Efficient visible light photocatalytic degradation of organic pollutants by WS2-modified CdS nanorods: a study on heterojunction composite catalysts

Cadmium sulfide (CdS), a metal-sulfide semiconductor, is widely recognized as a promising photocatalytic material. However, CdS also faces significant challenges, such as a high recombination rate of photogenerated electron–hole pairs and a susceptibility to photocorrosion, which collectively limit its broader application in photocatalytic processes. To overcome these limitations, further strategies need to be developed to enhance the stability and efficiency of CdS-based photocatalysts. We successfully synthesized a series of novel heterojunction catalysts, WS 2 -modified CdS (CdS/WS 2 ), using solvothermal methods. The composite catalysts were characterized using a variety of analytical techniques, and their degradation performance for pollutants under visible light was evaluated with rhodamine B (RhB) and nitenpyram (NTP) as model pollutants. The results indicated that the 8% CdS/WS 2 heterojunction composite catalyst achieved degradation efficiencies of 94.2% for RhB and 89.9% for NTP. The degradation rates of RhB and NTP were increased by factors of 5.2 and 7.1, respectively, compared to the unmodified CdS. Characterization of the optical and photoelectrochemical properties reveals that the incorporation of WS 2 onto CdS effectively enhances the transfer and separation of photoexcited electrons and holes. This study provides a simple and efficient approach for the design of semiconductor heterojunction photocatalytic materials. Graphical To address the high recombination rate of photogenerated carriers and the severe photocorrosion typically observed in the photocatalytic applications of cadmium sulfide (CdS) semiconductor materials, this study successfully fabricated WS 2 -modified CdS nanorod heterojunction catalysts (CdS/WS 2 ) via a solvothermal method. The uniform dispersion of WS 2 on the surface of CdS formed a well-defined heterojunction interface, which significantly facilitated the directional transfer of photogenerated electrons (e − ) from the conduction band (CB) of CdS to WS 2 . Meanwhile, photogenerated holes (h + ) remained in the valence band (VB) of CdS, thereby effectively suppressing electron–hole recombination and enhancing photocatalytic stability.