Hydrated rare-earth-metal ion-exchanged zeolite a: characterization by luminescence spectroscopy. Part 2.—The Eu3+ ion

Abstract

The luminescence properties of hydrated Eu³⁺-exchanged zeolite A at 4.2 K are reported. The luminescence spectra indicate that the Eu³⁺ ions in the zeolite cages are, unlike Eu³⁺ ions in hydrated zeolite Y, bound to framework oxygens. High-resolution measurements suggest that Eu³⁺ ions are located in two sites in the zeolite samples. The results confirm the conclusions from a previous study on the equivalent Gd³⁺-exchanged system. Information on the water coordination numbers of the Eu³⁺ ions in the zeolite samples is obtained from luminescence lifetime measurements on H₂O- and D₂O-containing samples. The possibility of using luminescence spectroscopy of Eu³⁺ to characterize the coordination of rare-earth-metal ions in zeolites is evaluated.