First-principles modeling for the electro-oxidation of small molecules
Advances in Electrocatalysis, Materials, Diagnostics and Durability
Electrocatalyst materials for low temperature fuel cells
Fundamental catalysis models
Published Online: 15 DEC 2010
Copyright © John Wiley & Sons, Ltd. All rights reserved.
Handbook of Fuel Cells
How to Cite
Neurock, M. 2010. First-principles modeling for the electro-oxidation of small molecules. Handbook of Fuel Cells. .
- Published Online: 15 DEC 2010
The electrocatalytic oxidation of small organic molecules is of great interest in the development of direct liquid fuel cells. While much is known concerning the overall electrocatalytic chemistry, the mechanisms and active sites which control these reactions remain elusive. The advances that have taken place in computation together with new method developments have made theory an invaluable partner with experiment in elucidating the mechanisms and sites that control electrocatalysis. Recent advances in ab initio methods for modeling electrochemical systems and their application to modeling the oxidation of methanol, formic acid and ethanol are discussed herein. The results reveal that while each of these fuels can be oxidized via direct and indirect routes, the controlling paths are function of the molecule as well as the size and configuration of the active surface sites. Methanol proceeds via indirect oxidation paths which require ensemble sizes of at least 3 metal atoms. Formic acid which internally contains CO2 proceeds instead via a direct path over just 1–2 metal atoms. Ethanol is oxidized primarily to acetaldehyde and acetic acid and requires the presence of defect sites to activate the CC bond. The unique nature of the active site for each of these fuels reveals different alloying effects.
- Ab initio density functional theory (DFT);
- electrocatalytic oxidation mechanisms;
- ensemble size effects