Raman spectroscopic investigation of the effect of H/sub 2/O on the molybdenum surface species in MoO/sub 3//Al/sub 2/O/sub 3/ catalysts
The Raman spectroscopic characterization of a set of MoO/sub 3//Al/sub 2/O/sub 3/ catalysts containing 3 to 25 wt% MoO/sub 3/ is presented. Controlled atmosphere measurements show that the Raman spectra of these catalysts are influenced drastically by the water content of the samples. Catalysts calcined in O/sub 2/ at 500/sup 0/ have spectra very different from previously reported spectra. The Mo=O stretching vibration is at about 1000 cm/sup -1/ in calcined samples, whereas in H/sub 2/O-exposed samples the frequency is near 950 cm/sup -1/. The position of the Mo=O stretching vibration is shown by repeated H/sub 2/O exposure, O/sub 2/ calcination cycles to be reversible between 950 and 1000 cm/sup -1/. Models for the interaction of H/sub 2/O with the surface molybdate species are presented and discussed with respect to the Raman data. 22 references, 6 figures.
- Research Organization:
- Pittsburgh Energy Technology Center, PA
- OSTI ID:
- 5937308
- Journal Information:
- J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 90; ISSN JCTLA
- Country of Publication:
- United States
- Language:
- English
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ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CATALYST SUPPORTS
CATALYSTS
CHALCOGENIDES
DATA
EXPERIMENTAL DATA
HYDROGEN COMPOUNDS
INFORMATION
MOLYBDENUM COMPOUNDS
MOLYBDENUM OXIDES
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
RAMAN SPECTRA
REFRACTORY METAL COMPOUNDS
SPECTRA
TRANSITION ELEMENT COMPOUNDS
WATER