WO 3 photocatalysts: Influence of structure and composition

Imre M. Szilágyi, Balázs Fórizs, Olivier Rosseler, A. Szegedi, Péter Németh, P. Király, G. Tárkányi, Balázs Vajna, K. Josepovits, K. László, A. Tóth, P. Baranyai, Markku Leskelä

Research output: Contribution to journalArticle

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Abstract

Hexagonal (h-) and monoclinic (m-) WO 3 nanoparticles with controlled composition (oxidized/yellow color or partially reduced/blue color) were prepared through annealing (NH 4) xWO 3- y. The formation, structure, composition, morphology, and optical properties of the samples were analyzed by powder X-ray diffraction, scanning and transmission electron microscopy combined with electron diffraction, and Raman, X-ray photoelectron, 1H magic angle spinning nuclear magnetic resonance, diffuse reflectance ultraviolet-visual, and photoluminescence spectroscopy. Their photocatalytic properties were tested by decomposing methyl orange in the aqueous phase and acetone in the gas phase. Oxidized m-WO 3 (m-WO 3 ox) was the most active photocatalyst both in the aqueous and in the gas phase, followed by the oxidized h-WO 3 (h-WO 3 ox) sample. Reduced h-WO 3 (h-WO 3 red) and m-WO 3 (m-WO 3 red) exhibited much lower activity. Thus, in contrast to TiO 2, where crystalline structure (rutile or anatase) plays a key effect in photocatalysis, for WO 3, it is the composition that is of greatest importance: the more oxidized the WO 3 sample, the better a photocatalyst it is. The crystal structure of WO 3 has only an indirect effect, in that it influences the composition of WO 3 samples. While oxidized m-WO 3 is completely oxidized, oxidized h-WO 3 is always in a partially reduced state due to the presence of stabilizing positive ions in its hexagonal channels. Consequently, an oxidized monoclinic WO 3 material will always provide better photocatalytic activity than an oxidized hexagonal one.

Original languageEnglish
Pages (from-to)119-127
Number of pages9
JournalJournal of Catalysis
Volume294
DOIs
Publication statusPublished - Oct 2012

Fingerprint

Photocatalysts
Chemical analysis
Gases
vapor phases
Color
color
Magic angle spinning
Photoluminescence spectroscopy
Photocatalysis
Photoelectrons
Acetone
positive ions
Electron diffraction
anatase
rutile
X ray powder diffraction
Titanium dioxide
metal spinning
acetone
photoelectrons

Keywords

  • Hexagonal
  • Monoclinic
  • Photocatalysis
  • WO

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry

Cite this

Szilágyi, I. M., Fórizs, B., Rosseler, O., Szegedi, A., Németh, P., Király, P., ... Leskelä, M. (2012). WO 3 photocatalysts: Influence of structure and composition. Journal of Catalysis, 294, 119-127. https://doi.org/10.1016/j.jcat.2012.07.013

WO 3 photocatalysts : Influence of structure and composition. / Szilágyi, Imre M.; Fórizs, Balázs; Rosseler, Olivier; Szegedi, A.; Németh, Péter; Király, P.; Tárkányi, G.; Vajna, Balázs; Josepovits, K.; László, K.; Tóth, A.; Baranyai, P.; Leskelä, Markku.

In: Journal of Catalysis, Vol. 294, 10.2012, p. 119-127.

Research output: Contribution to journalArticle

Szilágyi, Imre M. ; Fórizs, Balázs ; Rosseler, Olivier ; Szegedi, A. ; Németh, Péter ; Király, P. ; Tárkányi, G. ; Vajna, Balázs ; Josepovits, K. ; László, K. ; Tóth, A. ; Baranyai, P. ; Leskelä, Markku. / WO 3 photocatalysts : Influence of structure and composition. In: Journal of Catalysis. 2012 ; Vol. 294. pp. 119-127.
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