Perovskite-based catalysts for the control of nitrogen oxide emissions from diesel engines

Abstract

The good performance of modern diesel engines and their low fuel consumption have caused a continuous increase in the diesel engine vehicle population. However, under oxygen-rich conditions the conventional three-way catalysts are not able to reduce NO_x (NO + NO₂) emissions and a different approach is required. Presently, the lean NO_x trap (LNT, NSR) and selective catalytic reduction (SCR) are the most powerful methodologies to remove NO_x from lean-burn engines. The favourable method for the still unregulated N₂O abatement is nitrous oxide decomposition (deN₂O). Herein, we discussed the potential of perovskite-based catalysts to reduce nitrogen oxide emissions. The wide range of elemental compositions together with high thermal stability in oxidizing environments and low cost make these materials very attractive for automotive applications. This review is devoted to the aftertreatment system of the exhaust gases to reduce the nitrogen oxide emissions from diesel vehicles. In the following sections, we provide a review on the development of NSR, SCR and deN₂O over perovskite-based catalysts. The review emphasises the property–activity correlations in such catalytic applications. Finally, major conclusions are drawn and some research challenges are highlighted.