Resumo

PISARELLO, M. L. et al. Catalytic abatement jof pollutants from diesel exhausts. Lat. Am. appl. res. [online]. 2003, vol.33, n.3, pp.345-352. ISSN 0327-0793.

K and Co,K supported catalysts were studied to determine the mechanism of the soot combustion. The thermal stability of these catalysts and the resistance to water and sulfur are also addressed. The support plays an important role. La₂O₃ contributes through the formation of carbonate-type intermediates and CeO₂ supplies the oxygen necessary for the redox mechanism to take place. However, the addition of Co to the catalyst supported on La₂O₃, to supply the redox function, leads to a loss of the thermal stability as a consequence of the formation of a perovskite structure. The soot-catalyst contacting phenomenon was also addressed. A synergic La-K effect was observed, by which mechanical mixtures of soot with K-La₂O₃ showed higher rates than those observed when K and La were deposited on soot. Preliminary experiments using barium as a catalytic trap for NO_x and the simultaneous removal of NO_x and soot are also presented.

Palavras-chave : Soot Combustion; Nitric Oxide Removal; Cobalt - Potassium Catalysts.

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