Defect-assisted strong interfacial interaction in ZnIn₂S₄/WSe₂ heterojunction for efficient Photohydrogen production from seawater

The photocatalysts studied for hydrogen production from seawater have not been very effective in hydrogen production. In this paper, simple ZnIn₂S₄ (ZIS) and ZnIn₂S₄ with S defects (S_d-ZIS) were prepared by hydrothermal method, the presence of S defects provides unsaturated S atoms for the in situ growth of 0D WSe₂ QDs at the defects of 3D S_d-ZIS by the secondary hydrothermal method to obtain the 3D/0D S_d-ZIS/WSe₂ QDs complex (SZWx, x = 1,2,3). The formation of W-S bonds with strong coupling effects at their interfaces provides a channel for the fast separation of carriers. The seawater hydrogen production performance (6.40 mmol/g/h) of the best-performing SZW2 is 53.33 and 26.67 times higher than that of ZIS and S_d-ZIS, which tested with 0.10 M ascorbic acid as the sacrificial agents. The carrier dynamics mechanism of SZWx was further investigated by tests such as TRPL, TPV, and DFT calculations. This paper provides some ideas for future research on ZIS-based photocatalysts for efficient heterojunction interfacial carrier dynamics and seawater hydrogen production.