介孔二氧化钛纳米材料的可控制备及改性研究

发布时间：2018-01-09 18:13

本文关键词：介孔二氧化钛纳米材料的可控制备及改性研究　出处：《南昌航空大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着社会的进步和经济的快速发展,伴随而来的环境污染问题也日益严重,对环境污染的控制和治理已经成为人类亟待解决的重大问题。由于二氧化钛光化学性质稳定,对生物无毒,具有耐酸碱性和生物相容性,最重要的是其在光照下的电子-空穴分离能有效地将水中有机污染物催化氧化为水和二氧化碳等小分子化合物,因此二氧化钛纳米材料受到了越来越多的探索研究。作为一种新兴的水污染处理技术,虽然目前人们已经取得一定的进展,但还不算成熟,仍然存在着一些问题和不足,如其禁带较宽,只能对紫外光有响应,电子和空穴容易复合等。针对上述难题,本论文通过可控制备介孔二氧化钛纳米材料以及对二氧化钛纳米材料进行改性来抑制光生电子和空穴的复合,从而达到提高二氧化钛光催化活性的目的。具体研究内容如下:1、以钛酸四丁酯为钛源,以二氧化硅为模板采用水热法制备介孔单晶金红石相二氧化钛,研究了不同Ag掺杂量对介孔TiO2光催化性能的影响。在一定范围内,随着Ag掺杂量的增大,介孔TiO2的光催化性能会随之增强,当Ag掺杂量为5%为最佳。这是因为贵金属Ag能够产生等离子体共振效应,抑制光生电子和空穴的复合,从而增强介孔TiO2的光催化性能。而当Ag掺杂量超过5%时,随着Ag掺杂量的增加,介孔TiO2的光催化性能会随之减弱。这是因为当Ag掺杂量增大时,在光沉积的过程中Ag纳米颗粒发生团聚,堵塞介孔TiO2的通道,从而降低其光催化活性。2、以水热法对水热模板法制备的介孔单晶二氧化钛进行钨的掺杂,W6+的掺杂提高了TiO2的比表面积和孔体积,掺杂W6+的介孔二氧化钛的大比表面积为反应物的吸附提供了更多的活性位点,从而提高其光催化性能。与二氧化钛相比,掺杂W6+的二氧化钛的吸收边发生了红移,而且掺杂W6+的二氧化钛在200~400 nm吸收增强,这表明掺杂W6+的二氧化钛在紫外区具有很好的光催化性能。在模拟太阳光的条件下,掺杂W6+的二氧化钛的光催化性能优于二氧化钛,这是因为W6+的掺杂可以提高二氧化钛的电对分离效率,从而提高二氧化钛的光催化活性。3、以商业二氧化钛P25为基础,通过水热法制备了掺杂W6+的W-TiO2,以光沉积的方法制备了Au/TiO2,通过水热法和光沉积法结合制备了Au/W-TiO2。由于Au纳米颗粒的等离子体共振效应,沉积Au纳米颗粒的Au/TiO2和Au/W-TiO2在可见光区有一个很强的吸收带,说明贵金属Au的沉积拓展了二氧化钛对可见光区响应。与未掺杂的TiO2相比,掺杂W6+的TiO2能促使荧光的高效猝灭,这是因为TiO2导带上的光生电子在固溶体中可以被W6+捕获,从而抑制光生电子和空穴的复合。在光催化活性测试中,当在W-TiO2上沉积贵金属Au纳米颗粒后,其光催化降解速率明显高于TiO2、W-TiO2和Au/TiO2,这主要归因于掺杂的W6+和沉积的Au纳米颗粒的协同作用。
[Abstract]:With the development of society and economy, the problem of environmental pollution is becoming more and more serious. The control and control of environmental pollution has become an important problem to be solved urgently. Because of the photochemical stability of titanium dioxide, it is non-toxic to biology, acidproof and alkaline resistance and biocompatibility. The most important thing is that the electron-hole separation can effectively catalyze the oxidation of organic pollutants into small molecular compounds such as water and carbon dioxide. As a new water pollution treatment technology, although people have made some progress, but not mature. There are still some problems and shortcomings, such as wide band gap, only response to ultraviolet light, easy recombination of electrons and holes, and so on. In this thesis, mesoporous titania nanomaterials were prepared and modified to restrain the photogeneration of electrons and holes. In order to improve the photocatalytic activity of titanium dioxide, the specific research contents are as follows: 1. Using tetrabutyl titanate as titanium source and silicon dioxide as template, mesoporous rutile phase titania was prepared by hydrothermal method. The effect of Ag doping on the photocatalytic performance of mesoporous TiO2 was studied. In a certain range, the photocatalytic activity of mesoporous TiO2 will be enhanced with the increase of Ag doping content. When Ag doping amount is 5%, this is because Ag can produce plasmon resonance effect and restrain the combination of photogenerated electrons and holes. Therefore, the photocatalytic properties of mesoporous TiO2 were enhanced, and when the Ag doping amount was more than 5%, with the increase of Ag doping amount, the photocatalytic activity of mesoporous TiO2 was increased. The photocatalytic activity of mesoporous TiO2 will be weakened because the agglomeration of Ag nanoparticles in the photodeposition process blocks the channel of mesoporous TiO2. As a result, the photocatalytic activity of TIO _ 2 was reduced by hydrothermal method. The W _ 6 doping of mesoporous TIO _ 2 prepared by hydrothermal template increased the specific surface area and pore volume of TiO2. The large specific surface area of W6 doped mesoporous titanium dioxide provides more active sites for the adsorption of reactants, thus improving its photocatalytic performance. The absorption edge of W _ 6 doped TIO _ 2 is red-shifted, and the absorption of W _ 6 doped TIO _ 2 is enhanced at 200 ~ 400 nm. This shows that W6 doped titanium dioxide has good photocatalytic performance in UV region, and the photocatalytic performance of W6 doped titanium dioxide is superior to that of titanium dioxide under simulated solar light. This is because the doping of W6 can improve the separation efficiency of titanium dioxide, thus improving the photocatalytic activity of titanium dioxide. 3, based on commercial titanium dioxide P25. W-TiO2 doped with W6 was prepared by hydrothermal method and Au/TiO2 was prepared by photodeposition. Au / W-TiO _ 2 was prepared by hydrothermal method and photodeposition. Due to the plasmon resonance effect of au nanoparticles. Au/TiO2 and Au/W-TiO2 deposited au nanoparticles have a strong absorption band in the visible region. The results show that the deposition of noble metal au expands the response of TIO _ 2 to visible light. Compared with the undoped TiO2, the TiO2 doped with W _ 6 can promote the high efficiency quenching of fluorescence. This is because the photogenerated electrons in the TiO2 band can be captured by W6 in the solid solution, which inhibits the combination of photogenerated electrons and holes. The photocatalytic degradation rate of noble metal au nanoparticles deposited on W-TiO2 was significantly higher than that of TiO2W-TiO2 and Au/TiO2. This is mainly due to the synergism of doped W 6 and deposited au nanoparticles.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36

【相似文献】