可见光催化剂钒酸铋的制备及特性研究

发布时间：2018-01-08 00:22

本文关键词：可见光催化剂钒酸铋的制备及特性研究　出处：《天津科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：光化学转化是有机污染物在生态环境中有效去除的重要方式。随着我国水体环境和大气环境有机污染的日益严峻,有必要开发高效节能的光催化剂,其中可见光驱动催化剂的研发更是环境领域的重要课题。当今社会经济飞速发展,能源消耗和环境污染问题越来越突出,利用各种有效手段治理环境污染已经迫在眉睫。在越来越多的治理方法中,光催化技术由于在空气净化、废水处理、消毒杀菌等多个领域的研究和应用备受人们的重视。利用光催化剂降解有机污染物,不但能够得到有效处理,同时能不易带来二次污染。钒酸铋是一种新型可见光响应型半导体光催化剂,由于带隙相对较窄、可见光催化活性较高等优点而备受关注。因此钒酸铋光催化材料具有良好的应用前景。本研究以Bi(NO3)3 K·5H2O和NH4VO3为材料,采用水热反应合成法在一定条件(T=160℃和T=180℃, pH=2,3,4,5,6,7,8,9)制备了系列BiVO4,利用SRD、SEM、UV-Vis DRS对其结构进行性能表征,并用亚甲基蓝作为模拟物测试了BiVO4的可见光催化活性。讨论了不同温度、不同pH对钒酸铋晶体结构和光催化性能的研究,最后在钒酸铋催化条件下对2-氯代苯甲酸进行了初步的可见光降解研究。研究结果显示：水热温度、反应液pH对钒酸铋晶体结构有很大程度的影响。温度为180℃,pH为5的反应液中制备的钒酸铋在曝气和催化剂用量为1.5 g/L时其降解效率最好。XRD和SEM分析表明,pH=5时,样品为片状纯单斜相BiVO4, pH=2-4和pH=7-9时制备的是单斜相和四方相的混合相BiVO4，表明不同pH条件下制备的BiVO4样品晶型结构显著不同,其中过酸或过碱条件均不利于单斜晶型BiVO4的生成。亚甲基蓝可见光降解实验结果表明,pH为5时制备BiVO4对亚甲基蓝光解催化效果最好,可见光降解4小时后降解率高达72%左右,而pH值为2,4和9时BiVO4对亚甲基蓝的可见光催化降解率不到20.0%,说明制备溶液体系pH值显著影响BiVO4的可见光催化活性。利用最佳条件(水溶液,pH=5,T=180℃)制备的钒酸铋降解难降解物2-氯代苯甲酸,最好的降解效果为40%左右。离子液体制备的钒酸铋和掺杂稀土元素制备的钒酸铋的催化性能都没有普通制备的钒酸铋催化性能好。
[Abstract]:Photochemical transformation is an important way to remove organic pollutants effectively in the ecological environment. With the organic pollution of water environment in China and the atmospheric environment is becoming increasingly serious, it is necessary to develop efficient photocatalyst, which developed visible light driven catalyst is a more important task in the field of the environment. The rapid development of social economy, energy consumption and environmental pollution the problem has become increasingly prominent, take various effective means to control environmental pollution is imminent. In the management of more and more methods, photocatalytic technology in air purification, wastewater treatment, research and application in many fields such as sterilization much attention. By using the photocatalytic degradation of organic pollutants, not only can be treated effectively, at the same time not easy to bring two pollution. Bismuth vanadate is a new type semiconductor photocatalyst response to visible light, because the band gap is relatively narrow, The visible light photocatalytic activity and high concern. Therefore bismuth vanadate photocatalyst has good application prospects. This research is based on the Bi (NO3) 3 K - 5H2O and NH4VO3 as materials, synthesized by hydrothermal reaction method under certain conditions (T=160 DEG and T=180 DEG C, pH=2,3,4,5,6,7,8,9) prepared a series of BiVO4. The use of SRD, SEM, UV-Vis, DRS characterization of the structure, and using methylene blue as mimics the photocatalytic activity of BiVO4 was tested. Discuss the different temperature of bismuth vanadate crystal structure and photocatalytic properties of different pH, finally in bismuth vanadate catalytic conditions on 2- chlorobenzoate a preliminary study on visible light degradation. The results showed that the temperature of hydrothermal reaction solution, pH has great influence on the bismuth vanadate crystal structure. The temperature is 180 DEG C, pH reaction liquid 5 in preparation of bismuth vanadate by aeration and catalyst amount was 1.5 g/L The best degradation efficiency of.XRD and SEM analysis showed that pH=5, the sample sheet pure monoclinic phase of BiVO4, pH=2-4 and pH=7-9 are prepared monoclinic and tetragonal phase mixed BiVO4, showed that under different pH conditions for BiVO4 sample crystal structure by different generation in acid or alkali conditions is not conducive to the monoclinic BiVO4. The experimental results show that the photocatalytic degradation of methylene blue, pH 5 preparation of BiVO4 of methylene blue solution best catalytic effect, visible light degradation after 4 hours of degradation rate is as high as 72%, while the pH value was 2,4 and 9 BiVO4 on the photocatalytic degradation rate of methylene blue is not 20%, illustrate the solution preparation system pH value significantly affect the photocatalytic activity of BiVO4. The optimum conditions (water solution, pH=5, T=180 C) bismuth vanadate degradation preparation of refractory 2- chlorobenzoate degradation, the best is about 40%. Ionic liquid preparation The catalytic performance of bismuth vanadate prepared by bismuth vanadate and the rare earth doped bismuth vanadate has no better catalytic performance than the common bismuth vanadate.

【学位授予单位】：天津科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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