| RESEARCH |
A number of conference attendees presented results of studies aimed at treating soot, the other main diesel-engine pollutant. Debora Fino, materials science and chemical engineering assistant professor at Polytechnic University of Torino, Italy, reported on investigations designed to find suitable catalysts for diesel particulate filters. The filters, which are porous ceramic monoliths (one-piece bricks), trap soot particles on the catalyst-coated filter walls as exhaust gases diffuse through the filter. Fino explained that the traps are regenerated periodically by operating the engine in a way that momentarily boosts the exhaust temperature and burns the soot particles. Fino and coworkers prepared a number of substoichiometric lanthanum -chromium compounds, many of which contain sodium, potassium, or other alkali metals, and assessed their activity for soot combustion. The Torino group found that a lithium-substituted chromite compound, La0.8Cr0.9Li0.1O3, was the most active catalyst and that it regenerated the filter twice as fast and more thoroughly than uncatalyzed filters. On the basis of a photoelectron spectroscopy investigation, Fino attributed the high activity to weakly adsorbed O species on the catalyst surface. She added that, after exposing the catalyst to accelerated aging conditions, the material still exhibited high activity (J. Catalysis 2005, 229, 459). |
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