【作者】 崔婷；

【导师】 唐绍裘；

【作者基本信息】 湖南大学 ， 材料学， 2006， 硕士

【摘要】 由于纳米TiO₂具有良好的生物和化学惰性、较强的氧化性能、低成本、以及对光腐蚀和化学腐蚀的稳定性等,故其薄膜不仅能用作光催化降解和自洁净材料,还能杀死细菌及病毒,是目前光催化材料的研究重点,具有广阔的应用前景。本文首先以钛酸丁酯为前驱体采用溶胶-凝胶工艺制备了均匀透明的纳米TiO₂薄膜。通过对实验条件的研究先确定了原料的配比,为得到附着性能和成膜质量均良好的纳米薄膜,需要对基片进行适当的预处理,并控制溶胶的粘度在1.70-2.20mPa.S之间,提拉速度在2mm/s左右。对纳米TiO₂薄膜性能的研究表明:随着薄膜层数的增加薄膜厚度呈现出线性增长的趋势,但直线不通过原点。薄膜中颗粒的粒径随着薄膜层数的增加有增大的趋势。纳米TiO₂薄膜经550℃热处理后完全转化为锐钛矿相;850℃热处理后完全转变为金红石相;随热处理温度的升高颗粒逐渐长大。随后采用两步水解法制备了纳米TiO₂/SiO₂复合薄膜。研究发现:随热处理温度的升高,颗粒晶型由无定型向→锐钛矿→金红石转变,但转变温度提高,晶粒逐渐长大。SiO₂的存在导致晶粒大小和晶相含量发生变化:随着SiO₂含量的增加,晶型有向低温态转变的趋势,晶粒尺寸减小。经红外光谱检测,未经热处理的纳米薄膜含有较多有机基团,随热处理温度的升高,这些有机基团被排除,其中TiO₂的特征峰明显。最后对纳米TiO₂及TiO₂/SiO₂复合薄膜的亲水性和光催化性能进行了评价:薄膜层数与薄膜的亲水性关系不大,但光催化性能随薄膜层数的增加而增长;随着SiO₂的引入薄膜的接触角显著降低,亲水状态可以保持很长时间,含30%SiO₂的薄膜最优。随着热处理温度的升高及SiO₂含量的增加,光催化活性都先增大后减小。更多还原

【Abstract】 Nano titanium dioxide is of favorable biological and chemical inertness, strong oxidizability, low cost and long-term stability against photocorrosion and chemical corrosion. Nano TiO₂ and TiO₂/SiO₂ thin films are used photocatalysis degradation materials and self-cleaing materials, and can kill bacteria and virus.At present it is the hot spot in the research of photocatalysis, and it is of great value in the practical applications.Firstly, butyl titanate was used as precursor and the uniform and transparent nano titanium dioxide thin films were prepared successfully by Sol-Gel method in this paper. According to the experimental results, the optimum ratio of the materials was shown. The thin films of excellent adhesive power can be obtained by the appropriate substrate’s pretreatment, 1.70-2.20 Sol viscosity and 2mm/s coating velocity.Then properties of nano TiO₂ thin films were studied. The results showed that there was a linear relationship between the TiO₂ thin film thickness and the number of coating cycles, but the line didn’t go through the origin. Particle diameter increased gradually with increasing thin film thickness. The phase of thin films changed absolutely to anatase from amorphous phase at 550℃, and at last changed to rutile by heat treatment about 850℃. The average grain size increased gradually with increasing heat treatment temperature.Secondly, nano TiO₂/SiO₂ composite thin films were prepared by two-step hydrolyze method. The results indicated that the phase structure changed from amorphous phase to anatase, then to rutile, but the changed temperature enhanced. Grain size increased gradually with increasing temperature. SiO₂ content caused transformation of particle size and the percent of phase. With the increasing content of SiO₂, grain size decreased and crystalline phase had the trend of translating to low-temperature phase. According to the infrared spectrometric analyzer, when sample didn’t undergo heat treatment many organic group occur in the nano thin film. On the condition of upper temperature the organic group were eliminate little by little, and characteristic absorption peak of TiO₂ is obvious.Finally, hydrophilicity and photocatalytic activity of nano thin films were researched. The thickness of thin films affected unobviousdly hydrophilicity and photocatalytic activity increased gradually along with increasing thickness of films.更多还原