17O MAs and 3QMAS NMR investigation of crystalline V2O5 and layered V2O5·nH2O gels

Craig J. Fontenot, Jerzy W. Wiench, Glenn L. Schrader, Marek Pruski

Research output: Contribution to journalArticlepeer-review

37 Scopus citations

Abstract

The environments for oxygen sites in crystalline V2O5 and in layered vanadia gels produced via sol-gel synthesis have been investigated using 17O MAS and 3QMAS NMR. For crystalline V2O5, three structural oxygen sites were observed: V=O (vanadyl), V2O (doubly coordinated), and V3O (triply coordinated). Line-shape parameters for these sites were determined from numerical simulations of the MAS spectra. For the vanadia gels at various stages of dehydration, assignments have been proposed for numerous vanadyl, doubly coordinated, and triply coordinated oxygen sites. In addition, by correlating the 17O MAS and 3QMAS NMR, 51V MAS NMR, and thermogravimetric analysis data, the coordination of water sites has been established. On the basis of these results, the gel structure and its evolution at various stages of hydration have been detailed. Upon rehydration of the layered gel, we observed a preferred site for initial water readsorption. The oxygen atoms of these readsorbed water molecules readily exchanged into all types of oxygen sites even at room temperature.

Original languageEnglish (US)
Pages (from-to)8435-8444
Number of pages10
JournalJournal of the American Chemical Society
Volume124
Issue number28
DOIs
StatePublished - Jul 17 2002

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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