Preparation And Characterization Of Nano - BaTiO 3 And BaTiO 3 - Bi - 2 - O 3 Composite Photocatalysts Were Investigated

Barium titanate (BaTiO3) is well-known electroceramic material and has been widely used in electronics and nonlinear optics field. Recently, relying on the semiconductor, BaTiO3is also used to catalyze the photo degradation of organic dyes. In various applications, BaTiO3nanocrystals with special morphology is desired due to their excellent properties, such as high activity, improved dielectric properties, potential for device miniaturization, etc., than its bulk form. So, many researches are concentrated on the morphology-controlled synthesis of BaTiO3nanocrystals. In this work, the synthesis methods of monodispersed spheric and cuboid BaTiO3nanocrystals are investigated, and the photocatalytic activity of the obtained BaTiO3is measured. In addition, BaTiO3nanoparticles loaded Bi2O3and flower-like Bi2O3microparticles loaded BaTiO3are prepared, and their photocatalytic activities are studied. The main contents of this master’s thesis are as follows.1. Monondispersed spherical BaTiO3nanocrystals are prepared with solvothermal method by using different surfactants (1,1’-biphenyl-4’-cyano-4-butoxy phosphonic acid, phenylphosphonic acid acid, oleic acid) to restrain the aggration of nanoparticles. The influence of synthesis parameters such as the crystallization temperature, the amount of surfactant and the alkalinity of precursor mixture on the particle size, dispersity, and morphology of the resultant BaTiO3nanocrystals is studied. The results show that oleic acid is a situable surfactant agent, by which monodispersed near spherical BaTiO3nanocrystals with size about20nm can be prepared under the optimized synthesis conditions.2. To prepare monodispersed cuboid shaped BaTiO3nanocrystals with microwave-assistant hydrothermal method, the influence of synthesis parameters such as crystallization temperature and time, the molar ratio, alkalinity and concentration of precursor mixture on the particle size, dispersity and morphology of the resultant BaTiO3nanocrystals is studied systemly. An optimized synthesis condition is obtained, under which monodispersed cuboid shaped BaTiO3nanocrystals with size of about15nm are successfully prepared. By analyizing the process of morphology and crystallinity development of the quenched solid product from the synthesis system at interval time, a possible formation mechanism of the cuboid shaped BaTiO3 nanocrystals is presented. Finally the photocatalytic activity of the obtained BaTiO3nanocrytals is tested by a probe reaction of rhodamine B degradation, and it is found that BaTiO3nanocrystals can be used as photocatalyst under ultraviolet light irradiation.3. BaTiO3nanocrystals loaded little amount of Bi2O3are prepared with microwave-assistant hydrothermal method. The experiment of rhodamine B photocatalytic degration shows that the existence of Bi2O3is useless in improving the photocatalytic activity of BaTiO3nanocrystals. In addition, flower-like Bi2O3microspheres loaded BaTiO3nanocrystals are also prepared, and their photocatalytic activity is investigated.