Interfacial engineering of cobalt phosphide heterostructures confined in N,P-doped carbon for efficient bifunctional electrocatalysis in Zn–air batteries

Abstract

The current focus of research lies in the advancement of electrocatalysts based on phosphides, which exhibit exceptional features and robust stability in alkaline environments. In this study, we have successfully prepared a novel bifunctional electrocatalyst for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) by in situ phosphidation and carbonization using Co/Zn-ZIF as the template and melamine-polyphosphate (MPP) as the phosphorus source with a certain mass ratio. The resulting catalyst comprises nano-sized heterostructured particles of cobalt phosphides (a combination of Co₂P and CoP) confined in N,P-codoped porous carbon polyhedra, exhibits excellent electrocatalytic properties in alkaline media and can be utilized as an electrode material for efficient Zn–air batteries due to the exceptional properties of mixed-phase CoP@Co₂P heterostructured nanoparticles and its unique structural characteristics. The Zn–air battery demonstrates a high open-circuit voltage of 1.56 V, an outstanding peak power density of 215.1 mW cm⁻² and stable cycling over 580 hours. This study provides substantial evidence to support the feasibility of utilizing surface engineering techniques to create highly efficient bifunctional electrocatalysts for the purpose of metal–air battery applications.