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doi:10.22028/D291-24272
Titel: | V2O5/TiO2 catalytic xerogels raman and EPR studies |
VerfasserIn: | 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. |
Sprache: | Englisch |
Erscheinungsjahr: | 2002 |
Quelle: | Journal of sol-gel science and technology. - 25. 2002, S. 83-88 |
Kontrollierte Schlagwörter: | Katalysator Vanadium Vanadiumdioxid Titan Sol-Gel-Verfahren Elektronenspinresonanz Röntgendiffraktometrie FT-IR-Spektroskopie |
DDC-Sachgruppe: | 620 Ingenieurwissenschaften und Maschinenbau |
Dokumenttyp: | Journalartikel / Zeitschriftenartikel |
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 zu diesem Datensatz: | urn:nbn:de:bsz:291-scidok-25172 hdl:20.500.11880/24328 http://dx.doi.org/10.22028/D291-24272 |
Datum des Eintrags: | 15-Dez-2009 |
Fakultät: | SE - Sonstige Einrichtungen |
Fachrichtung: | SE - INM Leibniz-Institut für Neue Materialien |
Sammlung: | INM SciDok - Der Wissenschaftsserver der Universität des Saarlandes |
Dateien zu diesem Datensatz:
Datei | Beschreibung | Größe | Format | |
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aeg200204.pdf | 464,24 kB | Adobe PDF | Öffnen/Anzeigen |
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