ISSN:
1572-879X
Keywords:
Vanadium oxide catalyst
;
mixed oxide supports
;
ESR spectroscopy
;
Raman spectroscopy
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract ESR and Raman spectroscopy have been used to characterize monolayers of vanadia, which had been immobilized on titania and on a 20% TiO2/80% SiO2 mixed oxide support from a vanadyl alkoxide precursor. Characteristic vibrations observed in the Raman spectrum, as well as UV-visible reflection data, indicate that the most abundant vanadia species on the surface consists of disordered polymeric arrays: the central vanadium ion is surrounded by the tightly bound vanadyl oxygen, four oxygen ions in the basal plane, and a distant sixth oxygen ligand in bridging position to the support. From the ESR spectra the principal values ofg andA tensors are obtained, and their dependence on the support material and on the vanadia loading is investigated. Comparison with TPR measurements indicates that for structurally and chemically similar catalysts, the ESR-derived deviationΔg⊥ = g⊥ − g e from the free electrong value provides a useful measure of the V=O bond strength.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00765318
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