Effect of Ag-Doping on the Catalytic Activity of Polymer-Stabilized Au Clusters in Aerobic Oxidation of Alcohol

Abstract

A set of nearly monodisperse Au−Ag alloy clusters (size range 1.6−2.2 nm) with various Ag content (5−30%) was prepared by the co-reduction method in the presence of poly(N-vinyl-2-pyrrolidone) (PVP). The catalytic activities of the Au−Ag:PVP clusters were investigated for aerobic oxidation of p-hydroxybenzyl alcohol as a model reaction to understand the effect of Ag on the catalytic activity of Au clusters. It was found that the rate constants per unit surface area for Au−Ag:PVP clusters with small Ag content (<10%) were larger than those of monometallic Au:PVP clusters of comparable size. The enhancement of the catalytic activity by Ag doping is discussed in light of the electronic structure of the Au−Ag cores probed by X-ray photoelectron spectroscopy. The present results indicate that the partial anionic character of the Au core is important for the aerobic oxidation reactions of Au:PVP clusters.