TiO_2在Al_2O_3表面上分散状态的AEM研究

STUDIES ON TiO_2 DISTRIBUTION OVER Al_2O_3 BY AEM

本文运用AEM方法考察了制备技术对TiO_2在Al_2O_3表面分散状态的影响.发现嫁接法可使TiO_2非常均匀地分散在Al_2O_3表面上,浸渍法也能得到较为均匀的TiO_2分布,而沉淀法所得到的TiO_2分散度较差.TiO_3只聚集在Al_20_3表面上的局部区域。

TiO_2-Al_2O_3 binary oxides were prepared by precipitation from TiCl_4 solution withaqueous ammonia; impregnation, using evaporation from titanium isoproxide in iso-propanol; and grafting, using reaction of TiCl_4 vapour with OH^- group on Al_2O_3surface. AEM was used to examine the morphology of TiO_2 on Al_2O_3. The results showthat relative homogeneous distribution of TiO_2 on Al_2O_3 could be formed for im-pregnated samples when TiO_2 loading was not beyond one monolayer. A quite homo-geneous coverage of TiO_2 was obtained for grafting samples through anchoring ofTiCl_4 molecule on OH^- group of Al_2O_3 surface. As for precipitated samples thedistribution of TiO_2 was rather poor. TiO_2 covered only a part of Al_2O_3 surface.