Facile synthesis of carbon coated cobalt-cobalt molybdenum carbide as advanced bifunctional oxygen electrocatalyst for rechargeable Zn-air battery

To facilitate the development of rechargeable metal-air batteries, the exploration of high effective bifunctional electrocatalysts is essential. In this work, we report a facile strategy to synthesize N doped carbon (NC) encapsulated Co-Co6Mo6C2 (Co-Co6Mo6C2@NC) nano polyhedron using ZIF-67 as a precursor and investigated its catalytic performance for both oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). The introduction of Co6Mo6C2 into Co@NC can significantly improve the OER catalytic activity of the catalyst, while the high ORR catalytic activity of the catalyst is maintained. Specifically, Co-Co6Mo6C2@NC-5 shows a decent half-wave potential of 0.80 V for ORR, and a very low overpotential of 270 mV at 10 mA cm(-2) for OER, demonstrating its bifunctional activity. The rechargeable Zn-air battery assembled using Co-Co6Mo6C2@NC-5 exhibits a maximum power density of 90.75 mW cm(-2) and a high specific capacity of 768 mA h g(-1), as well as good durability of 50 h without attenuation in performance, highlighting its practical application. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study presents a facile strategy to synthesize N-doped carbon encapsulated Co-Co6Mo6C2 nano polyhedron using ZIF-67 as a precursor, which exhibits high catalytic activity for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The introduction of Co6Mo6C2 into Co@NC significantly enhances the OER catalytic activity of the catalyst while maintaining high ORR catalytic activity.