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 AuCl4-(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 AuCl4-(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.

67Highlights► Synthesis of Ag-Au NPs by a galvanic replacement approach between Ag and AuCl4-. ► Nanoparticles with controlled structures, compositions and optical properties. ► Evaluation of catalytic activities as a function of composition and structure. ► Increase of up to 10.9-folds due to increased Au content and hollow interiors.