Pure nitrogen-doped graphene aerogel with rich micropores yields high ORR performance

How good can the oxygen reduction reaction (ORR) performance of metal-free 3D carbon material be, if the ratio of micropores to all the micropores and mesopores in it can be greatly increased? To answer this question, a nitrogen doped graphene aerogel (NGA) with rich micropores is prepared by a facial one-pot assembly. Pores especially rich micropores introduced by the dense packing of graphene oxide (GO) precursor with small size facilitated by the crosslinking agent dopamine (DA) in walls of NGA with a large specific surface area (1631 m(2)/g) shorten the diffusion time and decrease the transport distance of O-2 inside the pores; a high N content (7.21 at %) increases the adsorption and diffusion of O-2 in NGA; consequently increase the ORR speed, rendering so far the largest ORR current density of NGA among reported metal-free carbon catalysts and Pt-based catalysts, promising for applications in fuel cells.