水热法一步合成核壳型TiO2/Al2O3纳米粉体的热力学分析

水热法一步合成核壳结构的工艺路线具有简化生产工艺、大大缩短生产时间的特点.所以研究制备具有核壳结构的前驱体热力学条件有重要的指导意义.热力学分析表明,在纳米Ti(OH)4表面包覆Al(OH)3的过程中,存在核包覆和膜包覆的竞争;而在其它条件不变的情况下,包覆物的过饱和度对包覆形态起到了决定性的影响.在较低的过饱和度下,可形成膜包覆;如果过饱和度过高,则形成核包覆.

Thermodynamic Analysis of Core-Shell TiO2/Al2O3 by One-Step Hydrothermal Method

The core-shell structure,s synthesis process by one-step hydrothermal method has remarkable peculiarities,such as simple procedures and short production cyc les.In order to get the precursor with the core-shell stucture,it,s important to study the thermodynamical conditions.Through the thermodynamic anal ysis of coating process,it was proved that Al(OH)3 nucleus coating Ti(OH)4 c ompetes with Al(OH)3 film coating Ti(OH)4.If other conditions are una ltered,the super-saturation of Al compound was determinant of ultimate coating result.If the super-saturation is lower, Al(OH)3 film can be obtained,otherwi se,dissociative Al(OH)3 particles can be acquired.