Competition between gas phase and surface oxidation of TiCl4 during synthesis of TiO2 particles

被引:86
作者
Pratsinis, SE [1 ]
Spicer, PT [1 ]
机构
[1] Univ Cincinnati, Dept Chem Engn, Cincinnati, OH 45221 USA
基金
美国国家科学基金会;
关键词
vapor phase material synthesis; chemical kinetics and particle growth; chemical vapor deposition; particle production; coagulation and surface growth;
D O I
10.1016/S0009-2509(98)00026-8
中图分类号
TQ [化学工业];
学科分类号
0817 ;
摘要
The effect of TiCl4 surface reaction on the size of product TiO2 particles is quantitatively investigated over a wide range of process conditions (temperature and reactant concentration) that are typically employed in industrial and research facilities. A model for titania aerosol dynamics is developed accounting for the simultaneous gas phase and particle phase (surface) oxidation rate of TiCl4. Using this model, the implications of these two chemical pathways on the size of product titania particles are elucidated. It is shown, for the first time, that TiCl4, oxidation on the surface of freshly formed titania particles is most important at high TiCl4 concentrations. A design diagram is presented mapping the significance of surface and gasphase oxidation of TiCl4 in terms of process temperature and initial TiCl4 mole fraction. The model predictions are compared with experimental results and conflicting interpretations of the mechanism of titania formation by TiCl4 oxidation in the literature are reconciled. This model can be used to investigate the significance of surface growth in gas-phase synthesis of fumed silica as well as other ceramic and metallic particles. (C) 1998 Elsevier Science Ltd. All rights reserved.
引用
收藏
页码:1861 / 1868
页数:8
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