In situ XPS confirms enhanced hydrogen evolution in S-scheme heterojunction Cd0.8Mn0.2S/Cu2WS4 via charge vectorial separation.

Solar-driven water splitting for hydrogen production is a vital approach to mitigating the energy crisis and achieving carbon neutrality and peak carbon emissions. Cd 0.8 Mn 0.2 S holds significant potential for photocatalytic hydrogen evolution but faces severe challenges due to photogenerated carrier recombination. To address this, we employed ultrasonic self-assembly to tightly couple Cu 2 WS 4 nanosheets with Cd 0.8 Mn 0.2 S nanoparticles, forming an S-scheme heterojunction to reduce carrier recombination rates. In this configuration, Cd 0.8 Mn 0.2 S acts as the electron acceptor, and Cu 2 WS 4 serves as the electron donor. The Cd 0.8 Mn 0.2 S/Cu 2 WS 4 structure creates a closely spaced interface, providing the shortest transfer distance for electron migration. The S-scheme heterojunction strategy effectively suppresses the recombination of photogenerated carriers, promoting vectorial separation. Under 10 W white light irradiation, the Cd 0.8 Mn 0.2 S/Cu 2 WS 4 composite photocatalyst exhibited remarkable hydrogen evolution activity, with a hydrogen production rate of 39.83 mmol g−1 h−1. This S-scheme heterojunction strategy lays the foundation for the structural design and large-scale application of high-activity visible-light photocatalysts. • Recombination of photogenerated carriers is inhibited. • Facilitated vector separation of photogenerated carriers. • In situ irradiated XPS validates the S-scheme heterojunction charge transfer mechanism. [ABSTRACT FROM AUTHOR]