摘要
用TiCl_4,AlCl_3混胶法制备了TiO_2/γ-Al_2O_3负载型载体。发现该载体具有优良的孔结构。XRD,XPS的研究发现,随着TiO_2负载量的增加,TiO_2/γ-Al_2O_3负载型载体存在着四种分散状态和表面结构。ISS实验还发现γ-Al_2O_3表面的能量中心是不均匀的,有强位作用中心和弱位作用中心,TiO_2在γ-Al_2O_3表面上分散总是优先结合在强位作用中心上。TEM的研究发现TiO_2/γ-Al_2O_3载体具有两种微观结构。
Supported TiO2/y-Al2O3 samples with different TiO2 contents wtre prepared with TiCl4 and A1C13 in a mixcdiy gelatinized way. All of the samples show quite good pore structure, i.e. specific surface area about 210m2/g, pore volume about 0.45ml/g. The distribution of ore diameter for a typical sample (0.20 g TiO2/g r-Al2O3) concentrates to 45-70 A. The surface state of the supported samples was characterized by XRD, XPS, ISS, TEM and some other techniques. The results show that there are four different surface states in different regions with different TiO2 loadings. And the surface of y-Al2O3 which is heterogeneous in energy shows two kinds of active site, one of them is quite strong and the other is weaker. TiO2 combines with strong sites preferably resulting in four different surface states. TEM demonstrates two kinds of texture on samples with different TiO2 contents.
