Open issues in oxidative catalysis for diesel particulate abatement

The next 2008 European legislation on diesel engines will impose the use of specific traps, placed in the car exhaust line, so as to meet very stringent particulate emission limits (0.005 g/km). This paper provides a survey of the status of advancement of R&D in the field of diesel particulate traps for both passenger cars and heavy-duty vehicles. Special emphasis is given to the combined use of traps and catalysts for trap regeneration purposes via catalytic combustion of the collected soot. Issues like trap materials selection (cordierite, SiC, Al2O3 fibers), catalyst development (fuel additives, catalyst coatings, …), catalytic vs. non-catalytic trap performance are addressed, providing a critical analysis on the techno-economical feasibility of the systems currently being developed by several car-components and catalyst manufacturers. Specific highlights of the research in progress at Politecnico di Torino in the framework of several European projects (CATATRAP, ART-DEXA and SYLOC-DEXA) will also be provided.