Platinum nanocrystals/graphene nanosheets (Pt-NCs/GNS) composite has been synthesized by a chemical reduction of PtCl62- with formic acid (HCOOH) at room temperature. TEM analyses indicate that most of the Pt-NCs with a length of 10 nm and width of 5 nm has uniformly growth along the graphene basal plane, making the effective contact of Pt and graphene, which would be favorable for enhancing the utility of Pt catalyst. Electrochemical tests show that the current density of the resulting Pt/GNS catalyst for methanol electro-oxidation is up to 412.6 A g(-1) Pt, which is about 2.3 times as that of the commercial Pt/C(JM) catalyst. Moreover, the Pt/GNS catalyst exhibits better durability toward methanol electro-oxidation and outstanding CO electro-oxidation activity than the commercial Pt/C(JM) catalyst. (C) 2012 Elsevier Ltd. All rights reserved.