Construction of Co 2 P-Ni 3 S 2 /NF Heterogeneous Structural Hollow Nanowires as Bifunctional Electrocatalysts for Efficient Overall Water Splitting.

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.