▎ 摘　　要

A facile in situ assembly strategy was developed for the fabrication of Pt-Au alloy nanoparticles (NPs) on nitrogen-doped graphene (N-G) sheets, and the as-fabricated Pt-Au/N-G nanocomposites were suitable for electrochemical applications. As characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction analysis and inductively coupled plasma-atomic emission spectroscopy techniques, Pt-Au alloy NPs with an average size of 4-5 nm were uniformly distributed on the N-G surface through intrinsic covalent bonds. The Pt-Au/N-G nanocomposites exhibited excellent electrocatalytic activity and stability towards the methanol oxidation reaction with the highest capability observed for a Pt/Au atomic ratio of 3/1. The unique electrochemical features are distinctive from those of N-free nanocomposites and commercially available Pt/C catalysts, indicative of the alloying effect of Pt-Au and their synergistic interaction with the N-G sheet, which may open up new possibilities for the preparation of N-G-based nanocomposites for other intensive applications as well.