Synthesis of Au@Pt core-shell nanoparticles with a monolayer Pt shell using the Au-catalytic-reduction strategy and the application in electrocatalysis

We have developed for the first time an Au-catalytic-reduction strategy to synthesize the core-shell structured Au@Pt nanoparticles (NPs). In the synthesized Au@Pt NPs, only monolayer Pt shell can be formed by the catalytic reduction of Pt2+in the presence of 15 nm Au NPs in HEPES buffer at room temperature. The structure and morphology of the as-prepared Au@Pt NPs were characterized by UV-visible absorption spectrum (UV-Vis), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma-atomic emission spectrum (ICP-AES). Electrochemical measurements displayed that the core-shell structured Au@Pt NPs with a monolayer Pt shell have good electrocatalytic performance for oxygen reduction reaction (ORR). The specific electrochemical surface area (ECSA, 183.40 cm2/mgPt) and mass activity (573.20 mA/mgPt at −0.075 V) of Au@Pt NPs were found to be 1.72 and 5.06 times higher than those of commercial Pt/C catalyst (102 cm2/mgPt, 113.39 mA/mgPt), respectively.