▎ 摘　　要

Pt nanoparticles were anchored on graphene nanosheets(GNs) with the aid of poly (diallyldimethylammonium chloride) (PDDA). The Pt ions were assembled first onto PPDA-modified graphene oxide nanosheets and then the caged Pt ions and graphene oxide were reduced simultaneously by ethylene glycol. As was supported by transmission electron microscopy, Pt nanoparticles were well-dispersed on GNs. Comparing with the commercial PVC and Pt/GNs(without PDDA) catalysts, the as-prepared Pt/PDDA-GNs nanohybrid exhibited an enhanced catalytic activity for the oxygen reduction reaction(ORR) and a significant improvement in the electrochemical durability. The enhanced durability could be ascribed to the increased Pt oxidation potential and to a strengthened metal-support interaction. The results show that PDDA plays an important role in the dispersion and stabilization of Pt nanoparticles on GNs, thus leading to an enhancement in both activity and durability of the catalyst for the ORR. This preparation procedure is effective and may be extended to synthesize other metal-graphene composites.