Combined NOx and soot abatement over Pt-Ba/γ-Al2O3 DPNR model catalyst

Due to progressive increase of the Diesel engines’ market and more stringent legislative regulations on vehicle emissions, in recent years considerable efforts have been devoted to the study of abatement technologies able to reduce both soot and NOx emissions. In the late ‘90 Toyota has developed a new after-treatment technology called Diesel Particulate-NOx Reduction (DPNR), consisting of a ceramic filter coated with a catalytic layer of NSR (NOx Storage-Reduction) catalyst. The system utilizes cyclic operations by switching between fuel-lean and fuel-rich conditions. The aim of the present study is to analyze the effects of the presence of soot on the behaviour of the DPNR catalysts in terms of NOx storage/reduction efficiency and to provide new insights on the role of stored NOx in soot combustion.