Platinum-catalyzed synthesis of water-soluble gold-platinum nanoparticles

The ability to control composition and size in the synthesis of bimetallic nanoparticles is important for the exploitation of the bimetallic catalytic properties. This paper reports findings of an investigation of a new approach to the synthesis of gold−platinum (AuPt) bimetallic nanoparticles in aqueous solution via one-phase reduction of AuCl4- and PtCl42- using a combination of reducing and capping agents. Hydrogen served as a reducing agent for the reduction of Pt(II), whereas acrylate was used as a reducing agent for the reduction of Au(III). The latter reaction was found to be catalyzed by the formation of Pt as a result of the reduction of Pt(II). Acrylate also functioned as capping agent on the resulting nanocrystals. By controlling the feed ratios of AuCl4- and PtCl42- and the relative concentrations of acrylate, an effective route for the preparation of AuPt nanoparticles with bimetallic compositions ranging from ∼4 to 90% Au and particle sizes ranging from 2 to 8 nm has been demonstrated. The c...