Electron paramagnetic resonance spectroscopy studies of Eu-Y and coexchanged EuFe-Y zeolites

Journal Article · Tue May 01 00:00:00 EDT 1990 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(90)90168-J· OSTI ID:6437702

Ulla, M A; Millman, W S ^[1]; Aparicio, L A; Balse, V R; Dumesic, J A ^[2]

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1. Univ. of Wisconsin, Milwaukee (USA)
2. Univ. of Wisconsin, Madison (USA)

Electron paramagnetic resonance (EPR) was used to probe the oxidation state of europium and the location of divalent europium cations in Eu-Y and EuFe-Y zeolite samples. Europium was present as trivalent cations following treatment in O{sub 2} at 770 K. Treatments in H{sub 2} or CO at 770 K led to formation of divalent cations, and perhaps also caused some reduction to lower oxidation states. Three EPR signals were observed for Eu{sup 2+}, giving rise to effective g values of 3, 4.9, and 6. The first and last signals are interpreted as being due to Eu{sup 2+} cations at sites I and II, respectively, while the latter signal is due to Eu{sup 2+} cations at sites I{prime} and II{prime}. The majority of the Eu{sup 2+} cations are at site I, and the amount of Eu at this site can be increased by reducing the sample in H{sub 2}, compared with reduction in CO. The presence of europium in site I forces the Fe{sup 2+} cations to occupy sites of lower coordination in the sodalite unit (sites I{prime} and II{prime}) and in the supercages (sites II and III{prime}).

• OSTI ID: 6437702
• Journal Information: Journal of Catalysis; (USA), Vol. 123:1; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
EUROPIUM
VALENCE
IRON
ZEOLITES
SURFACE PROPERTIES
CARBON MONOXIDE
CATIONS
ELECTRON SPIN RESONANCE
HIGH TEMPERATURE
HYDROGEN
OXIDATION
OXYGEN
YTTRIUM
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL REACTIONS
ELEMENTS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
IONS
MAGNETIC RESONANCE
MATERIALS
METALS
MINERALS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
RARE EARTHS
RESONANCE
TRANSITION ELEMENTS
400201* - Chemical & Physicochemical Properties