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Academic literature on the topic 'Complex Reaction Mechanism - Chemical Hydorgen Storage'
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Journal articles on the topic "Complex Reaction Mechanism - Chemical Hydorgen Storage"
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Brünle, Steffen, Martin L. Eisinger, Juliane Poppe, Deryck J. Mills, Julian D. Langer, Janet Vonck, and Ulrich Ermler. "Molybdate pumping into the molybdenum storage protein via an ATP-powered piercing mechanism." Proceedings of the National Academy of Sciences 116, no. 52 (December 6, 2019): 26497–504. http://dx.doi.org/10.1073/pnas.1913031116.
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The molybdenum storage protein (MoSto) deposits large amounts of molybdenum as polyoxomolybdate clusters in a heterohexameric (αβ)3cage-like protein complex under ATP consumption. Here, we suggest a unique mechanism for the ATP-powered molybdate pumping process based on X-ray crystallography, cryoelectron microscopy, hydrogen-deuterium exchange mass spectrometry, and mutational studies of MoSto fromAzotobacter vinelandii. First, we show that molybdate, ATP, and Mg2+consecutively bind into the open ATP-binding groove of the β-subunit, which thereafter becomes tightly locked by fixing the previously disordered N-terminal arm of the α-subunit over the β-ATP. Next, we propose a nucleophilic attack of molybdate onto the γ-phosphate of β-ATP, analogous to the similar reaction of the structurally related UMP kinase. The formed instable phosphoric-molybdic anhydride becomes immediately hydrolyzed and, according to the current data, the released and accelerated molybdate is pressed through the cage wall, presumably by turning aside the Metβ149 side chain. A structural comparison between MoSto and UMP kinase provides valuable insight into how an enzyme is converted into a molecular machine during evolution. The postulated direct conversion of chemical energy into kinetic energy via an activating molybdate kinase and an exothermic pyrophosphatase reaction to overcome a proteinous barrier represents a novelty in ATP-fueled biochemistry, because normally, ATP hydrolysis initiates large-scale conformational changes to drive a distant process.
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Song, Zihui, Wanyuan Jiang, Xigao Jian, and Fangyuan Hu. "Advanced Nanostructured Materials for Electrocatalysis in Lithium–Sulfur Batteries." Nanomaterials 12, no. 23 (December 6, 2022): 4341. http://dx.doi.org/10.3390/nano12234341.
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Lithium–sulfur (Li-S) batteries are considered as among the most promising electrochemical energy storage devices due to their high theoretical energy density and low cost. However, the inherently complex electrochemical mechanism in Li-S batteries leads to problems such as slow internal reaction kinetics and a severe shuttle effect, which seriously affect the practical application of batteries. Therefore, accelerating the internal electrochemical reactions of Li-S batteries is the key to realize their large-scale applications. This article reviews significant efforts to address the above problems, mainly the catalysis of electrochemical reactions by specific nanostructured materials. Through the rational design of homogeneous and heterogeneous catalysts (including but not limited to strategies such as single atoms, heterostructures, metal compounds, and small-molecule solvents), the chemical reactivity of Li-S batteries has been effectively improved. Here, the application of nanomaterials in the field of electrocatalysis for Li-S batteries is introduced in detail, and the advancement of nanostructures in Li-S batteries is emphasized.
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Liu, Qiang, Jialong Li, Bing Liang, Weiji Sun, Jianjun Liu, and Yun Lei. "Microscopic Flow of CO2 in Complex Pore Structures: A Recent 10-Year Review." Sustainability 15, no. 17 (August 28, 2023): 12959. http://dx.doi.org/10.3390/su151712959.
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To prevent CO2 leakage and ensure the safety of long-term CO2 storage, it is essential to investigate the flow mechanism of CO2 in complex pore structures at the pore scale. This study focused on reviewing the experimental, theoretical, and numerical simulation studies on the microscopic flow of CO2 in complex pore structures during the last decade. For example, advanced imaging techniques, such as X-ray computed tomography (CT) and nuclear magnetic resonance (NMR), have been used to reconstruct the complex pore structures of rocks. Mathematical methods, such as Darcy’s law, the Young–Laplace law, and the Navier-Stokes equation, have been used to describe the microscopic flow of CO2. Numerical methods, such as the lattice Boltzmann method (LBM) and pore network (PN) model, have been used for numerical simulations. The application of these experimental and theoretical models and numerical simulation studies is discussed, considering the effect of complex pore structures. Finally, future research is suggested to focus on the following. (1) Conducting real-time CT scanning experiments of CO2 displacement combined with the developed real-time CT scanning clamping device to achieve real-time visualization and provide a quantitative description of the flow behavior of CO2 in complex pore structures. (2) The effect of pore structures changes on the CO2 flow mechanism caused by the chemical reaction between CO2 and the pore surface, i.e., the flow theory of CO2 considering wettability and damage theory in a complex pore structures. (3) The flow mechanism of multi-phase CO2 in complex pore structures. (4) The flow mechanism of CO2 in pore structures at multiscale and the scale upgrade from microscopic to mesoscopic to macroscopic. Generally, this study focused on reviewing the research progress of CO2 flow mechanisms in complex pore structures at the pore scale and provides an overview of the potential advanced developments for enhancing the current understanding of CO2 microscopic flow mechanisms.
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Kim, Haegyum, and Young-Woon Byeon. "Understanding Ion-Exchange Reaction Mechanisms in Layered Oxide Cathodes for Beyond Li-Ion Batteries." ECS Meeting Abstracts MA2022-02, no. 4 (October 9, 2022): 452. http://dx.doi.org/10.1149/ma2022-024452mtgabs.
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Ion-exchange reactions are frequently used to develop novel metastable electrode materials for alkali-ion batteries that cannot be synthesized using direct chemical reactions. In fact, the ion-exchange reaction has been proven as an effective approach to develop novel transition metal oxide cathodes for lithium, sodium, and potassium ion batteries.[1-4] However, the solid-state ion-exchange mechanism and the resulting phase evolution are barely understood. In this work, we investigated the electrochemical ‘K-to-Na’ and ‘Na-to-K’ ion-exchange reaction mechanisms in layered oxide cathodes as it occurs using operando and ex situ structure characterization techniques.[5-6] Our study demonstrates that the ion-exchange occurs not by a simple Na/K interdiffusion in a given host structure. Instead, we discovered intriguing multi-phase evolutions according to the relative Na/K content, indicating that the ion-exchange systems may be more complex to interpret than the previously understood. We found that not only Na (or K)-layered oxide host interaction but also Na-K interaction affect the ion-exchange reactions. In this presentation, we will discuss how and why those parameters determine the ion-exchange reactions and resulting phase evolutions. References [1] S. Baskar et al. ECS Transactions 2017, 80, 357. [2] N. Naveen et al. Chem. Mater. 2018, 30, 2049. [3] C, Delmas et al. Mater. Res. Bull. 1982, 17, 117. [4] A. R. Armstrong et al. Nature 1996, 381, 499. [5] H. Kim et al. Chem. Mater. 2020, 32, 4312. [6] H. Kim et al. Energy Storage Materials. 2022, 47, 105
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Anderson, Grace C., Douglas Kushner, Alexis T. Bell, and Adam Z. Weber. "Impact of Proton Activity in PFSA Membranes on Electrochemical Kinetics Using Microelectrodes." ECS Meeting Abstracts MA2022-02, no. 42 (October 9, 2022): 1537. http://dx.doi.org/10.1149/ma2022-02421537mtgabs.
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Polymer-electrolyte fuel cells and electrolyzers (PEFC&Es) have the potential to play a prominent role in green energy technologies including transportation, chemical manufacturing, and grid-scale energy storage. PEFC&Es have made significant advancements in recent years, largely due to improvements in the catalyst layers, and especially at the ionomer/catalyst interface. However, it is not yet definitively known how this solid-state environment impacts electrochemical kinetics, especially under various operating conditions (e.g., temperature, humidity, etc.). Additionally, it is challenging to probe local conditions at the catalyst/ionomer interface using traditional analytical techniques. In this study, we explore the influence and nature of proton activity in Nafion and 3M ionomers using a specialized microelectrode setup containing a 50 μm platinum microelectrode in a solid-state three-electrode cell for hydrogen oxidation and evolution (HOR&HER) reactions. Proton activity was calculated through open circuit voltage measurements, and was found to increase with increasing water content, mirroring trends in reaction performance. The effect of proton activity on the reactions' kinetics was investigated using semi-empirical fitting with the Butler-Volmer equation, which gives insight into the reaction rate order and possible mechanism for the reactions. This study demonstrates that microelectrodes can be used to probe solid-state kinetics and can also elucidate complex ion interactions within the ionomer at the catalyst/ionomer interface.
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Nath, Debajyoti, and S. K. Mandal. "Magnetically influenced dielectric and electrical transport of inorganic–organic polymer-based hybrid nanocomposites." International Journal of Modern Physics B 34, no. 04 (January 2, 2020): 2050004. http://dx.doi.org/10.1142/s0217979220500046.
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Polymer-based hybrid nanocomposites of [Formula: see text]-([Formula: see text]) poly(vinylidene fluoride) (PVDF) ([Formula: see text], 0.6 and 0.7) have been prepared through low-cost chemical reaction process. The improvement of dielectric properties in polymer-based hybrid [Formula: see text]–PVDF nanocomposites can be utilized to make a suitable memory storage device. Surface modified [Formula: see text] (LFO) nanoparticles are well distributed inside the polymer resulting in improved dielectric constant and reduced dielectric loss. The study of complex and modulus impedance spectroscopy (IS) shows some interesting results for an influence of grain and grain boundary effects of electrical conductivity attributing the non-Debye type phenomena. The change of relaxation frequency with an applied magnetic field is ascribing the spin-dependent mechanism of electrical transport at grain boundaries (GBs). The fitting of Nyquist plot attributes the magnetic domain wall containing GB’s pinning center in the system. The higher concentration of filler LFO nanoparticles shows maximum values of dielectric constant assigning the Maxwell–Wagner–Sillars (MWS) polarization. The current study is focused towards the query to learn the complete study of magnetic field dependence electrical and dielectric properties in a system holding an excessive potential for a capable candidate for industrial applications.
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STEFFEN, Mark, Theresa M. SARKELA, Anna A. GYBINA, Terry W. STEELE, Nathaniel J. TRASSETH, Douglas KUEHL, and Cecilia GIULIVI. "Metabolism of S-nitrosoglutathione in intact mitochondria." Biochemical Journal 356, no. 2 (May 24, 2001): 395–402. http://dx.doi.org/10.1042/bj3560395.
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S-nitrosation of protein thiol groups by nitric oxide (NO•) is a widely recognized protein modification. Only few intracellular S-nitrosated proteins have been identified and it has been reported that S-nitrosation/denitrosation can serve as a regulatory process in signal-transduction pathways. Given the potential physiological importance of S-nitrosothiols, and considering that mitochondria are endowed with high levels of thiols and the biochemical requisites for synthesizing NO•, we examined the occurrence of S-nitrosoglutathione (GSNO) in intact, coupled rat liver mitochondria. These organelles contained 0.34nmol of GSNO/mg of protein, detected by HPLC with UV–visible and electrochemical detections. This concentration was dynamically modulated by the availability of NO•; its decay was affected mainly by GSH and superoxide dismutase in a reaction that entailed the generation of GSSG. On the basis of the relatively long half-life of GSNO and the negligible recovery of NO• during its decay, roles for GSNO as a storage and transport molecule for NO• are discussed. Moreover, the formation of GSNO and its reaction with GSH can be considered to be partly responsible for the catabolism of NO• via a complex mechanism that might result in the formation of hydroxylamine, nitrite or nitrous oxide depending upon the availability of oxygen, superoxide dismutase and glutathione. Finally, the high concentrations of GSH in the cytosol and mitochondria might favour the formation of GSNO by reacting with NO• ‘in excess’, thereby avoiding damaging side reactions (such as peroxynitrite formation), and facilitate the inactivation of NO• by generating other nitrogen-related species without the chemical properties characteristic of NO•.
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Samaniego Andrade, Samantha K., Shiva Shankar Lakshmi, István Bakos, Szilvia Klébert, Robert Kun, Miklós Mohai, Balázs Nagy, and Krisztina László. "The Influence of Reduced Graphene Oxide on the Texture and Chemistry of N,S-Doped Porous Carbon. Implications for Electrocatalytic and Energy Storage Applications." Nanomaterials 13, no. 16 (August 18, 2023): 2364. http://dx.doi.org/10.3390/nano13162364.
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In this work, we study the influence of reduced graphene oxide (rGO) on the morphology and chemistry of highly porous N,S-doped carbon cryogels. Simultaneously, we propose an easily upscalable route to prepare such carbons by adding graphene oxide (GO) in as-received suspended form to the aqueous solution of the ι-carrageenan and urea precursors. First, 1.25–5 wt% GO was incorporated into the dual-doped polymer matrix. The CO2, CO, and H2O emitted during the thermal treatments resulted in the multifaceted modification of the textural and chemical properties of the porous carbon. This facilitated the formation of micropores through self-activation and resulted in a substantial increase in the apparent surface area (up to 1780 m2/g) and pore volume (up to 1.72 cm3/g). However, adding 5 wt% GO led to overactivation. The incorporated rGO has an ordering effect on the carbon matrix. The evolving oxidative species influence the surface chemistry in a complex way, but sufficient N and S atoms (ca. 4 and >1 at%, respectively) were preserved in addition to the large number of developing defects. Despite the complexity of the textural and chemical changes, rGO increased the electrical conductivity monotonically. In alkaline oxygen reduction reaction (ORR) tests, the sample with 1.25 wt% GO exhibited a 4e− mechanism and reasonable stability, but a higher rGO content gradually compromised the performance of the electrodes. The sample containing 5 wt% GO was the most sensitive under oxidative conditions, but after stabilization it exhibited the highest gravimetric capacitance. In Li-ion battery tests, the coulombic efficiency of all the samples was consistently above 98%, indicating the high potential of these carbons for efficient Li-ion insertion and reinsertion during the charge–discharge process, thereby providing a promising alternative for graphite-based anodes. The cell from the 1.25 wt% GO sample showed an initial discharge capacity of 313 mAh/g, 95.1% capacity retention, and 99.3% coulombic efficiency after 50 charge–discharge cycles.
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Zhumadilova, Anar K., Elmira B. Madaliyeva, and Saule Z. Zhigitova. "Conditions for the Development of Phase Components K2CaP2O7 , KCaP3O9 in Toxic Dust." Scientific Horizons 24, no. 3 (August 28, 2021): 38–44. http://dx.doi.org/10.48077/scihor.24(3).2021.38-44.
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The present study analyses the composition and main components of toxic dust. To develop and understand the methods of controlling the dust generation process, it is necessary to study the data that provide detailed information about the reaction mechanism. The results of studies of the phase composition of dust conducted in the laboratory and their comparison with the data obtained earlier by other authors allowed establishing a fairly reliable diagnosis of the phase composition of dust. The analysis revealed that the dust of various phosphorus plants comprises the same basic components, yet the chemical bonds between them differ. The purpose of this study, conducted in the research laboratory of the Zhambyl Branch of LLP “Kazphosphate” (NDFZ) is to investigate the possibility of using new toxic dust, as well as the toxic dust from storage tanks to obtain NPK fertilisers. The study comprises three stages of investigating the oxidation of elementary phosphorus with nitric acid, since elementary yellow phosphorus is dangerous for the environment. As a result of the 1st stage of the study, it was found that toxic dust oxidised with nitric acid cannot be used as a fertiliser, since a non-technological mass is generated, such as acid resin, which is not suitable for drying and granulation. To neutralise the acid reaction mass, it was decided to use an aqueous solution of ammonia, thereby increasing the nutrient content and obtaining a complex NPK fertiliser. In the course of the study, the authors found in the 2nd and 3nd stages of the experiment that to obtain a productsuitable for fertilisation, it is necessary to strictly control the content of elemental phosphorus in the initial toxic dust and adjust the consumption of nitric acid based on its results
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De Lucia, Marco, Michael Kühn, Alexander Lindemann, Max Lübke, and Bettina Schnor. "POET (v0.1): speedup of many-core parallel reactive transport simulations with fast DHT lookups." Geoscientific Model Development 14, no. 12 (December 1, 2021): 7391–409. http://dx.doi.org/10.5194/gmd-14-7391-2021.
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Abstract. Coupled reactive transport simulations are extremely demanding in terms of required computational power, which hampers their application and leads to coarsened and oversimplified domains. The chemical sub-process represents the major bottleneck: its acceleration is an urgent challenge which gathers increasing interdisciplinary interest along with pressing requirements for subsurface utilization such as spent nuclear fuel storage, geothermal energy and CO2 storage. In this context we developed POET (POtsdam rEactive Transport), a research parallel reactive transport simulator integrating algorithmic improvements which decisively speed up coupled simulations. In particular, POET is designed with a master/worker architecture, which ensures computational efficiency in both multicore and cluster compute environments. POET does not rely on contiguous grid partitions for the parallelization of chemistry but forms work packages composed of grid cells distant from each other. Such scattering prevents particularly expensive geochemical simulations, usually concentrated in the vicinity of a reactive front, from generating load imbalance between the available CPUs (central processing units), as is often the case with classical partitions. Furthermore, POET leverages an original implementation of the distributed hash table (DHT) mechanism to cache the results of geochemical simulations for further reuse in subsequent time steps during the coupled simulation. The caching is hence particularly advantageous for initially chemically homogeneous simulations and for smooth reaction fronts. We tune the rounding employed in the DHT on a 2D benchmark to validate the caching approach, and we evaluate the performance gain of POET's master/worker architecture and the DHT speedup on a 3D benchmark comprising around 650 000 grid elements. The runtime for 200 coupling iterations, corresponding to 960 simulation days, reduced from about 24 h on 11 workers to 29 min on 719 workers. Activating the DHT reduces the runtime further to 2 h and 8 min respectively. Only with these kinds of reduced hardware requirements and computational costs is it possible to realistically perform the long-term complex reactive transport simulations, as well as perform the uncertainty analyses required by pressing societal challenges connected with subsurface utilization.