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Fourier-transform infrared/photoacoustic study of pyridine adsorbed on silica supported copper-molybdenum catalysts
Spectrochimica Acta, Vol. 51A, No. 1, pp. 1-9, 1995 • 1995
Publication Information
Authors
MOHAMED MOKHTAR MOHAMED
Keywords
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Journal
Spectrochimica Acta, Vol. 51A, No. 1, pp. 1-9, 1995
Publisher
Elsevier
Volume
Not Available
Issue
Not Available
Pages
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publication.type
International
Paper Link
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Supplementary Materials
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Abstract
Pyridine adsorption is used to study the acidic sites of silica-supported CuO-MoO 3 catalysts, with
reference to CuO/SiO2 and MoO3/SiO2 catalysts. At low wt% of copper, both Lewis and Bronsted acid sites
are present on the CuO-MoO3/SiO2 surface. A substantial decrease and then vanishing of the Bronsted acidity
is obtained as a result of increasing the copper loading. An approach confining the prevalence of Lewis acidity
over the Bronsted ones is described and discussed. A new band of Lewis acidity is observed at 1574 cm -1 and
attributed to the presence of CuMoO4 species. This band is not observed in the individual oxide form of both
CuO/SiO2 and MoO3/SiO2 catalysts. Carbon monoxide adsorption on CuO-MoO3/SiO 2 catalysts reflects a
major dispersion if it is compared with CuO/SiO: and MoO3/SiO~ catalysts and also gives a picture about the
expected structures of these supported oxide catalysts. Copper is found also to exert a major control on the
mode of interaction of molybdenum species with the silica surface. Moreover, important correlations and shifts
in the IR bands are evaluated and discussed.
reference to CuO/SiO2 and MoO3/SiO2 catalysts. At low wt% of copper, both Lewis and Bronsted acid sites
are present on the CuO-MoO3/SiO2 surface. A substantial decrease and then vanishing of the Bronsted acidity
is obtained as a result of increasing the copper loading. An approach confining the prevalence of Lewis acidity
over the Bronsted ones is described and discussed. A new band of Lewis acidity is observed at 1574 cm -1 and
attributed to the presence of CuMoO4 species. This band is not observed in the individual oxide form of both
CuO/SiO2 and MoO3/SiO2 catalysts. Carbon monoxide adsorption on CuO-MoO3/SiO 2 catalysts reflects a
major dispersion if it is compared with CuO/SiO: and MoO3/SiO~ catalysts and also gives a picture about the
expected structures of these supported oxide catalysts. Copper is found also to exert a major control on the
mode of interaction of molybdenum species with the silica surface. Moreover, important correlations and shifts
in the IR bands are evaluated and discussed.