Crystal-plane-dependent metal–support interaction in Au/TiO2

Abstract

Metal–support interactions between Au and TiO₂ are studied based on Au/TiO₂ catalysts with different TiO₂ crystal planes exposed. With ex situ XPS, TEM and in situ DRIFTS, we have investigated the crystal-plane-dependent metal–support interaction effects on the physiochemical properties of Au/TiO₂ catalysts. Based on the structural characterization and spectroscopic results, we can observe chemical oscillations (including the electronic structures of Au nanoparticles and the interaction between Au/TiO₂ catalysts and CO molecules) during alternate H₂ and O₂ pre-treatments. Their variation tendencies of oscillations are greatly dependent on the crystal planes of TiO₂ and the pre-treatment temperature. Furthermore, their surface and electronic changes after H₂ and O₂ pre-treatments can be well correlated with their catalytic activities in CO oxidation. Electron-transfer processes across the Au–TiO₂ interface are proved to be the origin accounting for their changes after H₂ and O₂ pre-treatments. The different electronic structures of different TiO₂ crystal planes should have relationships with the crystal-plane-dependent metal–support interaction effects in Au/TiO₂.