Gold-platinum bimetallic cluster catalysts for visible light-induced hydrogen production from water

Abstract

Simultaneous reduction of two kinds of noble metal ions by refluxing in alcohol in the presence of poly(N-vinyl-2-pyrrolidone) can generally give polymer-protected bimetallic clusters with a core structure. The structures of the clusters were determined by the EXAFS measurements. On the other hand, it is known that micelle-protected platinum clusters work as good catalysts for visible light-induced hydrogen production from water in a system of EDTA/Ru(bpy) 2+3 /methyl viologen. The stable dispersions of polymer- and micelle-protected gold/platinum bimetallic clusters were prepared by alcohol- and photoreduction, respectively. The dispersions prepared by photoreduction in the presence of micelle are mainly composed of the mixtures of monometallic gold and platinum clusters, which cannot work as more active catalysts than monometallic platinum clusters. In contrast, the dispersions prepared by alcohol-reduction in the presence of polymer are composed of Au/Pt bimetallic clusters with a “Pt-surrounded Au-core” structure, which are more active catalysts than the monometallic Pt clusters as catalysts for the hydrogen production.