The effect of the framework structure on the chemical properties of the vanadium oxide species incorporated within zeolites

Masakazu Anpo, Shinya Higashimoto, Masaya Matsuoka, Nurbosyn Zhanpeisov, Yasushi Shioya, Stanislaw Dzwigaj, Michel Che

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)

Abstract

V-silicalite catalysts (VS-1 and VS-2) prepared by hydrothermal synthesis have been studied by ESR, XAFS (XANES and EXAFS) and photoluminescence spectroscopy. The in situ characterization of these V-silicalites shows that vanadium is present within the zeolitic framework as a highly dispersed tetrahedrally coordinated V-oxides, VO4 unit, having a short V=O bond length. Photoluminescence spectroscopy in static and dynamic mode, as well as XAFS studies allow to detect in the V-silicalites different V species than that present in V-HMS or V/SiO2, in terms of V=O bond length, vibrational energy, bond angle and lifetime of the excited triplet state. It is suggested that the combined contribution of the neighboring Si-OH group attached to the VO4 unit and the zeolitic rigid framework structure of V-silicalites cause a more significant and pronounced effect on the chemical properties of the VO4 unit than the flexible structure of V-HMS or V/SiO2. Moreover, the dynamic quenching of the phosphorescence by the addition of reactant molecules such as NO or propane indicates that the V species in the excited triplet state can be expected to be the active sites for the photocatalytic reactions.

Original languageEnglish
Pages (from-to)211-217
Number of pages7
JournalCatalysis Today
Volume78
Issue number1-4 SPEC.
DOIs
Publication statusPublished - 2003 Feb 28
Externally publishedYes

Keywords

  • ESR
  • Photoluminescence
  • Vanadium silicalites
  • XAFS

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

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