Abstract: The visible-light-driven catalyst CeO2/ZnIn2S4 (CeO2/ZIS) was prepared via a hydrothermal method, and its photocatalytic degradation efficiency and mechanism for oxytetracycline (OTC) in water were explored. The morphological characteristics, crystal structure, thermal stability, specific surface area, and optical properties of the catalyst were analyzed by a series of characterization methods. The results showed that the visible light absorption performance of the spherical CeO2/ZIS composed of flakes was significantly improved compared with that of the monomer CeO2. Under the conditions of an initial content of OTC of 30 mg/L, a catalyst dosage of 0.20 g/L, a catalyst dosage of 7.0, and a xenon lamp power of 500 W, the optimal degradation efficiency of OTC by CeO2/ZIS reached 84%. The photocatalytic degradation of OTC by CeO2/ZIS followed a pseudo-first-order kinetic model, with an apparent rate constant of 0.1148 h-1. The exploration of degradation mechanism revealed that the holes (h+) and superoxide radicals (?O_2^-) played major roles during the degradation process of OTC. By combining experimental results with density functional theory (DFT) simulations, a reasonable photocatalytic mechanism for the system was proposed and the stability of the catalyst was verified. This work provides a preparation method for the visible-light-driven catalyst CeO2/ZIS, which can efficiently photocatalytically degrade oxytetracycline in water. The combination of theoretical calculations and experimental results has certain reference value for fully understanding the degradation process of antibiotic pollutants by visible-light-driven catalysts.

Key words: CeO₂/ZnIn₂S₄, oxytetracycline, photocatalysis, visible light

摘要： 本研究通过水热法制备了CeO2/ZnIn2S4 (CeO2/ZIS)可见光驱动催化剂，并探究其对水中土霉素(OTC)的光催化降解性能与机理。采用多种表征手段对催化剂的形貌特征、晶体结构、热稳定性、比表面积和光学性质进行分析。结果表明，由片状组成的花球状CeO2/ZIS复合材料，相较于单体CeO2，其可见光吸收性能明显提升。在OTC的初始含量为30 mg/L、催化剂投加量为0.20 g/L、溶液pH=7.0、氙灯功率为500 W的优化条件下，CeO2/ZIS对OTC的降解效果最佳，可达到84%。动力学研究表明，CeO2/ZIS光催化降解OTC的过程符合伪一级动力学模型，表观速率常数为0.1148 h-1。降解机理探究结果发现，空穴(h+)和超氧自由基(?O_2^-)是降解OTC过程中主要活性物种。结合密度泛函理论(DFT)计算，本研究提出了该催化体系的光催化机理，并验证了催化剂具有良好的稳定性。本工作提供了一种新型可见光驱动催化剂CeO2/ZIS的制备方法，CeO2/ZIS可以高效光催化降解水中土霉素，且理论计算与实验结果相互验证，为充分理解可见光催化剂降解抗生素类污染物的过程提供了重要参考。

关键词: CeO₂/ZnIn₂S₄, 土霉素, 光催化, 可见光