溶胶-凝胶法制备的纳米TiO_2结构相变及晶体生长动力学  

Structural transformation of nanocrystalline titania grown by sol-gel technique and the growth kinetics of crystallites

作　　者：胡林华[1] 戴松元[1] 王孔嘉[1] 

机构地区：[1]中国科学院等离子体物理研究所,合肥230031

出　　处：《物理学报》2003年第9期2135-2139,共5页Acta Physica Sinica

基　　金：国家重点基础研究规划项目(批准号 :G2 0 0 0 0 2 82 0 6);中科院知识创新方向性项目 (批准号:KGCX2_3 0 3_0 3 )资助的课题~~

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 。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 59.7kJ/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.

关 键 词：溶胶-凝胶法 纳米TIO2 制备 结构相变 晶体生长动力学 纳米粉末 二氧化钛 

分 类 号：O782[理学—晶体学]