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溶胶-凝胶法制备的纳米TiO2结构相变及晶体生长动力学

胡林华 戴松元 王孔嘉

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溶胶-凝胶法制备的纳米TiO2结构相变及晶体生长动力学

胡林华, 戴松元, 王孔嘉

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

Hu Lin-Hua, Dai Song-Yuan, Wang Kong-Jia
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  • 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 <503K时,粉末晶粒度增长较为缓慢,而当热处理温度>503K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503K时,样品就开始发生锐钛矿到金红石相的结 构相变,到543K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.
    Structural transformation of nanocrystalline titania prepared by sol_gel method with hydrolysis precursor titanium isopropoxide was investigated. At the same ti me, the growth kinetics of titania powders was also studied. It was found that t he 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 tem perature was higher than 503K. The activation energies for growth of anatase cry stallites in two temperature regions were calculated to be 18.5kJ/mol and 59.7 k J/mol respectively. The x_ray diffraction results show that the transformation f rom anatase phase to rutile phase starts at 503K and structural transformation f inished when temperature raises to 543K, which is a temperature much lower than that of the transformation reported in the literature.
    • 基金项目: 国家重点基础研究规划项目(批准号:G2000028206)和中科院知识创新方向性项目(批准号: KGCX2_303_03)资助的课题.
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  • 文章访问数:  8966
  • PDF下载量:  2214
  • 被引次数: 0
出版历程
  • 收稿日期:  2002-09-20
  • 修回日期:  2003-01-14
  • 刊出日期:  2003-09-20

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