Graphene supported nano particles of Pt-Ni for CO oxidation

► Graphene supported Pt, Ni and Pt-Ni nano particles synthesized by impregnation. ► Catalysts for CO oxidation. ► Metal particles highly dispersed on the graphene sheets with small average particle size. ► Pure graphene is inactive for CO oxidation. ► Supported Pt-Ni catalyst showed the best activity owing to the formation of Pt-Ni alloy on the graphene sheets.