Constructing the coordination environment of SO in NiS/WO₃/SnS₂ for photoelectrochemical water splitting

Photoelectrocatalytic (PEC) water splitting on photoelectrodes is ranked as a great challenge, which requires fast charge-carrier dynamics and sufficient catalytic active sites. Herein, we develop a surfactant-assisted synthetic strategy for synthesizing a lollipop-liked Z-scheme heterostructure composed by growing SnS₂ nanosheets and NiS nanoparticles (tips) on WO₃ nanorods. Particularly, the selective growth of SnS₂ on one end of the WO₃ nanorods allows for the complete exposure of the catalytic active sites of the WO₃ nanorods. Besides, the introduced interfacial SO bond creates a uniaxial transport channel that enhances the efficient movement of photogenerated charge carriers. Under the synergistic effect of the direct Z-scheme heterojunction and SO bonds, the optimized photoanode generates a superior current density of 2.78 mA cm^-2 under AM 1.5 G illumination, which is 6 times and 2 times that of WO₃ and WO₃/SnS₂. The photocurrent generated by NiS/WO₃/SnS₂-based photoanodes surpasses that of the majority of WO₃-based photoanodes deposited on fluorine-doped tin oxide (FTO). The design of ternary lollipop structure offers an effective approach to harnessing solar energy to achieve efficient photoelectrochemical water splitting performance.