Oxidation states of europium in zeolites. [Thermolytically dissociating water by using europium-exchanged zeolites]
Journal Article
·
· Inorg. Chem.; (United States)
Rare-earth metal ions have proven to be particularly useful in zeolite catalysis, both as stabilizing ions and by virtue of their redox chemistry. In the research reported here, the europium Moessbauer spectra of hydrated and dehydrated euorpium-exchanged zeolites A, Y, and ZSM-5 have been studied. Eu(OH)/sub 2/.H/sub 2/O, used to ion exchange Eu/sup 2 +/ into the zeolites, immediately oxidizes to an Eu/sup 3 +/ complex in a deoxygenated aqueous solution. This same reaction occurs in the solid state for Eu(OH)/sub 2/.H/sub 2/O. An investigation into the role of europium in the thermolytic decomposition of water has been made, and the redox changes from the 3+ to the 2+ oxidation states of europium in zeolites Y and ZSM-5 have been confirmed by EPR. The Moessbauer isomer shifts are sufficiently sensitive to detect the difference in the chemical environment of Eu/sup 3 +/ as a consequence of oxidation by chlorine and oxygen. No evidence of Eu/sup 4 +/ has been found in an isomer shift range of +- 35 mm/s. Metal ions produced by dissolving europium metal in liquid ammonia can be exchanged into the zeolites to give an Eu/sup 2 +/ species as indicated by Moessbauer spectroscopy.
- OSTI ID:
- 6721668
- Journal Information:
- Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 19; ISSN INOCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
08 HYDROGEN
080100 -- Hydrogen-- Production
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AMMONIA
CATALYSTS
CHEMICAL REACTIONS
ELECTRON SPIN RESONANCE
ELEMENTS
EUROPIUM
EUROPIUM COMPOUNDS
HYDRATION
HYDRIDES
HYDROGEN COMPOUNDS
HYDROGEN PRODUCTION
INORGANIC ION EXCHANGERS
ION EXCHANGE
ION EXCHANGE MATERIALS
MAGNETIC RESONANCE
MATERIALS
METALS
MINERALS
MOESSBAUER EFFECT
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
RARE EARTHS
REDOX REACTIONS
RESONANCE
SOLVATION
SPECTRA
VALENCE
WATER
ZEOLITES
080100 -- Hydrogen-- Production
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AMMONIA
CATALYSTS
CHEMICAL REACTIONS
ELECTRON SPIN RESONANCE
ELEMENTS
EUROPIUM
EUROPIUM COMPOUNDS
HYDRATION
HYDRIDES
HYDROGEN COMPOUNDS
HYDROGEN PRODUCTION
INORGANIC ION EXCHANGERS
ION EXCHANGE
ION EXCHANGE MATERIALS
MAGNETIC RESONANCE
MATERIALS
METALS
MINERALS
MOESSBAUER EFFECT
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
RARE EARTHS
REDOX REACTIONS
RESONANCE
SOLVATION
SPECTRA
VALENCE
WATER
ZEOLITES