正丁醇水溶液通氨气法制备TiO_2粉体

PREPARATION OF ULTRAFINE TITANIA POWDERS USING AMMONIA GAS IN n-BUTANOL AND WATER SOLUTION

以TiCl_4为原料,正丁醇和水的混合液为溶剂,通入氨气促使TiCl_4水解,制备出不同粒径的Ti02粉体。由X射线衍射、场发射扫描电镜和激光粒度仪对样品进行了表征。研究了温度、pH值对粉体的晶型、形貌和粒径的影响。结果表明:在80℃通氨气,3≤pH≤8时,所得TiO_2粉体均为锐钛矿和金红石的混相,且pH=3时制得的粉体为60nm左右的球形颗粒,分散性很好;而pH=6,8时所得的粉体团聚严重;室温(20～30℃)下通氨至pH=6也可得到分散性较好的无定型态TiO_2粉体,但粉体粒径增大,约170nm左右。

Ultrafme titania powders were prepared by the hydrolysis of TiCI4 using ammonia gas in a mixed solvent of n-butanol and water at low temperature. The properties of these powders were characterized by X-ray diffraction, field emission scanning electron microscopy and laser particle size analysis. The influences of various reaction conditions, such as pH values and reaction temperature on the size, crystalline phase and morphology of the titania powders were investigated. The experimental results show that the as-prepared powders are a mixture of anatase and futile at 80 ℃ purged with ammonia gas at pH values in the range of 3-8. At pH=3, the mean size of the powders is about 60 nm, with a narrow size distribution, and the shape of particles is spherical. However, serious aggregates can be formed at pH=6 and 8. At pH=6 and with the reaction temperature at room temperature （20-30 ℃）, the mean size of the powders is about 170nm and the crystal phase is the amorphous phase.