The Gel Mechanism Of Nano-TiO₂ Derived By Sol-Gel Method And The Phase Transformation

There are a lot of processes to prepare nano-TiO2. In those processes,because of the lower requirement of equipments, the simple technologic process and its products which provided with better homogeneousness,higher content and lower compositive temperature, the process of sol-gel to prepare power,film or coad of nono-TiO2 is in common use.During the process of sol-gel, there are many factors to result in the phase transformation of TiO2. Being looked at the aspect of application, it's always hope to contral the change from anatase phase to rutile phase artificially according to the actual need. Therefore, studying the structural transformation of nano-sized TiO2 by studying the change of nano-meter size has very important realistic meaning.In this project, firstly, the gel mechanism of nano- TiO2 derived by sol-gel method was studied from the following five aspects: the effect of different H2O content, nitric acid content, hydrolysis temperature and stir speed to gel time.Then, the relationship between the gel speed and the average crystallite size of nano- TiO2 powder was found by analyzing the average crystallite size of nano- TiO2 powder under different reaction conditions.Finally, the relationship between gel speed, average crystallite size and the phase transformation temperature from anatase phase to rutile was gained by studying the phase transformation temperature.