【作者】 张俊娟；

【导师】 赵高凌；

【作者基本信息】 浙江大学 ， 材料科学与工程， 2011， 硕士

【摘要】 纳米二氧化钛(Ti02)光催化材料具有氧化能力强、光催化活性高、稳定、无毒等优点,在环保领域,建筑领域,农业领域等得到了广泛的应用。本研究通过溶胶-凝胶法制备了三种不同形态的Ti02纳米材料,分别为Ti02纳米粉末,Ti02薄膜和Ti02纤维,并分别对其各项性能进行了研究。本文首先介绍了Ti02纳米材料及其光催化机理和影响因素,突出了Ti02在光催化领域的优势。在此基础上,展开了Ti02纳米晶的溶胶凝胶法低温制备的研究,并通过添加不同的成膜剂来制备Ti02薄膜,从而达到固定Ti02的目的。研究发现Ti02薄膜的光催化活性远差于Ti02纳米晶,于是本研究又利用溶胶凝胶法制备了Ti02纤维,提高了Ti02的光催化性能,同时也固定了Ti02,并通过Au的掺入来提高Ti02纤维的光催化活性。本研究利用X-Ray衍射(XRD),透射电镜(TEM),高分辨透射电镜(HRTEM),能量弥散X射线探测器(EDS),紫外可见吸收光谱(UV-Vis Abs),原子力显微镜(AFM)及接触角等测试手段研究了Ti02的结晶性能、微观结构、亲水性能及光催化性能,主要研究如下：在室温下,利用钛酸丁酯在过量的水中进行水解缩聚反应制得锐钛矿相的TiO2纳米晶,粒径为3-4 nm,且晶粒尺寸分布均匀。研究发现,样品的光催化活性随着水与钛酸丁酯的摩尔比n的增大先增大后减小,当n=120时,样品光催化活性最高。另外,将制得的Ti02粉末分别对甲基橙、亚甲基蓝及罗丹明B进行光降解发现,罗丹明B最易降解,其次为亚甲基蓝,甲基橙最难降解。在水性Ti02溶胶中加入有机成膜剂(PVP、PEG)并通过喷涂法制得Ti02薄膜样品。研究结果表明,添加PVP的Ti02薄膜表面较平整,膜厚度约为600 nm；添加PEG的Ti02薄膜表面粗糙度大,膜厚约为300 nm。另外,PVP及PEG的加入均提高了Ti02薄膜的亲水性能；当加入PVP或小分子量的PEG时,薄膜光催化性较差,而加入大分子量PEG,薄膜光催化性能较好。当PEG分子量为6000,加入量为10%时,Ti02薄膜样品的各项性能最好。采用溶胶凝胶法制备了TiO2及Au/TiO2复合纤维,研究结果表明,热处理后的Ti02呈锐钛矿结构,随着温度的升高,Ti02结晶度提高；加入的Au在Ti02纤维中形成了Au颗粒,颗粒尺寸为7-15 nm。Au的掺入显著地提高了Ti02纤维的光催化活性,且其光催化活性随着Au的掺入量的增加而增大。更多还原

【Abstract】 Nano-scaled TiO2 materials, which have many good characteristics such as powerful oxidation strength, high photocatalytic activity, high chemical stability, nontoxicity and so on, have been widely used in the field of environmental protection, construction and agriculture. In this study, sol-gel method was employed to prepare three different forms of TiO2 nano-scaled materials, including TiO2 nanopowder, TiO2 thin films and TiO2 fibers.At first, the TiO2 nano-scaled materials and the photocatalysis mechanism of TiO2 were introduced. Then the absolute advantage of the TiO2 nanocrystallines in the photocatalysis filed was highlighted. The study of sol-gel-derived TiO2-based nanocrystallines under low temperature was carried. Then the TiO2 thin films were prepared by adding different organic film-forming agent, in order to fix the TiO2. However, because the photocatalytic activity of thin films was far worse than the powder sample, we had prepared TiO2 fibers which not only had high photocatalytic properties, but also fixed the TiO2 through sol-gel method. Furthermore, the incorporation of Au could greatly enhance the photocatalytic activity of TiO2 fibers. X-ray diffraction (XRD), transmission electron microscopy (TEM), High resolution transmission electron microscopy (HRTEM), Energy Dispersive X-ray Detector (EDS), UV-Vis Absorption Spectra(UV-Vis Abs), Atomic Force Microscope (AFM) and water contact angle were used to understand the crystallization property, microstructure, optical property, hydrophilicity and photocatalytic property of the prepared TiO2 nano-scaled materials. The main research results were as follows:Tetrabutyl titanate was chosen as titanium precursor. TiO2 nanocrystallines were prepared by sol method under room temperature. The crystal size was 3-4 nm, and the size was well-distributed. The results demonstrated that as the water amount (n) increased, the crystal size increased, the photocatalytic activity increased first and then decreased. The TiO2 nanocrystallines had the highest photocatalytic activity when n=120. In addition, this paper researched the photodegradation of different TiO2 nanocrystallines to methyl orange, methyl ene blue and rhodamine B. It was found that rhodamine B was easy to degrade, methylene blue was the next, and methyl orange was difficult to degrade.The TiO2 thin films were obtained by adding organic film-forming agent (PVP, PEG) into water-based TiO2 sol. The research results showed that the surface of PVP-TiO2 thin films was smooth, and the thickness was about 600 nm. The surface of PEG-T1O2 thin films was rough, and the thickness was about 300 nm. And the addition of PVP and PEG was favourable to improve the performance of film hydrophilic. When the agent was PVP or small molecular weight of PEG, the photocatalytic of TiO2 film was low, and when the agent was large molecular weight PEG, the TiO2 film showed better photocatalytic properties. The TiO2 thin films showed the best properties when the molecular weight of PEG was 6000, and the addition of PEG were 10%.TiO2 fibers and Au/TiO2 composite fibers were developed via sol-gel approach. The results demonstrated that TiO2 was anatase after the heat treatment, and the size of Au particles was 7-15 nm. The incorporation of Au could greatly enhance the photocatalytic activity of TiO2, which increased with the addition of Au incorporation.更多还原