Patent ID: 8057745
Filing Date: 2011-11-15
Classification: B01D,B01J,F01N,Y02A,Y02T

Abstract:
1. A catalyst system for an vehicle exhaust gas purification device comprising two or more exhaust gas purification catalysts including two different exhaust gas purification catalysts (first and second catalysts), each supported on an inorganic structural carrier and disposed in an exhaust gas passage in the above order, wherein the first catalyst is located on the upstream side, and the second downstream-side catalyst contains a cerium/zirconium-base compound oxide (A), prepared by melting a starting mixture at its melting point or higher, the molten mixture being then cooled to produce an ingot and crushed, wherein: the first catalyst contains a cerium/zirconium complex oxide (A′) which is prepared by calcining a starting mixture of cerium and zirconium salts at a temperature at which it is not molten; the second catalyst further contains at least one active metal species (B) selected from the group consisting of platinum, palladium and rhodium; the active metal species (B) is supported by at least one species of heat-resistant inorganic oxide (C) selected from the group consisting of zirconia, γ-Al the inorganic structural carrier of the second catalyst is of a honeycomb structure (D), and the honeycomb structure (D) supports the cerium/zirconium-base compound oxide (A), active metal species (B) and heat-resistant inorganic oxide (C) as the second catalyst components at 5.0 to 200, 0.01 to 20 and 1 to 300 g per unit volume (L) of the structure (D), respectively.