Catalyst for exhaust gas purification, production method therefor, and method for purification of exhaust gas using the catalyst

A catalyst for the exhaust gas purification which comprises:

• a catalytically active component (I) having palladium and barium supported on a refractory inorganic oxide (A);
• and
• a catalytically active component (II) having either rhodium or a mixture of rhodium and platinum, and an additional component on a refractory inorganic oxide (B),
• wherein the molar ratio of barium to palladium (molar ratio of barium/palladium) in the catalytically active component (I) is 0.1 to 2, and provided that when rhodium and platinum are used in combination, a weight ratio of platinum/rhodium is ⅕ to 5,
• wherein the additional component is at least one member selected from the group consisting of scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), zirconium (Zr), iron (Fe), cobalt (Co), nickel (Ni), and oxides and composite oxides thereof, and the amount of the additional component to be added being in the range of 1 to 100 g, per liter of the catalyst for the exhaust gas purification,
• wherein the amount of the catalytically active component (I) to be supported is in the range of 10 to 300 g, per liter of the catalyst for the exhaust gas purification, and
• wherein the amount of the catalytically active component (II) to be supported is in the range of 10 to 300 g, per liter of the catalyst for the exhaust gas purification.