High Catalytic Activity of Au Clusters Supported on ZnO Nanosheets

Catalytic activity of metal clusters supported on a two-dimensional (2d) nanosheet has attracted great interest recently. In this paper, via first-principles calculations, we investigate for the first time Au catalysis on recently proposed 2d one- atom-thick ZnO nanosheets. An Au8 cluster adsorbed on a 2d ZnO sheet (Au8/ZnO) is chosen as a model catalyst, and the CO oxidation is used as the probe reaction for the catalytic activity. When adsorbed on 2d one-atom-thick ZnO, the Au8 cluster is found to adopt a planar structure and exhibit high catalytic activities for the CO oxidation with a low reaction barrier around 0.3 eV. The catalyzed CO oxidation highly prefers the Eley− Rideal (ER) mechanism, and the coadsorption of CO and O2 on the Au8 cluster plays an essential role in the ER type of reaction in which an additional CO approaches O2 in a vacuum. The high catalytic activity (low reaction barrier) is due to the charge transfer from Au8/ZnO to the antibonding 2π* orbital of the O2 molecule that is facilitated by the coadsorption of a CO molecule. These findings provide new opportunities for the future development of ZnO-based catalysts.