Zhong Xin, Zou Zheng-Shuo, Wang Hu-Lin, Huang Wei, Zhou Bin-Xue
Department of Environmental Science and Engineering, Beijing Normal University, Zhuhai 519000, China.
Materials (Basel). 2019 Nov 28;12(23):3952. doi: 10.3390/ma12233952.
In this study, magnetic visible light driven photocatalysts (bismuth ferrite, BiFeO, BFO and Co-doped bismuth ferrite, Co-BFO) were successfully prepared by the facile hydrothermal method. The catalyst was used in the application of heterogeneous persulfate (PS) system under visible LED light irradiation for the degradation of levofloxacin (LFX), proving to be an excellent photocatalyst when evaluated by various characterization methods. The effect of Co-doping in the BFO structure was investigated that the decrease of band gap width and the generated photoelectrons and holes would effectively reduce the recombination of photogenerated electron-hole pairs, leading to the enhancement photocatalytic activity. The results demonstrated that Co-BFO catalyst had a high photodegradation efficiency over a wide pH range of 3.0-9.0 and the Co-BFO-2 composite displayed the optimal catalytic performance. It was found that the degradation rate of LFX by Co-BFO-2 catalyst was 3.52 times higher than that of pure BFO catalyst under visible light condition. The free radical trapping experiments and EPR tests demonstrated that superoxide, photogenerated holes and sulfate radicals were the main active species in the photocatalytic degradation of LFX. And a possible photocatalytic degradation mechanism of LFX was proposed in the Vis/Co-BFO/PS process. These findings provided new insight of the mechanism of heterogeneous activation of persulfate by Co-BFO under visible light irradiation.
在本研究中，通过简便的水热法成功制备了磁性可见光驱动光催化剂（铋铁氧体，BiFeO₃，BFO和Co掺杂铋铁氧体，Co-BFO）。该催化剂用于在可见光发光二极管照射下的非均相过硫酸盐（PS）体系中降解左氧氟沙星（LFX），通过各种表征方法评估，证明是一种优异的光催化剂。研究了Co掺杂在BFO结构中的作用，发现带隙宽度的减小以及光生电子和空穴的产生会有效减少光生电子 - 空穴对的复合，从而提高光催化活性。结果表明，Co-BFO催化剂在3.0 - 9.0的宽pH范围内具有高光降解效率，且Co-BFO-2复合材料表现出最佳的催化性能。发现在可见光条件下，Co-BFO-2催化剂对LFX的降解速率比纯BFO催化剂高3.52倍。自由基捕获实验和电子顺磁共振测试表明，超氧自由基、光生空穴和硫酸根自由基是LFX光催化降解中的主要活性物种。并提出了Vis/Co-BFO/PS过程中LFX可能的光催化降解机制。这些发现为可见光照射下Co-BFO非均相活化过硫酸盐的机制提供了新的见解。
