Construction of Co2P‐Ni3S2/NF Heterogeneous Structural Hollow Nanowires as Bifunctional Electrocatalysts for Efficient Overall Water Splitting

Abstract Designing efficient and stable transition metal‐based catalysts for electrocatalytic water splitting is vital for the development of hydrogen production. Herein, a facile synthetic strategy is developed to fabricate transition metal‐based heterogeneous structural Co 2 P‐Ni 3 S 2 hollow nanowires supported on nickel foam (Co 2 P‐Ni 3 S 2 /NF). Owing to the multiple active sites provided by transition metal compounds, large surface area of the unique hollow nanowire morphology, and the synergistic effect of Co 2 P‐Ni 3 S 2 heterostructure interfaces, Co 2 P‐Ni 3 S 2 /NF requires ultralow overpotentials of 110, 164 mV for HER and 331.7, 358.3 mV for OER at large current densities of 100, 500 mA cm −2 in alkaline medium, respectively. Importantly, the two‐electrode electrolyzer assembled by Co 2 P‐Ni 3 S 2 /NF displays a cell voltage of 1.54 V at 10 mA cm −2 and operates stably over 24 h at 100 mA cm −2 , which performs better than reported transition metal‐based bifunctional electrocatalysts. This work presents a successful fabrication of transition metal‐based bifunctional HER/OER electrocatalysts at large‐current density and brings new inspiration for developing applicable energy conversion materials.