Direct Z-scheme SnS2/InS heterostructure for efficient visible-light photocatalytic hydrogen evolution

Hydrogen energy, as a clean and efficient energy carrier, holds significant strategic importance in addressing global climate change, facilitating the transition to sustainable energy systems, and promoting sustainable development. Utilizing solar energy for the production of clean hydrogen presents a viable solution to these challenges. In this study, based on Density Functional Theory (DFT) and first-principles calculations, a novel SnS2/InS van der Waals heterostructure is proposed. The results indicate that this heterojunction exhibits excellent energy, thermal, dynamical, and mechanical stability, with significant potential for experimental synthesis. Under illumination, the photo-excited electrons and holes transfer according to the Z-scheme mechanism, exhibiting high electron and hole mobility (242.782 cm2V−1s−1 and 145.133 cm2V−1s−1, respectively), significantly enhancing the efficiency of photocatalytic water splitting. Moreover, the heterojunction possesses a strong and broad optical absorption coefficient, reaching 3.17 × 104 cm−1 in the visible light range, and it spontaneously undergoes hydrogen evolution under acidic conditions (pH = 0), demonstrating a high solar-to-hydrogen conversion efficiency of up to 28.71%. Under a 1.5% tensile strain, the redox capability of the charge carriers in the heterojunction is further enhanced. These findings confirm that the SnS2/InS heterojunction is a highly promising photocatalytic material with substantial potential.