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 (MnFeO₂ ) 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 MnFeO₂ particles are uniformly immobilized in the nitrogen-doped porous carbon aerogels (MnFeO₂ /NPC). Nitrogen-doped carbon is introduced to construct porous mass-transfer channels and reduce self-aggregation of the MnFeO₂ particles. It is found that the formation of the MnFeO₂ phase greatly depends on the pyrolysis temperature. Benefiting from the synergy of MnFeO₂ and NPC, the MnFeO₂ /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.