【摘要】 以十六烷基三甲基溴化铵为结构导向剂,通过水热法合成了具有立方结构的含钕Nd鄄MCM鄄48介孔分子筛材料。XRD和TEM测试表明当nNd/nSi<0.05时可以获得典型的长程有序介孔立方结构相,随nNd/nSi比的增加,晶胞参数的增大和红外吸收光谱(FT鄄IR)的变化为Nd进入介孔分子筛骨架中提供了有力证据。N2吸附鄄脱附实验给出了其BET表面积为1195m2·g-1,BJH平均孔径为3.6nm。紫外鄄可见漫反射光谱(UV鄄Vis)证明钕氧形成一种八面体结构。X射线光电子能谱(XPS)进一步证明钕主要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 neodymium-modified MCM-48 molecular sieves were synthesized via a hydrothermal method using cethyltrimethylammonium bromide as template. The X-r ay diffraction and TEM indicate a well-ordered cubic mesoporous structure was ob tained when the Nd/Si molar ration was less than 0.05. With the increase of Nd/S i molar ration, the increase of unit cell parameters and the change of FT-IR pro vide powerful evidences for the incorporation of neodymium in the framework of m esoporous molecular sieves. Nitrogen adsorption-desorption suggests the BET surf ace area is 1 195 m2·g-1 and that the average pore diameter is 3.6 nm. Diffuse reflectance UV-Visible (UV-Vis) spectroscopy confirms the presence of neodymium in the octahedral position. X-ray photoelectron spectroscopy (XPS) studies furth er reveal that most of neodymium is trivalent in the framework of mesoporous mol ecular sieves.更多还原