Abstract A single-pot surfactant-free sol-gel method is reported for the facile and bulk synthesis of ultrafine-nanospherical CeO2/TiO2 composites with different CeO2 loadings and their photocatalytic-activity for the degradation and mineralization of tetracycline (TC) under visible-light irradiation is investigated for the first time. The incorporation of CeO2 favored the controlled crystalline growth of TiO2 in its anatase phase, and their crystallinity and particle size were significantly decreased. The textural and optical properties of TiO2 were also improved with the incremental addition of CeO2 by increasing their specific surface-area and visible-light absorption respectively. The optical band gap of TiO2 decreased to 2.24 eV with the incorporation of 1% CeO2 and it further decreased to 2.21 eV with the incremental amount of CeO2. Due to the formation of heterojunction in the composite, the recombination rate of electron-hole pairs was significantly decreased. A highest TC removal efficiency of ~99% was observed for 4% CeO2/TiO2 composite for a period of 80 min of visible-light irradiation. Moreover, 88.2% TC mineralization efficiency was achieved for a period of 240 min of visible light irradiation. The enhanced catalytic-activity could be attributed to the synergy of high degree of adsorption followed by an enhanced photocatalysis at the heterointerface formed by the adjacent contact between TiO2 and CeO2. The synergistic effects of low-particle size, high surface-area, enhanced visible-light absorption, reduced band-gap, and increased life-time of the photogenerated charge-carriers through the formation of heterointerface contributed to its high photocatalytic activity. The hydroxyl and superoxide-anion radicals played a superior role in the photocatalytic process. Moreover, the composites retained its efficiency for seven-cycles of reaction without any significant-loss in its activity and structural and textural stability.

中文翻译：

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CeO2负载量对单锅溶胶凝胶衍生的超细CeO2/TiO2纳米复合材料在可见光照射下有效降解四环素的结构、结构、光学和光催化性能的影响

摘要 报道了一种单锅不含表面活性剂的溶胶-凝胶法，可轻松批量合成具有不同 CeO2 负载量的超细纳米球 CeO2/TiO2 复合材料，及其在可见光下降解和矿化四环素 (TC) 的光催化活性。第一次研究光照射。CeO2 的掺入有利于 TiO2 在锐钛矿相中受控的晶体生长，并且它们的结晶度和粒度显着降低。TiO2 的结构和光学特性也随着 CeO2 的增量添加而得到改善，分别增加了它们的比表面积和可见光吸收。TiO2 的光学带隙随着 1% CeO2 的掺入降低到 2.24 eV，随着 CeO2 的增加，它进一步降低到 2.21 eV。由于复合材料中异质结的形成，电子-空穴对的复合率显着降低。在 80 分钟的可见光照射期间，4% CeO2/TiO2 复合材料的最高 TC 去除效率约为 99%。此外，在可见光照射 240 分钟内实现了 88.2% 的 TC 矿化效率。增强的催化活性可归因于高度吸附的协同作用，随后在由 TiO2 和 CeO2 之间的相邻接触形成的异质界面处增强的光催化作用。低粒径、高表面积、增强的可见光吸收、减小的带隙和通过形成异质界面增加光生载流子寿命的协同效应有助于其高光催化活性。羟基和超氧阴离子自由基在光催化过程中发挥了优越的作用。此外，复合材料在七个反应循环中保持其效率，而其活性和结构和质地稳定性没有任何显着损失。