Clean diesel power via microwave susceptible oxidation catalysts

The problem of soot emissions from diesel engines is introduced and the possible solution of combining doped perovskites and microwave (mw) irradiation to "clean up" diesel soot filters is outlined. Eighteen doped perovskite catalysts are synthesized and tested for propane and CO oxidation, which are taken as model components for soot. The activity, selectivity, and SO2 tolerance are compared under conventional heating and mw irradiation. By combining mw irradiation and doped perovskites, one can create "hot spots" on the catalyst, resulting in efficient and selective heating of the active site, as well as less poisoning. Sr-doped and Ce-doped manganese perovskites show the highest activity. These catalysts are also the most selective, and have a high mw susceptibility. Optimal SO2 tolerance is displayed by Cr perovskites, from which the La0.8Ca0.2CrO3 combination uniquely converts propane before CO, and therefore can be used to remove >C2 hydrocarbons from a mix with CO. Possible mechanistic scenarios are presented and discussed.