Please use this identifier to cite or link to this item: doi:10.22028/D291-24272
Title: V2O5/TiO2 catalytic xerogels raman and EPR studies
Author(s): Rodella, Cristiane B.
Franco, Roberto W. A.
Magon, Claudio J.
Donoso, Jose P.
Nunes, Luis A. O.
Saeki, Margarida J.
Aegerter, Michel A.
Sargentelli, Vagner
Florentino, Ariovaldo O.
Language: English
Year of Publication: 2002
OPUS Source: Journal of sol-gel science and technology. - 25. 2002, S. 83-88
SWD key words: Katalysator
DDC notations: 620 Engineering and machine engineering
Publikation type: Journal Article
Abstract: Raman spectroscopy and electron paramagnetic resonance (EPR) studies were performed on a series of V2O5/TiO2 catalysts prepared by a modified sol-gel method in order to identify the vanadium species. Two species of surface vanadium were identified by Raman measurements, monomeric vanadyls and polymeric vanadates. Monomeric vanadyls are characterized by a narrow Raman band at 1030 cm-1 and polymeric vanadates by two broad bands in the region from 900 to 960 cm-1. The Raman spectra do not exhibit characteristic peaks of crystalline V2O5. These results are in agreement with those of X-ray diffractometry (XRD) and Fourier Transform Infrared (FT-IR) previously reported (C.B. Rodella et al., J. Sol-Ge. Sci. Techn., submitted). at least tree families of V4+ ions were identified by EPR investigations. The analysis of the EPR spectra suggests that isolated V4+ ions are located in sites with octahedral symmetry substituting for Ti4+ ions in the rutile structure. Magnetically interacting V4+ ions are also present as pairs of clusters giving rise to a broad and structureless EPR line. At higher concentration of V2O5, a partial oxidation of V4+ to V5+ is apparent from the EPR results.
Link to this record: urn:nbn:de:bsz:291-scidok-25172
Date of registration: 15-Dec-2009
Faculty: SE - Sonstige Einrichtungen
Department: SE - INM Leibniz-Institut für Neue Materialien
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