Tailoring the structure, composition, optical properties and catalytic activity of Ag–Au nanoparticles by the galvanic replacement reaction

This Letter reports on the synthesis of Ag–Au nanoparticles (NPs) with controlled structures and compositions via a galvanic replacement reaction between Ag NPs and AuCl 4 - (aq) followed by the investigation of their optical and catalytic properties. Our results showed the formation of porous walls, hollow interiors and increased Au content in the Ag–Au NPs as the volume of AuCl 4 - (aq) employed in the reaction was increased. These variations led to a red shift and broadening of the SPR peaks and an increase of up to 10.9-folds in the catalytic activity towards the reduction of 4-nitrophenol relative to Ag NPs.