Studies on the deactivation of NOx storage-reduction catalysts by sulfur dioxide

C. Sedlmair, Kulathuiyer Seshan, A. Jentys, J.A. Lercher

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The interaction of sulfur dioxide with a commercial NOx storage-reduction catalyst (NSR) has been investigated using in situ IR and X-ray absorption spectroscopy. Two pathways of catalyst deactivation by SO2 were identified. Under lean conditions (exposure to SO2 and O2) at 350 °C the storage component forms barium sulfates, which transform from surface to hardly reducible bulk sulfate species. The irreversible blocking of the Ba sites led to a decrease in NOx storage capacity. Under fuel rich conditions (SO2/C3H6) at 350–500 °C evidence for the formation of sulfides on the oxidation/reduction component (Pt) of the catalyst was found, which blocks the metal surface and thus hinders the further reduction of the sulfides.
Original languageUndefined
Pages (from-to)413-419
JournalCatalysis today
Issue number1-4
Publication statusPublished - 2002


  • NSR
  • Deactivation
  • METIS-209816
  • Sulfur dioxide
  • IR-74849

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