First-principles study of thePt∕CeO2(111)interface

The adsorption of platinum on the ceria (111) surface may change the reduction and redox properties of $\mathrm{Ce}{\mathrm{O}}_{2}$. The density functional theory with the inclusion of on-site Coulomb interaction has been used to study the properties of Pt adsorbed on the (111) surfaces of stoichiometric and reduced ceria. In all cases, strong interactions are found between the Pt and the surfaces. The Pt-O-Ce bonds may be formed between the Pt adatom and the surface in the preferred adsorption mode. The adsorption on the reduced surface is stronger than on the unreduced surface. The formation energy of an O vacancy at the $\mathrm{Pt}∕\mathrm{Ce}{\mathrm{O}}_{2}(111)$ interface is lower than on the clean $\mathrm{Ce}{\mathrm{O}}_{2}(111)$ surface due to the existence of the lower lying partially occupied metal induced gap states including mainly the $\mathrm{Pt}\phantom{\rule{0.2em}{0ex}}4d$ states below the empty $\mathrm{Ce}\phantom{\rule{0.2em}{0ex}}4f$ band.