有序介孔La_2Zr_2O_7的制备与表征

Preparation and Characterization of Ordered Mesoporous La_2Zr_2O_7

以F127作为模板剂,通过溶剂蒸发诱导自组装法合成了具有有序孔结构、孔径分布均匀的介孔锆酸镧,系统研究了不同煅烧温度处理后介孔锆酸镧的相组成、比表面积、孔径及其分布以及微观结构。结果表明,经800℃处理后,样品开始晶化,完全晶化的样品中仅含锆酸镧相。经600℃煅烧后样品的比表面积为136 m2/g,孔体积为0.14 cm3/g,800℃煅烧后比表面积仍达90 m2/g,显示出较好的热稳定性。随着煅烧温度进一步升高,样品的比表面积和孔体积急剧减小,表明该方法制备的介孔锆酸镧最高耐热温度为800℃。透射电子显微镜观察发现,400℃去除模板后,样品具有有序介孔结构,预期其具有较好的催化性能。

The ordered mesoporous lanthanum zirconate was synthesized by an evaporation induced self-assembly(EISA) method with F127 as a template.The structure and textural properties were investigated.The results show that the crystallization temperature of the as-obtained powder is 800 ℃,and there is only lanthanum zirconate phase found in the well crystallized samples.The specific surface area and pore volume of the samples calcined at 600 ℃ are 136 m2/g and 0.14 cm3/g,respectively,and the specific surface area of the sample calcined at 800 ℃ is still 90 m2/g.The specific surface area and the pore volume of the samples decrease dramatically with further increasing the calcination temperature,indicating the optimum temperature at which the mesoporous lanthanum zirconate can be resist is 800 ℃.According to the images of transmission electron microscopy,the ordered mesopores appear after the removal of the template,giving the better catalytic properties.