EXHAUST GAS PURIFYING CATALYST

摘要

PROBLEM TO BE SOLVED: To reconcile the purifying capacity and oxidative reaction of nitrogen oxides under an oxygen excessive atmosphere of a low temp. region. SOLUTION: A honeycomb carrier is coated with inorg. matter based on activated alumina containing barium on which platinum is supported as a first layer and subsequently coated with inorg. matter based on activated alumina as a second layer and inorg. matter based on a zeolite powder ion-exchanged with copper is further applied to the second layer as a third layer to botain an exhaust gas purifying catalyst. In this catalyst, the amt. of barium contained in the first coating layer is set to 5-25g/L as BaO with respect to catalyst vol. and the supporting amt. of platinum is set to 0.2-0.6g/L as Pt with respect to the catalyst vol.