SITE-SELECTIVE LINE BROADENING IN MAGIC-ANGLE-SPINNING SI-29 NMR OF CUX ZEOLITE

Abstract

The effect of a paramagnetic Cu2+ ion exchange on NMR line broadening was examined by using magic angle spinning Si-29 NMR spectroscopy. The NMR spectrum showed very selective, local line broadening effects for the Si atoms in the SiO4 framework units, onto which the Cu2+ is thought to be exchanged. This effect was used to investigate the local ion-exchange site selectivity of Cu2+ over Na+, Zn2+, Y3+, and Ag+ in X zeolites.