【摘要】 根据统计物理学方法推导出锐钛矿型TiO₂向金红石型TiO₂转化率关系式为InX_A=-v₀texp（-2U_x/kT）,其中X_A为TiO₂中锐钛矿型的含量,v₀和U_x分别锐钛矿型TiO₂原子的振动频率和势函数,t、k和T分别为煅烧时间、玻兹曼常数和煅烧温度.TiO₂为三原子分子,理论上v₀和U_x计算十分复杂,本文通过在不同温度及时间下煅烧氨水水解TiOSO₄产物的方式制备了锐钛矿型、混晶型及金红石型纳米TiO₂粉末,将XRD分析所测数据及相应温度、时间条件代入转化率关系式,拟合求得:v₀=5.3×10¹⁰/s,U_x=2.71×10^-12J.实验所测_A-t及X_A-T曲线与计算拟合曲线吻合较好,说明用氨水水解TiOSO₄产物的方式制备的锐钛矿型纳米TiO₂向金红石型纳米TiO₂的转化为扩散型转变.更多还原

【Abstract】 Based on the method of statistical physics , the relation equation lnXA=-v₀t exp（-2U_x/ kT） for the change of anatase TiO₂ into rutile TiO₂ is established, where XA is the contents of anatase in the sample, v₀ and U_z are, respectively, the vibration frequency and potential function of an anatase atom, t, k and T are calcination time, Boltzmann constant and calcination temperature, respectively. Because TiO₂ is a molecule with three atoms, it is very difficulty to calculate its v₀ and U_z theoretically. In this article, the nanometer TiO₂ powder with different proportion of anatase was got by calcining the hydrolysising products of the TiOSO₄ solution under different calcination temperatures or times. The values of v₀ and U_z(v₀=5. 3×10¹⁰/s,U_z=2. 71×10^-12 J) were obtained by using the XRD data and corresponding temperature and time. The calculation curves of XA—T and XA—t are in agreement with the experimental results. It shows that the change mechanism from anatase TiO₂ to rutile TiO₂ is the diffuse one.更多还原