Theoretical insights into the mechanism of photocatalytic reduction of CO₂ and water splitting over II-VI zinc chalcogenide semiconductor

The reduction of greenhouse gas emissions and the energy problem, which have received a lot of attention recently, can be addressed in substantial ways through photocatalytic carbon dioxide (CO₂) reduction and water splitting. However, the lack of knowledge of the complex chemical mechanisms hinders the development of novel catalysts. Therefore, theoretical calculations can effectively explain the theory behind the experiments and thus have a significant role in understanding the complex chemical mechanisms. Here, recent computational developments in zinc chalcogenide-based water splitting and CO₂ reduction photocatalysts, including ZnX (X = O, S, Se, Te) and related composite catalysts, are presented in detail. This review focuses on various approaches such as defect engineering, crystal facet engineering, solid solutions, and heterojunction construction that are used to improve the charge separation, visible light absorption, and photocatalytic performance of II-VI zinc chalcogenides. Finally, the challenges and perspectives are also discussed. We hope that this review will help to understand the rational design of zinc chalcogenide-based catalysts for CO₂ photoreduction and water splitting.