Bi系异质结光催化剂的设计及其抗生素降解机理研究

发布时间：2018-10-08 21:48

【摘要】：近年,Bi系光催化材料因其资源丰富、可见光区有响应等优点备受关注,但由于光生电子和空穴易复合的特性限制了Bi系光催化材料的应用。构建p-n异质结和形貌控制有利于光生电子和空穴的分离、提升其光催化性能。本文中采用水热法和原位转换法分别设计构建了BiOBr/BiVO_4 p-n异质结和带有特殊结构的BiOCl/BiVO_4 p-n异质结,通过对制备材料的系列表征以及光电化学和光催化性能测试,探究不同反应条件对复合材料的形成、材料的形貌以及材料的光催化性能的影响。利用复合材料对抗生素诺氟沙星的降解实验,对降解性能及机理进行了探究分析。实验结果表明,在制备BiOBr/BiVO_4 p-n异质结时,只有当CTAB和HNO3同时存在才能形成BiOBr/BiVO_4复合材料。BiOBr/BiVO_4 p-n异质结光催化降解RhB的效率较纯的BiVO_4而言有了明显的提高,这主要归因于BiVO_4和BiOBr之间形成的内建电场能有效的抑制光生电子-空穴的复合。在制备BiOCl/BiVO_4 p-n异质结时,HCl的浓度对BiOCl/BiVO_4复合材料的形貌以及性能的影响非常显著。由于p-n异质结和特殊形貌结构的共同作用,BiOCl纳米片与BiVO_4介孔纺锤体相互交错的BiOCl/BiVO_4复合材料的光催化性能得到了进一步的提升。分析诺氟沙星的降解机理,发现在反应过程中起主要作用的是空穴。因此要实现对抗生素的降解,不仅仅需要光生电子和空穴的有效分离,还需要光生空穴具有较强的氧化能力。
[Abstract]:In recent years, Bi-B-based photocatalytic materials have attracted much attention because of their rich resources and response in visible region. However, the application of Bi photocatalytic materials is limited by the easy recombination of photogenerated electrons and holes. The formation of p-n heterojunction and morphology control are beneficial to the separation of photogenerated electrons and holes, and the photocatalytic properties of p-n heterojunction are improved. In this paper, BiOBr/BiVO_4 p-n heterojunction and BiOCl/BiVO_4 p-n heterojunction with special structure were designed and constructed by hydrothermal method and in-situ conversion method, respectively. The effects of different reaction conditions on the formation, morphology and photocatalytic properties of composites were investigated. The degradation performance and mechanism of antibiotic norfloxacin were studied by using composite materials. The experimental results show that when BiOBr/BiVO_4 p-n heterojunction is prepared, the efficiency of photocatalytic degradation of RhB in BiOBr/BiVO_4 composite. BiOBr-BiVOP 4p-n heterojunction can only be obtained when CTAB and HNO3 exist simultaneously. The photocatalytic degradation efficiency of RhB is higher than that of pure BiVO_4. This is mainly due to the fact that the built-in electric field formed between BiVO_4 and BiOBr can effectively inhibit the combination of photogenerated electrons and holes. The concentration of BiOCl/BiVO_4 p-n heterojunction has a significant effect on the morphology and properties of BiOCl/BiVO_4 composites. Because of the interaction of p-n heterojunction and special morphology, the photocatalytic properties of BiOCl/BiVO_4 composites interlaced with BiVO_4 mesoporous spindles were further improved. The degradation mechanism of norfloxacin was analyzed. Therefore, the degradation of antibiotics requires not only the effective separation of photogenerated electrons and holes, but also the strong oxidation ability of photogenerated holes.
【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;O644.1

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