Location and adsorbate interactions of copper(II) ion in Cu(II)-exchanged K-L zeolite by electron spin resonance and electron spin echo modulation spectroscopy

Abstract

The interaction of Cu(II) with deuterated adsorbates in Cu(II)-exchanged K-L channel-type zeolite was studied by electron spin resonance (ESR) and electron spin echo modulation (ESEM) spectroscopies. It was found that in the hydrated zeolite the major Cu(II) species is octahedrally coordinated to six water molecules with the complex located in the main channels. Evacuation at room temperature was sufficient to remove three of these water molecules, leaving the Cu(II) coordinated to three water molecules and anchored to the zeolite lattice by coordination to three zeolitic oxygens. A minor Cu(II) species was also detected with reverse g values characteristic of trigonal bipyramidal coordination