▎ 摘　　要

A facile method has been developed to synthesize a high-quality platinum nanoparticle (PtNP) decorated graphene via one-step gamma-ray induced reduction of graphite oxide (GO) and chloroplatinic acid at room temperature. GO and Pt(IV) precursor salt could be co-reduced by the electrons generated from the radiolysis of ethylene glycol under gamma-ray irradiation. The synchronous reduction of the metal precursor and regulation of pH greatly increased the ratio of C/O in the reduced GO (RGO). PtNPs with an average diameter of 1.8 nm were uniformly dispersed on the surface of RGO sheets. The as-prepared PtNP-RGO composites as supercapacitor electrodes displayed a specific capacitance of 154 F g-(1) at a current density of 0.1 A g(-1) and the value retained as high as 72.3% at 20 A g(-1) which was significantly enhanced compared to 16.2% capacity retention of RGO prepared by the same method. The investigation of electrochemical performances suggests that PtNPs play an important role in enhancing supercapacitor performance with high rate capability by accelerating the electron transfer and increasing the electrochemical active surface area of RGO.