Patent ID: 7071141
Filing Date: 2006-07-04
Classification: B01D,B01J,C01G,C01P,Y02T

Abstract:
1. A catalyst system for use in reducing emissions from an exhaust gas stream comprising: a first catalyst for optimizing the storage of NOx emissions under lean air/fuel ratios, comprising a Perovskite-type ABO the A cation sites are occupied by lanthanide ions and the B cation sites are occupied by cobalt ions, wherein from about 1 to up to 70% of the lanthanide A cation sites are substituted with a NOx trapping metal selected from the group consisting of barium, magnesium, and potassium, wherein from about 1 to up to 60% of the cobalt B cation sites are substituted with a metal selected from the group consisting of platinum, rhodium, iron, copper and manganese; and a second catalyst for optimizing the reduction of hydrocarbon, NOx and CO emissions under stoichiometric air/fuel ratios, comprising a catalyst mixture PM-Rh where PM is a catalyst material selected from the group consisting of platinum, palladium and combinations thereof, wherein the first and second catalysts are closely coupled, the first catalyst being placed in a forward position and the second catalyst being placed in a downstream position in the exhaust stream.