【作者】 宗建娟；

【导师】 杨辉；

【作者基本信息】 浙江大学 ， 材料物理与化学， 2010， 硕士

【摘要】 TiO₂作为一种半导体光催化材料,具有效率高、能耗低、无毒、稳定性好等优点,在环境污染治理方面应用前景广阔。其中,TiO₂薄膜由于能通过在多种基材上的负载应用,克服粉体型TiO₂易聚集、难回收等问题,受到了广泛关注。近年来,随着TiO₂薄膜在工程塑料,有机涂层等不耐热或大面积难以加热材料表面应用需求的增加,其低温制备成为该领域研究的热点。本文对TiO₂薄膜的低温制备及应用进行了研究,提出利用以TiO₂纳米晶溶胶为主要成分的有机/无机复合涂膜液,低温负载制备TiO₂薄膜的研究课题。论文以价格低廉的TiOSO₄无机盐为前驱体,采用胶溶法制备TiO₂纳米晶溶胶,并设计TiO₂纳米晶溶胶/醋丙乳液、TiO₂纳米晶溶胶/有机硅溶胶复合体系,解决单一TiO₂纳米晶溶胶涂膜不均匀、薄膜附着力欠佳等应用问题。主要研究工作包括以下几个方面:（1）TiO₂纳米晶溶胶的制备及优化研究以价格低廉的TiOSO₄为原料,采用沉淀-胶溶工艺,研究了酸性和中性两类TiO₂纳米晶溶胶的制备方法,重点考察了溶胶制备条件对TiO₂结晶度、粒径大小以及溶胶光催化活性的影响。优化的酸性TiO₂溶胶制备条件为:水浴胶溶温度60℃,水浴胶溶时间6h,HNO₃的添加量H⁺:Ti⁴⁺=4。优化的中性TiO₂溶胶制备条件为:pH=7～8,水浴温度65℃,水浴时间4h,H₂O₂的添加量为H₂O₂:Ti⁴⁺=16。酸性和中性两类TiO₂纳米晶溶胶的对比研究表明,酸性TiO₂溶胶在溶胶稳定性及光催化活性方面均优于中性TiO₂溶胶。（2）TiO₂/醋丙复合薄膜制备及性能研究选择醋丙乳液与TiO₂纳米晶溶胶复合,着重考察了复合体系中TiO₂用量对薄膜结构与性能的影响。结果表明:TiO₂纳米晶溶胶/醋丙乳液复合体系具有较高的稳定性和良好的成膜特性;涂膜后,随TiO₂含量的增大,薄膜表面的TiO₂粒子增多,薄膜粗糙度增大;当复合薄膜中添加的TiO₂溶胶浓度由0.1 mol/L提高到0.3mol/L时,紫外光激发下复合薄膜对罗丹明B的分解率由53.8%提高到了78.8%,对水的接触角由66°降低到50°。（3）TiO₂/有机硅复合薄膜制备及性能研究采用胶溶法制备以醇为主要溶剂的TiO₂纳米晶溶胶,并与有机硅溶胶进行复合。在此基础上,开展复合溶胶在聚碳酸酯板（PC板）表面的涂膜研究,主要考察了TiO₂溶胶添加量、TiO₂溶胶浓度以及涂膜层数对复合薄膜结构与性能的影响。结果表明:TiO₂溶胶添加量为40wt%时,复合溶胶的成膜性较好;添加的TiO₂溶胶浓度为0.3mol/L时,获得的复合薄膜具有良好的光催化性能,对罗丹明B的降解率达到74.4%;当涂膜层数为2层时,在保证复合薄膜中TiO₂负载量的同时,薄膜均匀、无开裂现象,并且具有较好的光透过率。更多还原

【Abstract】 TiO₂ is a kind of semiconductor photocatalysts with excellent properties such as high efficiency,low energy consumption,innocuity,good stability,which makes it have important applications in renewable energy and environment fields.TiO₂ thin films is researched widely as it can overcome the shortcomings of TiO₂ powder that is easy to agglomerate and difficult to recycle when being applied on a variety of substrate,.In recent years,with the increasing demand of application in surfaces of materials which do not resist heat or the surface area is too large to heat,such as engineering plastics,organic coatings and so on,It is becoming hot to prepare TiO₂ thin film at low temperature.In this paper we researched the low temperature preparation and application of TiO₂ thin film,put forward the research programe of preparing TiO₂ thin film by nano-crystal TiO₂ sol,prepared TiO₂ sol with anatase using low-cost inorganic salts TiOSO₄ as precursors by colloidal chemical method,designed the composite system of nano-crystal TiO₂ sol/vinyl acetate-acrylate latex,nano-crystal TiO₂ sol/organosilicon sol,so as to solve practical application problem such as ununiformity and poor adhesion of film prepared by pure nano-crystal TiO₂ sol.Specific major tasks include the following aspects:（1） Study on preparation and optimization of TiO₂ nanocrystalline solUsing low-cost TiOSO₄ as precursors,preparation of acid and neutral TiO₂ sol were studied by peptizing method The impact of preparing conditions on crystallinity degree, particle size.photocatalytic efficiency of TiO₂ sol were emphatically investigated. Optimized preparing conditions of acid TiO₂ sol are as follows:peptizing temperature and time were 60℃and 6h separately,adding amount of HNO₃ was H⁺:Ti⁴⁺=4.Optimized preparation conditions of neutral TiO₂ sol are as follows:peptizing temperature and time were 65℃and 4h separately,adding amount of H₂O₂ was H⁺:Ti⁴⁺=16 By comparing acid and neutral TiO₂ sol,it is known that the stability and photocatalytic activity of acidic TiO₂ sol are better than that of neutral TiO₂ sol.（2） Study on preparation and properties of vinyl acetate-acrylate/TiO₂ composite film The acid TiO₂ nanocrystalline sol was added into vinyl acetate-acrylate latex.The impact of TiO₂ content in the compound system on the structure and properties of the film were emphatically investigated.The results show that the composite coating solution has high stability and excellent film forming property.With the increase of TiO₂ sol addition,the amount of TiO₂ particles in the surface of the film increases,which leads to the increase of roughness of the film.When the concentration of the TiO₂ sol increases from 0.1 mol/L to 0.3mol/L,decomposition rate of the composite film to rhodamine B increases from 53.8%to 78.8%and the contact angle decreased from 66°to50°after the UV irradiation.（3） Study on preparation and properties of organosilicon/TiO₂ composite filmEthanol based acid TiO₂ nanocrystalline sol was prepared by colloidal chemical method and then added in organosilicon sol.On this basis,research on preparing films on the surface of polycarbonate sheet（PC sheet） by composite coating solution were carried out.The adding amount of TiO₂ sol,concentration of TiO₂ sol and coating layers of the composite fihn were mainly studied.The results show that when the adding amount of TiO₂ sol is 40wt%,fihn forming property of the composite coating solution is well.When the concentration of the TiO₂ sol is 0.3mol/L,photocatalytic performance of the composite film is the best,and decomposition rate of the composite film to rhodamine B was 74.4%.When the coating layer was two,it guarantees much TiO₂ particles on the PC sheet,and the film is uniformity,less crack and has sufficient light transmittance.更多还原