Simultaneous Removal of Soot and NOx from Lean-Burn Engine Emissions Over Potassium Dititanate-Based Catalysts

Abstract

There has been little progress for removing soot and NOx simultaneously from the emissions of diesel engines. For soot combustion, the current commercial choice is Pt-based catalysts, which are expensive and sulfur sensitive. For NOx storage, Ba in Pt-Ba/Al2O3 has some drawbacks of reacting easily with SOx and Al2O3 to become inactive at high temperatures. In this work, potassium titanates were systematically investigated both as catalysts and as NOx adsorbents. It was revealed that K2Ti2O5 had bi-functional roles of oxidizing soot and storing NO and NO2 under fuel lean condition of engine emissions. Novel NOx storage-reduction catalysts were developed by doping metals (Pt, Cu, Ce, Co etc.) on K2Ti2O5. Simultaneous removal of soot and NOx could be achieved over K2Ti2O5-based catalysts.