Rare earth Ce³⁺/Ce⁴⁺ redox effect coupled S-scheme heterojunction synergistically boost electron transfer for...

Photocatalysis ranks among the most prospective technologies for the elimination of antibiotics in aqueous systems, for its high efficiency, eco-friendliness and capability to achieve pollutant mineralization. However, conventional photocatalysts is severely hindered by the low efficiency of the photogenerated carriers, which from carrier density and rapid recombination. To address this challenge, a novel g-C₃N₄/LaCeO₃ (CN/LCO) S-scheme heterojunction photocatalyst was developed. Systematic characterization results implied that the S-scheme heterojunction markedly accelerated interfacial electron transfer and enhanced effective harnessing of photogenerated electrons and holes. Furthermore, the Ce³⁺/Ce⁴⁺ redox cycle supplementing electrons for LCO. Their synergistic effect promoted the transfer of photogenerated carriers. The enhanced efficiency of electron-hole pair separation and utilization promotes the generation of reactive oxygen species (•O₂^- and •OH), enabling efficient decomposition and mineralization of antibiotics. The rate constant of composite sample for tetracycline degradation was almost 1.73 and 2.14 times those of CN and LCO, respectively. Stability and reusability tests showed that composite sample had maintained its performance during the five treatment cycles, with only a 9% reduction. Moreover, the continuous flow of CN/LCO catalytic membrane reactor allowed TC to be removed continuously and efficiently in visible light. Finally, liquid chromatography-mass spectrometry was coupled with algal and mung bean toxicity assays, confirming that the system realized not just efficient TC degradation but also a marked reduction in the toxic impacts of substance. This study provided new light on the charge transfer mechanism of heterojunction photocatalysts, while presenting a novel approach to efficient photocatalytic antibiotic removal via modified g-C₃N₄ photocatalysts.