Strategic Synthesis of Trimetallic Au@Pd@Pt Core−Shell Nanoparticles from Poly(vinylpyrrolidone)-Based Aqueous Solution toward Highly Active Electrocatalysts

Our recent study has shown that Pluronic F127 triblock copolymer can assist the formation of unique Au@Pd@Pt triple-layered core−shell-structured nanoparticles consisting of a Au core, a Pd inner layer, and nanoporous Pt outer shell (J. Am. Chem. Soc.2010, 132, 13636). Pluronic F127 is a very typical surfactant that is commonly used in the synthesis of mesoporous silica and carbon, but Pluronic F127 is very rarely used for the synthesis of metallic nanostructures. Herein, we expand our previous concept to further demonstrate that such interesting Au@Pd@Pt nanoparticles can be easily synthesized by using poly(vinylpyrrolidone) (PVP) instead of Pluronic F127. PVP is a very typical capping and structure-directing agent used for the synthesis of various metallic nanostructures. The present synthetic route using a PVP-based aqueous solution will greatly contribute to the further design of multilayered metallic nanoarchitectures with designed compositions and desired functions. Furthermore, a detailed investigation on the electrocatalytic activity of the trimetallic nanoparticles is also performed.