Here we report a simple one-pot microwave-polyol reduced method to anchor platinum nanoparticles on graphene with the aid of poly (diallyldimethylammonium chloride) (PDDA), forming a Pt/PDDA-G hybrid (Pt/PDDA-G). High Pt metal loadings, up to 85 wt.% with a mean size of 1.4 nm, were densely in situ decorated on PDDA-modified graphene surfaces. The electrochemical tests showed that the activity and stability of Pt supported on PDDA-graphene hybrid substrates for methanol oxidation were better than that of Pt supported on graphene sheets, also better than the widely used Pt/carbon black electro-catalysts with the same Pt content on the electrode. This improved activity indicates that PDDA plays a crucial role in the highly dispersion and stabilization of Pt nanoparticles on graphene and PDDA-G are able to an alternative support for Pt immobilization in direct methanol fuel cells. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.