二氧化钛基纳米材料光催化剂的设计

发布时间：2018-07-29 16:40

【摘要】：随着全球化的发展,我们对能源的需求越来越多,然而,自然界中可利用的能源的含量却远远小于人们的需求。因此寻找和研发可持续能源,这是十分重要也是非常必要的。在众多半导体光催化剂中商用二氧化钛(P25)因其化学性质稳定、耐光腐蚀、催化活性高、氧化能力强、价格低廉、无毒;并且Ti02半导体可以应用于太阳能电池把太阳能有效的转化为化学能。Ti02纳米材料因其化学性质稳定、无毒和能有效去除大气和水中的污染物而成为解决能源和环境问题的理想材料,并引起了各国研究者广泛的兴趣。但是由它较大的禁带宽度(3.2 eV)导致对太阳光的吸收只有紫外光部分,而紫外光只占太阳光的很小一部分,因此非常影响它的使用效率与潜在应用价值。这就需要我们在研究过程中,要找到一个合适的思想和办法去改善它的缺点,优化它的性能,使它能更好的应用于实际的生产和操作过程。随着纳米技术的发展,实验室在制备Ti02纳米材料技术上,已经能可控制备粒径较小,形貌均一的半导体纳米材料。在本论文中,我们报告了表面碳化的Ti02 NFs,通过化学气相沉积法(CVD),实现了C和Ti02NFs两者之间的协同作用,既调节了光学带隙又增强了电子转移能力,最终体高了光催化性能。通过第一原理计算,结果表明,在引入碳以后,C和Ti02NFs之间确定形成碳氧双键(主要是C=O)接口,成为能带结构和局部电荷分布的调制器,促进了光催化剂在可见光区的敏感性,加快了光电子转移到表面,从而提高了光催化降解重金属铬离子的溶液的活性。综上所述,以我们的实验室条件,我们以二氧化钛为原材料设计了一系列的半导体异质结构光催化剂用于光裂解水产氢以及污水处理。具体细节内容如下:1、利用静电纺丝的方法制备TiO2纳米纤维,其不同于其他Ti02纳米材料的有点在于以下几点:Ti02纳米纤维因其独特的纤维结构而拥有很大的比表面积,这个优异的特点使其在光催化过程中有效的分离光照所产生的载流子,使得电子和空穴各尽其责。2、Ti02纳米纤维具有很强的还原重金属离子以及光催化降解有机染料的能力,并且能够做到循环再利用,体现其高效的可利用性。3、用TiO2纳米纤维材料作为基材料,利用化学气相沉积法(CVD)和其他材料两步合成异质结,异质结所形成的新能带结构则可充分地吸收太阳光,从而提高光催化效率。
[Abstract]:With the development of globalization, we need more and more energy. However, the amount of energy available in nature is far less than that of people. Therefore, it is very important and necessary to find and develop sustainable energy. Among many semiconductor photocatalysts, commercial titanium dioxide (P25) is characterized by its stable chemical properties, high photo-corrosion resistance, high catalytic activity, strong oxidation ability, low price and non-toxic. And Ti02 semiconductors can be used in solar cells to convert solar energy efficiently into chemical energy. Ti02 nanomaterials are stable because of their chemical properties. Non-toxic and effective removal of pollutants in the atmosphere and water has become an ideal material for solving energy and environmental problems, and has attracted extensive interest of researchers all over the world. However, due to its large bandgap (3.2 EV), the absorption of solar light is only part of ultraviolet light, and ultraviolet light only accounts for a small part of the solar light, so it has a great impact on its efficiency and potential application value. This requires us to find a suitable idea and method to improve its shortcomings, optimize its performance, and make it more applicable to the actual production and operation process in the research process. With the development of nanotechnology, the laboratory has been able to control the preparation of Ti02 nanomaterials with smaller particle size and uniform morphology. In this paper, we report the surface carbonation of Ti02 NFS. The synergistic effect between C and Ti02NFs is realized by chemical vapor deposition (CVD),) method, which not only adjusts the optical band gap but also enhances the electron transfer ability, and finally increases the photocatalytic performance. Through the first principle calculation, the results show that the carbon-oxygen double bond (mainly CIO) interface is formed between C and Ti02NFs after the introduction of carbon, which becomes a modulator with energy band structure and local charge distribution, which promotes the sensitivity of photocatalyst in the visible region. The photoelectron transfer to the surface increases the photocatalytic activity of the solution for the degradation of heavy metal chromium ion. In conclusion, under our laboratory conditions, we designed a series of semiconductor heterostructure photocatalysts for photocracking of aquatic hydrogen and sewage treatment using titanium dioxide as raw material. The specific details are as follows: 1. TiO2 nanofibers are prepared by electrospinning, which is different from other Ti02 nanomaterials in that the following points: Ti02 nanofibers have a large specific surface area due to their unique fiber structure. This excellent feature enables it to effectively separate carriers produced by light in the photocatalytic process, making the electrons and holes do their part in the reduction of heavy metal ions and photocatalytic degradation of organic dyes. And it can be recycled to reflect its high availability. The TiO2 nanofiber material is used as the base material. The heterojunction is synthesized by chemical vapor deposition (CVD) and other materials in two steps. The new energy band structure formed by the heterojunction can fully absorb solar light and improve the photocatalytic efficiency.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;O643.36

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