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摘要：工业与科学技术在当今社会得到了了飞速发展，也使各种各样的环境问题日益突出，为了保护生态平衡，实现可持续发展，节约能源和控制环境污染已经成为亟待解决的重大问题。研究发现，一些半导体材料在光照条件下具有光催化性能，由于半导体本身的能带结构，受光照激发后会产生具有氧化和还原性能的载流子，这些载流子可与有机污染物反应使其发生降解从而实现净化的效果。半导体光催化材料具有广泛的研究与发展前景。
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半导体光催化剂Bi2Fe4O9在可见光下可以有良好的响应。我们通过采用水热法（hydrothermal method），以Bi(NO3)3•5H2O和Fe(NO3)3•9H2O为原料，控制NaOH浓度、保温温度和保温时间，制备单相Bi2Fe4O9。然后利用X射线衍射(XRD)分析所得样品是否为纯相，通过扫描电子显微镜(SEM)观察样品表面形貌，在光催化器中使制得样品在模拟可见光下对罗丹明B(RhB)的进行降解，最后用紫外-可见分光光度计(UV-vis)分析以吸收值表征降解程度。控制不同的NaOH浓度、保温时间、保温温度、RhB的pH值等，找到最好的合成参数制备Bi2Fe4O9纳米粉体。19246
关键词：Bi2Fe4O9 窄带系半导体 水热 降解 RhB
毕业论文设计说明书（论文）外文摘要
Title Study on the photocatalytic performance of Bi2Fe4O9 semiconductor photocatalyst
Abstract
Nowadays with the rapid development of industry and technology, various environmental issues have become increasingly serious. In order to maintain the ecological balance and achieve sustainable development, energy conservation and environmental pollution control have become major problems that have to be faced and solved. With further research, it has been discovered that some semi-conductor materials exhibit photocatalytic performances under light-illumination.
In this paper, Bi2Fe4O9 nanoparticles have been synthesized by a hydrothermal method with Bi(NO3)3•5H2O and Fe(NO3)3•9H2O as raw materials. Their visible-light response phtocatalytic activities have been studied as well. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV - vis absorption spectroscopy. The photocatalytic activity has been estimated by the degradation of RhB under visible light irradiation. Different parameters such as NaOH concentration, holding time, holding temperature and pH value of RhB etc. have been controlled to find the best way to synthesize Bi2Fe4O9 nanopowders.
Key words：Bi2Fe4O9 , narrow band gap semiconductor , hydrothermal method , degradation, RhB
目 录
1 绪论 1
1.1 光催化现象概述 1
1.2 半导体光催化反应机理 1
1.3 影响半导体光催化剂催化活性的因素 3
1.3.1 半导体能带结构的影响 3
1.3.2 半导体晶体结构的影响 3
1.3.3 半导体粒径的影响 3
1.4 常用的表征方法 4
1.4.1 X射线衍射分析(XRD) 4
1.4.2 X射线光电子能谱分析(XPS) 5
1.4.3 扫描电子显微分析(SEM) 5
1.4.4 紫外-可见光吸收光谱分析(UV-vis) 5
1.4.5 透射电子显微分析(TEM) 6
1.5 半导体光催化剂的研究 6
1.5.1 复合半导体改性 6
1.5.2 光敏化改性 7
1.5.3 贵金属沉积 7
1.5.4 离子掺杂 7
1.6 选题意义 8