Construction of nickel selenides heterointerfaces with electron redistribution for solar-driven water splitting

Developing heterostructures electrocatalysts was a promising method to improve the water splitting efficiency. However, due to the difficulty of synthesis, such low-cost and high-activity heterostructures electrocatalysts have not been developed. In this work, Ni3Se2/NiSe heterostructure nanosheets with rich-phase boundaries were synthesized by soaking at room temperature and annealing treatment using nickel foam as both Ni source and substrate. Such a nanosheet-like Ni3Se2/NiSe heterostructure could expose more active sites and efficient mass transfer at solid-liquid-gas three-phase interfaces, which exhibits a lower overpotential of 336 mV at 100 mA cm−2 and exceptional stability over 80 h at the current density of 300 mA cm−2 for OER in alkaline solution. Furthermore, the heterostructures electrode implements solar-driven water with a high solar-to-hydrogen efficiency of 18.3%. This heterostructure strategy might be a major breakthrough for improving the transition metal selenides and designing high-active and stable catalysts for electrochemical water oxidation.