Microscopic Insight into the Activation of O2 by Au Nanoparticles on ZnO(101) Support

We carry out density functional theory calculations to cast insight on the microscopic mechanism of the activation of O2 by Au7 cluster on ZnO(101)-O support. The excellent catalytic activity of Au/ZnO catalyst was ascribed to the distribution of polarized surface charge associated with interface structure. It is found the stoichiometric ZnO(101)-O easily adsorbs and dissociates O2 to form very stable oxygen-saturated surface. For Au7 on stoichiometric ZnO(101)-O surface, the two Au atoms neighboring to O could accumulate positive charges, which then upshift the d-band centers toward the Fermi level. These favor the adsorption and dissociation of O2, providing two Au activation sites. In contrast, for the Au7 on the oxygen-saturated ZnO(101)-O, all Au atoms become neighboring to O and consequently provide seven activation sites. The workfunction difference between the Au7 and support induces effective polarized surface charges, substantially promoting O2 adsorption and dissociation both dynamically and th...