Boosting the photocatalytic efficiency of sulfur doped BiOCl via visible light and advanced oxidative processes integration for organic pollutant removal

S-doped BiOCl nanosheets with tunable band structure were successfully synthesized via a solvothermal method. • Bifunctional vis/PMS system was constructed, enabling synergistic photocatalysis and PMS activation. • Enhanced performance is attributed to improved visible-light absorption and efficient charge separation. • Non-•OH dominated pathway involving •O 2 − , 1 O 2 , and h + governs the degradation process. Elemental doping was considered as an effective strategy for modulating the band structure of semiconductors. In this study, Sulfur doped BiOCl nanosheet catalysts were prepared by a solvothermal method and systematically characterized using XRD, FTIR, SEM, TEM, XPS, and DRS to analyze their crystalline structurdeclaration. e, morphology, surface chemistry, and optical characteristics. The optimized S-doped BiOCl (BiOCl-S) catalyst demonstrated remarkable catalytic performance in the vis/PMS synergistic system. Experimental results validated that the optimal degradation efficiency of the BiOCl-S catalysts was achieved at 4% S-doping, beyond which further increasing the S content led to a decline in activity. Under optimal condition, the BiOCl-S catalyst achieved 97.08% RhB removal within 25 min in the vis/PMS synergistic system, representing a substantial improvement over individual visible-light (32.55%) or PMS-only (48.69%) systems. Cyclic tests validated the outstanding stability of the catalyst. The key reactive species responsible for pollutant degradation, as identified through radical trapping experiments, were found to be holes (h + ), superoxide radicals (•O₂ − ), and singlet oxygen ( 1 O₂). Mechanistic investigation revealed that the enhanced catalytic activity originated from two effects such as enhanced visible-light absorption capability and effective activation of peroxymonosulfate (PMS) through bismuth ion mediation. This dual-function mechanism enables efficient pollutant degradation through combined photocatalytic and advanced oxidation pathways.