Low-Temperature Carbide-Mediated Growth of Bicontinuous Nitrogen-Doped Mesoporous Graphene as an Efficient Oxygen Reduction Electrocatalyst.

Abstract

Nitrogen-doped graphene exhibits high electrocatalytic activity toward the oxygen reduction reaction (ORR), which is essential for many renewable energy technologies. To maximize the catalytic efficiency, it is desirable to have both a high concentration of robust nitrogen dopants and a large accessible surface of the graphene electrodes for rapid access of oxygen to the active sites. Here, 3D bicontinuous nitrogen-doped mesoporous graphene synthesized by a low-temperature carbide-mediated graphene-growth method is reported. The mesoporous graphene has a mesoscale pore size of ≈25 nm and large specific surface area of 1015 m2 g-1 , which can effectively host and stabilize a high concentration of nitrogen dopants. Accordingly, it shows an excellent electrocatalytic activity toward the ORR with an efficient four-electron-dominated pathway and high durability in alkaline media. The synthesis route developed herein provides a new economic approach to synthesize bicontinuous porous graphene materials with tunable characteristic length, porosity, and chemical doping as high efficiency electrocatalysts for a wide range of electrochemical reactions.