Patent ID: 7795172
Filing Date: 2010-09-14
Classification: B01D,B01J,Y02A,Y02T

Abstract:
1. A layered exhaust treatment catalyst comprising (a) a carrier; (b) a bottom layer deposited on the carrier, said bottom layer consisting essentially of an oxygen storage component supported on a refractory metal oxide; (c) a first layer deposited on the bottom layer, said first layer comprising a palladium metal component, a platinum metal component and an oxygen storage component supported on a refractory metal oxide, the ratio of the palladium metal component to the platinum metal component being in the range of about 5:1 to about 200:1; and (d) a second layer deposited on the first layer comprising a rhodium metal component, a platinum metal component and an oxygen storage component supported on a refractory metal oxide, the ratio of the rhodium metal component to the platinum metal component being in the range of about 5:1 to about 30:1, wherein the oxygen storage component in the bottom layer, first layer and second layer is independently selected from the group consisting of ceria, lanthania, praseodymia, a ceria-praseodymia composite, a ceria-praseodymia-zirconia composite, a ceria-praseodymia-zirconia-neodymia composite and a ceria-lanthania-praseodymia-zirconia-neodymia composite.