scholarly journals Alkali Cation Effect on CO2 Electroreduction to CO: A Local Colligative Property

2021 ◽  
Author(s):  
Seung-Jae Shin ◽  
Hansol Choi ◽  
Stefan Ringe ◽  
Da Hye Won ◽  
Chang Hyuck Choi ◽  
...  
Keyword(s):  
Interface Design ◽  
High Performance ◽  
Effective Means ◽  
Multiscale Simulation ◽  
Reduction Reaction ◽  
Cation Effect ◽  
Cation Concentration ◽  
Rate Determining Step ◽  
First Order Kinetics ◽  
Co2 Electroreduction

Abstract Converting carbon dioxide (CO2) into valuable products is one of the most important processes for a sustainable society. Especially, the electrochemical CO2 reduction reaction (CO2RR) offers an effective means, but its reaction mechanism is not yet fully understood. Here, we demonstrate that cation-coupled electron transfer (CCET) is a rate-determining step in the CO2RR to carbon monoxide. The first-principles-based multiscale simulation identifies a single cation that coordinates a CO2− intermediate adsorbed on Ag electrode. The CCET is experimentally verified by a collapse of the CO2RR polarization curves upon correcting Nernstianly for a bulk cation concentration. As further confirmation, a kinetic study shows that the CO2RR obeys first-order kinetics on a local cation concentration. Finally, this work unveils that the cation effect on CO2RR originates from the local colligative property, and further highlights the importance of ion-pairing tendency for electrochemical interface design to achieve high-performance CO2 electrolysis.

scholarly journals Alkali Cation Effect on CO2 Electroreduction to CO: A Local Colligative Property

2021 ◽  
Author(s):  
Seung-Jae Shin ◽  
Hansol Choi ◽  
Stefan Ringe ◽  
Da Hye Won ◽  
Chang Hyuck Choi ◽  
...  
Keyword(s):  
Interface Design ◽  
High Performance ◽  
Effective Means ◽  
Co2 Reduction ◽  
Multiscale Simulation ◽  
Reduction Reaction ◽  
Cation Effect ◽  
Cation Concentration ◽  
Electrochemical Co2 Reduction ◽  
Co2 Electroreduction

Converting carbon dioxide (CO2) into valuable products is one of the most important processes for a sustainable society. Especially, the electrochemical CO2 reduction reaction (CO2RR) offers an effective means, but its reaction mechanism is not yet fully understood. Here, we demonstrate that cation-coupled electron transfer (CCET) is a rate-determining step in the CO2RR to carbon monoxide. The first-principles-based multiscale simulation identifies a single cation that coordinates a CO2− intermediate adsorbed on Ag electrode. The CCET is experimentally verified by a collapse of the CO2RR polarization curves upon correcting Nernstianly for a bulk cation concentration. As further confirmation, a kinetic study shows that the CO2RR obeys first-order kinetics on a local cation concentration. Finally, this work unveils that the cation effect on CO2RR originates from the local colligative property, and further highlights the importance of ion-pairing tendency for electrochemical interface design to achieve high-performance CO2 electrolysis.

scholarly journals Concerted Cation–Electron Transfer Mechanism for CO2 Electroreduction

2021 ◽  
Author(s):  
Seung-Jae Shin ◽  
Hansol Choi ◽  
Stefan Ringe ◽  
Da Hye Won ◽  
Chang Hyuck Choi ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Interface Design ◽  
High Performance ◽  
Alkali Metal Cation ◽  
Effective Means ◽  
Co2 Reduction ◽  
Multiscale Simulation ◽  
Electron Transfer Mechanism ◽  
Electrochemical Co2 Reduction ◽  
Co2 Electroreduction

Converting carbon dioxide (CO2) into valuable products is one of the most important processes for a sustainable society. Especially, the electrochemical CO2 reduction reaction (CO2RR) offers an effective means, but its reaction mechanism is not yet fully understood. Here, we demonstrate that concerted cation–electron transfer (CCET) is a key catalytic step in the CO2RR to carbon monoxide. The first-principles-based multiscale simulation identifies a single cation that coordinates a CO2− intermediate adsorbed on Ag electrode. The CCET is experimentally verified by a collapse of the CO2RR polarization curves upon correcting for the thermodynamic activity of the cation. As further confirmation, a kinetic study shows that the CO2RR obeys first-order kinetics on the local cation concentration at the electric double layer (estimated by measuring the electrode surface charge). Finally, this work unveils the fundamental origin of different CO2RR activity depending on the species of alkali metal cation, and further highlights the importance of ion-pairing tendency of the cations for electrochemical interface design to achieve high-performance CO2 electrolysis.

Revealing well-defined cluster-supported bi-atom catalysts for enhanced CO2 Electroreduction: A theoretical investigation

2021 ◽  
Author(s):  
Huong Thi Diem Bui ◽  
Viet Q. Bui ◽  
Seong-Gon Kim ◽  
Yoshiyuki Kawazoe ◽  
Hyoyoung Lee
Keyword(s):  
High Activity ◽  
Theoretical Investigation ◽  
First Principles ◽  
High Performance ◽  
Reduction Reaction ◽  
First Principles Calculations ◽  
Co2 Electroreduction

It remains a great challenge to explore high-performance electrocatalysts for CO2 reduction reaction (CO2RR) with high activity and selectivity. Herein, we employ first principles calculations to systematically investigate an emerging...

Parallel Computing for Tire Simulations

2011 ◽  
Vol 39 (3) ◽  
pp. 193-209 ◽  
Author(s):  
H. Surendranath ◽  
M. Dunbar
Keyword(s):  
High Performance ◽  
Effective Means ◽  
Cost Effective ◽  
Turnaround Time ◽  
Careful Consideration ◽  
Rolling Contact ◽  
Element Analysis ◽  
Parallel Solvers ◽  
Design Changes ◽  
Highly Nonlinear

Abstract Over the last few decades, finite element analysis has become an integral part of the overall tire design process. Engineers need to perform a number of different simulations to evaluate new designs and study the effect of proposed design changes. However, tires pose formidable simulation challenges due to the presence of highly nonlinear rubber compounds, embedded reinforcements, complex tread geometries, rolling contact, and large deformations. Accurate simulation requires careful consideration of these factors, resulting in the extensive turnaround time, often times prolonging the design cycle. Therefore, it is extremely critical to explore means to reduce the turnaround time while producing reliable results. Compute clusters have recently become a cost effective means to perform high performance computing (HPC). Distributed memory parallel solvers designed to take advantage of compute clusters have become increasingly popular. In this paper, we examine the use of HPC for various tire simulations and demonstrate how it can significantly reduce simulation turnaround time. Abaqus/Standard is used for routine tire simulations like footprint and steady state rolling. Abaqus/Explicit is used for transient rolling and hydroplaning simulations. The run times and scaling data corresponding to models of various sizes and complexity are presented.

scholarly journals Efficient Catalytic Conversion of Polysulfides by Biomimetic Design of “Branch-Leaf” Electrode for High-Energy Sodium–Sulfur Batteries

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Wenyan Du ◽  
Kangqi Shen ◽  
Yuruo Qi ◽  
Wei Gao ◽  
Mengli Tao ◽  
...  
Keyword(s):  
Active Sites ◽  
High Performance ◽  
Electrochemical Reaction ◽  
Molecular Layer ◽  
Specific Capacity ◽  
High Energy ◽  
Reduction Reaction ◽  
Biomimetic Design ◽  
Co Nanoparticles ◽  
Sodium Sulfur

AbstractRechargeable room temperature sodium–sulfur (RT Na–S) batteries are seriously limited by low sulfur utilization and sluggish electrochemical reaction activity of polysulfide intermediates. Herein, a 3D “branch-leaf” biomimetic design proposed for high performance Na–S batteries, where the leaves constructed from Co nanoparticles on carbon nanofibers (CNF) are fully to expose the active sites of Co. The CNF network acts as conductive “branches” to ensure adequate electron and electrolyte supply for the Co leaves. As an effective electrocatalytic battery system, the 3D “branch-leaf” conductive network with abundant active sites and voids can effectively trap polysulfides and provide plentiful electron/ions pathways for electrochemical reaction. DFT calculation reveals that the Co nanoparticles can induce the formation of a unique Co–S–Na molecular layer on the Co surface, which can enable a fast reduction reaction of the polysulfides. Therefore, the prepared “branch-leaf” CNF-L@Co/S electrode exhibits a high initial specific capacity of 1201 mAh g−1 at 0.1 C and superior rate performance.

scholarly journals Mixed Lithium and Sodium Ion Aprotic DMSO Electrolytes for Oxygen Reduction on Au and Pt Studied by DEMS and RRDE

2021 ◽  
Author(s):  
M. Hegemann ◽  
P. P. Bawol ◽  
A. Köllisch-Mirbach ◽  
H. Baltruschat
Keyword(s):  
Oxygen Reduction ◽  
Product Distribution ◽  
Reduction Reaction ◽  
Mixed Electrolytes ◽  
Peroxide Formation ◽  
Pt Electrode ◽  
Rate Determining Step ◽  
Differential Electrochemical Mass Spectrometry ◽  
Redox Couples ◽  
Pt Electrodes

AbstractIn order to advance the development of metal-air batteries and solve possible problems, it is necessary to gain a fundamental understanding of the underlying reaction mechanisms. In this study we investigate the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER, from species formed during ORR) in Na+ containing dimethyl sulfoxide (DMSO) on poly and single crystalline Pt and Au electrodes. Using a rotating ring disk electrode (RRDE) generator collector setup and additional differential electrochemical mass spectrometry (DEMS), we investigate the ORR mechanism and product distribution. We found that the formation of adsorbed Na2O2, which inhibits further oxygen reduction, is kinetically favored on Pt overadsorption on Au. Peroxide formation occurs to a smaller extent on the single crystal electrodes of Pt than on the polycrystalline surface. Utilizing two different approaches, we were able to calculate the heterogeneous rate constants of the O2/O2− redox couple on Pt and Au and found a higher rate for Pt electrodes compared to Au. We will show that on both electrodes the first electron transfer (formation of superoxide) is the rate-determining step in the reaction mechanism. Small amounts of added Li+ in the electrolyte reduce the reversibility of the O2/O2− redox couples due to faster and more efficient blocking of the electrode by peroxide. Another effect is the positive potential shift of the peroxide formation on both electrodes. The reaction rate of the peroxide formation on the Au electrode increases when increasing the Li+ content in the electrolyte, whereas it remains unaffected on the Pt electrode. However, we can show that the mixed electrolytes promote the activity of peroxide oxidation on the Pt electrode compared to a pure Li+ electrolyte. Overall, we found that the addition of Li+ leads to a Li+-dominated mechanism (ORR onset and product distribution) as soon as the Li+ concentration exceeds the oxygen concentration. Graphical abstract

Tunable mesoporous manganese oxide for high performance oxygen reduction and evolution reactions

2016 ◽  
Vol 4 (2) ◽  
pp. 620-631 ◽  
Author(s):  
Islam M. Mosa ◽  
Sourav Biswas ◽  
Abdelhamid M. El-Sawy ◽  
Venkatesh Botu ◽  
Curtis Guild ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Manganese Oxide ◽  
Oxygen Reduction ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
High Performance ◽  
Reduction Reaction ◽  
Noble Metal Catalysts ◽  
Highly Active ◽  
State Of Art

Understanding the origin of manganese oxide activity for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is a key step towards rationally designing of highly active catalysts capable of competing with the widely used, state-of-art noble metal catalysts.

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