Kinetics of anatase phase transformation of TiO2 NPs synthesized using controlled hydrolysis technique
Kinetics of anatase phase transformation of TiO2 NPs synthesized using controlled hydrolysis technique
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DOI：
10.1007/s00339-018-2021-7
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发表时间：
2018-09-01
影响因子：
2.7
通讯作者：
Jose, M.
中科院分区：
文献类型：
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作者：
Kalaiarasi, S.;Jose, M.
采用粉末X射线衍射（XRD）分析方法研究了不同温度和不同时间下纳米TiO 2锐钛矿-金红石相转变的热动力学。从900 ℃开始观察到金红石相（101）的XRD峰的衍射强度降低，这证实了金红石相的演变。研究了925 ℃和950 ℃下转变金红石质量分数随时间变化的等温曲线，并用约翰逊- Mehl-Avrami方程进行了拟合。采用热重分析和差热分析对纳米TiO 2的热行为进行了表征。此外，在较高的温度范围内的合成的TiO 2纳米颗粒的比热容报告。通过对实验结果的概括，我们发现通过控制水解技术合成的TiO 2纳米颗粒处于过渡态，并且可以得出结论：界面成核和生长位点的改善是通过活化能来实现的。不同的时间导数计算的活化能被发现是39千卡/摩尔，64千卡/摩尔和175千卡/摩尔。
Thermal kinetics of TiO2 NPs at varying time and at different temperatures for anatase-rutile phase transition was investigated by Powder XRD diffraction analysis. Decrease in the diffraction intensities of XRD peaks of anatase phase (101) was observed from 900 degrees C onwards, which substantiates the evolution of rutile phase. Isothermal curves of transformed rutile mass fraction as a function of varying time were investigated at 925 degrees C and 950 degrees C and the data were fitted using Johnson- Mehl-Avrami equation. Thermal behavior of nanostructured TiO2 was characterized using thermogravimetry and differential analyses. In addition, specific heat capacities of the synthesized TiO2 NPs at higher temperature range were reported. By recapitulating the results, we indicate that TiO2 NPs synthesized by controlled hydrolysis technique prolongs the transition state and it can be concluded that interfacial nucleation and growth site improvements are accomplished by activation energy. Activation energy calculated for varying time derivatives was found to be 39 kcal/mol, 64 kcal/mol and 175 kcal/mol.