Spectroscopic study of the surface of zeolite Y. Part 4.—Infra-red studies of structural hydroxyl groups and adsorbed water on some transition metal ion-exchanged zeolites

Abstract

Infra-red spectra of transition metal cation zeolites have been observed during dehydration and subsequent rehydration at various temperatures. Structural silanol groups analogous to those observed on hydrogen Y zeolite are observed as well as hydroxyl groups specific to the exchanged cations. There appears to be no relationship between the physical properties of the cations and the hydroxyl group frequencies. Rehydration of the 500°C dehydrated zeolites results in a strong absorption band near 3680 cm^–1 due to adsorbed water associated with the cations. For copper and silver, evacuation at elevated temperature simply removed the water, whereas for the other cations studied dissociation of the water occurred and structural hydroxyl groups were formed.