Effect of SO2 and SO3 Exposure to Cu-CHA on Surface Nitrate and N2O Formation for NH3-SCR
Artikel i vetenskaplig tidskrift, 2024

We report effects of SO2 and SO3 exposure on ammonium nitrate (AN) and N2O formation in Cu-CHA used for NH3-SCR. First-principles calculations and several characterizations (ICP, BET, XRD, UV-vis-DRS) were applied to characterize the Cu-CHA material and speciation of sulfur species. The first-principles calculations demonstrate that the SO2 exposure results in both (bi)sulfite and (bi)sulfate whereas the SO3 exposure yields only (bi)sulfate. Furthermore, SOx adsorption on framework-bound dicopper species is shown to be favored with respect to adsorption onto framework-bound monocopper species. Temperature-programmed reduction with H-2 shows two clear reduction states and larger sulfur uptake for the SO3-exposed Cu-CHA compared to the SO2-exposed counterpart. Temperature-programmed desorption of formed ammonium nitrate (AN) highlights a significant decrease in nitrate storage due to sulfur species interacting with copper sites in the form of ammonium/copper (bi)bisulfite/sulfate. Especially, highly stable sulfur species from SO3 exposure influence the NO2-SCR chemistry by decreasing the N2O selectivity during NH3-SCR whereas an increased N2O selectivity was observed for the SO2-exposed Cu-CHA sample. This study provides fundamental insights into how SO2 and SO3 affect the N2O formation during ammonium nitrate decomposition in NH3-SCR applications, which is a very important topic for practical applications.


AN (ammonium nitrate)


TPD (temperature-programmed desorption)



Joonsoo Han

Chalmers, Kemi och kemiteknik, Kemiteknik

Joachim Bjerregaard

Chalmers, Fysik, Kemisk fysik

Henrik Grönbeck

Chalmers, Fysik, Kemisk fysik

Derek Claude Creaser

Chalmers, Kemi och kemiteknik, Kemiteknik

Louise Olsson

Chalmers, Kemi och kemiteknik, Kemiteknik


2694-2488 (eISSN)

Vol. In Press

Cu-CHA zeolite-based catalysts for the selective catalytic reduction of NOx in exhaust diesel gas: addressing the issue of Sulfur Stability (CHASS)

Europeiska kommissionen (EU) (EC/H2020/955839), 2021-06-01 -- 2025-05-31.


Oorganisk kemi

Fysikalisk kemi




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