Study of Cu/sup 2 +/-doped zeolite NaH-ZSM-5 by electron spin resonance and electron spin echo modulation spectroscopies
Zeolite NaH-ZSM-5 doped with Cu/sup 2 +/ cations is studied by electron spin resonance (ESR) and electron spin echo modulation (ESEM) spectroscopies. It is found that in the hydrated zeolite the Cu/sup 2 +/ is octahedrally coordinated to six water molecules with the complex located at the intersection between two zeolitic channels. Evacuation at room temperature is sufficient to remove three of these water molecules, leaving the Cu/sup 2 +/ coordinated to three water molecules and anchored to the zeolite lattice by coordination of zeolitic oxygen. Activation to 400/sup 0/C produces one Cu/sup 2 +/ species which is either recessed from or inaccessible to the main channels. Adsorption of polar molecules such as water, ammonia, pyridine, and alcohols causes the rapid migration of the Cu/sup 2 +/ into cation positions in the main channels. The Cu/sup 2 +/ forms complexes with two molecules of methanol, three of ethanol, three of pyridine, and four of ammonia. From the lack of /sup 27/Al modulation in the ESEM spectra it is postulated that the Cu/sup 2 +/ cations are not preferentially located adjacent to the negatively charged AlO/sub 2//sup -/ lattice units.
- Research Organization:
- Univ. of Houston, TX
- OSTI ID:
- 6389177
- Journal Information:
- J. Phys. Chem.; (United States), Vol. 91:15
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
54 ENVIRONMENTAL SCIENCES
COPPER COMPOUNDS
MOLECULAR STRUCTURE
ZEOLITES
ACOUSTIC ESR
CATIONS
DOPED MATERIALS
ELECTRON SPIN RESONANCE
EXPERIMENTAL DATA
HYDRATES
CHARGED PARTICLES
DATA
INFORMATION
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
IONS
MAGNETIC RESONANCE
MATERIALS
MINERALS
NUMERICAL DATA
RESONANCE
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties
500200 - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)