Nitrogen-doped reduced graphene oxide supports for noble metal catalysts with greatly enhanced activity and stability

Abstract

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 2.5nm 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.