Interfacial engineering of BiSbO4/Ag2S p-n heterojunction with directed internal electric field for enhanced Chlorpyrifos photocatalytic degradation

Chlorpyrifos (CPF), as a widely applied organophosphate insecticide, poses a severe threat to ecological safety and human health due to its environmental persistence and potential neurotoxicity. Photocatalysis is considered an effective strategy for removing organic pollutants from aquatic systems. This study constructed a novel BiSbO 4 /Ag 2 S heterojunction photocatalyst to enhance the utilization efficiency of visible light. An exploration was conducted into the impact of various environmental factors on CPF degradation, and a subsequent analysis was performed on the degradation mechanism. Experimental results indicated that a CPF degradation rate of approximately 97% was achieved within 2 h of visible light irradiation. After five consecutive cycles, the degradation efficiency decreased by 12.91%, demonstrating its robust reusability. Superoxide radicals (·O 2 − ) and photogenerated holes (h + ) were identified as the primary reactive species playing a crucial role in the degradation process. Furthermore, the intermediate products formed during CPF degradation were analyzed, potential degradation pathways were proposed, and the toxicity of both CPF and its intermediates was assessed. The construction of a BiSbO 4 /Ag 2 S p-n heterojunction induced a directed internal electric field that effectively regulated the spatial charge transfer and separation, thereby facilitating the efficient production of reactive species for enhanced CPF degradation. This study provided new insights for developing high-efficiency heterojunction materials to remove persistent pesticide pollutants from the environment.