以嵌段共聚物为模板制备介孔二氧化钛

发布时间：2018-06-18 09:30

  本文选题：介孔TiO_2 + F-TiO_2　； 参考：《济南大学》2017年硕士论文

【摘要】：随着石油、煤炭和天然气等资源的减少、能源需求的不断增加以及环境污染的加剧,能量转换与储存技术(如染料敏化太阳能电池(DSCs)、燃料电池、锂离子电池)和光催化降解有机污染物技术受到人们的高度重视并取得巨大进展,但仍有许多科学问题仍阻碍该类技术需的发展。介孔二氧化钛(TiO_2)是较好的电极材料,其性能的好坏能够决定太阳能电池的光电转换效率;纳米级的二氧化钛还能作为光催化剂,对有机污染物有优异的催化降解效果。所以,研究TiO_2纳米材料的制备方法以提高其性能已成为研究的热点之一。本论文首先用TiCl_4为原料,采用水热法,经过水解、沉淀、氧化、络合以及回流结晶的过程制备了F掺杂的TiO_2纳米粒子(F-TiO_2)。F掺杂的TiO_2纳米粒子表现出了优异的光催化性能,并对合成TiO_2纳米粒子的各影响因素进行了探究,得到了最佳的合成方案。其次,通过以嵌段共聚物F127为模板,钛酸四异丙酯(TTIP)和TiCl_4为无机前驱体,利用溶胶-凝胶法合成有机-无机杂化TiO_2薄膜,经焙烧除去嵌段共聚物,制备出介孔TiO_2;同时以F掺杂的TiO_2纳米粒子与F127共组装,制备出介孔TiO_2纳米材料。(1)F掺杂TiO_2纳米粒子:以TiCl_4为原料,首先水解制成溶胶-凝胶,在碱性条件下使其沉淀后,经过滤重新分散到水中,通过H2O_2氧化制成高钛酸溶液,在NaF存在下回流结晶,得到F-TiO_2棒状纳米粒子。在合成过程中不使用表面活性剂或封端剂。结果表明:NaF/TiCl_4的摩尔比在锐钛矿型F-TiO_2纳米粒子形态的形成中起重要作用;F-离子能进入TiO_2的晶格,并在TiO_2的表面吸附。制备的F-TiO_2纳米粒子,在UV和可见光照射下,都显示出对亚甲基蓝染料的高光催化活性,表明F-TiO_2纳米粒子是废水处理中污染物亚甲基蓝染料的有效光催化降解催化剂。同时探讨了影响TiO_2纳米粒子形态和性能的其它因素,包括温度、浓度以及其它卤族元素,得出了最佳合成温度为100℃,NaF/TiCl_4的摩尔比为4/1。(2)介孔TiO_2的制备:以嵌段共聚物F127在乙醇溶液中形成的胶束为模板,与TiO_2的前驱体TTIP在浓HCl中缓慢水解或TiCl_4在乙醇中形成的溶胶-凝胶为无机组分进行共组装,分别探究了F127/无机前驱体摩尔比、溶剂挥发速率、溶胶-凝胶的配置时间、胶体形成温度、老化时间以及焙烧方式等因素,得出了F127/无机前驱体的最佳摩尔比,适当地升高溶液的温度及减小溶剂的挥发速率,都有利于有序介孔TiO_2的形成。同时以F掺杂的TiO_2纳米粒子与F127共组装,制备介孔TiO_2纳米材料,得到的介孔TiO_2平均孔径为8.57 nm,孔体积为0.45 cm~3/g。
[Abstract]:As resources such as oil, coal and natural gas decrease, energy demand increases and environmental pollution intensifies, energy conversion and storage technologies (such as dyestuff sensitized solar cells, DSCsO, fuel cells, etc.), Lithium ion batteries (Li-ion batteries) and photocatalytic degradation of organic pollutants have been paid great attention to and great progress has been made. However, there are still many scientific problems that hinder the development of these technologies. Mesoporous titanium dioxide (TiO2) is a good electrode material, its performance can determine the photovoltaic conversion efficiency of solar cells, and nanometer titanium dioxide can be used as photocatalyst for the degradation of organic pollutants. Therefore, it has become one of the hotspots to study the preparation method of TIO _ 2 nanomaterials in order to improve their properties. In this paper, TiCl4 was first used as raw material, and through hydrolysis, precipitation, oxidation, complexation and refluxing crystallization, F-doped TiO2 nano-particles were prepared by hydrothermal method, and F-TiO-2 nanoparticles exhibited excellent photocatalytic properties. The factors affecting the synthesis of TIO _ 2 nanoparticles were investigated and the optimum synthesis scheme was obtained. Secondly, organic-inorganic hybrid TiO-2 films were synthesized by sol-gel method using block copolymer F127 as template, tetraisopropyl titanate TTIP) and TiCl4 as inorganic precursors, and block copolymers were removed by calcination. The mesoporous TiO-2 was prepared, and the F-doped TiO-2 nanoparticles were co-assembled with F127. The mesoporous TiO-2 nanomaterials were prepared by using TiCl4 as raw material, and TiCl4 was used as raw material to prepare sol-gel, which was precipitated under alkaline conditions. The perovskite solution was oxidized by H _ 2O _ 2 and refluxed and crystallized in the presence of NAF to obtain F-TiO2-like nanocrystalline particles. No surfactant or capping agent is used in the synthesis process. The results show that the mole ratio of w / naf-TiCl4 plays an important role in the formation of anatase F-TiO2 nanoparticles. F- ions can enter the lattice of TiO2 and adsorb on the surface of TiO2. The prepared F-TiO2 nanoparticles showed high photocatalytic activity for methylene blue dyes under UV and visible light irradiation, indicating that F-TiO-2 nanoparticles are effective photocatalytic degradation catalysts for methylene blue dyes in wastewater treatment. Other factors affecting the morphology and properties of TiO-2 nanoparticles, including temperature, concentration and other halogen elements, were also discussed. The optimum synthesis temperature is 100 鈩，

本文编号：2035003