热处理温度对纳晶TiO2微结构和光催化活性的影响

摘要

Nanocrystalline TiO2 was prepared by sol-gel method with tetrabutyl titanate modified by acrylic acid. The effects of heat treatment on microstructure were examined using XRD, TEM, BET and TG-DTA. The experimental results indicate that heat treatment significantly affects both microstructure and photoactivity. Results show that there is a relationship between microstructure and photoactivity.Heat treatment of the sample at temperature higher than 400 ℃ is essential for removal of organic components and to acquire perfect nanocrystalline TiO2. As roasting temperature is up to 600 ℃, the particle size and rutile content increase with increasing roasting temperature, which results in decrease of photoactivity. The proper roasting temperature is about 400 ～ 600 ℃ and the samples prepared in this range have high photocatalytic activity in degradation of brilliant red X-3B.%以丙烯酸修饰的钛酸丁酯为前躯体,采用溶胶-凝胶法制备纳晶TiO2.用XRD,TEM,BET以及TG-DTA考察了热处理温度对纳晶TiO2微结构的影响.测试结果表明,热处理温度对样品的微结构以及光催化活性有很大的影响.采用溶胶-凝胶法制备纳晶TiO2的最佳焙烧温度范围为400～600℃,低于400℃样品中的有机成分难以彻底消除且样品的结晶度不高;高于600℃,TiO2颗粒存在明显的热团聚,使晶粒尺度变大,粒径分布不均以及比表面积显著降低,这些因素都会造成样品活性降低.