碳掺杂的TiO2与ZnO S型异质结协同提高四环素光催化降解性能

Carbon doped TiO2 and ZnO S-scheme heterojunction synergistically enhance the photocatalytic degradation performance of tetracycline

  • 摘要: 四环素是一种常用的广谱抗生素,广泛应用于医学和农业中,但其不合理使用导致大量残留药物随废水排入自然水体,对环境造成不利影响。本文采用一步水热法制备PAN@ZnO/TiO2,经过高温煅烧制备管状复合催化剂ZnO/C-TiO2。采用XRD、SEM、TEM、XPS和FTIR等手段对催化剂进行表征,证明了碳掺杂的TiO2与ZnO异质结的成功制备。光学和光电化学表征结果表明,ZnO/C-TiO2具有最佳的可见光吸收能力和光生电子与空穴分离能力。以四环素为目标污染物,探究了催化剂在可见光照射下对四环素的降解性能。结果表明,ZnO/C-TiO2对40 mg/L的四环素具有最佳的光催化降解效率(74.29%)。光催化活性的提高归因于S型ZnO/C-TiO2异质结的构建,加速了光生电子与空穴的分离。此外,该复合材料还可以有效降解亚甲基蓝、甲基橙、罗丹明B等染料。同时,稳定性实验表明ZnO/C-TiO2经5次循环后,具有良好的稳定性。

     

    Abstract: Tetracycline is a commonly used broad-spectrum antibiotic widely used in medicine and agriculture, but its improper use leads to a large amount of residual drugs being discharged into natural water bodies with wastewater, causing adverse effects on the environment. PAN@ZnO/TiO2 was prepared by one-step hydrothermal method, and the tubular composite catalyst ZnO/C-TiO2 was prepared by high temperature calcination.The catalysts were characterized by XRD, SEM, TEM, XPS, and FTIR, which demonstrated the successful preparation of carbon-doped TiO2 and ZnO heterojunction. The results of optical and photoelectrochemical characterization show that ZnO/C-TiO2 has the best visible light absorption capacity and photogenerated electron-hole separation ability. The degradation performance of the catalyst for tetracycline under visible light irradiation was investigated using tetracycline as the target pollutant. The results show that ZnO/C-TiO2 has the best photocatalytic degradation efficiency (74.29%) for 40 mg/L tetracycline. The improvement of photocatalytic activity is attributed to the construction of S-scheme ZnO/C-TiO2 heterojunction, which accelerates the separation of photogenerated electrons and holes. In addition, the composites can also effectively degrade methylene blue, methyl orange, rhodamine B and other dyes. At the same time, the stability experiment shows that ZnO/C-TiO2 has good stability after 5 cycles.

     

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