Strong Metal Support Interaction as a Key Factor of Au Activation in CO Oxidation

We address the question of the nature of Au NP activation and through a combination of experimental and theoretical techniques. In situ XPS measurements of Au TiO2 during CO oxidation show high catalytic activity can be associated with the formation of an ionic Au species. DFT calculations performed on Au TiO2 show that the formation of such ionic Au is due to a strong metal support interaction between Au and reduced and defective TiO2. TEM supports these findings, indicating the formation of an overlayer of transition metal oxide support on Au NPs after CO oxidation. These results suggest TiO2 lattice oxygen is involved directly in CO oxidation, which was confirmed with labeled 18O2 experiment