Optimizing Surface N‐Doping of Fe‐N‐C Catalysts Derived from Fe/Melamine‐Decorated Polyaniline for Oxygen Reduction Electrocatalysis

Abstract The insufficient active site density and poor stability of iron and nitrogen co‐doped carbon (Fe‐N‐C) catalyst remain as great challenges for advanced oxygen reduction reaction (ORR). Surface N‐doping together with Fe species is considered as an efficient strategy to enhance the catalytic activity and stability of Fe‐N‐C. Here, we report a facile preparation of high performing Fe‐N‐C catalysts derived from Fe/melamine‐decorated polyaniline. The optimal catalyst displays much better ORR onset and half‐wave potentials (1.00 and 0.86 V) than that of the melamine‐free catalyst (0.97 and 0.83 V) and even the commercial Pt/C (0.99 and 0.83 V), respectively. It also shows a decent stability during 20 000 cycles of accelerated durability test (ADT) with only 15 mV loss in the half‐wave potential. Physical and electrochemical characterizations demonstrate that introduction of melamine could increase the percentage of surface pyrrolic N species and non‐crystalline Fe species, which would be responsible for the significant improvement in the catalytic performance toward ORR.