) in an acetone/water mixture 50/50 v/v at 573 K and 20 barg hydrogen. This strategic depolymerisation-hydrogenolysis process resulted in the molecular weight of the SCL being reduced by half while the polydispersity also decreased. Catalysts significantly improved product yield compared to thermolysis. Specific metals directed product distribution and yield, Rh/Al2O3 gave the highest overall yield (13%), but Ni/Al2O3 showed the highest selectivity to a given product (~32% to 4-ethylphenol). Mechanistic routes were proposed either from lignin fragments or from the main polymer. Catalysts showed evidence of carbon laydown that was specific to the lignin rather than the catalyst. These results showed that control over selectivity could be achievable by appropriate combination of catalyst, lignin and solvent mixture.
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Ni, Zhijiang, Xuefei Zhang, Jirong Bai, Zhilei Wang, Xi Li, and Yanhu Zhang. "Potassium promoted core–shell-structured FeK@SiO2-GC catalysts used for Fischer–Tropsch synthesis to olefins without further reduction." New Journal of Chemistry 44, no. 1 (2020): 87–94. http://dx.doi.org/10.1039/c9nj03947c.
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The GC and K promoted Fe-based catalysts prepared by modified sol–gel method, which omits the complex and high energy consumption reduction process, can be used directly for highly efficient FTS and thus will be more promising in the future.
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Jia, Tai Xuan, Shao Feng Yan, and Zi Li Liu. "Preparation and Catalytic Properties of SrFe2O4 in Selective Oxidation." Advanced Materials Research 396-398 (November 2011): 751–54. http://dx.doi.org/10.4028/www.scientific.net/amr.396-398.751.
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The effect of catalyst atomic ratio on the performance of styrene selective oxidation by H2O2 as probe reaction over spinel type strontium ferrate prepared through sol-gel method was investigated. The catalyst evaluation results show that the optimum catalyst atomic ratio was n(Fe):n(Sr)= 2:1 with high catalytic activity. The catalysts were detected by XRD. The optimum calcination temperature was 700 °C. Micro-structure and essence disciplinarian of strontium ferrate were disclosed. Under normal atmospheric pressure and 0.5 g catalyst dosage conditions, the optimum feed ratio, reactive temperature and reactive time are n(H2O2):n(styrene)=1:1, 343 K and 9 h, respectively. The selectivition and yield of benzaldehyde were 65.7% and 34.3%, respectively. The technological process route possessed under ambient conditions with advantage such as excellent properties in product.
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Cherevko, Serhiy, Konrad Ehelebe, Daniel Escalera López, Julius Knöppel, YuPing Ku, and Maja Milosevic. "(Invited) Electrocatalysts Dissolution Assessment in Fuel Cell and Water Electrolysis Research." ECS Meeting Abstracts MA2022-01, no. 49 (July 7, 2022): 2052. http://dx.doi.org/10.1149/ma2022-01492052mtgabs.
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Durability and degradation are in the focus of modern electrocatalysis research. Before moving to real applications, e.g. fuel cells in transportation or water electrolyzers for production of green hydrogen, novel electrocatalytic materials must prove acceptable stability, but “how to test the stability of electrocatalysts”? In the relatively mature proton exchange membrane fuel cell (PEMFC) research, stability is evaluated using various accelerated stress tests (ASTs). Unfortunately, even for the most studied Pt/C electrocatalysts, degradation processes like carbon corrosion and Pt dissolution that occur during common ASTs are not easily distinguishable [1]. Moreover, advanced electrocatalysts such as different shape-controlled Pt alloy nanostructures, showing promising stability in ASTs performed in model aqueous systems, are often rendered useless when moved to real applications [2]. Catalysts free of platinum-group-metals, e.g. FeNC, demonstrate different degradation extents if tested in oxygen or argon [3]. Iridium oxides, the state of the art oxygen evolution reaction (OER) electrocatalysts, are prone to dissolution in aqueous media but much more stable in solid electrolyte based electrolyzers [4]. These examples demonstrate the need for rethinking current approaches to test electrocatalyst stability. This work highlights our recent results on using coupled electrochemical techniques and tuned gas diffusion electrode (GDE) and membrane electrode assembly (MEA) cells in fuel cell and water electrolysis research. It shows that by hyphenating GDE with inductively coupled plasma mass spectrometry (ICP-MS) it is possible to investigate dissolution of electrocatalysts, such as Pt/C for PEMFC and Fe-N-C for anion exchange membrane fuel cells (AEMFC), in-operando at conditions closely resembling those in real devices [5, 6]. As another representative example, the use of model MEAs to address the discrepancy of Ir dissolution in aqueous and solid polymer electrolytes is given [7]. Based on these examples, new strategies to test and understand electrocatalysts’ degradation are discussed. References: [1] E. Pizzutilo et al., On the need of improved accelerated degradation protocols (ADPs): Examination of platinum dissolution and carbon corrosion in half-cell tests, J. Electrochem. Soc., 163 (2016) F1510-F1514. [2] K. Kodama et al., Challenges in applying highly active Pt-based nanostructured catalysts for oxygen reduction reactions to fuel cell vehicles, Nature Nanotechnology, 16 (2021) 140-147. [3] K. Kumar et al., On the influence of oxygen on the degradation of Fe-N-C catalysts, Angew. Chem. Int. Ed., 59 (2020) 3235-3243. [4] S. Geiger et al., The stability number as a metric for electrocatalyst stability benchmarking, Nature Catalysis, 1 (2018) 508-515. [5] K. Ehelebe et al., Platinum dissolution in realistic fuel cell catalyst layers, Angew. Chem. Int. Ed., 60 (2021) 8882-8888. [6] Y.-P. Ku et al., Oxygen reduction reaction causes iron leaching from Fe-N-C electrocatalysts, (2021) Submitted, DOI: 10.21203/rs.3.rs-1171081/v1. [7] J. Knöppel et al., On the limitations in assessing stability of oxygen evolution catalysts using aqueous model electrochemical cells, Nature Communications 12 (2021) 2231.
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Zhang, Jianli, Shipeng Lu, Xiaojuan Su, Subing Fan, Qingxiang Ma, and Tiansheng Zhao. "Selective formation of light olefins from CO2 hydrogenation over Fe–Zn–K catalysts." Journal of CO2 Utilization 12 (December 2015): 95–100. http://dx.doi.org/10.1016/j.jcou.2015.05.004.
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Miyakoshi, Akihiko, Akifumi Ueno, and Masaru Ichikawa. "Mn-substituted Fe–K mixed oxide catalysts for dehydrogenation of ethylbenzene towards styrene." Applied Catalysis A: General 216, no. 1-2 (August 2001): 137–46. http://dx.doi.org/10.1016/s0926-860x(01)00555-5.
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Satthawong, Ratchprapa, Naoto Koizumi, Chunshan Song, and Pattarapan Prasassarakich. "Light olefin synthesis from CO2 hydrogenation over K-promoted Fe–Co bimetallic catalysts." Catalysis Today 251 (August 2015): 34–40. http://dx.doi.org/10.1016/j.cattod.2015.01.011.
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Nesic, Jelena, Dragan Manojlovic, Milica Jovic, Biljana Dojcinovic, Predrag Vulic, Jugoslav Krstic, and Goran Roglic. "Fenton-like oxidation of azo dye using mesoporous Fe/TiO2 prepared by microwave-assisted hydrothermal process." Journal of the Serbian Chemical Society 79, no. 8 (2014): 977–91. http://dx.doi.org/10.2298/jsc131001143n.
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Fe-doped TiO2 photocatalysts with different content of Fe (0.5, 1.6, 3.4 and 6.4%) were synthesized by the microwave-hydrothermal method and characterized by XRD, N2 physisorption at 77 K and DRS. The characterization showed that Fe ions are highly dispersed in the TiO2 lattice. It was found that all the synthesized catalysts had the mesoporous structure and Fe doping increased BET surface areas. The UV-Vis study showed that the absorption spectra shifted to a longer wavelength (red shift) with an increase in the dopant concentration. The photocatalytic activity of the samples was evaluated by the decolorization of textile dye Reactive Blue 52 (RB) in aqueous solutions under sun-like radiation in the presence of H2O2 (heterogeneous photo-Fenton process). The photocatalyst with 3.4% Fe was found to be the most efficient with H2O2. The effect of the initial pH of the dye solution was assessed and dissolution of iron ions was studied, as a function of pH value. It was concluded that decolorization is more favorable in acidic pH and when pH >4, the releasing of Fe ions in solution was negligible. Photocatalytic degradation of 4-chlorophenol (4-CP) was investigated under the optimal conditions and proved that our catalyst was capable to degrade colorless pollutants.
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Guo, Wei, Wen Gui Gao, Hua Wang, and Jun Jie Tian. "Higher Alcohols Synthesis from CO2 Hydrogenation over K2O-Modified CuZnFeZrO2 Catalysts." Advanced Materials Research 827 (October 2013): 20–24. http://dx.doi.org/10.4028/www.scientific.net/amr.827.20.
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The CuZnFeZrO2 catalysts were synthesized by co-precipitation method.,and then used to synthesize different content of K2O modified CuZnFeZrO2 catalysts by deposition-precipitation method.Hydrogenation of CO2 to higher alcohols over (K2O)x/CuZnFeZrO2 catalysts were investigated at 523 K,3.0 MPa and 3000 h-1.These catalysts were characterized by X-ray diffraction (XRD),temperature programmed reduction of H2 (H2-TPR),and temperature-programmed desorption of CO2 (CO2-TPD).The results showed the addition of an appropriate amount of Potassium to the CuZnZrO2 catalysts improved catalytic activity ,the space time yield (STY) and C2+OH selectivity. When the Fe content is 5% best, at this time the space time yield of selectivity and alcohol of C2+ alcohol reaches the maximum value, this time space and time conversion rate is 0.32g/ml·h.