Simultaneous removal of NO and carbon particulates over lanthanoid perovskite-type catalysts

The simultaneous removal of carbon particulate and NOx has been studied ove r perovskite-type oxides prepared by malic acid method. The catalysts were modified to enhance the activity by substitution of metal into A- or B-site of perovskite oxide. In the LaCoO3 catalyst, the partial substitution of C s into A-site enhanced the catalytic activity in the combustion of soot par ticulate and NO reduction. In La1-xCsxCoO3 catalysts, the ignition temperat ure of carbon particulate decreases with increasing x values and shows almo st constant values at substitution of x > 0.2 and NO conversion also shows the similar tendency. In the Cs-substituted oxide, the ignition temperature of carbon particulate slightly decreased in the order Co > Mn > Fe of B-si te metal cation but NO conversion showed almost similar values. With increa sing NO concentration, NO conversion decreased but the ignition temperature moved to high temperature when the NO concentration was higher than 1000 p pm. The carbon particulate played an important role on the reduction of NO, but NO had little effect on the oxidation of carbon particulate. (C) 2000 Published by Elsevier Science B.V.