基于纳米铋基异质结光催化剂的制备、表征及其性能研究

发布时间：2018-09-01 07:26

【摘要】：针对当前光催化技术领域中光催化剂存在光催化效率低,太阳能利用低以及成本过高等关键问题,围绕着开发高效,低成本,光响应范围宽这一目标来合成新型的光催化剂,选用铋基作为载体进行半导体光催化剂的负载,以光催化剂的性能为导向来进行一系列复合铋基异质结光催化剂的设计合成,使光催化剂性能能够得到一定程度的改进与提高。本论文主要的研究的内容如下:1.通过对溶胶凝胶法制备工艺的优化改进,成功制备出了BiFeO_3纳米光催化材料;以L-半胱氨酸为硫源通过原位合成法在BiFeO_3表面生成Bi_2S_3,合成的Bi_2S_3/BiFeO_3异质结光催化材料具有纳米球形花状结构。在可见光下反应60分钟,异质结复合材料能够对目标降解物孔雀石绿实现完全光降解。由于Bi_2S_3在BiFeO_3表面的成功负载,使得到的光催化剂性能得到了提高,对有机污染物的光催化降解效果明显。在实验中对光催化剂的生长机理以及光催化作用机理进行了详细阐述。因此,在环境污染治理中将具有广泛的应用前景。2.通过优化溶胶凝胶法制备工艺制备出了g-C_3N_4/BiFeO_3异质结复合光催化材料;合成并表征了g-C_3N_4/BiFeO_3纳米复合材料,由于g-C_3N_4和BiFeO_3的有效复合,g-C_3N_4优良电子输运特性,能够有效的转移光生载流子,可以提高光生电子和光生空穴的分离效率,并且拓宽了光的响应范围。该异质结材料在处理难降解有机污染物双酚A方面表现出巨大的应用潜力。3.以三聚氰胺为原料通过高温裂解法制备出的g-C_3N_4纳米材料;以乙二醇甲醚为溶剂采用溶剂热法合成g-C_3N_4/BiVO_4异质结材料,并表征了该异质结材料。结果表明该材料具有多孔球形结构,由于g-C_3N_4的优良的光生载流子输运特性,能够提高光生电子和光生空穴的分离效率,增强g-C_3N_4/BiVO_4的可见光催化性能,在可见光下能够在40分钟内完全降解100ml 20mg/l孔雀石绿溶液,为该材料在实际中的应用提供了可能。
[Abstract]:Aiming at the key problems of low photocatalytic efficiency, low utilization of solar energy and high cost in the field of photocatalytic technology at present, a new type of photocatalyst is synthesized by focusing on the development of high efficiency, low cost and wide range of light response. A series of composite bismuth based heterojunction photocatalysts were designed and synthesized by using bismuth as the carrier to support the semiconductor photocatalyst and the performance of the photocatalyst was guided. The photocatalyst performance could be improved and improved to a certain extent. The main contents of this thesis are as follows: 1. Through the optimization and improvement of the preparation process of sol-gel method, BiFeO_3 nano-photocatalytic materials were successfully prepared. Using L-cysteine as sulfur source, Bi_2S_3/BiFeO_3 heterojunction photocatalytic materials synthesized by in situ synthesis of Bi_2S_3, on the surface of BiFeO_3 have nano-spherical flower-like structure. Under visible light for 60 minutes, the heterojunction composite could achieve complete photodegradation of the target degradation malachite green. Due to the successful loading of Bi_2S_3 on the surface of BiFeO_3, the photocatalytic performance of the obtained photocatalyst was improved, and the photocatalytic degradation of organic pollutants was obvious. The growth mechanism and photocatalytic mechanism of photocatalyst were discussed in detail. Therefore, in the environmental pollution treatment will have a wide range of application prospects. 2. G-C_3N_4/BiFeO_3 heterojunction composite photocatalytic materials were prepared by optimizing the sol-gel method, and g-C_3N_4/BiFeO_3 nanocomposites were synthesized and characterized. Due to the excellent electron transport characteristics of g-C_3N_4 and BiFeO_3, the photogenerated carriers can be effectively transferred. It can improve the separation efficiency of photogenerated electrons and holes, and widen the response range of light. The heterojunction material shows great application potential in the treatment of refractory organic pollutant bisphenol A. G-C_3N_4 nanocrystals were prepared by pyrolysis of melamine and g-C_3N_4/BiVO_4 heterojunction materials were synthesized by solvothermal method using ethylene glycol methyl ether as solvent and characterized. The results show that the material has porous spherical structure. Because of the excellent photogenerated carrier transport characteristics of g-C_3N_4, the separation efficiency of photogenerated electrons and photogenerated holes can be improved, and the visible photocatalytic performance of g-C_3N_4/BiVO_4 can be enhanced. The 100ml 20mg/l malachite green solution can be completely degraded in 40 minutes under visible light, which makes it possible for the material to be applied in practice.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36

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