An S-Scheme CeO₂/Bi₂O₂S heterojunction photoanode for the photoelectrocatalytic degradation of sulfamethoxazole in synthetic and real wastewater

We prepared an S- scheme heterojunction photoanode using cerium oxide (CeO₂) and bismuth oxysulfide (Bi₂O₂S) for the photoelectrocatalytic degradation of sulfamethoxazole. The CeO₂ /Bi₂O₂S photoanode was synthesised via an in-situ hydrothermal method, ensuring strong contact and efficient charge transfer between the CeO₂ and Bi₂O₂S. The materials and photoanode were characterized with XRD, XPS, photoluminescence, and photoelectrochemistry. The S-scheme configuration observed in the formation of heterojunction in CeO₂ /Bi₂O₂S photoanode was responsible for the improved photoelectrocatalytic performance for the visible light-assisted degradation of sulfamethoxazole. Operational parameters such as the effect of pH and current density were examined. The extent of sulfamethoxazole mineralisation was calculated to be 72 % using the total organic carbon (TOC) measurement. The LC-MS analysis was used to predict the degradation pathway and products. Furthermore, the photoelectrocatalytic efficiency of the CeO₂/Bi₂O₂S photoanode was investigated in real wastewater matrices with TOC removal of 54 %. Therefore, the S scheme CeO₂/Bi₂O₂S photoanodes lends itself to photoelectrochemical water treatment applications.