Gold clusters on Nb-doped SrTiO3: effects of metal-insulator transition on heterogeneous Au nanocatalysis

Abstract

Doping induced metal-insulator transition (MIT) in transition-metal (TM) oxides has been the topic of continued interest outside the field of catalysis chemistry. In this paper, via ab initio (GGA+U) calculations, we show that Nb-doping induced MIT in SrTiO₃ causes a dimensionality crossover of supported Au clusters, and at the same time, greatly enhances the stability and catalytic activity of these clusters. Underlying the predicted high catalytic activity of Au clusters towards the CO oxidation is the MIT induced interaction between the O₂ antibonding 2π* orbital and Au conduction bands, leading to a shift in the population of electrons from Au to the antibonding orbital and the activation of the O₂ molecule. We expect these results to provide a new methodology for the control of catalytic performance of TM-oxide supported Au nanoclusters.