A　facile　hydrothermal　method　has　been　proposed　to　prepare　reduced　graphene　oxide　(RGO)　and　enhance　its　reducing　ability.　For　the　first　time,　the　spontaneous　redox　reaction　between　PtCl42-　and　RGO　has　been　reported　and　no　additional　reductants　or　surfactants　were　needed.　X-ray　photoelectron　spectroscopy　and　transmission　electron　microscope　images　were　used　to　characterize　the　synthesized　Pt　nanoparticles　supported　on　RGO　sheet　(PtNPs/RGO)　composites.　The　reaction　mechanism　has　been　investigated　by　changing　the　medium　pH　of　the　reaction.　We　further　proved　that　the　electro-catalytic　property　of　PtNPs/RGO　could　be　tuned　and,　because　of　the　clean,　well-dispersed　PtNPs　and　the　synergistic　effect　between　the　PtNPs　and　RGO,　the　PtNPs/RGO　expressed　higher　electro-catalytic　activity　and　better　tolerance　for　methanol　oxidization　than　a　commercial　Pt/C　catalyst.　(c)　2013　Elsevier　Ltd.　All　rights　reserved.