溶胶—凝胶法制备二氧化钛粉体与薄膜研究

发布时间：2018-08-26 07:22

【摘要】：TiO2作为一种光催化剂具有廉价、无毒,在水溶液中稳定等优点,成为最有开发前途的绿色环保型催化剂之一。纳米TiO2具备良好的耐侯性、耐化学腐蚀性、抗紫外线能力强、透明性优异等特点,用途广泛。将纳米TiO2制备成薄膜既可解决催化剂分离和难回收的问题,还可克服悬浮相催化剂稳定性差和易中毒等缺点,具有重要的理论研究和实际应用价值。本文以钛酸丁酯、无水乙醇、冰醋酸、高纯水为原料,采用溶胶-凝胶(sol-gel)法进行了TiO2粉体和薄膜的制备研究,考察了工艺条件对溶胶、粉体及薄膜性质的影响。通过X射线分析(XRD)、差示扫描量热(DSC)、光学显微镜等测试技术对溶胶、粉体和薄膜进行了表征,主要研究内容及相关结论如下： (1)采用溶胶-凝胶法,研究了不同原料配比及反应温度对形成凝胶时间的影响,结果表明：溶胶凝胶形成时间随加水量的增加而缩短；随无水乙醇用量的增加而延长；随冰醋酸用量的增加而延长,但达到一定量后再增加冰醋酸用量就会缩短溶胶凝胶形成时间；反应温度升高溶胶凝胶形成时间缩短。 (2)重点研究了制备TiO2粉体的工艺条件及TiO2粉体晶型转变的影响因素。优化出制备TiO2粉体的合适工艺条件：钛酸丁酯、水、无水乙醇、冰醋酸的物质的量之比为1:4:25:1,反应温度为25℃。 (3)TiO2粉体的晶型转变过程是一种依赖于升温速率的动力学过程。TiO2粉体晶型转变体积分数的增大,其晶型转变激活能随之增大； (4)焙烧温度和焙烧时间是影响TiO2晶体结构转变的主要因素,随着焙烧温度的升高,TiO2晶型结构逐步由无定形态向锐钛矿→锐钛矿和金红石混合晶型→金红石转变；随焙烧时间的延长,金红石晶型含量逐渐增大,锐钛矿相含量逐渐减少； (5)升温速率、原料配比、强磁场等对TiO2晶体结构没有太大的影响,影响的只是锐钛矿型和金红石型结构TiO2粉体的相对含量； (6)焙烧温度对TiO2粉体粒度有一定的影响,焙烧温度的升高,粉体粒度增大；但TiO2粉体的粒度分布变窄； (7)升温速率对粉体粒度有一定的影响。最高焙烧温度相同,升温速率快,所得粉体粒度较小； (8)不同原料配比对粉体粒度有一定的影响。相同焙烧条件下,水量较大时的原料,所制得的粉体粒度较小。 (9)利用正交实验获得了旋转涂膜法制备TiO2薄膜的合适工艺条件：钛酸丁酯、水、无水乙醇、冰醋酸的物质的量之比为1:3:25:1、反应温度为25℃、涂膜次数为2次。
[Abstract]:As a kind of photocatalyst, TiO2 has many advantages, such as low cost, non-toxicity, stability in aqueous solution, etc. It has become one of the most promising green environmental protection catalysts. The problems of separation and hard recovery of the catalyst can also overcome the disadvantages of poor stability and poisoning of the suspended phase catalyst, which has important theoretical research and practical application value.
In this paper, titanium dioxide powder and thin film were prepared by sol-gel method with butyl titanate, anhydrous ethanol, glacial acetic acid and high purity water as raw materials, and the effects of processing conditions on the properties of sol, powder and thin film were investigated. The films were characterized, and the main research contents and conclusions were as follows:
(1) The effects of the ratio of raw materials and reaction temperature on the gelation time were studied by sol-gel method. The results showed that the gelation time was shortened with the increase of the amount of water, prolonged with the increase of the amount of absolute ethanol, and prolonged with the increase of the amount of glacial acetic acid. The sol-gel formation time will be shortened and the formation time of sol-gel will be shortened.
(2) The technological conditions of preparing titanium dioxide powder and the influencing factors of crystal transformation of titanium dioxide powder were studied.
The ratio of butyl titanate, water, absolute alcohol and glacial acetic acid is 1:4:25:1, and the reaction temperature is 25 C.
(3) The crystalline transformation of TiO2 powder is a kinetic process depending on the heating rate, and the activation energy of crystalline transformation increases with the increase of the volume fraction of crystalline transformation.
(4) The calcination temperature and time are the main factors affecting the crystal structure transformation of titanium dioxide. With the increase of calcination temperature, the crystal structure of titanium dioxide gradually transforms from amorphous to anatase-anatase-rutile mixed crystal to rutile. With the increase of calcination time, the rutile content increases gradually and the anatase phase content decreases gradually. Less;
(5) The heating rate, the ratio of raw materials and the strong magnetic field have little effect on the crystal structure of titanium dioxide, but only the relative content of anatase and rutile titanium dioxide powders.
(6) The calcination temperature has certain influence on the particle size of TiO2 powder, the particle size increases with the increase of calcination temperature, but the particle size distribution becomes narrow.
(7) The heating rate has a certain effect on the particle size of the powders.
(8) Different raw material ratios have certain influence on the particle size of the powders. Under the same roasting conditions, the powders prepared with higher water content have smaller particle size.
(9) the suitable technological conditions for preparing TiO2 thin films by rotating coating method were obtained by orthogonal experiment.
The mass ratio of butyl titanate, water, ethanol and glacial acetic acid is 1:3:25:1, the reaction temperature is 25 C and the coating times are 2 times.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TB383.2;TB383.3

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