Fe-N-doped mesoporous carbon loaded on reduced graphene oxides with dual active sites for efficient oxygen reduction catalysts

摘要: Transition metal/nitrogen/carbon (M-N/C) catalysts are considered as one of the most promising candidates to replace Pt/C catalysts for oxygen reduction reactions (ORR). Here, we have designed novel reduced graphene oxides (rGO) supported Fe-N-doped carbon (Fe-N-C/rGO) catalysts via simple pyrolysis of polypyrrole(Ppy)-FeO-GO composites. The as-prepared catalysts induced an onset potential of 0.94 V, a half-wave potential of 0.81 V in alkaline solutions, which is much better than that of the counterpart N-C and N-C/rGO catalysts, and comparable to that of Pt/C catalysts. Moreover, the Fe-N-C/rGO catalysts showed improved durability and higher tolerance against methanol crossover than Pt/C in alkaline solutions. This superior ORR perfomance can be ascribed to the combined catalytic effect of both Fe-based nanoparticles (Fe3O4, Fe4C) and Fe-Nx sites, as well as fast mass transfer and accessible active sites benefitting from the mesporous structure and high specific surface area. This work provides new insight for synthesis of a more promising non-platinum electrocatalyst for metal-air batteries and fuel-cell applications.