【作者】 杨晓辉；

【导师】 宋秀芹；

【作者基本信息】 河北师范大学 ， 无机化学， 2004， 硕士

【摘要】 纳米TiO₂具有许多独特的物理化学性质，广泛应用于涂料、造纸、印刷、化纤、化妆品、催化剂、抗菌剂、污水处理等行业。纳米TiO₂作为光催化剂所具有的广谱、安全节能等独特性质使其成为光催化领域应用前景最广阔的材料之一。 目前纳米TiO₂光催化体系主要有粉末悬浮体系和负载型光催化体系。悬浮型光催化体系由于存在易凝聚和难回收等缺点，给实际应用带来了一定的困难。克服这一困难的有效途径是开发利用负载型TiO₂。核-壳型纳米结构TiO₂复合颗粒，克服了由于颗粒小，易中毒失活、易团聚，不易回收等缺点。核-壳粒子的一个重要扩展是通过加热或溶解除去“核”，使之产生空心球壳。纳米结构TiO₂空心球不仅具备纳米颗粒的高表面积和高活性，而且密度低，并可能由此产生一系列特殊的性能，故具有重要的研究意义和应用空间。本论文应用溶胶凝胶与自组装技术相结合的方法制备了纳米结构的TiO₂及空心球，并对自组装机理进行了探讨。 主要内容有： （1） 利用溶胶凝胶与自组装技术相结合，以钛酸四丁酯、乙醇为原料，阴离子表面活性剂作为自组装介质，制得了不同层数、不同含量、不同表面结构的核-壳型的纳米结构TiO₂／γ-Al₂O₃复合材料，探讨了不同的实验条件对于组装过程和结果的影响； （2） 以十二烷基磺酸钠作为自组装介质，通过十二烷基磺酸钠在γ-Al₂O₃上吸附等温线的测定，结合Zeta电位、接触角以及红外图谱数据，探讨了纳米结构TiO₂／γ-Al₂O₃的组装机理。结论是：在指定的实验条件下，γ-Al₂O₃表面带正电荷，与带负电荷的十二烷基磺酸钠首先形成单分子层吸附，随后有机链通过非极性基团吸附，形成半胶团结构，极性基团向外，表面荷—层负电荷。依靠静电引力吸附配置好的溶胶中的荷正电的TiO₂粒子，从而将TiO₂纳米粒子组装到γ-Al₂O₃表面。组装机理的探讨对确定最佳的制备工艺条件，控制反应过程提供了重要的理论指导； （3） 分别以钛酸四丁酯、四氯化钛为原料，选用一定的溶剂配制成溶胶，十二烷基磺酸钠作为自组装介质。选择不同的条件，如温度、酸度、陈化时间等，在直径为0.25mm左右的聚苯乙烯微球上组装上了纳米结构TiO₂，随后通过控制升温速率及煅烧温度将聚苯乙烯核除去，获得了不同含量、不同结构、不同形貌和晶型的纳米结构TiO₂空心球； （4） 对以上所制的样品进行了XRD、SEM、IR、X射线能谱、国标法标定、TG-DTA分析等表征，研究结果表明：1、自组装介质可改变载体表面的微环境。在载体表面的吸附量及表面吸附状态可通过控制其浓度来控制，控制不同的浓度载体表面可带不同电荷。2、控制不同的酸度、温度、反应时间、锻烧温度可制备不同晶型、不同形貌的纳米结构Ti02及空心球。3、随着组装次数的增加，TIOZ的含量线性增加，致密性、均匀性增强; （5）利用纳米结构Ti02作为光催化剂，对苯酚溶液进行了降解实验。研究表明不同的晶型、不同催化时间、不同的组装次数对光催化效应有不同的影响。更多还原

【Abstract】 Nanometer-sized TiO2 has many unique physical and chemical properties. It is used extensively in many fields, such as dope, paper-making, printing, chemical fiber, cosmetics, catalysts, antimicrobial and disposal of waste water. Because of safety and energy saving, nanometer-sized TiO2 is regarded as one of the most useful materials in catalyst fields.At present, the photocatalysis systems of nanometer-sized TiO2 mainly consist of powder-suspended system and coated-photocatalysis system. But the nano-powder is not suitable to be reclaimed and segregated and therefore is far away from the application in large-scale at the moment. To conquer these difficulties, coated nanometer-sized TiO2 can be used. Core-shell style nanometer-sized TiO2 does not have these shortcomings. One of its important extended uses is to get a hollow sphere by removing the core when heated or dissolved. This hollow sphere has low density, special polarity and optical property. The aim of this thesis is to fabricate nanostructure TiO2 and hollow sphere by combining the sol-gel technology and layer by layer self-assembly method. At the same time the mechanism of the self-assembly is studied. The major work includes the following aspects:1. Sol-gel technology and layer by layer self-assembly methods is utilized, with Ti(OC4H9)4 and C2H5OH as the raw material, 12 alkyl sodium sulphate (C12H24SO4Na) aqueous solution serving as organic self-assembly monolayer. Different layer numbers, different contents and different surface structures nanometer titanium dioxide have been successfully assembled on the Al2O3 surface. The influence of different experimental conditions on the preparation is studied.2. 12 alkyl sodium sulphate (Ci2H24SO4Na) aqueous solution serving as self-assembly medium, we investigate the mechanism of self-assembly by measuring the absorption isotherm, Zeta potential, contact angle, and spectrum of IR. It shows that r -Al2O3 has positive electricity on its surface and can form a single-molecule-layer absorption withC12H24SO4Na. By means of the absorption of the organic chain of two C12H24SO4Namolecules then it will be a double-molecule-layer absorption and form a half-micelle absorption. In this structure the polar group is towards outside so it carries negative electricity on the surface and it can absorb the particle in the sol which carries positive electricity. In this way the nanometer particle TiO2 can be assembled on the surface of the r -Al2O3. The investigation of the mechanism of self-assembly will give us a direction for the study of optimizing the preparing conditions and the control of the reaction process.3. Utilizing Ti(OC4H9)4 and low-cost TiCl4 as raw materials, a certain substance as solvent, C12H24SO4Na as self-assembly medium we have prepared nanostructure TiO2 successfully on the surface of Pst microball whose diameter is about 0.25mm in different conditions, such as temperature, acidity, and laid time etc. Then we have prepared hollow-sphere which has different contents, different structures, different features and crystal forms by controlling the temperature-changing ratios and the calcination temperatures.4. All of the above samples have been characterized by XRD, SEM, X-ray energy spectrum, IR, TG-DTA and titanium method etc. The research results show: ㏕he self-assembly medium can influence the microenvironment of the carrier surface and the absorption content. The absorption state of the carrier surface can be controlled by altering the self-assembly medium concentration and the alternation also lead to the change of the electric property of the carrier surface. (2) Controlling different conditions of the acidity, temperature, reaction time, calcination temperature we can prepare different crystal forms, different features nanostructure TiO2 and hollow ball. (3) With the increase of the number of the layers, the content of titanium dioxide increases in basic line and the carrier surface becomes fine and compact.5. Photocatalytic activity of nanostructure TiO2 has been studied by更多还原