FT-IR study of the surface properties of the spinels NiAl sub 2 O sub 4 and CoAl sub 2 O sub 4 in relation to those of transitional aluminas

Journal Article · Sun Sep 01 00:00:00 EDT 1991 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1016/0021-9517(91)90333-Y· OSTI ID:5731245

Busca, G; Lorenzelli, V; Escribano, V S; Guidetti, R ^[1]

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1. Univ. di Genova (Italy)

The surface chemistry of {delta}-Al{sub 2}O{sub 3}, NiAl{sub 2}O{sub 4}, and CoAl{sub 2}O{sub 4} has been investigated comparatively by FT-IR spectroscopy using adsorbed carbon monoxide and pyridine as probe molecules. The surface OHs of the inverse spinel NiAl{sub 2}O{sub 4} are different and resemble those of other normal spinels. Both carbon monoxide and pyridine adsorption provide evidence for the presence of tetrahedral Al{sup 3+} ions exposed on the surface of the inverse spinel NiAl{sub 2}O{sub 4}. On the normal spinel CoAl{sub 2}O{sub 4} octahedral Al{sup 3+} ions predominate with respect to the tetrahedral ones, also present because of partial inversion. Ni{sub 2+} and Co{sub 2+} ions are also detected on the respective surfaces. Slight modifications to the literature criteria are suggested for the assignments of the IR bands to surface OHs and of adsorbed pyridine on aluminas.

• OSTI ID: 5731245
• Journal Information: Journal of Catalysis; (United States), Vol. 131:1; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALUMINIUM OXIDES
SURFACE PROPERTIES
COBALT COMPOUNDS
NICKEL COMPOUNDS
SPINELS
ADSORPTION
ALUMINATES
CARBON MONOXIDE
CATALYSTS
FOURIER TRANSFORMATION
HETEROGENEOUS CATALYSIS
HYDROXYL RADICALS
INFRARED RADIATION
PYRIDINES
SPECTROSCOPY
ALUMINIUM COMPOUNDS
AZINES
CARBON COMPOUNDS
CARBON OXIDES
CATALYSIS
CHALCOGENIDES
ELECTROMAGNETIC RADIATION
HETEROCYCLIC COMPOUNDS
INTEGRAL TRANSFORMATIONS
MINERALS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
RADIATIONS
RADICALS
SORPTION
TRANSFORMATIONS
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties