LAUSR

Abstract The development of transition-metal electrocatalyst is of great importance to bring down costs and enhance performance for fuel cells and water splitting. The multiple efforts have been concentrated on bifunctional electrocatalysts toward hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). Only a few works reach desirable durability and performance levels. Here, Co/VN heterostructure with rational porous structure is formed in response to the sensible cobalt and vanadium ratio. Owing to synergistic interaction of holey interconnected structure with large surface area of 57 m2 g−1 and abundant interfaces between Co and VN phases, Co/VN@NC presents superior bifunctional electrocatalytic performance towards both HER and ORR. Co/VN@NC drives the reaction with low overpotential η10 of 96 mV and Tafel slope of 82 mV dec−1 along with outstanding stability for HER. Furthermore, Co/VN@NC obtains an onset potential (0.954 V) and half-wave potential (0.796 V) with superior methanol tolerance and durability for ORR.