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Portrait of Reine Wallenberg. Photo: Kennet Ruona

Reine Wallenberg

Professor, Coordinator Materials Science

Portrait of Reine Wallenberg. Photo: Kennet Ruona

Analysis of the state and size of silver on alumina in effective removal of NOx from oxygen rich exhaust gas

Author

  • K Arve
  • F Klingstedt
  • K Eranen
  • DY Murzin
  • L Capek
  • J Dedecek
  • Z Sobalik
  • B Wichterlova
  • K Svennerberg
  • Reine Wallenberg
  • Jan-Olov Bovin

Summary, in English

Ag/alumina catalysts with different silver contents for octane-SCR were prepared by impregnation and incipient wetness methods. Activity tests revealed that the decisive factor for high activity is not only a high dispersion of silver, but also the ability of the system to redisperse clustered silver. Determination of dispersion by TEM/HAADF and O-2-chemisorption experiments resulted in values close to each other even if the results were not directly comparable. This is suggested to be due to not complete silver reduction below 700 degrees C and the samples being very heterogeneous in terms of particle size, e.g., having a bimodal size distribution. Small charged Ag-n(delta+) clusters containing 2-8 silver atoms highly prevailed in the samples containing < 2 wt% Ag and exhibiting high octane-SCR activity In highly loaded Ag/alumina samples or those reduced and reoxidized at high temperature (> 400 degrees C), large metallic particles are stabilized, resulting in poor conversion of NOx to N-2.

Department/s

  • Centre for Analysis and Synthesis

Publishing year

2006

Language

English

Pages

1076-1083

Publication/Series

Journal of Nanoscience and Nanotechnology

Volume

6

Issue

4

Document type

Journal article

Publisher

American Scientific Publishers

Topic

  • Nano Technology

Keywords

  • exhaust gas
  • removal of NOx
  • silver

Status

Published

ISBN/ISSN/Other

  • ISSN: 1533-4880