Investigation of methanol oxidation over Au/catalysts using operando IR spectroscopy: determination of the active sites, intermediate/spectator species, and reaction mechanism.

FTIR spectroscopy coupled with mass spectrometry has been used to study the mechanism of methanol oxidation at low temperatures on nanostructured Au/CeO(2) and Au/TiO(2) catalysts. Activity and selectivity toward CO(2) have been investigated through simultaneous analysis of adsorbed surface species and gaseous species, and some key steps in the oxidation pathway, active sites, and intermediate species are proposed. Among the detected species, some kinds of methoxy species formed on the support were identified as intermediates, which further transform into formates whose oxidation was found to be the rate-determining step for the reaction.