Studies on the solid-state ion exchange of nickel ions into zeolites using DRS technique

The coordination of Ni2þ ions in the dehydrated nickel-exchanged zeolites was investigated from the analysis of diffuse reflectance spectra. Solid-state ion exchange method was used to prepare nickel-containing mordenite, Y, L and mazzite zeolites. In the dehydrated mordenite and zeolite Y, nickel cations are presented in both forms of tetrahedral and distorted tetrahedral symmetries. The relative amount of tetrahedral and distorted tetrahedral nickel species are related to the heating temperature and heating time used for calcinations. In the dehydrated zeolite L and mazzite, Ni2þ ions are mainly in the distorted octahedral symmetries. q 2004 Elsevier B.V. All rights reserved