Interface and doping engineering of Co-based electrocatalysts for enhanced oxygen reduction and evolution reactions

The fabrication of highly efficient bifunctional catalyst for oxygen evolution/reduction reaction (OER/ORR) is essential for high performance rechargeable Zn-air batteries. Herein, we present a method of simultaneous interface/doping engineering to prepare bifunctional oxygen electrocatalyst for rechargeable Zn-air batteries. The Fe-Co2P/Co heterostructure was covered by N-doped carbon boxes (Fe-Co2P/Co@NC), and the surface electronic structure of Fe-Co2P/Co@NC was tailored through the controlled co-doping of P and Fe. Theoretical calculation revealed a significant charge accumulation at the interface of Fe-Co2P and Co, demonstrating a strong synergy in Fe-Co2P/Co@NC catalyst. The as-prepared Fe-Co2P/Co@NC catalyst exhibited an excellent catalytic performance for ORR/OER as well as rechargeable Zn-air batteries with large power density (783 mA h gZn−1), high open circuit voltage (1.54 V) and long charge/discharge stability (155 h). This work provides a new approach for the construction of interface-rich heterostructure electrocatalysts for oxygen catalysis.