Directional Electron Transfer in CuInS2/Mo2S3 S-Scheme Heterojunctions for Efficient Photocatalytic Hydrogen Production

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.