超声溶胶-凝胶法制备强酸性介孔材料

Synthesis of Strong Acidic Mesoporous Materials by Ultrasonic Sol-Gel Method

在不使用有机模板剂和孔调节剂的情况下,以无机盐为原料制备了锆和钛修饰的硅铝介孔材料及担载铂的电子-酸性双功能介孔材料.激光粒度仪和N2吸附-脱附等温线表征的结果显示,制备方法对溶胶的粒度分布和材料的结构性质有较大的影响.吡啶吸附-脱附的红外光谱表明所得材料具有强的表面酸性,利用XPS和H2-TPR等表征手段确定了材料强表面酸性的来源.1-己烯加氢异构反应表明所合成的材料具有良好的催化活性.

Mesoporous materials with large pore size are much in demand for the reactions involving large molecules. However, their applications are limited by the weak acidity as compared with that of microporous zeolites. In this paper, a novel method was developed to synthesize strong acidic mesoporous materials. Cheap in- organic salts were used to synthesize Zr- and Ti-modified silica-alumina mesoporous materials and supported Pt electron-acid bifunctional mesoporous materials by ultrasonic sol-gel method without any types of templates or pore-regulating agents. The samples were characterized by pyridine adsorption and desorption, IR spectroscopy, XPS and H2-TPR. Their catalytic performance was evaluated by using hydroisomerization reaction of 1-hexene. Pyridine adsorption-desorption and IR spectroscopy indicate that these samples have strong surface acidity. The XPS and H2-TPR results suggest that the interactions between platinum and the supports exist in the samples. Hydroisomerization reaction of 1-hexene shows that the samples have high catalytic activity. It is concluded that their strong surface acidity results from the interactions between metal and the supports.