Patent ID: 7718562

Claim:
A method of reducing emissions from an exhaust gas stream comprising: providing a first catalyst for optimizing the storage of NO x emissions under lean air/fuel ratios, comprising a Perovskite-type ABO 3 crystal structure wherein 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 NO x trapping metal selected from the group consisting of barium, magnesium and potassium to result in a charge balanced crystal structure that forms oxygen vacancies to promote NO x storage, 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; providing a second catalyst for optimizing the reduction of hydrocarbon, NO x and CO emissions under stoichiometric air/fuel ratios comprising a catalyst mixture PM-Rh wherein 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; and wherein the first catalyst has the formula La 0.5 Ba 0.5 CO 0.9 Rh 0.1 O 3 .