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研究了采用溶胶-凝胶法经由前驱物钛酸四异丙酯水解制备纳米TiO2结构相变及锐钛矿晶体生长动力学过程.研究结果表明,在酸性条件下水解,由于高压热处理温度的变化导致锐钛矿向金红石相的结构相变,锐钛矿相纳米TiO2生长活化能在250℃以下和以上分别为(15.8±4.5)kJ/mol和(80.2±1.0)kJ/mol;而在碱性条件下水解的活化能值为(3.5±0.4)kJ/mol.在不发生结构相变的条件下,酸性水解条件下锐钛矿相纳米TiO2生长速率相比没有碱性条件下快,即表明在酸性条件下提高锐钛矿生长速率主要依靠提高温度来实现,而在碱性条件下,可以通过延长高压热处理时间使得晶体生长速率加快,该研究成果对实现锐钛矿相纳米TiO2晶体尺寸控制和将来批量化制备提供了理论和实验指导.
The phase transition of anatase crystal and the growth kinetics of anatase crystal were studied by sol-gel method via the hydrolysis of precursor tetraisopropyl titanate.The results show that under the acidic conditions, due to the change of high-pressure heat treatment temperature Which led to the phase transition from anatase to rutile phase. The activation energy of anatase phase nano-TiO2 was (15.8 ± 4.5) kJ / mol and (80.2 ± 1.0) kJ / mol respectively at 250 ℃ and above; Under acidic conditions, the activation energy of hydrolysis was (3.5 ± 0.4) kJ / mol. Under the condition of no structural phase transition, the growth rate of anatase phase nano-TiO2 under acidic hydrolysis was faster than that under alkaline conditions The results show that the growth rate of anatase under acidic conditions mainly depends on the increase of temperature. Under alkaline conditions, the growth rate of crystal can be accelerated by prolonging the time of high pressure heat treatment. Control and future batch preparation provide theoretical and experimental guidance.