The chemical nature of SO2 poisoning of Cu-CHA-based SCR catalysts for NOx removal in diesel exhausts

Abstract

This study addresses the impact of SO2 exposure on the catalytic performance of a Cu-chabazite-based SCR catalyst, as used in diesel exhausts, to reduce the emission of NOx through the NH3-SCR reaction. The SCR activity is determined by a reaction of NO with the [Cu2II(NH3)4O2]2+ intermediate. The same intermediate is also the most reactive Cu-species towards SO2. We demonstrate here that the reaction with NO at 200 °C is limited after exposure of the [Cu2II(NH3)4O2]2+ complex to SO2 or SO2/O2. Heating the catalyst to 300 °C in NO restores the reaction, albeit at a significantly lower rate. The lower reactivity towards NO indicates that exposure of [Cu2II(NH3)4O2]2+ to SO2 induces changes in the chemistry of Cu in the catalyst. This implies that poisoning of Cu-chabazite catalysts by SO2 is, at least in part, of the chemical nature, and may be not limited to the physical pore blocking.

Graphical abstract: The chemical nature of SO2 poisoning of Cu-CHA-based SCR catalysts for NOx removal in diesel exhausts

Supplementary files

Article information

Article type
Paper
Submitted
26 Jun 2024
Accepted
16 Aug 2024
First published
19 Aug 2024
This article is Open Access
Creative Commons BY license

Catal. Sci. Technol., 2024, Advance Article

The chemical nature of SO2 poisoning of Cu-CHA-based SCR catalysts for NOx removal in diesel exhausts

A. Yu. Molokova, D. Salusso, E. Borfecchia, F. Wen, S. Magliocco, S. Bordiga, T. V. W. Janssens, K. A. Lomachenko and G. Berlier, Catal. Sci. Technol., 2024, Advance Article , DOI: 10.1039/D4CY00792A

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