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

• Preparation of ZnIn 2 S 4 with S defects (S d -ZIS) from excess S sources. • 3D/0D S d -ZIS/WSe 2 QDs heterojunction constructed by growing WSe 2 QDs on 3D spherical S d -ZIS. • The presence of S defects enhances the coupling at the heterojunction interface. • The H 2 production rate of SZW2 in seawater is 53.33 times higher than that of ZnIn 2 S 4 . • Carrier dynamics were studied by TRPL , TPV and DFT calculations. The photocatalysts studied for hydrogen production from seawater have not been very effective in hydrogen production. In this paper, simple ZnIn 2 S 4 (ZIS) and ZnIn 2 S 4 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 WSe 2 QDs at the defects of 3D S d -ZIS by the secondary hydrothermal method to obtain the 3D/0D S d -ZIS/WSe 2 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.