Nanostructured catalysts for diesel soot combustion

Several cobaltite catalysts were prepared by combustion synthesis, characterized, and tested as catalysts for diesel soot combustion. The Rb-substituted cobaltite catalyst showed the highest activity as a consequence of its greater easiness to be reduced from La0.9Rb0.1Co(III)O3 to La0.9Rb0.1Co(II)O2.5, which were pointed out as the key players in the soot oxidation state. This catalyst was tested on real flue gases in innovative catalytic wall-flow traps. The catalytic materials characterized by the highest easiness of the cobalt (III) B site to be reduced to cobalt (II) were developed, with attention to their compatibility with either trap material or the poisoning components present in diesel exhaust gas, e.g., SOx.