Catalytic role of metal oxides in gold-based catalysts: a first principles study of CO oxidation on TiO2 supported Au.

CO oxidation on TiO2 supported Au has been studied using density functional theory calculations. Important catalytic roles of the oxide have been identified: (i) CO oxidation occurs at the interface between Au and the oxide with a very small barrier; and (ii) O2 adsorption at the interface is the key step in the reaction. The physical origin of the oxide promotion effect has been further investigated: The oxide enhances electron transfer from the Au to the antibonding states of O2, giving rise to (i) strong ionic bonding between the adsorbed O2, Au, and the Ti cation; and (ii) a significant activation of O2 towards CO oxidation.