Ce-Doped In₂S₃ for Enhanced H₂O₂ Adsorption and Surface Hydroxyl Radical Engineering: Boosting Fenton-like Catalysis via Synergistic Redox Regulation

The photo-Fenton-like process is recognized due to its remarkable effectiveness in degrading recalcitrant organic pollutants, primarily due to its superior oxidative capabilities. In this work, we synthesized Ce-doped In2S3 hollow-tube catalysts via a precursor-assisted method utilizing MIL-68(In). Within the photo-Fenton-like system, cerium acts as a Fenton-like cocatalyst, activating adsorbed H2O2 through heterolytic cleavage and subsequently generating reactive oxygen species crucial for tetracycline (TC) degradation. Specifically, Ce selective adsorption of H2O2 modulates the prevalent reactive species, shifting the dominant radical type from surface-bound ·OH to free ·OH radicals. Furthermore, the biological toxicity of TC degradation intermediates and their associated ecological risks were systematically evaluated. Radical speciation and reaction pathways were elucidated through a combination of density functional theory calculations and electron paramagnetic resonance analysis, culminating in a proposed catalytic mechanism. These results provide valuable insights into the rational design of photocatalysts aimed at antibiotic degradation and substantially expand the potential applications of rare-earth elements within advanced oxidation technologies.