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Articles 151 - 180 of 209
Full-Text Articles in Computational Chemistry
Analyzing The Free Energy Of Ions Sampling A Voltage Gated Sodium Ion Channel, Isabel Varghese
Analyzing The Free Energy Of Ions Sampling A Voltage Gated Sodium Ion Channel, Isabel Varghese
Honors Theses
Voltage gated sodium ion channels are implicated in cardiac diseases, seizures, etc., and they play a role in maintaining ionic homeostasis in cells. Computational studies use prokaryotic model because they are simpler but function similarly to human voltage gated sodium ion channels. This study uses molecular dynamics (MD) to study three specific questions regarding voltage gated sodium ion channels of Magnetococcus marinus. The first question in this study is how the free energy of sodium diffusion compares to that of calcium ion diffusion. We were not able to find any physically significant information due to poor sampling and a lack …
From Evaluating The Performance Of Approximations In Density Functional Theory To A Machine Learning Design, Pedram Tavazohi
From Evaluating The Performance Of Approximations In Density Functional Theory To A Machine Learning Design, Pedram Tavazohi
Graduate Theses, Dissertations, and Problem Reports (ETD)
Density-functional theory (DFT) has gained popularity because of its ability to predict the properties of a large group of materials a priori. Even though DFT is exact, there are inaccuracies introduced into the theory due to the approximations in the exchange-correlation (XC) functionals. Over the 50 years of its existence, scientists have tried to improve the design of the XC functionals. The errors introduced by these functionals are not consistent across all types of solid-state materials. In this project, a high throughput framework was utilized to compare the theoretical DFT predictions with the experimental results available in the Inorganic Crystal …
Heterogeneous Oxidation Of Multi-Component Aqueous Organic Aerosols: The Effect Of Transport Phenomena And Reaction Compartment On Reaction Kinetics., Tadini Wenyika Masaya
Heterogeneous Oxidation Of Multi-Component Aqueous Organic Aerosols: The Effect Of Transport Phenomena And Reaction Compartment On Reaction Kinetics., Tadini Wenyika Masaya
Graduate Theses, Dissertations, and Problem Reports (ETD)
The surface-bulk partitioning of small organic molecules in aqueous droplets was investigated using molecular dynamics. The air-particle interface was modeled using a 80-Å cubic water box containing series of organic molecules and surrounded by gaseous OH radicals. The properties of the organic solutes within the interface and the water-bulk were examined at a molecular-level using density profiles and radial pair distribution functions. Molecules containing only polar functional groups such as urea and glucose are found predominantly in the water bulk, forming an exclusion layer near the water surface. Substitution of a single polar group by an alkyl group in sugars …
Cyclic Voltammetric Simulations On Batteries With Porous Electrodes, Xue-Fan Cai, Sheng Sun
Cyclic Voltammetric Simulations On Batteries With Porous Electrodes, Xue-Fan Cai, Sheng Sun
Journal of Electrochemistry
Lithium-ion batteries (LIBs) are among the most widely used energy storage devices. Whole-cell modeling and simulations of LIBs can optimize the design of batteries with lower costs and higher speeds. The Pseudo-Two-Dimensional (P2D) electrochemical model is among the most famous whole-cell models and widely applied in LIB simulations. P2D model consists of a series of kinetic equations to model Li+/Li diffusion in working/counter electrodes and electrolytes, which are filled in the porous electrodes and separator, and reactions at the interface of electrolyte and active particles. The traditional applications of P2D model, however, are limited to the cases where …
Adsorption Of Helium On A Charged Propeller Molecule: Hexaphenylbenzene, Siegfried Kollotzek, Florent Calvo, Serge Krasnokutski, Fabio Zappa, Paul Scheier, Olof E. Echt
Adsorption Of Helium On A Charged Propeller Molecule: Hexaphenylbenzene, Siegfried Kollotzek, Florent Calvo, Serge Krasnokutski, Fabio Zappa, Paul Scheier, Olof E. Echt
Faculty Publications
Physisorption on planar or curved graphitic surfaces or aromatic rings has been investigated by various research groups, but in these studies the substrate was usually strictly rigid. Here we report a combined experimental and theoretical study of helium adsorption on cationic hexaphenylbenzene (HPB), a propeller-shaped molecule. The orientation of its propeller blades is known to be sensitive to the environment, with substantial differences between the molecule in the gas phase and in the crystalline solid. Mass spectra of HenHPB+, synthesized in helium nanodroplets, indicate enhanced stability for ions containing n = 2, 4, 14, 28, 42, …
Dft Study Of NiM@Pt1AuN-M-1 (N=19, 38, 55, 79; M = 1, 6, 13, 19) Core-Shell Orr Catalyst, Wen-Jie Li, Dong-Xu Tian, Hong Du, Xi-Qiang Yan
Dft Study Of NiM@Pt1AuN-M-1 (N=19, 38, 55, 79; M = 1, 6, 13, 19) Core-Shell Orr Catalyst, Wen-Jie Li, Dong-Xu Tian, Hong Du, Xi-Qiang Yan
Journal of Electrochemistry
The slow kinetics of oxygen reduction reaction (ORR) limits the performance of low temperature fuel cells. Thus, it needs to design effective catalysts with low cost. Core-shell clusters (CSNCs) show promising activity because of their size-dependent geometric and electronic effects. The ORR activity trend of Nim@Pt1Aun-m-1(n = 19, 38, 55, 79; m = 1, 6, 13, 19) was studied using the GGA-PBE-PAW methods. The adsorption configurations of *O, *OH and *OOH were optimized and the reaction free energies of four proton electron (H+ + e-) transfer steps …
Computational Methodologies For The Simulation And Analysis Of Low-Frequency Vibrations In Molecular Crystals, Sara Jean Dampf
Computational Methodologies For The Simulation And Analysis Of Low-Frequency Vibrations In Molecular Crystals, Sara Jean Dampf
Dissertations - ALL
Quantum mechanical models are used to calculate a host of physical phenomena in molecular solids ranging from mechanical elasticity to the energetic stability ordering of polymorphs. However, with the many software packages and methodologies available, it can be difficult to select the most suitable model for the problem at hand without prior knowledge. A promising approach for evaluating the performance of solid-state models is the comparison of the simulations to experimentally measured low-frequency (sub-200 cm-1) vibrational spectra. As this region is dominated by weak intermolecular forces and shallow potential energy surfaces, even slight miscalculations in the solid-state packing arrangements can …
Structural, Dynamic, Elastic And Electronic Properties Of Anin (A = Li, Na, Mg, Ca): First-Principles Calculations, Xia-Min Huang, Li-Hong Zhang, Shun-Qing Wu, Yong Yang, Zi-Zhong Zhu
Structural, Dynamic, Elastic And Electronic Properties Of Anin (A = Li, Na, Mg, Ca): First-Principles Calculations, Xia-Min Huang, Li-Hong Zhang, Shun-Qing Wu, Yong Yang, Zi-Zhong Zhu
Journal of Electrochemistry
Ternary transition metal nitrides ANiN (A = Li, Na, Mg, Ca) are potential electrode materials for rechargeable batteries. The physical properties, such as the thermodynamic stability, the electronic band gap as well as the elastic stability, are important for their battery applications. Here, comparative studies are performed for the structural, dynamic, elastic and electronic properties of ANiN by the first-principles method. The calculations on the cohesive energy versus unit-cell volume and phonon spectra are employed to determine the most stable structures of ANiN. The calculated elastic constants of the most stable structures indicate that the Born-Huang criterion for the elastic …
Complexes With Atomic Gold Ions: Efficient Bisligand Formation, Felix Duensing, Elisabeth Gruber, Paul Martini, Marcelo Goulart, Michael Gatchell, Bilal Rasul, Olof E. Echt, Fabio Zappa, Masoomeh Mahmoodi-Darian, Paul Scheier
Complexes With Atomic Gold Ions: Efficient Bisligand Formation, Felix Duensing, Elisabeth Gruber, Paul Martini, Marcelo Goulart, Michael Gatchell, Bilal Rasul, Olof E. Echt, Fabio Zappa, Masoomeh Mahmoodi-Darian, Paul Scheier
Faculty Publications
Complexes of atomic gold with a variety of ligands have been formed by passing helium nanodroplets (HNDs) through two pickup cells containing gold vapor and the vapor of another dopant, namely a rare gas, diatomic molecule (H2, N2, O2, I2, P2), or various polyatomic molecules (H2O, CO2, SF6, C6H6, adamantane, imidazole, di-cyclopentadiene, and fullerene). The doped HNDs were irradiated by electrons; ensuing cations were identified in a high-resolution mass spectrometer. Anions were detected for benzene, di-cyclopentadiene, and fullerene. For most …
Sf6+: Stabilizing Transient Ions In Helium Nanodroplets, Simon Albertini, Stefan Bergmeister, Felix Laimer, Paul Martini, Elisabeth Gruber, Fabio Zappa, Milan Ončák, Paul Scheier, Olof E. Echt
Sf6+: Stabilizing Transient Ions In Helium Nanodroplets, Simon Albertini, Stefan Bergmeister, Felix Laimer, Paul Martini, Elisabeth Gruber, Fabio Zappa, Milan Ončák, Paul Scheier, Olof E. Echt
Faculty Publications
There are myriads of ions that are deemed too short-lived to be experimentally accessible. One of them is SF6+. It has never been observed, although not for lack of trying. We demonstrate that long-lived SF6+ can be formed by doping charged helium nanodroplets (HNDs) with sulfur hexafluoride; excess helium is then gently stripped from the doped HNDs by collisions with helium gas. The ion is identified by high-resolution mass spectrometry (resolution m/Dm = 15000), the close agreement between the expected and observed yield of ions that contain minor sulfur isotopes, and collision-induced dissociation …
Electronic Transitions In Rb2+ Dimers Solvated In Helium, Simon Albertini, Paul Martini, Arne Schiller, Harald Schöbel, Elham Ghavidel, Milan Ončák, Olof E. Echt, Paul Scheier
Electronic Transitions In Rb2+ Dimers Solvated In Helium, Simon Albertini, Paul Martini, Arne Schiller, Harald Schöbel, Elham Ghavidel, Milan Ončák, Olof E. Echt, Paul Scheier
Faculty Publications
We have measured depletion spectra of the heteronuclear (85Rb87Rb+) dimer cation complexed with up to 10 He atoms. Two absorption bands are observed between 920 and 250 nm. The transition into the repulsive 12Sigmau+ state of HeRb2+ gives rise to a broad feature at 790 nm (12650 cm–1); it exhibits a blueshift of 98 cm–1 per added He atom. The transition into the bound 1 2Piu state of HeRb2+ reveals vibrational structure with a band head at < 15522 cm–1, a harmonic …
Theoretical Study On Electrical Properties Of Molecular Junctions Of Viologen Derivatives, Zhuan-Yun Cai, Jia Liu, Si-Yuan Guan, De-Yin Wu, Zhong-Qun Tian
Theoretical Study On Electrical Properties Of Molecular Junctions Of Viologen Derivatives, Zhuan-Yun Cai, Jia Liu, Si-Yuan Guan, De-Yin Wu, Zhong-Qun Tian
Journal of Electrochemistry
In this paper, the electrical properties of molecular junctions formed N,N′-bis(4-thioalkyl)-4,4′-bipyridinium (viologen) moiety between two gold (Au) electrodes have been investigated by combining density functional theory and non-equilibrium Green’s functional approach. To modulate the viologen molecule to be a cation with one and two positive charges (V+ and V2+), we introduce one and two trifluoroacetic acid ions (TFA-) around the molecule, respectively. The valence states of V+ and V2+ are confirmed by checking Mulliken and NBO charges. Then the relationship between molecular conductance and electronic structures of the neutral state …
Numerical Simulations Of Current And Temperature Distribution Of Symmetrical Double-Cathode Solid Oxide Fuel Cell Stacks Based On The Theory Of Electric-Chemical-Thermal Coupling, Cheng-Rong Yu, Jian-Guo Zhu, Cong-Ying Jiang, Yu-Chen Gu, Ye-Xin Zhou, Zhuo-Bin Li, Rong-Min Wu, Zheng Zhong, Wan-Bing Guan
Numerical Simulations Of Current And Temperature Distribution Of Symmetrical Double-Cathode Solid Oxide Fuel Cell Stacks Based On The Theory Of Electric-Chemical-Thermal Coupling, Cheng-Rong Yu, Jian-Guo Zhu, Cong-Ying Jiang, Yu-Chen Gu, Ye-Xin Zhou, Zhuo-Bin Li, Rong-Min Wu, Zheng Zhong, Wan-Bing Guan
Journal of Electrochemistry
Solid oxide fuel cell (SOFC) is a high-efficient clean conversion device for future energy management. Because of the low antioxidant reduction ability and complex thermal stress, the structure of traditional asymmetrical thin anode-supported planar SOFC is easily to be broken under stack operating conditions. To overcome these defects, a new complete symmetrical SOFC based on double-sided cathodes was developed. To study the influences of gas flow direction and current collection mode on the cell performance inside stack, a numerical model was established by finite element method based on the theory of electro-thermo-chemo multiphysical coupling. By applying this model, the molar …
Pitting Behavior Of Stainless Steel In Simulated Marine Atmosphere Based On Electrochemical Noise, Jun-Hao Deng, Gui Wang, Jie-Zhen Hu, Pei-Chang Deng, Huan-Huan Hu
Pitting Behavior Of Stainless Steel In Simulated Marine Atmosphere Based On Electrochemical Noise, Jun-Hao Deng, Gui Wang, Jie-Zhen Hu, Pei-Chang Deng, Huan-Huan Hu
Journal of Electrochemistry
A measurement system for detecting the atmospheric corrosion of stainless steels was built based on electrochemical noise technology. The electrochemical noise data have been collected for 304 stainless steels which were exposed to the simulated marine atmospheric environment. The pitting behaviors of 304 stainless steels were studied by analyzing the electrochemical noise results with the time domain spectrogram, statistic, frequency domain spectrogram and shot noise theory. Meanwhile, potentiodynamic polarization and morphological analysis were also used as assistant measurements. It has shown that the 304 stainless steel in the whole wet-dry cycle could be divided into three stages, including passivation stage, …
Cyclic Voltammetry Coupled With Faradic Adsorption/Desorption Processes: A Finite Element Simulation, Jia-Yao Guo, Duan Chen, Jie Zhang, Dong-Ping Zhan
Cyclic Voltammetry Coupled With Faradic Adsorption/Desorption Processes: A Finite Element Simulation, Jia-Yao Guo, Duan Chen, Jie Zhang, Dong-Ping Zhan
Journal of Electrochemistry
Heterogeneous electron transfer (HET) coupled with Faradic adsorption/desorption is the fundamental processes involved in hydrogen evolution reaction, oxygen reduction reaction, carbon dioxide reduction reaction, and methanol oxidation reaction. However, the electrochemical behaviors of HET coupled with Faradic adsorption/desorption are complicated, and difficult to get the interface reaction kinetics quantitatively. In this paper, finite element method was adopted to simulate the cyclic voltammetric behaviors of HET coupled with Faradic adsorption/desorption processes by using the Fick’s second law and Langmuir isotherm. The cyclic voltammograms when reactant or product adsorbed weakly or strongly were simulated, and they agreed well with the classical results. …
Insight Into The Important Solid/Liquid Double Layer From First-Principles Calculations, Ya-Hui Fang, Zhi-Pan Liu
Insight Into The Important Solid/Liquid Double Layer From First-Principles Calculations, Ya-Hui Fang, Zhi-Pan Liu
Journal of Electrochemistry
Solid/liquid double layer is of fundamental importance in electrochemistry. It has been a challenge and focus to understand the equilibrium and the dynamic phenomena (e.g., chemical reactions) at the electrode/electrolyte double layer in a unified theoretical framework. In recent years, rapid expansion and development have been done in the application of first principles density function theory (DFT) simulation on the double layer. This article reviews the current theoretical methods for electrochemistry modeling, such as reaction center model, thermodynamic method and double reference model. The progress in the computation procedures based on first principles periodic continuum solvation method (DFT/CM-MPB) for obtaining …
Molecular Dynamics Simulations Of Phase Behaviour And Structural Studies Of Guanidinium Triflate Ionic Liquid And Its Mixture With Water And N-Methyldiethanolamine For Carbon Dioxide Removal, Naimah Haron
Student Works (2020-2029)
Molecular dynamics (MDs) simulations with an all-atom force field have been carried out to understand the phase equilibrium behaviour of aqueous guanidinium triflate [gua][OTf] ionic liquid (IL) (binary system) at 440.15 K, as well as the phase equilibrium behaviour of N-methyl diethanolamine (MDEA) with aqueous [gua][OTf] IL (ternary system) at 298.15 K. This work further elaborated the understanding of absorption mechanism of carbon dioxide (CO2) into ternary system at 298.15 K. For binary system, the simulations measured changes in different physical properties such as density, structural, bonding properties (radial distribution function (RDF)), water clustering and hydrogen bonding) and dynamic property …
Tools For Understanding Static Structure Factors And Their Application To Simulations Of Liquids, Travis Mackoy
Tools For Understanding Static Structure Factors And Their Application To Simulations Of Liquids, Travis Mackoy
Graduate Research Theses & Dissertations
Molecular dynamics (MD) simulations can be used to compute static structure factors (��(��)) and provide an interpretation of the underlying periodic atomic ordering. MD simulations complement experimentally measured ��(��) by allowing qualitative assignment of peaks to various ordering, such as cation-anion ordering in ionic liquids, via decomposition of ��(��) into partial ��(��). Here we present a method for classifying interatomic distances that allows for quantitative peak assignment and visualization of atoms that contribute most to each peak in calculated ��(��) for soft materials. The method is illustrated by investigating ��(��) for the ionic liquid 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide (C4C1pyrrTFSI), which shows two …
Dft Study Of Water Assisted Hydrogen Dissociation On Gold Nanoparticles, Jia-Li Chen, Xia-Guang Zhang, De-Yin Wu, Zhong-Qun Tian
Dft Study Of Water Assisted Hydrogen Dissociation On Gold Nanoparticles, Jia-Li Chen, Xia-Guang Zhang, De-Yin Wu, Zhong-Qun Tian
Journal of Electrochemistry
The gold nanoparticles (GNPs) show special activity toward hydrogen (H2) dissociation, comparing with bulk gold. Such activity is significantly affected by the existence of water. To inspect the influence of water on GNPs catalyzed H2 dissociation, we carried out density functional theory (DFT) calculations along the reaction paths for water clusters (H2O)m (m = 1, 2, 3, 7) assisted H2 dissociation on gold clusters (Aunδ, n = 3 ~ 5; δ = 0, 1). Our calculated results show that water benefits to the H2 dissociation. The dissociation mechanism varies …
Simulation Of Fractal Growth On Metal Wire Electrode, Li-Feng Ding, Pei-Yuan Mao, Jun Cheng, Yu-Lan Niu, Yu-Hao Wen, Wei Chen
Simulation Of Fractal Growth On Metal Wire Electrode, Li-Feng Ding, Pei-Yuan Mao, Jun Cheng, Yu-Lan Niu, Yu-Hao Wen, Wei Chen
Journal of Electrochemistry
During processes of metal electrodepostion, there exist many complex morphological forms such as dendritic growing in the cathode deposited metal edge, which will seriously affect the quality of the electrodeposited product and current efficiency during machining. Investigations on dendritic crystal growing process and morphology could help controlling growth of electrolysis precipitate. In this work, Python and Matlab softwares were used, and the model of parallel electrode electrodeposition was established based on the diffusion-limited aggregation (DLA) model. By analyzing the law of fractal growth at different conditions of the particles number, probability, electrode spacing, the movement step length and orientation drift, …
Numerical Simulation Of Output Performance In Pemfc, Xin Luo, Shi-Zhong Chen, Yu-Hou Wu
Numerical Simulation Of Output Performance In Pemfc, Xin Luo, Shi-Zhong Chen, Yu-Hou Wu
Journal of Electrochemistry
The COMSOL software was used to analyze the output performances in proton exchange membrane fuel cell(PEMFC) under three kinds of flow fields. Under the same operating conditions, the performance differences among single serpentine flow field, interdigitated flow field and mixed flow field are compared, and the causes of the differences in the output performances of PEMFC under three kinds of flow fields were analyzed. The simulation results showed that the output performance of the mixed flow field was the best, the output performance of the interdigitated flow field the second and the output performance of single serpentine flow field the …
Simulation Analysis In Dynamic Performance Of Proton Exchange Membrane Fuel Cell Under Starting Condition, Yan Xiao, Ying-Jie Chang, Wei Zhang, Qiu-Hong Jia
Simulation Analysis In Dynamic Performance Of Proton Exchange Membrane Fuel Cell Under Starting Condition, Yan Xiao, Ying-Jie Chang, Wei Zhang, Qiu-Hong Jia
Journal of Electrochemistry
Based on the equivalent circuit model, by considering both the dynamic gas pressure model and the dynamic heat transfer model, a lumped parameter model is developed. The start process of the fuel cell is simulated by using SIMULINK software. The undershoot of the voltage is observed from the simulation results, and the response time of the voltage is basically the same as that of the fuel cell temperature, which indicates that the temperature has great influence on the dynamic performance of the fuel cell. From the perspective of the temperature, the dynamic responses of the thermodynamic potential, the activation overvoltage, …
Surface Chemical Properties Of Mo2C, W2C, Mo2N And W2N Probed With Co, Co2 And O2 Adsorption: A Dft Analysis, Jingyun Ye, Tianyu Zhang, Lingyun Xu, Shuxia Yin, Krishanthi Weerasinghe, Pamela Ubaldo, Ping He, Qingfeng Ge
Surface Chemical Properties Of Mo2C, W2C, Mo2N And W2N Probed With Co, Co2 And O2 Adsorption: A Dft Analysis, Jingyun Ye, Tianyu Zhang, Lingyun Xu, Shuxia Yin, Krishanthi Weerasinghe, Pamela Ubaldo, Ping He, Qingfeng Ge
Journal of Electrochemistry
Transition metal carbides and nitrides are attractive materials for electrodes in many electrochemical energy storage and conversion applications. In the present study, we use density functional theory slab calculations to characterize the surface chemical properties of molybdenum (Mo) and tungsten (W) carbides and nitrides, namely, Mo2C, W2C, Mo2N and W2N with the adsorption of CO, CO2 and O2. These probing molecules provide measures of in both acidity/basicity and redox property of for the surfaces of these carbides and nitrides. Our results show that Lewis basic sites were responsible for CO2 …
Electrostatic Interactions Of Water In External Electric Field: Molecular Dynamics Simulations, Qiang Zhu, Zigui Kan, Jing Ma
Electrostatic Interactions Of Water In External Electric Field: Molecular Dynamics Simulations, Qiang Zhu, Zigui Kan, Jing Ma
Journal of Electrochemistry
A series of molecular dynamics simulations with or without external electric field have been carried out for a bulk water with periodic boundary condition. The difference in radial distribution function of interatomic O…O distance is subtle, with and without external electric field, except for the orientation of dipole moments of water molecules. Without the applied external electric field, distribution of the orientation angle of dipole moments is rather broad. The induced local electric field is analyzed as a function of altitude in direction of electric field. The variation of the local induced electric field is increased as the increase of …
Dynamic Simulation Of Oxygen Reduction Reaction In Pt/C Electrode For Proton Exchange Membrane Fuel Cells, Shang Li, Fen Zhou, Lei Chen, Mu Pan
Dynamic Simulation Of Oxygen Reduction Reaction In Pt/C Electrode For Proton Exchange Membrane Fuel Cells, Shang Li, Fen Zhou, Lei Chen, Mu Pan
Journal of Electrochemistry
It is an urgent need to reduce the Pt loading in electrode for practical fuel cell applications worldwide. Herein, we theoretically investigate the oxygen distribution, generated current, and minimum Pt loading of Pt/C electrode for practical applications based on kinetic model of oxygen reduction reaction. The results indicate that with increasing electrode effective thickness to 40 mm, serious concentration polarization is expected for Pt/C electrode. To generate a power density of 1.4 W⋅cm-2 (2.1A⋅cm-2@0.67 V) for fuel cell, the cathode catalyst layer thickness in PEMFC should be as thin as 3 mm. The minimum Pt loading will …
Electrochemical Catalysis: A Dft Study, Li Li, Zi-Dong Wei
Electrochemical Catalysis: A Dft Study, Li Li, Zi-Dong Wei
Journal of Electrochemistry
In this review, we focus on achievements in electro-catalysis based on the density function theory study. The relationships among the electrode potential, electronic structure of catalysts and electro-catalytic activity are summarized in three parts: the adsorption and desorption of species, electron transfer, and stability of catalysts. The electrode potential and the electronic structure (d-band center or Fermi (HOMO) energy) of catalysts significantly influence the formation, adsorption and desorption of surface species on electrode. The electro-catalytic activity can be improved by modulating the electrode potential and electronic structure of catalysts.
Effects Of Oxygen Coverage And Hydrated Proton Model On The Dft Calculation Of Oxygen Reduction Pathways On The Pt(111) Surface, Li-Hui Ou, Sheng-Li Chen
Effects Of Oxygen Coverage And Hydrated Proton Model On The Dft Calculation Of Oxygen Reduction Pathways On The Pt(111) Surface, Li-Hui Ou, Sheng-Li Chen
Journal of Electrochemistry
DFT calculation is used to study various possible steps in the oxygen reduction reaction (ORR), including the adsorption and dissociation process of O2 and the serial protonation process of dissociated products to form H2O on the Pt(111) surface. By using slabs of different sizes, and different numbers of pre-adsorbed oxygen atoms, the coverage effects on the pathways are investigated. The calculated results using different hydrated proton models are also compared. It is shown that the initial step of the ORR is the formation of a protonated end-on chemisorbed state of OOH*, which can transform to an unprotonated …
A Dft Calculation Screening Of Pt-Based Bimetallic Catalysts For Oxygen Reduction, Li-Hui Ou, Sheng-Li Chen
A Dft Calculation Screening Of Pt-Based Bimetallic Catalysts For Oxygen Reduction, Li-Hui Ou, Sheng-Li Chen
Journal of Electrochemistry
Developing Pt-lean catalysts for oxygen reduction reaction (ORR) is the key for large-scale application of proton exchange membrane fuel cell (PEMFC). In this paper, we have proposed a multiple-descriptor strategy for screening efficient and durable ORR alloy catalysts of low Pt content. We argue that an ideal Pt-based bimetallic alloy catalyst for ORR should possess simultaneously negative alloy formation energy, negative surface segregation energy of Pt and a lower oxygen binding ability than pure Pt. By performing detailed DFT calculations on the thermodynamics, surface chemistry and electronic properties of various Pt-M alloys (M refers to non-precious transition metals in the …
A New Random Walk Simulation Model For Study Of Diffusion Behavior Of Single Particle Within Two-Dimensional Space, Jianwei Zhao, Lili Chen, Yingqiang Fu, Shaohong Li, Tiannan Chen, Shijie Zhang
A New Random Walk Simulation Model For Study Of Diffusion Behavior Of Single Particle Within Two-Dimensional Space, Jianwei Zhao, Lili Chen, Yingqiang Fu, Shaohong Li, Tiannan Chen, Shijie Zhang
Journal of Electrochemistry
Research on diffusion behaviors is of significant value in that it is closely related to transport phenomena in micro-chemistry. However, the effects of variables on diffusion are still unclear. Here, we developed and programmed a simulation methodology along with data analysis, which was capable to simulate the diffusion of a particle within twodimensional heterogeneous space in large timescale; the effects of periodically arranged impenetrable barriers of specific shape and lateral drifting velocity on diffusion behavior were studied. As well as standard mean square displacement analysis, a new method, the appearance probability distribution method, was introduced, which revealed whether the particle …
Application Of First Principles Calculations In Anode Materials For Lithium Ion Batteries, Tian-Ran Zhang, Dai-Xin Li, Si-Qi Yang, Zhan-Liang Tao, Jun Chen
Application Of First Principles Calculations In Anode Materials For Lithium Ion Batteries, Tian-Ran Zhang, Dai-Xin Li, Si-Qi Yang, Zhan-Liang Tao, Jun Chen
Journal of Electrochemistry
First principles calculations play an important role in the study and development of new materials for lithium batteries. In this paper, we review the application of first principles calculations in the design of anode materials, including the modeling of the interaction of lithium in the anode materials, capacity, voltage, electrochemical reaction process, diffusion, rate capability, the relationship between the structure and properties, and the experimental phenomena interpreting. Based on the discussions, we emphasize on the importance of first principles calculations and demonstrate their requirement for further development.