Pt‐Like Oxygen Reduction Activity Induced by Cost‐Effective MnFeO₂/N‐Carbon

The development of effective and affordable electrocatalysts for the oxygen reduction reaction (ORR) is critical for the renewable‐energy technologies. Here, we present a new manganese iron oxide (MnFeO 2 ) as a cost‐effective material for the ORR with Pt‐like electrochemical properties. Pyrolysis of hybrid agar hydrogel on NaCl nanocrystals furnishes a unique structure in which the active MnFeO 2 particles are uniformly immobilized in the nitrogen‐doped porous carbon aerogels (MnFeO 2 /NPC). Nitrogen‐doped carbon is introduced to construct porous mass‐transfer channels and reduce self‐aggregation of the MnFeO 2 particles. It is found that the formation of the MnFeO 2 phase greatly depends on the pyrolysis temperature. Benefiting from the synergy of MnFeO 2 and NPC, the MnFeO 2 /NPC can actually be as good as the Pt/C catalyst for the ORR, with an onset‐potential of 0.98 V and a half‐wave potential of 0.86 V, combined with demonstrating a superior stability and tolerance to methanol.