Double Aberration-corrected TEM/STEM of tungstated zirconia nanocatalysts for the synthesis of paracetamol

K. Yoshida, N. R. Shiju, D. R. Brown, E. D. Boyes, P. L. Gai

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We report highly active tungstated zirconia nanocatalysts for the synthesis of paracetamol by Beckmann rearrangement of 4-hydroxyacetophenone oxime. Double aberration-corrected (2AC)-TEM/STEM studies were performed in a JEOL 2200FS FEG TEM/STEM at the 1 Angstrom (1 0.1 nanometer) level. Observations at close to zero defocus were carried out using the AC-TEM as well as AC-STEM including high angle annular dark field (HAADF) imaging, from the same areas of the catalyst crystallites. The studies from the same areas have revealed the location and the nanostructure of the polytungstate species (clusters) and the nanograins of zirconia. The AC (S)TEM was crucial to observe the nanostructure and location of polytungstate clusters on the zirconia grains. Polytungstate clusters as small as 0.5 nm have been identified using the HAADF-STEM. The nanostructures of the catalyst and the W surface density have been correlated with paracetamol reaction studies. The results demonstrate the nature of active sites and high activity of the tungstated zirconia nanocatalyst, which is an environmentally clean alternative to the current homogeneous process.
Original languageEnglish
Title of host publicationElectron Microscopy and Analysis Group Conference 2009 (EMAG 2009)
PublisherTaylor & Francis
Pages-
Number of pages4
Volume241
DOIs
Publication statusPublished - 1 Jan 2010

Publication series

NameInstitute of Physics Conference Series
Publisher IOP Publishing LTD
Volume241
ISSN (Print)1742-6588

Keywords

  • TRANSMISSION ELECTRON-MICROSCOPY
  • EPSILON-CAPROLACTAM

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