Electronic Structures of Ag and Au Adsorbed on TiO₂(110) Surfaces by First-Principles Calculations

Abstract

We have investigated electronic structures and charge transfers of Ag and Au supported on the TiO₂(110) surface, using first-principles calculation. In order to investigate the effect of stoichiometry on the electronic structures, we examined Au and Ag adsorption on three kinds of TiO₂(110) surface with different stoichiometry; the perfect stoichiometric surface, Ti-rich surface, and O-rich surface. We considered the on-top site above the bridging-oxygen atom (site A) and above the five-fold titanium atom (site B) for the perfect stoichiometric surface, the bridging-oxygen vacant site (site C) for the Ti-rich surface, and the six-fold titanium vacant site (site D) for the O-rich surface as the adsorption site. The adhesive energies between the metal layer and the TiO₂(110) surface for the non-stoichiometric surfaces are much larger than that for the stoichiometric surface. And the Ag atom strongly interacts with the surface oxygen atoms at surface, while the Au atom strongly interacts with the surface titanium atoms at surface. The interaction between the metal and the TiO₂(110) surface depends on the surface stoichiometry and the kind of metal species.