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.