S-scheme carbon doped-TiO/ZnInS heterojunction for enhanced photocatalytic degradation of microcystin-LR and hydrogen evolution.

Photocatalytic degradation of pollutants coupled with hydrogen (H) evolution has emerged as a promising solution for environmental and energy crises. However, the fast recombination of photoexcited electrons and holes limits photocatalytic activities. Herein, an S-scheme heterojunction carbon doped-TiO/ZnInS (C-TiO/ZnInS) was designed by substituting oxygen sites within C-TiO by ZnInS. Under visible light irradiation, the optimal C-TiO/ZnInS exhibits a higher degradation efficiency (88.6%) of microcystin-LR (MC-LR), compared to pristine C-TiO (72.9%) and ZnInS (66.8%). Furthermore, the H yield of the C-TiO/ZnInS reaches 1526.9 μmol g h, which is 3.83 times and 2.87 times that of the C-TiO and ZnInS, respectively. Experimental and theoretical investigations reveal that an internal electric field (IEF) informed in the C-TiO/ZnInS heterojunction, accelerates the separation of photogenerated charge pairs, thereby enhancing photocatalytic efficiency of MC-LR degradation and H production. This work highlights a new perspective on the development of high-performance photocatalysts for wastewater treatment and H generation.