The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

A High-Resolution Electron Microscopy Investigation of TiO2(B)-Supported Vanadium Oxide Catalysts

På svenska

Author

Summary, in English

TiO2(B) crystals were found to be isomorphic with those of its precursor, K2Ti4O9. The former crystals had a large number of facetted voids, 3–30 nm, formed as a result of the removal of potassium and water in preceding hydrolysis and calcination steps, respectively. TiO2(B)-supported vanadium oxide catalysts with loadings in the range 0.25−10 theoretical layers were prepared by impregnation of the support with an oxalic acid solution of NH4VO3 followed by calcination in air. HREM micrographs of catalysts with a low vanadium loading, recorded using a low electron-dose imaging technique, showed that the surfaces, in the initial stage, were without any anomalous surface structure. This observation may be due to a similar structure of the support and the deposited vanadia phase. At high vanadium loadings, both amorphous and crystalline particles were seen, in agreement with the features revealed by the use of IR spectroscopy. For catalysts with low vanadium loadings, the IR difference spectra showed the presence of tetrahedrally coordinated V4+ and V5+ species. In a fully converged electron beam, reduction of the support and the vanadia phases occured, resulting in the formation of small crystallites. The catalysts were used for the oxidation of toluene to benzaldehyde. However, contrary to what has been observed for the ammoxidation producing benzonitrile, no enhanced catalytic properties, in comparison with those of crystalline V2O5, were obtained using TiO2(B) as support.

Publishing year

1990

Language

English

Pages

246-260

Publication/Series

Journal of Catalysis

Volume

126

Issue

1

Document type

Journal article

Publisher

Elsevier

Topic

  • Chemical Engineering
  • Chemical Sciences
  • Production Engineering, Human Work Science and Ergonomics

Status

Published

ISBN/ISSN/Other

  • ISSN: 1090-2694