Influence of Oxygen Vacancies on the Properties of Ceria-Supported Gold

The adsorption of CO on narrosized gold particles deposited on a cerium oxide substrate is strongly influenced by the roughness and concentration of oxygen vacancies of the CeOx substrate surface. Literature showed that Au nucleates at step edges on oxidized samples. For oxidized samples we found that the Au dispersion is dependent on the surface roughness. A rough CeO2 surface has a higher step density, which results in a Au higher particle density with a smaller average diameter. Other studies showed that Au nucleates on oxygen vacancies on reduced CeOx substrates. We found that small Au particles adsorbed on oxygen vacancies exhibit a significantly higher Au 4f binding energy than Au particles on oxidized CeO2. Relatively less CO adsorbs on small Au particles on a reduced substrate, with a significantly lower adsorption energy than on Au on an oxidized substrate. For larger particles the influence of oxygen vacancies in the substrate is negligible.