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 the photocatalysts with excellent broadband light harvesting capacity to be extensively applied in many 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 its photoactivity and long-term effectiveness, thereby the essential processing of CdS-based photocatalyst is a primary task to improve its photocatalytic performance and expand its applications. This article systematically reviewed the latest research advance of CdS-based photocatalytic materials based on 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 on improving the separation and migration of bulk excitons, enhancing surface reaction kinetics and increasing photostability of CdS photocatalysts. Furthermore, the specific research advance of CdS-based photocatalysts in 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 subsequent directions in future research were outlooked, including the construction of new composite structures, in-depth investigation on reaction mechanisms, design/development of practical reaction devices and so on. This review article provides an important guidance for improving the performance of CdS-based photocatalytic materials and promoting their practical application.

Scheme 1. Microstructure regulation, hybridization and applications of CdS-based photocatalytic materials.