丁二醇对TiO2纳米晶体水热生长动力学的影响

Effects of Butylene Glycol on the Growth Kinetics of TiO_2 Nanocrystal under Hydrothermal Condition

采用水热法,以丁二醇和水作为混合溶剂,研究了二氧化钛纳米晶体的生长机理。X射线衍射(XRD)结果显示产物为锐钛矿纳米TiO2。用透射电镜(TEM)、高分辨透射电镜(HRTEM)等对不同时间的晶体结构进行表征,发现晶体生长具有明显的奥斯特瓦尔德熟化(OR)特征。颗粒粒径均处于纳米级,其粒径数值随温度增加而变大。丁二醇作为溶剂兼表面活性剂对于纳米晶体的生长起到重要调节作用。采用OR方程,分别对220℃、180℃、140℃三个温度下纳米Ti O2的生长进行模拟,模拟曲线和实验结果吻合很好,并获得其生长活化能为15.0 k J/mol。

Using butylene glycol and water as mixed solvent,the TiO2 nanocrystallines were prepared by hydrothermal method,and its growth mechanism were investigated. The XRD patterns show that the products are anatase. The construction feather of the nanoparticles for the different times were characterized by TEM and HRTEM. The results show that the Ostwald Ripening mechanism is dominant in the nanoparticle growth. The particle size is in the nanoscale and as the temperature increasing.Butylene glycol makes the important effect in the growth process. Ostwald ripening equation was employed to fit the nanoparticle growth data in order to elucidate growth mechanisms operating during hydrothermal aging at three different temperatures such as 220 ℃,180 ℃,140 ℃. Fitting curves agree well with the experiment results and the apparent active energy is 15.0 k J / mol.