Nitrogen-doped porous carbon embedded with cobalt nanoparticles for excellent oxygen reduction reaction.

Nitrogen-doped hierarchical porous carbon (CNx-Co) samples embedded with cobalt nanoparticles are selectively prepared with polyethylenimine (PEI) as both the carbon and nitrogen sources. By processing at different temperature, CNx-Co-800 and CNx-Co-1000 are selectively prepared and the materials exhibit excellent electrocatalytic activity in the oxygen reduction reaction (ORR). The ORR measurements show that sample processed at the higher temperature delivers better performance due to the larger Co and graphitic nitrogen concentrations. CNx-Co-1000 also shows more tolerance against methanol crossover and outstanding durability towards ORR, making it a promising Pt-free electrocatalyst for ORR under alkaline conditions. The method demonstrated here is a general strategy to prepare other metal or metal alloy/porous carbon hybrid materials.