【摘要】 以低浓度的十六烷基三甲基溴化铵为结构导向剂,在碱性条件下通过水热法合成了具有立方结构的含钇Y MCM 48介孔分子筛材料。XRD测试表明当Y/Si<0.05时可以获得典型的长程有序介孔立方结构相,随Y/Si比的增加,晶胞参数的增大和红外吸收光谱(FTIR)的变化为Y进入介孔分子筛骨架中提供了有力证据。N2吸附-脱附实验给出这种立方介孔材料的BET表面积为1180m2·g-1,BJH平均孔径为3.4nm。紫外 可见漫反射光谱(UV vis)证明钇以一种六配位的形式存在。X射线光电子能谱(XPS)进一步证明钇以三价形式存在于立方介孔分子筛骨架中。更多还原

【Abstract】 The cubic yttrium-modified MCM-48 molecular sieves were synthesized via a hydrothermal method using CTAB as template with low surfactant to inorganic precursor ratios in the alkaline condition. The X-ray diffraction indicates that the well-ordered cubic mesoporous structure was obtained when the Y/Si molar ratio is less than 0.05. With the increase of Y/Si molar ratio, the increase of unit cell parameters and the change of FTIR provide powerful evidences for the incorporation of yttrium in the framework of mesoporous molecular sieves. Nitrogen adsorption suggests the BET surface area is 1180 m²·g^-1 and that the average pore diameter is 3.4 nm. Diffuse reflectance UV-visible （UV-vis） spectroscopy confirms that the presence of yttrium is six coordinating. X-ray photoelectron spectroscopy （XPS） studies reveal that yttrium is trivalent in the framework of mesoporous molecular sieves.更多还原