氧化钛基复合光催化材料的制备及性能研究

发布时间：2018-06-14 09:02

本文选题：氧化钛基 + 石墨烯　；参考：《陕西科技大学》2016年硕士论文

【摘要】：近年来,半导体光催化技术因其在清洁环境、光解水制氢及绿色有机合成等领域的潜在应用而备受关注。而二氧化钛(TiO2)因为它的价廉、易得、无毒无害、高的化学稳定性、强的抗光腐蚀性等优点,成为了到目前为止研究最为广泛也最深入的一种半导体光催化剂。然而,TiO2在环境保护过程中由于自身存在两方面的缺陷而受到了限制：一方面,TiO2属于宽禁带的半导体,它对太阳能的利用率很低,仅仅只能吸收波长比较短的一部分紫外光(387nm)；另一方面,在光催化反应过程中TiO2的光生载流子的复合率较高,导致光量子的效率较低。为解决上述问题,研究者们采取了很多不同的方法,如金属或非金属离子掺杂,贵金属修饰,与独特结构的碳基纳米材料的复合,如碳纳米管,氧化石墨以及石墨烯,与其他半导体的耦合,包括Bi2WO6,WO3和CdS等等,以提高其在可见光区的应用和光催化反应中的量子效率。因此,本论文以TiO2为基体,通过选择不同的复合相,构建不同结构形貌的氧化钛基复合光催化材料,采用XRD、SEM、TEM、UV-vis、IR和XPS等分析手段对样品进行了检测表征,并测试了不同的复合光催化剂对模拟有机污染物的光催化降解性能,探讨了不同的复合相在提高TiO2的光催化性能上起到的作用。取得的主要研究成果如下：(1)以钛酸丁酯为钛源,采用简单的可控水解法制备了二氧化钛/石墨烯/二氧化钛三层核壳结构复合光催化剂,并研究了最外层不同TiO2的负载量对于光催化性能产生的影响。结果发现：TiO2核材料的粒径约为800nm,负载在最外层的TiO2颗粒尺寸约为30～50nm,所制备的三层核壳结构复合光催化剂表现出了对甲基橙模拟污染物优异的光催化降解性能。(2)以SiO2为模板剂,采用控制钛酸丁酯的水解以及表面反应法成功制备出了石墨烯包裹二氧化钛空心球纳米复合材料。TiO2空心球的直径约为350～400nm,厚度约15nm,最外层的石墨烯的厚度约为5nm。光催化实验结果表明,还原的氧化石墨烯包裹在TiO2表面后,很大程度提高了样品的光催化性能。(3)以P25为钛源,通过两步水热法成功制备出了MoS2/TiO2复合光催化材料,其中TiO2纳米带的宽度在50～150nm之间,长度约为几个微米。当适量的MoS2纳米颗粒负载在TiO2纳米带表面时,一方面增大了光催化剂的比表面积,使得在暗反应过程中对模拟污染物的吸附得到增强；另一方面,MoS2纳米颗粒负载在Ti02纳米带表面与之形成异质结构,有效促进了光生电子和空穴对的分离,从而提高了样品的光催化性能。(4)以P25为钛源,通过水热以及煅烧的过程成功制备了MoO3/TiO2复合光催化材料。Mo03纳米片沿着Ti02纳米带的表面生长,并与其相交形成三维的异质结构。MoO3/TiO2复合材料的光催化效果比纯相的Ti02纳米带和Mo03纳米片都优异,这是由于在MoO3/TiO2异质结构的界面处形成了Ti-O-Mo键,使得电子可以直接从Ti02的价带转移到Mo03的导带,扩大了样品的光响应范围。
[Abstract]:In recent years, semiconductor photocatalysis has attracted much attention because of its potential applications in the clean environment, photolysis of hydrogen and green organic synthesis, and titanium dioxide (TiO2) has become the most widely and deeply studied so far because of its low price, easy availability, innocuity, high chemical stability and strong anti photocorrosion. A semiconductor photocatalyst. However, TiO2 is limited by two defects in its environmental protection. On the one hand, TiO2 is a wide band of semiconductors, which is very low in utilization of solar energy and only only absorbs a fraction of the UV light (387nm) with shorter wavelengths; on the other hand, the photocatalytic reaction is over. In order to solve the above problems, the researchers have taken many different methods to solve these problems, such as metal or nonmetallic ion doping, noble metal modification, and the combination of carbon based nanomaterials with unique structures, such as carbon nanotubes, graphite oxide and graphene, and other semi conductors. The coupling of the body, including Bi2WO6, WO3 and CdS, etc. to improve the quantum efficiency in the application of visible light and the photocatalytic reaction. Therefore, this paper uses TiO2 as the matrix to construct a titanium oxide based composite photocatalyst of different structure morphology by selecting different composite phases and using XRD, SEM, TEM, UV-vis, IR and XPS to analyze the sample. The photocatalytic degradation performance of different composite photocatalysts on simulated organic pollutants was tested and the effects of different composite phases on the photocatalytic properties of TiO2 were investigated. The main achievements were as follows: (1) two oxidation was prepared by simple controllable hydrolysis of butyl titanate as titanium source. Titanium / graphene / titanium dioxide three layer shell structure composite photocatalyst was used to study the effect of the loading amount of the outer TiO2 on the photocatalytic performance. The results showed that the particle size of the TiO2 nuclear material was about 800nm, the size of the TiO2 particle loaded at the most outer layer was about 30 to 50nm, and the composite photocatalyst of the three layer core shell structure was prepared. The photocatalytic degradation performance of methyl orange simulated pollutants was excellent. (2) using SiO2 as a template, using the hydrolysis of butyl titanate and the surface reaction method, the diameter of the.TiO2 hollow sphere coated with graphene coated titanium dioxide hollow spheres was about 350 ~ 400nm, the thickness was about 15nm and the thickness of the most outer layer of graphene. The results of 5nm. photocatalytic experiment showed that the reduction of graphene oxide wrapped on the surface of TiO2 greatly improved the photocatalytic properties of the samples. (3) the MoS2/TiO2 composite photocatalyst was successfully prepared by two steps of hydrothermal method with P25 as the titanium source. The width of the TiO2 nanoribbons was between 50 and 150nm and the length was about several microns. When the amount of MoS2 nanoparticles is loaded on the surface of TiO2 nanoscale, the specific surface area of the photocatalyst is increased on the one hand, and the adsorption of simulated pollutants is enhanced during the dark reaction; on the other hand, the MoS2 nanoparticles are loaded on the surface of the Ti02 nanometers to form a heterogeneous structure, which effectively promotes the separation of the photoelectron and hole pairs. The photocatalytic properties of the samples were improved. (4) P25 was used as a titanium source, and the surface growth of the MoO3/TiO2 composite photocatalyst.Mo03 nanoscale along the Ti02 nanoscale was successfully prepared by the hydrothermal process and the calcining process. The photocatalytic effect of the heterogeneous structure of.MoO3/TiO2 composite was compared with that of the pure phase Ti02 nanometers and Mo. 03 nanoscale films are excellent, which is due to the formation of a Ti-O-Mo bond at the interface of the MoO3/TiO2 heterostructure, which allows electrons to be transferred directly from the valence band of Ti02 to the guide band of Mo03, expanding the photoresponse range of the sample.
【学位授予单位】：陕西科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36;O644.1

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