^(29)Si(^(27)Al)MAS NMR考察镧离子在LaDAlY型沸石中的作用

Investigation of the Role of Lanthanum Ions in LaDAlY Zeolites with ^(29)Si, ^(27)Al MAS NMR

用^(29)Si(^(27)Al)MAS NMR和辅加乙酰丙酮(acac)处理样品的静态^(27)Al NMR研究了镧离子对脱铝Y型沸石(DAIY)骨架硅、铝和非骨架铝(EFAL)的影响.结果表明,^(29)Si MAS谱的化学位移及其形状不仅取决于连接[SiO_4]四面体的[AlO]-四面体数目,而且还与引入镧离子的量有关.镧离子的引入导致^(27)Al MAS谱的明显宽化和不对称形变.另外,还讨论了镧离子对非骨架铝的影响.

The influence of lanthanum ions on the framework silicon, aluminum and extra-framework aluminum of LaDAlY zeolites has been studied by using 29Si, 27A1 MAS NMR and static 27Al NMR with acetylacetone treatment. The results show that the chemical shifts and peak profile depend not only on the number of [AlO4]- tetrahedra connected to [SiO4] tetrahedra, but also on the amount of exchanged lanthanum ions. It was also found from 27Al MAS NMR that the introduction of lanthanum ion makes the peak profile of framework aluminum broadening and asymmetrical. In addition, the effect of lanthanum ions on extra-framework aluminum in LaDAlY zeolites was discussed.