Patent ID: 7473665

Claim:
An exhaust gas-purifying catalyst system, comprising a plurality of catalyst layers including a first and a second catalyst layers, supported on a support structure, the first catalyst layer coming into contact with an exhaust gas stream firstly among the plurality of catalyst layers, the second catalyst layer is provided adjacent to the first catalyst layer, the first catalyst layer containing a first noble metal active component comprising rhodium, together with a powder of a barely water-soluble barium compound comprising barium sulfate in an amount of 0.05 mol to 0.2 mol per volume in liter of the support structure the first layer also containing cerium zirconium complex oxide, the second catalyst layer containing a second noble metal active component, a barely water-soluble barium compound comprising barium sulfate in an amount of 0.05 mol to 0.2 mol per volume in liter of the support structure, the second layer also containing cerium zirconium complex oxide.