TiO_2载体表面酸性的研究

Studies of the Surface Acidity of TiO_2 Carriers

利用NH_3吸附和吡啶吸附红外技术研究TiO_2的制备条件对其表面酸性的影响。结果表明,用NH_3水中和TiCl_4溶液方法制备的TiO_2(A)表面有较强的L酸中心,中和条件对表面酸性中心数目和强度有显著影响。由TiOSO_4水解方法制备的TiO_2(B)表面具有较强的L酸中心和较弱的B酸中心,引入不同添加剂可有效地调变TiO_2载体表面的酸性。

The effect of preparation technique on the surface acidity of TiO_2 carrier was studied by NH_3-TPD and infrared spectroscopy of pyridine adsorption. The results show that: (1) TiO_2(A) prepared by neutralizing TiCl_4 solution with ammonia water exhibits a Lewis acid site, and its strength and amount are obviously influenced by preparation conditions. (2) TiO_2(B) prepared by hydrolysis of TiOSO_4 has strong Lewis and weak Bronsted acid sites. The introduction of K, Mg, Zn, Ca, Al and Si can effectively modify the surface acidity of TiO_2.