一种合成六方板状Zr-Ce-SBA-15介孔材料的新方法

A Novel Method for Synthesis of Zr-Ce-SBA-15 Mesoporous Materials with Hexagonal-platelet Morphology

以P123为模板剂,正硅酸乙酯为硅源,氯化氧锆和硝酸亚铈为无机前驱盐,在不外加无机酸的条件下,利用无机前驱盐自身水解产生的弱酸性环境,通过水热合成路线一步合成了具有大的径轴比、短孔道、六方板状形貌的Zr-Ce-SBA-15介孔材料.利用粉末X射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、电感耦合等离子体原子发射光谱(ICP-AES)和氮气吸附等手段对所合成的样品进行了表征.结果表明,合成的材料具有类似于SBA-15的二维六方介孔结构,孔径、孔容和比表面积分别为5.6nm,0.96cm3/g和776m2/g.与常规SBA-15相比,这种短孔道、大径轴比的六方板状介孔材料在吸附、分离及催化等领域中能更有效地促进分子的扩散传递.

Highly ordered mesoporous Zr-Ce-SBA-15 silica with hexagonal-platelet morphology was synthesized through a hydrothermal route by using pluronic P123 as a template, tetraethyl orthosilicate as a silica source, zirconyl chloride and cerous nitrate as a precursor. The main strategy of this method was to utilize the acidity self-generated from the hydrolysis of inorganic salts in the aqueous solutions, where no addition of mineral acids was necessary. The as-synthesized materials were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, inductively coupled plasma atomic emission spectrometry （ICP-AES） and N2 adsorption. Characterization reveals that the Zr-Ce-SBA-15 possesses a 2D hexagonal mesoporous structure similar to SBA-15. The average pore size, pore volume and specific surface area of the materials is 5.58 nm, 0.96 cm^3/g and 776 m^2/g, respectively. The hexagonal-platelet Zr-Ce-SBA-15 materials were superior to the conventional SBA-15 of rod or fiber morphology in facilitating molecular diffusion when they were used in the adsorption, separation and catalysis processes.