Pt nanoparticles supported on nitrogen-doped reduced graphene oxide (NRGO) were investigated for use as proton exchange membrane fuel cell catalysts. Artfully, NRGO was synthesized using a lyophilisation-assisted N-doping method, and simultaneous reduction of graphene oxide (GO) was achieved. A nitrogen content as high as 5.06% was obtained with pyridinic-N as the dominant nitrogen species. Pt nanoparticles with an average diameter of 2.5 nm were uniformly loaded on NRGO using impregnation methods. Both cyclic voltammetry and oxygen reduction reaction (ORR) measurements revealed a higher catalytic activity and lower losses of the electrochemically active surface area of this novel Pt/NRGO catalyst in comparison to those of the Pt/GO and conventional Pt/C catalysts. Significantly, the catalytic activity of the Pt/NRGO in ORR showed almost no degradation even after 1000 potential cycles, indicating that our new catalysts have excellent stability. A mechanism for improving the ORR activity and the stability of the Pt/NRGO was tentatively proposed and discussed. (c) 2012 Elsevier B.V. All rights reserved.