DirectionalElectron Transfer in CuInS₂/Mo₂S₃ S‑Scheme Heterojunctions forEfficient Photocatalytic Hydrogen Production

Abstract

The photocatalytic conversion of solar energy to hydrogen is a promising pathway toward clean fuel production, yet it requires advancement to meet industrial-scale demands. This study demonstrates that the interface engineering of heterojunctions is a viable strategy to enhance the photocatalytic performance of CuInS₂/Mo₂S₃. Specifically, CuInS₂ nanoparticles are incorporated into Mo₂S₃ nanospheres via a wet impregnation technique to form an S-scheme heterojunction. This configuration facilitates directional electron transfer, optimizing electron utilization and fostering efficient photocatalytic processes. The presence of an S-scheme heterojunction in CuInS₂/Mo₂S₃ is corroborated by in situ irradiation X-ray photoelectron spectroscopy and density functional theory analyses, which confirm the directional movement of electrons at the interface of heterojunction. Comprehensive characterization of the heterojunction photocatalyst, including phase, structural, and photoelectric property assessments, reveals a significant specific surface area and light absorption capability. These attributes augment the number of active sites available in CuInS₂/Mo₂S₃ for proton reduction reactions. This study offers a pragmatic approach for designing metal sulfide-based photocatalysts via strategic interface engineering, potentially advancing the field toward sustainable hydrogen production.