Reducible inverse CeOx-based catalyst as a potential candidate for electroreduction

Abstract

The inverse metal oxide/metal catalyst is very suitable for electrochemical reaction due to unique catalytic properties of metal oxide with small size and good conductivity of metal. To clarify the potential applications of inverse catalyst in electrochemistry, especially for reducible oxides, an inverse CeOx/Ag(111) model electrocatalyst was constructed and investigated by Density Functional Theory (DFT) for CO2 electrochemical reduction. It is found that Ag atoms acting as an electron donor, can partially reduce Ce4+ to Ce3+ in the supported CeOx cluster leading to the formation of interfacial Ce3+ active sites, which could promote the adsorption and reduction of CO2. As expected, all elementary reaction involved in the CO2 electrochemical reduction are more facile on CeOx/Ag(111) than pure Ag catalyst. Besides, the generation of CH3OH and CH4 is favored on CeOx/Ag(111), whereas the formation of CO, CH2O and H2 is obviously suppressed. More importantly, the weak interaction between H2O and CeOx cluster is beneficial for the desorption of OH intermediate, which makes the regeneration of the catalyst become easier and result in a great recyclability. All those results demonstrate that CeOx/Ag(111) is a potential excellent electrochemical catalyst.