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The latest emission regulations for mobile and stationary applications require the use of aftertreatment methods for NOx and diesel particulate filters (DPF) for particulate matter (PM). SCR catalysts were evaluated by laboratory experiments and the most promising SCR catalysts were also scaled up to full-size. Development with copper (Cu) and iron (Fe) on zeolitic materials (Beta, ZSM-5, SAPO, chabazite) has resulted in the new generation of thermally durable SCR (selective catalytic reduction) catalysts, which have also an improved sulfur tolerance and a low N2O formation tendency. Opposite to Cu on Beta and ZSM-5, Cu on chabazite and SAPO showed clearly lower N2O formation. Cu-SCR catalysts had a low dependency on NO2/NOx but Fe-SCR catalysts required a higher NO2/NOx ratio (>0.3) to keep a high NOx efficiency.

The tightening pollutant emission limits require the use of active aftertreatment methods for NOx and particulate matter (PM). Diesel particulate filter (DPF) is a part of commercial aftertreatment system (ATS). PM accumulated in DPF is continuously passively or periodically actively regenerated with the assistance of efficient diesel oxidation catalysts (DOC) having a high efficiency and durability in hydrocarbon (HC), NO and CO oxidation reactions. A high HC concentration during fuel feeding in active regeneration is demanding for DOC. The deactivation in air, hydrothermal, sulfation and active regeneration conditions were evaluated with platinum (Pt-) and platinum-palladium (PtPd)-DOCs by laboratory simulations using the ageing temperature and time as primary variables. The oxidizing conditions with a high oxygen concentration without HCs were deactivating DOCs clearly more than active regeneration conditions with a low oxygen and high HC concentration at 700-800°C.