Insights into reaction mechanisms of ethanol electrooxidation at the Pt/Au(111) interfaces using density functional theory
Understanding ethanol electrooxidation reaction kinetics is fundamental to the development of direct ethanol fuel cells. The utilization of binary PtAu catalysts has been reported recently as an effective strategy to enhance ethanol electrocatalytic oxidation; however, the catalytic reaction mechanisms are still unclear. In this work, we systematically studied the ethanol electrooxidation reaction mechanisms on Pt/Au(111) model surfaces at an atomic level through high level density functional theory (DFT) calculations; particularly the flat (111) terrace and the stepped (111) × (110) and (111) × (100) interfaces with diverse surface atomic arrangements were considered, respectively. It was found that for ethanol dissociation, the flat (111) terrace is more active than the stepped (111) × (110) and (111) × (100) interfaces. The stepped interfaces, however, could activate water from the aqueous electrolyte solution to form adsorbed OH* at the electrode potential below 0.53 V vs. SHE (standard hydrogen electrode), which is of great importance in coupling with the CH3CO* intermediate formed from ethanol dissociation to produce acetic acid as the final product of the ethanol electrooxidation reaction without releasing CO2. The C–C bond splitting process for ethanol oxidation to form C1 products was very limited. The terrace sites can facilitate both ethanol decomposition and acetic acid formation at the electrode potential above 0.53 V vs. SHE. Our results clearly identify the fact that for ethanol electrooxidation reactions, with an increase in electrode potential, the active sites on Pt/Au(111) surfaces change from those at the stepped interfaces to the flat terrace sites.
Funding
National Natural Science Foundation of China (NSFC 21903001)
Natural Science Foundation of Anhui Province (1908085QB58)
Sustainable Hydrogen Production from Seawater Electrolysis
Engineering and Physical Sciences Research Council
Find out more...Royal Society and the Newton Fund through the Newton Advanced Fellowship award (NAF\R1\191294)
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Chemical Engineering
Published in
Physical Chemistry Chemical PhysicsVolume
24Issue
44Pages
27277 - 27288Publisher
Royal Society of ChemistryVersion
- AM (Accepted Manuscript)
Rights holder
© Royal Society of ChemistryPublisher statement
This paper was accepted for publication in the journal Physical Chemistry Chemical Physics and the definitive published version is available at https://doi.org/10.1039/d2cp03186hAcceptance date
2022-10-17Publication date
2022-10-21Copyright date
2022ISSN
1463-9076eISSN
1463-9084Publisher version
Language
- en