不同晶型纳米二氧化钛的水热合成

Hydrothermal synthesis of nanosized titania with different crystal forms

水热法合成了不同晶型、形貌和大小的纳米二氧化钛。利用X射线衍射(XRD)和透射电镜(TEM)对所得的样品进行了表征。研究了pH值、水热反应温度和水热反应时间对纳米二氧化钛晶型、形貌和晶粒尺寸的影响。结果表明,前驱体pH值是决定产品晶型、晶粒尺寸和形貌的主要因素。随着水热反应温度的升高,纳米二氧化钛的晶粒尺寸逐渐变大,但pH=3.0时所形成的锐钛矿型纳米二氧化钛的晶粒尺寸却几乎不变;随着水热反应时间的延长,金红石型纳米二氧化钛晶粒的生长速度最快,而锐钛矿型的纳米二氧化钛的晶粒生长速度则最慢。

The nanosized titania with different crystal forms, morphologies and particle sizes was prepared by hydrothermal method. Samples of the product were characterized by X - ray powder diffraction （XRD） and transmission electron microscopy （TEM）. The effects of pH value, hydrothermal treatment temperature and time on the crystal phase, morphology and crystalline particle size of nanosized titania were investigated. The results showed that the pH value of precursor was the key factor in determining the crystal form, particle size and morphology of product. Following the raising of temperature, the crystalline particle size of product increases, but the crystalline particle size of anatase titania prepared at pH = 3.0 was nearly unchanged Following the extension of hydrothermal treatment time, the growth rate of crystalline particle size of titania of rutile type is the fastest, while the growth rate of that of anatase type is the slowest.