Morphological Effects of Gold Clusters on the Reactivity of Ceria Surface Oxygen

Well-defined {100}-faceted ceria nanocube-supported gold nanoclusters with various morphologies, including individual atom, monolayer, multilayer and nanoparticle, have been synthesized and systematically investigated combined with density functional theory calculations. A strong morphological effect of gold clusters on the reactivity of ceria surface oxygen has been identified. The reducibility and CO oxidation activities of Au/CeO2 catalysts increased significantly as the morphology of the gold clusters changed from single atoms to monolayer, then to multilayer, then nanoparticles. It was revealed that up to a bilayer of gold clusters were needed for desirable catalytic performance in the Au/CeO2 system. The transfer of electrons from gold clusters to the surface Ce–O groups of ceria and strong Au–Au interactions play significant roles in determining the reducibility of surface oxygen of CeO2.