BiOI光催化剂对亚甲基蓝降解性能研究

四川理工学院毕业论文

BiOI光催化剂对亚甲基蓝

降解性能研究

学 生：闫登云 学 号：09131010220 专 业：环境工程

班 级：环境工程2009.2班 指导老师：袁东

四川理工学院材料与化学工程学院

二〇一三年六月

四川理工学院毕业论文 中文摘要

BiOI光催化剂对亚甲基蓝降解性能研究

摘要

近年来，光催化技术在治理有机物污染方面发展迅速。卤氧化铋 BiOX （X= F，Cl，Br，I）作为一类新型的光催化剂，由于具有特殊的层状结构和内部电场，能够有效地实现光生电子-空穴对的分离，从而显示出优异的光催化性能。其中，BiOX 的带隙随X从Cl到I逐渐减小，BiOI具有最小的带隙，呈现出极佳的可见光光催化活性。

本文以KI和Bi（NO3）3·5H2O为原料，用溶剂热法在水热反应釜中反应合成BiOI。通过X射线衍射（XRD）、扫描电子显微镜（SEM）等方法对合成的光催化剂进行表征，对合成样品的组成、结构与光催化性能之间的关系进行了研究。并以亚甲基蓝为模型化合物，在可见光下对不同条件下的BiOI光催化活性进行了研究。

关键词：光催化；可见光；BiOI；亚甲基蓝

I

四川理工学院毕业论文 英文摘要

Synthesis of Bismuth BIOI Based Photocatalysts and Study on the Photocatalytic Activities

Abstract

In recent years，various advanced oxidation processes（AOPs）have been developed rapidly in treating of wastewater. Recently，bismuth oxyhalides（BiOX，X = F，Cl，Br and I）have drawn much attention because of their possessing unique structure of alternate [Bi2O2]2+sheets with the X-slabs and the internal electric fields between positive slabs and anionic slabs， which are more effective in improving the separation of photoinduced electron-hole pairs，and therefore have demonstrated excellent photocatalytic activities and are offering a new family of promising photocatalysts. Among them，BiOI has the strongest absorption in the visible light region because it has the smallest band gap（1.8 eV）. Herein，BiOI can also be used as a new research direction in environmental remediation.

A general one-pot solvothermal process was explored to prepare BiOI powders by employing ethylene glycol as the solvent.The prepared samples were characterized by XRD，SEM to investigate the structure，morphology，photocatalytic activity and the photocatalytic mechanism of photocatalysts. The photocatalytic mechanism for MB degradation by BiOI under visible light irradiation was also presented.

Keywords: photocatalysis; visible light; BiOI; methylene blue

II

四川理工学院毕业论文 目录

目录

1绪论 ............................................................................................................................................ 1

1.1半导体光催化研究背景 ..................................................................................................... 1 1.2半导体光催化作用机理 ..................................................................................................... 2

1.2.1能带理论 .................................................................................................................. 2 1.2.2光催化机理 .............................................................................................................. 2 1.3影响半导体光催化活性的主要因素 ................................................................................. 5

1.3.1半导体能带结构对催化剂活性的影响 .................................................................. 5 1.3.2晶体尺寸和比表面积对光催化活性的影响 .......................................................... 5 1.3.3晶体缺陷对光催化活性的影响 .............................................................................. 5 1.4 BiOX（X = Cl，Br，I）光催化剂 .................................................................................. 6 1.5本课题研究的主要内容 ..................................................................................................... 7

2实验部分 ................................................................................................................................. 8

2.1实验主要仪器及试剂 ......................................................................................................... 8

2.1.1实验主要仪器 .......................................................................................................... 8 2.1.2实验主要试剂 .......................................................................................................... 8 2.2 BiOI光催化剂样品的制备 ............................................................................................... 9 2.3 BiOI光催化剂样品的表征 ............................................................................................... 9

2.3.1 X射线衍射测试 ...................................................................................................... 9 2.3.2扫描电子显微镜 ...................................................................................................... 9 2.4 BiOI光催化剂对亚甲基蓝的降解 ................................................................................. 10

3结果与讨论 .......................................................................................................................... 13

3.1 BiOI的表征 ..................................................................................................................... 13

3.1.1 BiOI样品的XRD分析 ........................................................................................ 13 3.1.2 BiOI样品的SEM分析 ......................................................................................... 14 3.2 BiOI光催化剂对亚甲基蓝的降解 ................................................................................. 14

3.2.1亚甲基蓝初始浓度的影响 .................................................................................... 14 3.2.2可见光下BiOI催化剂投加量对降解率的影响 .................................................. 15 3.2.3可见光下光照时间对降解率的影响 .................................................................... 17 3.2.4催化剂的循环使用对光降解率的影响 ................................................................ 18

4结论与展望 .......................................................................................................................... 19

4.1结论 ................................................................................................................................... 19

III

四川理工学院毕业论文 目录

4.2展望 ................................................................................................................................... 19

参考文献 ................................................................................................................................... 21 致谢 .............................................................................................................................................. 23 附录 .............................................................................................................................................. 24

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