Platinum - cobalt (PtCo) alloy based highly efficient nano electro-catalysts on reduced graphene oxide (rGO) matrix have been synthesized for the electro-oxidation of methanol, by chemical reduction method. Different molar ratio of Pt (IV) and Co (II) ions along with graphene oxide (GO) were reduced using ethylene glycol to obtain PtCo nanoparticles onto rGO sheets (Pt/rGO, PtCo (1:1)/rGO, PtCo (1:5)/rGO, PtCo (1:9)/rGO and PtCo (1:11)/rGO) with 20 wt. % metal and 80 wt. % rGO. The average particle size of PtCo nanoparticles onto rGO support was observed to be 2-5 nm using XRD and TEM analysis. The PtCo (1:9)/rGO nanocomposite catalyst exhibited similar to 23 times higher anodic current density compare to commercially available Pt/C catalyst (1.68 mA/cm(2)) for methanol oxidation reaction. The peak power density of 118.4 mW/cm(2) was obtained for PtCo (1:9)/rGO catalyst in direct methanol fuel cell (DMFC) at 100 degrees C, 1 bar, and 2 M methanol as anode feed, which is similar to 3 times higher than that of Pt/C catalyst. The results indicate the potential application of synthesized nanocomposite catalyst in commercial DMFCs. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.