Fe–N-Doped Mesoporous Carbon with Dual Active Sites Loaded on Reduced Graphene Oxides for Efficient Oxygen Reduction Catalysts

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 (ORRs). Here, we have designed novel reduced graphene oxide (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 and a half-wave potential of 0.81 V in alkaline solutions, which is much better than those 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 performance 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 benefiting from the mesoporous structure and high specific surface area. This work provides new insight for synthesis of a more promising nonplatinum electrocatalyst for metal–air batteries and fuel-cell applications