【摘要】 在表面活性剂浓度很低(n(CTAB)/n(SiO2)=0.05,n(CTAB)/n(H2O)=8.3×10-4)的合成体系中,从具有β沸石次级结构单元的溶胶前驱体出发,在碱性条件下合成了高度规整六方排列的介孔分子筛。采用XRD、N2吸附-脱附、FT-IR、HRTEM、DTG、NMR和水热处理等手段,表征了样品的结构特征和性能。结果表明,以低浓度表面活性剂为模板,可以得到孔壁含β沸石次级结构单元的高度有序的介孔分子筛;铝元素主要以四配位状态存在于介孔分子筛骨架中。与普通MCM-41相比,此法合成的样品呈现较高的水热稳定性,主要是由于沸石次级结构单元进入分子筛孔壁,提高了骨架的聚合度和孔壁的厚度。更多还原

【Abstract】 Mesoporous molecular sieves with the structure of MCM-41 have been synthesized in alkaline situation,by using the cationic surfactants of low concentration（n（CTAB）/n（SiO₂）=0.05,n（CTAB）/n（H₂O）=8.3×10（-4）） as template and the gel contaning secondary building units of β zeolite as precursors.The ordered mesoporous materials were characterized by XRD,N₂ adsorption and desorption,FT-IR,HRTEM,DTG,NMR and hytrothermal treatment methods.The results indicated that the samples had ordered hexagonal structure with β zeolite secondary units in its pore walls,which are thicker than the walls of MCM-41 synthesized by normal hydrothermal ways.The synthesized materials were superior to conventional MCM-41 with respect to their higher hydrothermal stability.The retention of zeolite-like connectivity of tetrahedral AlO₄ and SiO₄ units upon assembling the nanoclusters into mesostructured materials and thicker framework pore walls contributed to the good hydrothermal stability greatly.更多还原