Surface domain potential difference-mediated efficient charge separation on a defective ZnIn2S4 microsphere photocatalyst

Low-efficiency charge separation in metal sulfides is a major obstacle to realizing high photocatalytic performance. Herein, we propose the concept of a similar surface domain potential difference between adjacent microdomains with and without surface S vacancies on ZnIn2S4 to mediate charge separation. Defective ZnIn2S4 microspheres (DZISNPs) are prepared through a solvothermal method combined with a low-temperature hydrogenation surface engineering strategy. The as-prepared DZISNPs with a narrowed bandgap of 2.38 eV possess a large specific surface area of 178.5 m(2) g(-1), a pore size of 6.89 nm, and a pore volume of 0.36 cm(3) g(-1), which further improves the visible light absorption. The resultant DZISNPs exhibit excellent visible light activity (2.15 mmol h(-1) g(-1)), which is similar to two-fold higher than that of the original DZISNP. The experimental results and DFT calculations reveal that the enhanced property can be a result of the surface S vacancy-induced surface domain potential difference, promoting the spatial separation of electrons and holes. Furthermore, the long-term stability of the DZISNPs indicates that the formation of surface S vacancies can inhibit the photocorrosion of ZnIn2S4. This strategy provides new insights for fabricating highly efficient and stable sulfide photocatalysts. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

In this study, a surface domain potential difference induced by surface S vacancies was proposed to mediate charge separation in defective ZnIn2S4 microspheres, leading to enhanced visible light absorption and photocatalytic activity. This engineering strategy provides new insights for fabricating highly efficient and stable sulfide photocatalysts.