Facile single-step ammonia heat-treatment and quenching process for the synthesis of improved Pt/N-graphene catalysts

► A facile single-step heat-treatment and quenching process is developed to prepare composite catalyst. ► Simultaneous reduction and functional doping of graphene oxide, and loading of Pt catalyst are realized. ► Well-dispersed electrocatalysts of Pt nanoparticles on nitrogen-doped graphene are obtained. ► The composite catalysts present excellent catalytic activity for methanol electro-oxidation. ► The facile process is promising to synthesize other graphene based composite electrocatalysts.