Vacancy-engineered S-scheme MoS2/ZnIn2S4 heterojunction for bifunctional photocatalytic H2 evolution and H2O2 production

Clean and sustainable energy conversion technology is a key contemporary scientific topic, and photocatalytic hydrogen production offers a new way to address the energy crisis. Here, based on the synergistic strategy of vacancy engineering and S-scheme heterostructure construction, a bifunctional photocatalyst of MoS 2 /ZnIn 2 S 4 -Vs (MoS 2 /ZIS-Vs) with sulfur vacancies (Vs) was developed by one-pot hydrothermal method. The best sample’s hydrogen production efficiency was 75.34 mmol·g −1 ·h −1 , which is 21 times higher than that of unmodified ZIS (3.42 mmol·g −1 ·h −1 ). Meanwhile, under air atmospheric conditions, its H 2 O 2 yield is 1126.66 μmol·g −1 ·h −1 , which is approximately 1.92 times that of ZIS (587.20 μmol·g −1 ·h −1 ). Under oxygen atmosphere conditions, this rises to 2144.84 μmol·g −1 ·h −1 , which is approximately twice the amount in an air atmosphere. Multiple characterizations show MoS 2 /ZIS-Vs’s vacancy engineering and heterostructure adjust ZIS’s band structure, enhance light absorption, and boost charge separation/transfer, with good stability. The DFT calculations show that MoS 2 /ZIS-Vs has an extremely low Gibbs free energy (−0.03 eV). This indicates that the synergistic action of the S-scheme heterojunction and sulfur vacancies significantly reduces the reaction barrier, thereby improving hydrogen and H 2 O 2 production efficiency. The research findings show that it has important application value in the field of solar energy conversion.