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Zirconia-Supported Vanadium Oxide Catalysts for Ammoxidation and Oxidation of Toluene: A Characterization and Activity Study

Sanati, Mehri LU ; Andersson, Arne LU ; Wallenberg, L R and Rebenstorf, B (1993) In Applied Catalysis A: General 106(1). p.51-72
Abstract
A series of samples of vanadia supported on monoclinic zirconia were prepared with nominal loadings from a half up to sixteen theoretical vanadia layers. The samples were characterized with X-ray diffraction, scanning electron microscopy combined with energy dispersive X-ray analysis, high-resolution electron microscopy, Raman and diffuse reflectance infrared spectroscopy, and were used in the oxidation and the ammoxidation of toluene. At loadings in the monolayer range, Raman and infrared bands from decavanadate-like and dehydrated tetrahedral vanadia species were at ca. 990 and ca. 1025 cm−1, respectively. Raman bands at 821 and 880 cm−1 were present only at the lowest loading and are characteristic of orthovanadate and pyrovanadate... (More)
A series of samples of vanadia supported on monoclinic zirconia were prepared with nominal loadings from a half up to sixteen theoretical vanadia layers. The samples were characterized with X-ray diffraction, scanning electron microscopy combined with energy dispersive X-ray analysis, high-resolution electron microscopy, Raman and diffuse reflectance infrared spectroscopy, and were used in the oxidation and the ammoxidation of toluene. At loadings in the monolayer range, Raman and infrared bands from decavanadate-like and dehydrated tetrahedral vanadia species were at ca. 990 and ca. 1025 cm−1, respectively. Raman bands at 821 and 880 cm−1 were present only at the lowest loading and are characteristic of orthovanadate and pyrovanadate species, respectively. X-ray diffraction, Raman and infrared spectroscopic results revealed formation of some crystalline V2O5 and ZrV2O7 at loadings exceeding a theoretical monolayer. In this case, consideration of Raman intensity variations allowed the conclusion that additional non-crystalline vanadia must be present. According to high-resolution electron micrographs, this vanadia consists of an amorphous overlayer, 4–8 atomic layers thick. In toluene oxidation zirconia-supported vanadia compared with crystalline V2O5 was found less selective for benzaldehyde formation. In toluene ammoxidation, on the other hand, vanadia on zirconia was found to possess good activity and selectivity for benzonitrile formation. Amorphous vanadia was the most active structure on zirconia, while the selectivities for nitrile and aldehyde formations were almost independent of the loading for one theoretical layer and above. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
catalyst characterization (BET/XRD/DRIFTS/FT-Raman spectroscopy/EDX/SEM / HREM), toluene oxidation, toluene ammoxidation, vanadie-zirconia, zirconia (monoclinic)
in
Applied Catalysis A: General
volume
106
issue
1
pages
51 - 72
publisher
Elsevier
external identifiers
  • wos:A1993MJ80900004
  • scopus:0027701310
ISSN
0926-860X
DOI
10.1016/0926-860X(93)80155-J
language
English
LU publication?
yes
id
4a9f9d32-5f54-433f-87f3-349c561b26d9 (old id 1975448)
date added to LUP
2011-06-17 12:24:45
date last changed
2017-04-09 04:23:27
@article{4a9f9d32-5f54-433f-87f3-349c561b26d9,
  abstract     = {A series of samples of vanadia supported on monoclinic zirconia were prepared with nominal loadings from a half up to sixteen theoretical vanadia layers. The samples were characterized with X-ray diffraction, scanning electron microscopy combined with energy dispersive X-ray analysis, high-resolution electron microscopy, Raman and diffuse reflectance infrared spectroscopy, and were used in the oxidation and the ammoxidation of toluene. At loadings in the monolayer range, Raman and infrared bands from decavanadate-like and dehydrated tetrahedral vanadia species were at ca. 990 and ca. 1025 cm−1, respectively. Raman bands at 821 and 880 cm−1 were present only at the lowest loading and are characteristic of orthovanadate and pyrovanadate species, respectively. X-ray diffraction, Raman and infrared spectroscopic results revealed formation of some crystalline V2O5 and ZrV2O7 at loadings exceeding a theoretical monolayer. In this case, consideration of Raman intensity variations allowed the conclusion that additional non-crystalline vanadia must be present. According to high-resolution electron micrographs, this vanadia consists of an amorphous overlayer, 4–8 atomic layers thick. In toluene oxidation zirconia-supported vanadia compared with crystalline V2O5 was found less selective for benzaldehyde formation. In toluene ammoxidation, on the other hand, vanadia on zirconia was found to possess good activity and selectivity for benzonitrile formation. Amorphous vanadia was the most active structure on zirconia, while the selectivities for nitrile and aldehyde formations were almost independent of the loading for one theoretical layer and above.},
  author       = {Sanati, Mehri and Andersson, Arne and Wallenberg, L R and Rebenstorf, B},
  issn         = {0926-860X},
  keyword      = {catalyst characterization (BET/XRD/DRIFTS/FT-Raman spectroscopy/EDX/SEM / HREM),toluene oxidation,toluene ammoxidation,vanadie-zirconia,zirconia (monoclinic)},
  language     = {eng},
  number       = {1},
  pages        = {51--72},
  publisher    = {Elsevier},
  series       = {Applied Catalysis A: General},
  title        = {Zirconia-Supported Vanadium Oxide Catalysts for Ammoxidation and Oxidation of Toluene: A Characterization and Activity Study},
  url          = {http://dx.doi.org/10.1016/0926-860X(93)80155-J},
  volume       = {106},
  year         = {1993},
}