CO oxidation through the formation of carboxyl intermediate on Pt(111) surface: A first principles study

Abstract

The interaction of gas molecules with metal surfaces is extensively studied both theoretically and experimentally. An example of this interaction is the oxidation reaction of carbon monoxide (CO) by hydroxyl (OH) catalyszed by platinum (Pt) in the direct methanol fuel cells (DMFCs). Here, the work offers a simulation of the CO oxidation reaction by the formation of carboxyl group intermediates (COOH) based on the total energy calculation of density functional theory (DFT). The discussion here focuses on the energetics for the reaction of CO(ads) + OH(ads) → COOH(ads) and the decomposition of COOH(ads) → CO2(ads) + H(ads) on the Pt(111) surface. The calculation results show that the formation of COOH(ads) requires an energy of 0.39 eV, whereas the decomposition of COOH(ads) into CO2(ads) and H(ads) requires an activation energy of 0.14 eV. These results indicate that oxidation of CO by the COOH intermediate on Pt(111) surface is possible to occur, considering that the total energy required for the reaction is very low.