Catalytic Role of Metal Oxides in Gold-Based Catalysts: A First Principles Study of CO Oxidation onTiO2Supported Au

CO oxidation on ${\mathrm{T}\mathrm{i}\mathrm{O}}_2$ 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) ${\mathrm{O}}_2$ 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 ${\mathrm{O}}_2$, giving rise to (i) strong ionic bonding between the adsorbed ${\mathrm{O}}_2$, Au, and the Ti cation; and (ii) a significant activation of ${\mathrm{O}}_2$ towards CO oxidation.