【摘要】 讨论了采用溶胶 -凝胶法经由先驱物钛酸四异丙脂水解而制备的纳米TiO2 粉末的结构相变 ,并讨论了该纳米粉末的生长动力学机理 .结果表明 ,水解pH值为 0 9,当高压釜热处理温度 <5 0 3K时 ,粉末晶粒度增长较为缓慢 ,而当热处理温度 >5 0 3K时 ,粉末粒度明显长大 .应用相变理论计算出了纳米TiO2 颗粒的两阶段的生长激活能 ,分别是 18 5kJ mol和 5 9 7kJ mol.XRD物相分析表明 ,高压釜热处理温度达到 5 0 3K时 ,样品就开始发生锐钛矿到金红石相的结构相变 ,到 5 4 3K就基本实现了这一结构相变 ,使得这一相变温度比其他文献中报道的又降低了许多更多还原

【Abstract】 Structural transformation of nanocrystalline titania prepared by sol_gel method with hydrolysis precursor titanium isopropoxide was investigated. At the same time, the growth kinetics of titania powders was also studied. It was found that the grain size of the powders increased slowly with autoclave heating temperature up to 503K, when hydrolysis pH value was 0 9, but grew rapidly when heating temperature was higher than 503K. The activation energies for growth of anatase crystallites in two temperature regions were calculated to be 18 5kJ/mol and 59 7 kJ/mol respectively. The x_ray diffraction results show that the transformation from anatase phase to rutile phase starts at 503K and structural transformation finished when temperature raises to 543K, which is a temperature much lower than that of the transformation reported in the literature.更多还原