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Vanadium Oxide on TiO2(B) - a HREM Study of Catalysis by Support Interaction

Wallenberg, Reine LU ; Andersson, Arne LU and Sanati, Mehri LU (1990) In Ultramicroscopy 34(1-2). p.33-40
Abstract
A model catalyst system with a loading range between 1/4 to 10 theoretical layers of vanadium oxide on TiO2(B ) support was tried for selective ammoxidation and oxidation of toluene. In the case of ammoxidation, a peak in conversion rate per unit surface area was found for a catalyst with a coverage of about 2 theoretical layers, indicating a strong interaction between the catalyst and the otherwise inactive support. The presence and amount of vanadium oxide on the support surface was verified by diffuse reflectance infrared spectroscopy, energy-dispersive elemental X-ray mapping and chemical analysis. By high resolution electron microscopy, the 32~ volume loss of the K2Ti409 support precursor on calcination was shown to be achieved by... (More)
A model catalyst system with a loading range between 1/4 to 10 theoretical layers of vanadium oxide on TiO2(B ) support was tried for selective ammoxidation and oxidation of toluene. In the case of ammoxidation, a peak in conversion rate per unit surface area was found for a catalyst with a coverage of about 2 theoretical layers, indicating a strong interaction between the catalyst and the otherwise inactive support. The presence and amount of vanadium oxide on the support surface was verified by diffuse reflectance infrared spectroscopy, energy-dispersive elemental X-ray mapping and chemical analysis. By high resolution electron microscopy, the 32~ volume loss of the K2Ti409 support precursor on calcination was shown to be achieved by formation of microscopic, facetted voids ("negative crystals") in the bulk of the material. Initially, surfaces appeared dean and without any anomalous surface features. This can be explained by similar scattering power of V and Ti, and similar structure types. However, the active phase could be "developed" to visibility by prolonged exposure to the electron beam, which produced 1-2 am particles of reduced vanadium oxides on the surface. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Ultramicroscopy
volume
34
issue
1-2
pages
33 - 40
publisher
Elsevier
external identifiers
  • WOS:A1990EL15500006
  • Scopus:0025514226
ISSN
0304-3991
DOI
10.1016/0304-3991(90)90054-P
language
English
LU publication?
yes
id
6d8ee8c3-03f1-425b-a3aa-392972313c51 (old id 2007180)
date added to LUP
2011-06-30 13:59:44
date last changed
2016-10-13 04:41:28
@misc{6d8ee8c3-03f1-425b-a3aa-392972313c51,
  abstract     = {A model catalyst system with a loading range between 1/4 to 10 theoretical layers of vanadium oxide on TiO2(B ) support was tried for selective ammoxidation and oxidation of toluene. In the case of ammoxidation, a peak in conversion rate per unit surface area was found for a catalyst with a coverage of about 2 theoretical layers, indicating a strong interaction between the catalyst and the otherwise inactive support. The presence and amount of vanadium oxide on the support surface was verified by diffuse reflectance infrared spectroscopy, energy-dispersive elemental X-ray mapping and chemical analysis. By high resolution electron microscopy, the 32~ volume loss of the K2Ti409 support precursor on calcination was shown to be achieved by formation of microscopic, facetted voids ("negative crystals") in the bulk of the material. Initially, surfaces appeared dean and without any anomalous surface features. This can be explained by similar scattering power of V and Ti, and similar structure types. However, the active phase could be "developed" to visibility by prolonged exposure to the electron beam, which produced 1-2 am particles of reduced vanadium oxides on the surface.},
  author       = {Wallenberg, Reine and Andersson, Arne and Sanati, Mehri},
  issn         = {0304-3991},
  language     = {eng},
  number       = {1-2},
  pages        = {33--40},
  publisher    = {ARRAY(0x9284180)},
  series       = {Ultramicroscopy},
  title        = {Vanadium Oxide on TiO2(B) - a HREM Study of Catalysis by Support Interaction},
  url          = {http://dx.doi.org/10.1016/0304-3991(90)90054-P},
  volume       = {34},
  year         = {1990},
}