Structural and acid/base properties of supported europium oxides

Journal Article · Wed Feb 22 23:00:00 EST 1995 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100008a022· OSTI ID:6766153

Shen, J ^[1]; Lochhead, M J; Bray, K L; Dumesic, J A ^[2]; Chen, Y ^[3]

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1. Univ. of Wisconsin, Madison, WI (United States) Nanjing Univ. (China)
2. Univ. of Wisconsin, Madison, WI (United States)
3. Nanjing Univ. (China)

Microcalorimetric and infrared spectroscopy studies of ammonia and carbon dioxide adsorption were carried out to investigate the number, strength, and type of acid/base sites of europium oxide supported on [gamma]-Al[sub 2]O[sub 3] and SiO[sub 2]. X-ray diffraction, luminescence spectroscopy, and Mossbauer spectroscopy were used to characterize the structure, bonding, and valence of the europium atoms. Europium oxide neutralizes acid sites on [gamma]-Al[sub 2]O[sub 3], lowering the initial heat of ammonia adsorption from 155 to 120 kJ/mol. Both Lewis and Bronsted acid sites exist on Eu[sub 2]O[sub 3]/Al[sub 2]O[sub 3] samples, with Lewis acid sites in dominance. Europium oxide increases the number and strength of base sites on [gamma]-Al[sub 2]O[sub 3], with the initial heat of carbon dioxide adsorption increasing from 145 to 160 kJ/mol. Surface hydroxyl groups and oxygen anions are responsible for base sites on the Eu[sub 2]O[sub 3]/[gamma]-Al[sub 2]O[sub 3] samples. The addition of europium oxide to SiO[sub 2] increases the number and strength of acid sites, with the initial heat for ammonia adsorption increasing from 85 to 125 kJ/mol. Europium oxide on silica shows few basic sites. Luminescence spectra show that Eu[sup 3+] ions occupy a range of dissimilar bonding sites on both supports. 31 refs., 13 figs., 1 tab.

• OSTI ID: 6766153
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 99:8; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400201* -- Chemical & Physicochemical Properties
ADSORPTION
AMMONIA
CALORIMETRY
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CATALYST SUPPORTS
CATALYSTS
CHALCOGENIDES
COHERENT SCATTERING
DIFFRACTION
EMISSION SPECTRA
EMISSION SPECTROSCOPY
EUROPIUM COMPOUNDS
EUROPIUM OXIDES
FLUORESCENCE SPECTROSCOPY
HYDRIDES
HYDROGEN COMPOUNDS
LUMINESCENCE
MICROANALYSIS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
OXIDES
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
SCATTERING
SORPTION
SORPTIVE PROPERTIES
SPECTRA
SPECTROSCOPY
SURFACE PROPERTIES
X-RAY DIFFRACTION