| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust gas cleaning catalyst and method of using the exhaust gas cleaning catalyst capable of demonstrating a sufficient NOx cleaning action of the catalyst, which catalyst has a high NOx cleaning capacity under a lean atmosphere in which catalysts of the prior arts could not demonstrate sufficient activity and has an excellent NOx purification capacity even after high temperature endurance. SOLUTION: This exhaust gas cleaning catalyst contains zeorite carrying at least one kind of noble metal selected from the group consisting of platinum, palladium, rhodium and iridium and alumina, the content of the zeorite carrying the noble metal is 30-200 g per liter of the catalyst and 20-300 g of the alumina per liter of the catalyst is contained and the alumina has an average particle size of 1-30 μm, a small-pore volume of 0.1-1.0 cc/g and a specific area of 50-500 m<2> . This exhaust gas cleaning catalyst is used for a vehicle of a lean burn engine or a diesel engine wherein air fuel ratio of stoichiomerty and air-fuel ratio within a range of 15-50 are repeated. |
