A nanostructured TiO₂ powder was produced by a sol–gel method. The resultant powder was sintered at different temperatures ranging from 300°C to 800°C, for a constant time of 2 h. X-ray diffraction (XRD) results indicated that an increase in sintering temperature caused a transformation of the TiO₂ powder from amorphous to polycrystalline. At temperatures lower than 500°C, a pure polycrystalline anatase phase was present, while a rutile phase was present at 800°C. A gradual transformation from the anatase to rutile phase occurred between 500°C and 800°C. A high-resolution transmission electron microscope (HRTEM) with selected area electron diffraction (SAED) capability was used to elucidate the shape and size of the particles as well as their electron diffraction. The TEM images displayed an increase in particle size from 20 nm to 90 nm when the sintering temperature was increased from 300°C to 800°C. The SAED patterns supported the XRD results. The diffuse reflectance data for the investigated samples were used to estimate their bandgap energy (\( E_{\rm{g}} \)), which revealed that samples sintered at 500°C and 800°C had energy gap values of 3.18 eV and 3.01 eV, corresponding to pure anatase and pure rutile phases, respectively. Current–voltage (I–V) measurements were carried out on the sintered samples to calculate sample resistivity at room temperature. The results showed a slight increase in conductivity with increased sintering temperature up to 700°C, followed by a significant increase at 800°C.

中文翻译：

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热处理对溶胶-凝胶法制备的纳米结构TiO 2粉末物理性能的影响

纳米结构的TiO ₂粉末是通过溶胶-凝胶法生产的。将所得粉末在300℃至800℃的不同温度下烧结2小时的恒定时间。X射线衍射（XRD）结果表明，烧结温度的升高引起了TiO ₂的相变。粉末从无定形到多晶。在低于500℃的温度下，存在纯的多晶锐钛矿相，而在800℃下存在金红石相。在500℃至800℃之间发生了从锐钛矿相到金红石相的逐渐转变。具有选定区域电子衍射（SAED）功能的高分辨率透射电子显微镜（HRTEM）用于阐明颗粒的形状和大小及其电子衍射。当烧结温度从300℃增加到800℃时，TEM图像显示出粒径从20nm增加到90nm。SAED模式支持XRD结果。被调查样品的漫反射数据用于估计其带隙能量（\（E _ {\ rm {g}} \）），表明在500°C和800°C烧结的样品的能隙值分别为3.18 eV和3.01 eV，分别对应于纯锐钛矿相和纯金红石相。电流-电压（我- V）的测量进行了上的烧结样品在室温下，以计算样品的电阻率。结果表明，随着烧结温度的升高，电导率略有提高，最高到700°C，然后在800°C时显着提高。