Latest advances in the design, preparation and application of CdS-based photocatalysts

Cadmium sulfide (CdS), a typical transition metal sulfide, exhibits prominent broadband light-harvesting capacity and photoredox activity owing to its low work function (E_g ≈ 2.4 eV) and appropriate band structure. Therefore, it is regarded as an important candidate for preparing photocatalysts with excellent broadband light-harvesting capacity for extensive application in various fields. However, a large number of studies have indicated that the sluggish photoexciton migration and the susceptibility to photocorrosion of pure CdS photocatalysts greatly affect their photoactivity and long-term effectiveness. Therefore, the essential processing of CdS-based photocatalysts is required to improve their photocatalytic performance and expand their applications. This article systematically reviewed the latest research on CdS-based photocatalysts, encompassing their modification strategies and application fields. It focused on elaborating the intrinsic influence mechanisms of various strategies, such as microstructure regulation, heterojunction construction, heteroatom doping and surface modification, in improving the separation and migration of bulk excitons, enhancing surface reaction kinetics and increasing the photostability of CdS photocatalysts. Furthermore, the specific research progress on CdS-based photocatalyst applications such as hydrogen evolution, CO₂ reduction, nitrogen fixation, H₂O₂ production, value-added conversion of low-value chemicals and pollutant treatment was summarized. Finally, the shortcomings and challenges of CdS-based photocatalysts in practical application were summarized, and the directions for future research were presented, including the construction of new composite structures, in-depth investigation of reaction mechanisms, and design/development of practical reaction devices. This review article provides important guidance for improving the performance of CdS-based photocatalytic materials and promoting their practical applications.