Al掺杂对硅基介孔材料MCM-41结构的影响

Effects of Al Isomorphous Substitution on the Structure of Silica MCM-41

以水玻璃为硅源,在无压体系中合成含Al的硅基MCM-41,并采用XRD、TEM、27Al MASNMR及N2吸附-脱附等表征手段,系统研究Al的引入对MCM-41结构的影响。研究结果表明:Al原子对MCM-41骨架Si进行同晶取代后,Al以四配位骨架和六配位骨架外Al的形式存在,Al-MCM-41仍能保持长程有序的一维孔道结构。并且随着Al掺杂量的增加,孔径和孔体积减小,当Si/Al=25时比表面积达最高值。

A1-MCM-41 mesoporous material was prepared by using water-glass as the silicon source in an open-vessel. The effects of doping with A1 on the structure of silica mesoporous material have been researched. XRD, TEM, 27A1 MAS NMR and nitrogen adsorption-desorption isotherms have been employed to characterize the specimens. It has been found that the mesoporous still remains the well-ordered mesostructure after doping with A1 and AI atoms have been inserted into the framework of MCM-41. N2 adsorption-desorption isotherms confirmed that the pore diameter and pore volume were decreased with the increasing of AI. Its specific surface area was increased to maximum when the ratio of Si/A1 is 25.