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Formaldehyde emissions of vehicles with combustion engines, burning oxygenated fuels are a major challenge for exhaust gas aftertreatment systems. This study shows the impact of such emissions for NH3-SCR, with a high NO2-ratio.

Catalysis letters (2021). doi:10.1007/s10562-021-03771-w, Published by Springer Science + Business Media B.V, Dordrecht [u.a.]

Catalysts : open access journal 11(11), 1339 (2021). doi:10.3390/catal11111339 special issue: "Special Issue "New Challenges in Electrocatalysts for Fuel Cells and Hydrogen Production" / Special Issue Editors: Dr. Davide Clematis, Guest Editor; Prof. Dr. Fabrice Mauvy, Guest Editor; Dr. Jan Van Herle", Published by MDPI, Basel

Catalysts : open access journal 12(9), 953 (2022). doi:10.3390/catal12090953 special issue: "Special Issue "Catalytic Treatment of Air Pollutants (VOCs, PACs, PCDDs/PCDFs, Soot, NOx, CO) II" / Special Issue Editor: Dr. Fan Lin, Guest Editor; Prof. Dr. Jong-Ki Jeon, Guest Editor", Published by MDPI, Basel

The washcoat composition and the catalytic properties of two commercially available lean NOx traps (LNTs) were investigated. Both catalysts contained nominally the same NOx storage and catalytic materials but differed strongly in their amount and activity as well as in the composition of their layered washcoat architecture. In lean-rich cycle experiments under realistic engine-out gas compositions using a laboratory gas test bench, the LNTs showed comparable NOx storage behavior. At temperatures below 250 °C, the lean phase durations last up to 300 s until 50 % of the NOx storage capacity is reached. The simultaneously calculated NOx storage efficiencies drop rapidly below 35 %, resulting in a high NOx slip. Strong variations were observed in N2O and NH3 selectivity and in CO slip during regeneration of both LNTs caused by the different oxygen storage capacity (OSC), water gas shift (WGS) activity and rhodium distribution in the catalytic layers. Based on the obtained results, proposals were made to optimize the storage and regeneration performance, leading to highly efficient LNT catalysts for coupling with a downstream SCR catalyst.