Preparation of S-scheme heterojunction photocatalyst Y2O3/BiOCl and visible light degradation of ofloxacin: Photocatalytic mechanism, DFT calculation, degradation pathway, and toxicity evaluation

The contamination of antibiotics and heavy metals in water is a growing concern, and photocatalytic technology offers a green and efficient solution for removing contaminants from water. In this paper, a novel S-scheme heterojunction photocatalyst Y2O3/BiOCl was successfully designed and synthesized. The degradation of ofloxacin by Y2O3/BiOCl-3 composite photocatalyst under visible light was 87.81 %. The main active substance that acts is center dot O2- . The proposed primary kinetic constant was 0.0151 min-1, 4.98 and 17.97 times higher than BiOCl and Y2O3, respectively. The improved photocatalytic properties exhibited by Y2O3/BiOCl composites stem from establishing an S-scheme heterojunction interface between Y2O3 and BiOCl, significantly enhancing their visible light harvesting capability and facilitating an efficient separation of charge carriers. The pathways and byproducts associated with the degradation of OFX were thoroughly investigated utilizing Density Functional Theory along with High-Resolution Liquid Chromatography coupled with Mass Spectrometry. Furthermore, an assessment of the potential toxicity exhibited by the intermediary degradation compounds was conducted. This article combines Y2O3 with BiOCl to form a photocatalytic material, providing a reference for designing highperformance photocatalysts.