O2 adsorption on MO2 (M=Ru, Ir, Sn) films supported on rutile TiO2(110) by DFT calculations: Probing the nature of metal oxide-support interaction.

To explore metal oxide-support interaction and its effect on O2 adsorption, periodic DFT calculations were used to explore the most preferred O2 molecular and dissociative adsorption on stoichiometric (MO2) and defective (MO2-x) (M=Ru, Ir, Sn) films supported on rutile TiO2(110), and compared with that on pure surfaces without TiO2(110) support. For defective RuO2-x films, it is revealed that the TiO2(110) support and the film thickness have an evident impact on the O2 adsorbed species. On the contrary, the two factors show little influence for defective IrO2-x and SnO2-x films. The analyses for Bader charge and density of states indicate that the reducibility change of the unsaturated surface Ru atoms, which are adjacent to the bridge oxygen vacancies, is responsible for this O2 adsorption alteration. These results provide insights into the oxide-oxide interaction, and its effect on the properties of supported oxide catalysts.