Incorporation of vanadium in mesoporous MCM-41 and microporous AFI zeolites

K. J. Chao, C. N. Wu, H. Chang, L. J. Lee, Shu Fen Hu

Research output: Contribution to journalArticle

132 Citations (Scopus)

Abstract

Vanadium-containing silicate MCM-41 (V-MCM-41) zeolite and aluminophosphate AFI (VAPO-5) zeolite were synthesized and characterized by spectroscopic techniques. In as-synthesized form, the vanadyl ions (VIV=O)2+ were found to be the major vanadium species in the form of atomic dispersion on AFI by EPR and to exist simultaneously with tetrahedral (Td) V5+ in MCM-41 by UV-vis. 29Si MAS NMR investigations suggested that the vanadium ions might attach to MCM-41 through interaction with the silanol groups on the internal wall of hexagonal tubes. The V5+ (in Td) ions are incorporated into the lattice of MCM-41 during synthesis, while the VO2+ (in Td) is the loosely bound V species. The results of Raman spectroscopy indicated that the rodlike aggregation of cationic surfactant (cetyltrimethylammonium bromide, CTAB) was encapsulated in the intrachannel space of synthetic MCM-41 as in an aqueous solution. After calcination and hydration, the V4+ species in as-synthesized V-MCM-41 was totally oxidized to +5 as shown by UV-vis and EPR spectroscopies, and they further aggregated as two-dimensional vanadate chain species that were nonuniformly deposited on the wall of MCM-41 channels as verified by Raman and HREM with EDS spectroscopies, while the V5+ species of synthetic V-MCM-41 remains stable in a tetrahedral coordination. Comparatively, two types of VO2+ ions were observed in as-synthesized VAPO-5 by EPR and they could be oxidized by calcination treatment. The presence of water vapor facilitates the oxidation of (VIV=O)2+ and the formation of V2O5 cluster instead of isolated (VV=O)3+ species.

Original languageEnglish
Pages (from-to)6341-6349
Number of pages9
JournalJournal of Physical Chemistry B
Volume101
Issue number33
Publication statusPublished - 1997 Aug 14

Fingerprint

Zeolites
Vanadium
Multicarrier modulation
zeolites
vanadium
silicates
Silicates
roasting
Ions
Paramagnetic resonance
ions
Vanadates
vanadates
Calcination
Spectrum Analysis
spectroscopy
Spectroscopy
hydration
water vapor
bromides

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

Incorporation of vanadium in mesoporous MCM-41 and microporous AFI zeolites. / Chao, K. J.; Wu, C. N.; Chang, H.; Lee, L. J.; Hu, Shu Fen.

In: Journal of Physical Chemistry B, Vol. 101, No. 33, 14.08.1997, p. 6341-6349.

Research output: Contribution to journalArticle

Chao, KJ, Wu, CN, Chang, H, Lee, LJ & Hu, SF 1997, 'Incorporation of vanadium in mesoporous MCM-41 and microporous AFI zeolites', Journal of Physical Chemistry B, vol. 101, no. 33, pp. 6341-6349.
Chao, K. J. ; Wu, C. N. ; Chang, H. ; Lee, L. J. ; Hu, Shu Fen. / Incorporation of vanadium in mesoporous MCM-41 and microporous AFI zeolites. In: Journal of Physical Chemistry B. 1997 ; Vol. 101, No. 33. pp. 6341-6349.
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