Iron doping enhances ZIF-67 based hierarchical carbon bifunction catalyst for oxygen reduction and evolution reactions

Rational design of inexpensive and durable bifunctional oxygen catalysts is essential to facilitate the commercialization of Zn-air batteries. Hence, we report an electrocatalyst with bifunctional catalytic activity, namely Fe species doped into N, S co-doped carbon encapsulated Co catalysts (e-Fe/Co@NSC). Benefiting from the hierarchical porous structure and multiple adsorption sites, the optimized e-Fe/Co@NSC-20 exhibits excellent oxygen evolution reaction (OER) performance, requiring only overpotential of 282 mV to drive a current density of 10 mA cm −2 . More importantly, the e-Fe/Co@NSC-20 also exhibited excellent oxygen reduction reaction (ORR) performance with a half-wave potential of 0.816 V, successfully revealing that it has excellent bifunctional properties. Moreover, Zn-air battery assembled with e-Fe/Co@NSC-20 catalyst as air electrodes have high open-circuit voltage (1.472 V), power density (136 mW cm −2 ) and specific capacity (639 mAh g −1 Zn ), outperforming Pt/C + RuO 2 -based Zn-air battery. This study provides constructive assistance in the design of electrocatalysts with bifunctional properties for Zn-air battery.