Abstract：
Building a heterojunction is a fascinating option to guarantee sufficient carrier separation and transfer efficiency, but the mechanism of charge migration at the heterojunction interface has not been thoroughly studied. Herein, MIL-53(Fe)/Bi4O5I2 photocatalyst with a Z-scheme heterojunction structure is constructed, which achieves efficient photocatalytic decontamination under solar light. Driven by the newly-built internal electric field (IEF), the formation of Fe-O-Bi electron migration channel allows for rapid separation and transfer of charge carriers at the heterojunction interface, confirmed by the material characterization and density functional theory (DFT) calculation. The narrower band gap and improved visible light response also contribute to the enhanced photocatalytic activity of composite materials. With levofloxacin as the target pollutant, the optimal MIL-53(Fe)/Bi4O5I2 achieves complete removal of pollutant within 150 min, the photocatalysis rate of which is ca. 4.4 and 26.0 times that of pure Bi4O5I2 and MIL-53(Fe), respectively. Simultaneously, the optimal composite material exhibits satisfactory photodegradation of seven fluoroquinolones, and the photocatalysis rates are as follows: lomefloxacin > ciprofloxacin > enrofloxacin > norfloxacin > pefloxacin > levofloxacin > marbofloxacin. DFT calculations reveal a positive relationship between degradation rate and Fukui index (ƒ0) of main carbon atoms in seven fluoroquinolones. This study sheds light on the existence of electron migration channels at Z-scheme heterojunction interface to ensure sufficient photoinduced carrier transfer, and reveals the influence of pollutant structure on photolysis rate.
摘要：
构建异质结是保证足够的载流子分离和转移效率的迷人选择，但是异质结界面电荷迁移的机理还没有得到深入的研究。在这里，构建了具有Z方案异质结结构的MIL-53(Fe)/Bi4O5I2光催化剂，在太阳光下实现高效的光催化净化。在新建的内部电场（IEF）的驱动下，Fe-O-Bi电子迁移通道的形成允许电荷载流子在异质结界面的快速分离和转移，经材料表征和密度泛函理论(DFT)计算证实。较窄的带隙和改进的可见光响应也有助于增强复合材料的光催化活性。以左氧氟沙星为目标污染物,最佳MIL-53(Fe)/Bi4O5I2在150min内实现污染物的完全去除，其光催化速率约为。是纯Bi4O5I2和MIL-53(Fe)的4.4倍和26.0倍，分别。同时,最佳的复合材料表现出令人满意的光降解7氟喹诺酮，光催化率如下:洛美沙星>环丙沙星>恩诺沙星>诺氟沙星>培氟沙星>左氧氟沙星>马尔波沙星。DFT计算揭示了7种氟喹诺酮类药物中主要碳原子的降解速率与Fukui指数（f0）之间的正相关关系。这项研究揭示了Z方案异质结界面处电子迁移通道的存在，以确保足够的光诱导载流子转移，并揭示了污染物结构对光解速率的影响。
