▎ 摘　　要

Graphene nanosheets (GS) were formed by the thermal-expansion method. Large micropores about 1-2nm were produced, which might provide abundant anchor sites for fixing catalyst. Platinum nanoparticles (NPs) supported on exfoliated GS (Pt/GS) were synthesized through an improved impregnation approach and mixture gas (5% H-2 in N-2) reduction. SEM and TEM images indicated the simple and clean method can effectively synthesize Pt with uniform dispersion and small size (below 3nm) on the 2D specific and stratiform GS. The different amounts of Pt loaded on carbon carriers have been investigated respectively to evaluate the preferable electrocatalyst. Experimental results showed that Pt/GS of 20wt.% initiated CO oxidation at the lowest onset potential in comparison with the commercial Pt/C (JM), indicating a higher CO tolerance of Pt/GS catalysts. In addition, Pt/GS of 20wt.% exhibited enhanced electrocatalytic activity and high durability towards methanol oxidation. The high performance is exclusively attributed to synergistic effects of exfoliated GS and ultrafine size Pt NPs. Combining a melt-diffusion strategy with the effective reduction of Pt precursors by the hydrogen gas, this present method is easy to scale up and possesses a significant potential for synthesizing anode electro-catalyst of direct methanol fuel cells.