An infared spectroscopy and temperature-programmed desorption study of CO on MoO[sub 3]/Al[sub 2]O[sub 3] catalysts: Quantitation of the molybdena overlayer

Journal Article · Thu Jan 14 04:00:00 EST 1993 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100104a032· OSTI ID:6341324

Diaz, A L; Bussell, M E ^[1]

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1. Western Washington Univ., Bellingham (United States)

The adsorption of CO on pure [gamma]-Al[sub 2]O[sub 3] and a series of MoO[sub 3]/Al[sub 2]O[sub 3] catalysts with different Mo loadings has been investigated using infrared (IR) spectroscopy and temperature-programmed desorption (TPD). Carbon monoxide adsorbs selectively on Al[sup 3+] sites on the uncovered, free alumina portion of the surface; these sites are created by dehydroxylation of the alumina. As the Mo loading is increased, the CO adsorption capacity of the catalysts decreases in a linear fashion as the MoO[sub 3] overlayer covers an increasing fraction of the alumina support. Overlayer growth saturates at a loading of (42[+-]3) [times] 10[sup 13] Mo atoms/cm[sup 2] and corresponds to less than a complete monolayer as 14 [+-] 5% of the alumina support remains uncovered. Extrapolation of the overlayer growth curve to monolayer coverage allows calculation of a MoO[sub 3] cross-sectional area of [approx]22[Angstrom][sup 2], in good agreement with values predicted by theoretical models. 37 refs., 11 figs.

• OSTI ID: 6341324
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 97:2; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ABSORPTION SPECTROSCOPY
ADSORPTION
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CHALCOGENIDES
DESORPTION
MOLYBDENUM COMPOUNDS
MOLYBDENUM OXIDES
OXIDES
OXYGEN COMPOUNDS
REFRACTORY METAL COMPOUNDS
SORPTION
SORPTIVE PROPERTIES
SPECTROSCOPY
SURFACE PROPERTIES
TRANSITION ELEMENT COMPOUNDS