The integration of Mo2C-embedded nitrogen-doped carbon with Co encapsulated in nitrogen-doped graphene layers derived from metal–organic-frameworks as a multi-functional electrocatalyst

Abstract

High-performance multi-functional electrocatalysts are highly desirable for various energy storage and conversion devices. In this study, we report a one dimensional N-doped carbon nanostructure, containing Mo₂C and Co nanoparticles encapsulated in nitrogen-doped graphene layers (Mo₂C@NC/Co@NG) as a multi-functional electrocatalyst. The optimized Mo₂C@NC/Co@NG exhibited high activities and stabilities towards oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). The experimental results demonstrate that the high activities and stabilities of the multi-functional catalysts are ascribed to the synergistic effect between Mo₂C, Co, and N dopants. Typically, the optimized Mo₂C@NC/Co@NG catalyst delivered a HER current density of 10 mA cm⁻² at a small overpotential of 142 mV. Furthermore, a rechargeable zinc–air battery with the optimized Mo₂C@NC/Co@NG as OER and ORR bifunctional catalyst showed a high round-trip efficiency and robust cycling stability, superior to the battery assembled with the benchmarked mixture of Pt/C and IrO₂ as the air electrode. This study provides a simple method to reasonably design and fabricate highly efficient and stable multi-functional catalysts for clean and sustainable energy storage and conversion devices.