TiO_2-Al_2O_3复合载体的比较研究

The Comparative Study on TiO_2-Al_2O_3 Composites

对用混胶法和共沉淀法分别制备的TiO2－Al2O3复合载体（TiO2含量为0．08g／gγ－Al2O3）进行了对比研究，采用的表征方法有XRD，XPS，LRS等，得出的结论如下：两种载体均保持了γ－Al2O3的骨架结构，但TiO2的分散状态不尽相同．混胶样品中TiO2主要以表面富集的形式分散在γ－Al2O3表面，这有利于集二者的优点于一体；共沉淀样品中TiO2趋于整个体相均匀分散，这有利于相互作用后形成新的性能．

TiO2-Al2O3 composites (TiO2 content is 0.08gTiO2/gAl2O3) were prepared by two methods: mixing gel and coprecipitation, and characterized by XRD, XPS, and LRS. The results show that γ-Al2O3 is the only species of crystal to be identified by XRD for both samples treated at 550℃ for 5 hours, but the forms of TiO2 are different. TiO2 is dispersed on the surface for the sample by mixing gel. As to the composite by copre cipitation, TiO2 is dispersed so well in the bulk that it is difficult to be detected by XRD or LRS.