系列硅铝比纳米薄层ZSM-5分子筛的合成和表征

Synthesis and Characterization of Nanosheet ZSM-5 Zeolites with Different SiO_2/Al_2O_3 Molar Ratios

以自制不对称双子季铵盐表面活性剂为模板, 在水热合成体系中控制合成系列硅铝比纳米薄层ZSM-5分子筛.采用X射线衍射（XRD）、N2吸附-脱附、X射线荧光光谱（XRF）、扫描电镜（SEM）和27Al魔角旋转核磁共振（27Al MAS-NMR）对合成的样品进行了表征. 详细研究了晶化温度、晶化时间、结构导向剂（SDA）用量、碱度等对合成的影响和纳米薄层ZSM-5分子筛的形成过程. 结果表明： 分子筛硅铝比越高, 结构导向剂用量越大, 所需的晶化时间越短; 晶化温度越高, 晶化时间越短; 且不同硅铝比纳米薄层ZSM-5分子筛的形貌规整度、比表面积和介孔/微孔孔容比例随着硅铝比而变化.

Nanosheet ZSM-5 zeolites with different SiO2/Al2O3 molar ratios have been hydrothermally synthesized by an organic surfactant with a diquaternary ammoniumgroup. The samples were characterized by X-ray diffraction （XRD）, N2 adsorption-desorption, X-ray fluorescence spectroscopy （XRF）, scanning electron microscopy （SEM） and 27Al magic angle spinning nuclear magnetic resonance （27Al MAS-NMR） techniques. The synthesis conditions of the nanosheets ZSM-5 were studied, including the synthesis factors such as crystallization temperature and time, the amount of structure-directing agent （SDA） and alkalinity. The results showed that shorter crystallization times were required when synthesis was conducted at higher crystallization temperatures, higher SiO2/Al2O3 ratios, larger amounts of structure-directing agent were used, and higher SiO2/Al2O3 ratios. The morphology, BET and mesopore volume changed with increasing SiO2/Al2O3.