Formation of multishell Au@Ag@Pt nanoparticles by coreduction method: a microscopic study

Metallic nanoparticles of Ag–Pt double-shell on Au-core ([email protected]@Pt [email protected] NPs) with a hollow-granular shell structure were synthesized by coreduction method, a combination of galvanic replacement reaction with a coreducing agent. Their nanostructures were examined in detail at different reduction reaction periods to gain insights into the mechanism of Ag–Pt double-shell formation on Au-core, as well as the competitive role of each reduction reaction. The multishell NPs were found to contain a degree of hollows with the inner surface composed of both Ag and Pt, while the outer surface composed of granular Pt. The coreduction method contributed to the success of increasing Pt surface area that will further benefit catalytic applications of the NPs.