NOx storage capacity of yttria-stabilized zirconia-based catalysts

Authors:     W.Y. Hernández, A. Hadjar, M. Klotz, J. Leloup, A. Princivalle, C. Tardivat, C. Guizard, P. Vernoux

Abstract:
A NO_x chemisorption study was performed on yttria-stabilized zirconia (YSZ), an O₂− ionically conducting ceramic. NO₂ chemisorption on YSZ as well as NO + O₂ interactions on Pt/YSZ catalyst were clearly correlated to the presence of surface oxygen vacancies. A remarkable NO_x storage capacity was obtained on Pt/YSZ powdered catalysts, by combining nitrates formation and NO₂ adsorption on oxygen vacancies. Under cycling conditions (lean phase/rich phase: 3 min/2 min) and using propene as a reductant, powdered Pt-Rh catalyst exhibited overall NO_x abatement conversion of around 75% at 250 and 300^◦C. Pt/Rh/YSZ catalysts were finely dispersed in the porosity of SiC mini diesel particulate filters (DPFs). Quite reproducible and stable NO_x conversions were achieved in cycling conditions with values around 50% between 250 and 400^◦C. In addition, YSZ-based catalysts have shown high thermal resistance and sulfur tolerance.

Keywords:
Yttria-stabilized zirconia
Oxygen vacancies
Ionic conductor
NO_x storage-reduction
Diesel particulate filters

Published in: Applied Catalysis B: Environmental (Volumes 130–131, Pages 1-336, 7 February 2013)

Publisher: Elsevier  

ISSN Information: 0926-3373

NOx storage capacity of yttria-stabilized zirconia-based catalysts

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