Synergistic engineering of surface hydroxyls and oxygen vacancies in Ov@SnZnAl-LDH for adsorption-enhanced visible-light photocatalytic antibiotic removal

Antibiotic contamination in aquatic environments poses significant ecotoxicological risks to ecosystems and human health, necessitating efficient and sustainable remediation technologies. Herein, we report a robust visible-light-driven photocatalyst, Ov@SnZnAl-LDH, fabricated via a facile alkali-etching strategy that simultaneously regulates surface hydroxyl density and generates abundant oxygen vacancies. Experimental characterizations combined with density functional theory calculations demonstrate that the engineered oxygen vacancies induce bond elongation and optimize the surface electronic structure, synergistically enhancing antibiotic adsorption and charge separation and transfer. The optimized Ov@SnZnAl-LDH exhibits a tetracycline hydrochloride (TCH) degradation rate constant of 0.0211 L mg −1 min −1 , which is 30-fold higher than that of commercial g-C 3 N 4 . Mechanistic studies using electron paramagnetic resonance spectroscopy and reactive species quenching experiments confirm that •O 2 - is the primary reactive species dominating the oxidative ring-opening of TCH, with h + playing a secondary but significant role. Furthermore, the catalyst maintains excellent stability and performance in complex real-world water matrices and continuous-flow reactor systems. This work provides molecular-level insights into surface defect engineering, offering a promising, environmentally safe approach for mitigating antibiotic pollution and reducing associated ecotoxicological hazards.