论文总字数:22107字
摘 要
随着人类社会不断进步与发展,能源危机和化石燃料燃烧引起的全球变暖引起了人们的广泛关注。光催化作为一种绿色、清洁的方法被认为是解决这些问题的最有效的方法之一。光催化直接利用太阳能这一取之不尽用之不竭的绿色能源,不仅天然无污染,而且储量富足。太阳能降解有机物是通过光催化反应完成的,可以应用在环境治理和避免能源危机方面。
因为半导体的能带结构特征,光催化降解能够产生强氧化和还原性的物质,将有机物转化为水、二氧化碳和其他无毒害物质。纳米材料结构具有小尺寸效应、表面效应和量子效应的优势,并且复合后能带的匹配可以有效的增加入射光的吸收和光生电子-空穴的自由分布,从而显著提高光催化效率。本论文从分析新型纳米材料BiVO4的不同生长方法和生长机制出发,利用液相反应法制备一种以CuO为壳核的半导体复合纳米结构的BiVO4/CuO。首先用XRD、EDS、SEM等方法测其物理特征,再对样品进行液相光催化分解罗丹明B(RhB)测试。对比紫外光和可见光条件下BiVO4和BiVO4/CuO复合结构的光催化性能。探讨BiVO4复合纳米结构的可见光应用前景。研究结果表明以CuO为壳核生长的复合半导体纳米结构的BiVO4/CuO是以BiVO4为主相,能被检测到少量的CuO的锐钛矿相,有着较为规则的几何外形。复合半导体纳米结构的BiVO4/CuO在可见光下可以在一定程度的提高了BiVO4的催化效率。
关键词:复合纳米结构BiVO4/CuO、降解污染、光催化
Abstract
With the continuous progress and development of human society, the global warming caused by energy crisis and fossil fuel combustion has attracted wide attention. Photocatalysis, as a green and clean method, is considered to be one of the most effective ways to solve these problems. Photocatalysis directly utilizes solar energy, an inexhaustible green energy, which is not only natural and pollution-free, but also abundant in reserves. As a chemical advanced oxidation-reduction technology, semiconductor photocatalysis technology can directly use sunlight to drive a series of important chemical reactions, convert low-density solar energy into high-density chemical energy or directly degrade and mineralize organic matter.
Because of the band structure of semiconductor, photocatalytic degradation can produce strong oxidative and reductive substances, which can transform organic substances into water, carbon dioxide and other non-toxic substances. The structure of nanomaterials has the advantages of small size effect, surface effect and quantum effect, the band match two photocatalysts can effectively increase the range of absorption of incident light and the free diffusion length of photogenerated electrons and holes, thus significantly improve the photocatalytic efficiency. In this thesis, BiVO4/CuO nanocomposites with CuO as shell were prepared by liquid-phase reaction based on the analysis of different growth methods and growth mechanisms of BiVO4. RhB used as the referenced pollutant which is measured by liquid phase photocatalytic decomposition. The photocatalytic properties of BiVO4 and BiVO4/CuO composite structures under ultraviolet and visible light conditions were compared. The application prospects of BiVO4 composite nanostructures in visible light were discussed. The results show that BiVO4/CuO nanostructures grown with CuO as shell are mainly composed of BiVO4, and a small amount of anatase phase of CuO can be detected, which has a relatively regular geometric shape. BiVO4/CuO nanostructured composite semiconductors can improve the catalytic efficiency of BiVO4 to a certain extent under visible light.
KEY WORDS: Composite nanostructure BiVO4/CuO, pollution degradation,photocatalytic
目 录
摘 要
Abstract
第一章 绪论 1
1.1 引言 1
1.2 纳米材料概述 1
1.2.1 纳米材料分类和性质 1
1.2.2 纳米材料最新研究 2
1.3 光催化概述 3
1.3.1半导体光催化反应机制 3
1.3.2 新型光催化材料 4
1.3.3 CuO简介 5
1.3.4 复合半导体材料的光催化 5
1.3.5 光催化的最新研究 5
1.4论文选题及主要研究内容 6
第二章 纳米BiVO4性质、制备及其应用 7
2.1 BiVO4的性质概述 7
2.1.1单斜BiVO4晶体结构 7
2.2纳米BiVO4的制备方法 8
2.2.1溶胶凝胶法 8
2.2.2沉积-沉淀法 8
2.2.3模板剂法 8
2.2.4水热合成法 8
2.3案例分析 9
2.3.1BiVO4@Co-MIm的形态特征 9
2.3.2SiO2/BiVO4杂化颜料的合成与着色 10
第三章 BiVO4/ CuO纳米复合材料的制备及其光催化效应 12
3.1BiVO4/ CuO纳米复合材料的制备条件 12
3.1.1实验方案 12
3.1.2实验原料及设备 12
3.1.3主要原料与设备简介 13
3.2实验内容 15
3.2.1 光催化降解测试 15
3.2.2 BiVO4/ CuO复合材料的制备过程 16
3.3实验结果与分析 17
3.3.1 BiVO4/CuO复合材料形貌表征 17
3.3.2 BiVO4/CuO复合材料成分分析 19
3.3.3 BiVO4/CuO复合材料光催化性能表征 20
3.4结论 22
结论 24
参考文献 25
致 谢 27
- 绪论
1.1引言
纳米技术在半导体材料上的应用称为半导体纳米科技,并通过某些方法制造出的有独特性质的特殊材料。半导体材料的物化性质将发生显著变化如其尺寸缩小到纳米范围,并且高表面积或量子效应引起的独特性能也可被呈现出来。其在多个领域的应用已呈现出诱人的应用前景。例如在纳米医学、纳米电子、生物材料、能源生产和消费产品等方面。
随着人类社会不断进步与发展,能源危机和化石燃料燃烧引起的全球变暖引起了人们的广泛关注。光催化作为一种绿色、清洁的方法被认为是解决这些问题的最有效的方法之一。光催化直接利用太阳能这一取之不尽用之不竭的绿色能源,不仅天然无污染,而且储量富足。太阳能转变为化学能或降解有机物是通过光催化反应完成的,可以应用在环境治理和避免能源危机方面。[1]~[3]
1.2纳米材料概述
纳米材料一般是指在组成材料的基本组成单元中,至少在一个维度上在1到100纳米(10-9米)之间大小的材料。具有纳米尺寸的材料通常具有独特的光学、电学或力学性质。纳米材料正慢慢地向商业化靠拢,成为我们的消费品。
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