声化学及非金属改性BiOCl光催化剂的制备及其光催化性能研究

发布时间：2018-01-07 11:31

本文关键词：声化学及非金属改性BiOCl光催化剂的制备及其光催化性能研究　出处：《江西理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：半导体光催化技术作为一种高效、绿色去除有机污染物的方法,其在环境保护领域有着广阔的应用前景。BiOCl是一种高效稳定的新型光催化剂,具有材料易得、制备方法简单、对环境无污染等诸多优点。目前大多数的BiOCl改性集中在贵金属沉积和构筑金属半导体异质结等方法上,相对来说,声化学及非金属改性BiOCl光催化剂的研究鲜有报道。本文以提高BiOCl光催化活性为目标,首先系统研究了不同乙二醇浓度和不同超声时间对BiOCl结构和光催化性能的影响。然后在最佳乙二醇浓度的基础上,进一步研究了非金属单质掺杂及非金属化合物复合对BiOCl的结构和光催化性能的影响。主要研究内容如下:1.采用声化学辅助溶剂热法合成了系列BiOCl纳米片光催化剂。考察了不同乙二醇(EG)浓度和超声时间对BiOCl光催化性能的影响。研究结果表明,适当的超声时间和EG/H_2O体积比有利于催化剂比表面积的提高,同时可以丰富催化剂表面羟基(-OH)的数量和提高光生电子和空穴的分离效率。当超声时间为60 min,乙二醇和水(EG/H_2O)体积比为1/4时,合成的BiOCl表现出最佳的光催化活性。2.采用简单的溶剂热法制备了非金属元素(F/B)掺杂BiOCl纳米片光催化剂。表征分析结果表明,非金属元素(F/B)掺杂能增大催化剂的比表面积、细化颗粒尺寸、减少光生电子和空穴的复合和提高载流子的利用率。考察了降解多种有机污染物的光催化性能测试。实验结果表明,非金属元素(F/B)掺杂能有效提高BiOCl的光催化性能。3.采用简单的溶剂法制备了SiO_2/BiOCl纳米片光催化剂,实验结果表明,当SiO_2的复合量为1.88%时,SiO_2/BiOCl表现出最佳的光催化降解活性。SiO_2的存在不仅能改善催化剂的表面性能和增大催化剂的比表面积,而且SiO_2表面的缺陷位点是很好的电子陷阱,能加快电子和空穴的分离效率,提高催化剂的光催化活性。循环降解实验表明,SiO_2/BiOCl复合光催化剂具有很好的稳定性。4.在SiO_2改性BiOCl光催化剂的基础上,进一步探究了C@SiO_2复合对BiOCl形貌和光催化性能的影响。结果表明,C@SiO_2复合能进一步提高BiOCl的光催化活性。以上研究表明,声化学及非金属修饰BiOCl可以改善催化剂表面性能、调控晶面结构和加快光生电子和空穴分离效率,从而有效提高了BiOCl光催化剂对有机污染物的光催化降解性能。
[Abstract]:Semiconductor photocatalytic technology is a highly efficient and green method to remove organic pollutants. BiOCl is a new photocatalyst with high efficiency and stability in the field of environmental protection. At present, most of the modification of BiOCl is focused on the methods of precious metal deposition and the construction of metal semiconductor heterojunction, relatively speaking. There are few reports on sonochemistry and nonmetallic modified BiOCl photocatalysts. The aim of this paper is to improve the photocatalytic activity of BiOCl. The effects of different concentration of ethylene glycol and different ultrasonic time on the structure and photocatalytic performance of BiOCl were studied systematically, and then on the basis of the optimal concentration of ethylene glycol. The effects of nonmetallic doping and nonmetallic compound on the structure and photocatalytic properties of BiOCl were further investigated. The main contents are as follows:. 1. A series of BiOCl nanocrystalline photocatalysts were synthesized by sonochemical assisted solvothermal method. The effects of EGG concentration and ultrasonic time on the photocatalytic performance of BiOCl were studied. Proper ultrasonic time and EG/H_2O volume ratio can improve the specific surface area of the catalyst. At the same time, it can enrich the amount of hydroxyl group on the catalyst surface and improve the separation efficiency of photogenerated electrons and holes, when the ultrasonic time is 60 min. When the volume ratio of ethylene glycol to water EGP / H _ 2O is 1/4. The synthesized BiOCl showed the best photocatalytic activity. 2. The nonmetallic element F / B doped BiOCl photocatalyst was prepared by a simple solvothermal method. The doping of nonmetallic elements F / B can increase the specific surface area of the catalyst and refine the particle size. The photocatalytic properties of photocatalytic degradation of various organic pollutants were investigated by reducing the combination of photogenerated electrons and holes and increasing the efficiency of carriers. The photocatalytic activity of BiOCl can be improved effectively by doping the nonmetallic element (F / B). 3. The photocatalyst of SiO_2/BiOCl nanocrystalline was prepared by simple solvent method. The experimental results show that the photocatalytic activity of SiO_2/BiOCl nanoparticles can be improved by F- / B doping. 3. When the compound of SiO_2 is 1.88. SiO_2/BiOCl showed that the existence of the best photocatalytic degradation activity. SiO2 can not only improve the surface performance of the catalyst and increase the specific surface area of the catalyst. Moreover, the defect sites on the surface of SiO_2 are good electron traps, which can accelerate the separation efficiency of electron and hole and improve the photocatalytic activity of the catalyst. SiO_2/BiOCl composite photocatalyst has good stability. 4. On the basis of SiO_2 modified BiOCl photocatalyst. The effects of C@ SiO-2 composite on the morphology and photocatalytic properties of BiOCl were further investigated. The photocatalytic activity of BiOCl can be further improved by CSOO _ 2 / C _ 2O _ 2 compounding. The results show that sonochemistry and nonmetallic modification of BiOCl can improve the surface performance of the catalyst. The photocatalytic degradation of organic pollutants by BiOCl photocatalyst was improved by regulating the crystal structure and accelerating the efficiency of photoelectron and hole separation.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X505;O643.36

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