| 摘要 |
PROBLEM TO BE SOLVED: To provide a method which subjects NOx in the generated exhaust gas to catalytic decomposition with high durability by means of combustion of fuel supplied by the periodic rich/lean method even at a high reaction temperature under the existence of oxygen, sulfur oxide or water. SOLUTION: In this method for subjecting nitrogen oxide to catalytic reduction, a catalyst consisting of a surface catalyst layer (A) having the first catalyst ingredient which consists of a mixture or a multiple oxide between a cerium oxide (a) and an oxide (b) of at least one element selected from zirconium, gadolinium, terbium, samarium and lanthanum (therein, a mixture or a multiple oxide between cerium oxide and a zirconium oxide is excluded), and the second catalyst ingredient which consists of at least one kind (c) selected from rhodium, palladium, rhodium oxide and palladium oxide and an inner catalyst layer (B) having a catalyst ingredient (a) of at least one kind selected from platinum, rhodium, palladium and oxides thereof and a carrier (b) is used. |
