Cu doped SnS2 nanostructure induced sulfur vacancy towards boosted photocatalytic hydrogen evolution

Abstract Tin disulfide (SnS2) has been recognized as a promising nonprecious photocatalyst for hydrogen evolution using solar energy. Herein, sulfur vacancies are introduced to SnS2 photocatalyst by doping Cu for improving photocatalytic efficiency. The generation of sulfur vacancies enables formation of a new donor level near the conduction band minimum (CBM), resulting in the higher separation efficiency of photogenerated carriers and increased carrier density. Additionally, a theoretical study reveals that incorporating Cu and sulfur vacancies reduces the work function of SnS2, making it easier for photogenerated electrons to react with water. As a result, the hydrogen generation rate of sample 5%Cu/SnS2-x reaches 1.37 mmol h-1 g-1 under visible-light, far exceeding (more than 6 times) that of pure SnS2 nanoplates. This work not only reinforces the new understanding of defect engineering in SnS2-based photocatalysts but also provides valuable guides in rationally designing new efficient photocatalysts.