Katalysator för behandling av avgaser och ett avgassystem som innefattar en sådan katalysator

摘要

The present invention concerns a catalytic converter for treating exhaust from a combustion engine (1). The catalytic converter (5) comprises wall elements (5b) that form a plurality of longitudinal channels (5a) in the catalytic converter for receiving exhaust. The wall elements (5b) comprise a first outer layer (5b1) that presents an external surface of the longitudinal channels (5a) and a second inner layer (5b2) that is arranged internally around the first layer (5b1). The first layer comprises a first active catalytic material that promotes a catalytic reaction between nitrogen oxide and ammonia. The second layer (5b2) comprises a material that has the ability to store nitrogen oxide and a second active catalytic material that has a greater ability to promote the oxidation of nitrogen monoxide into nitrogen dioxide than the first catalytic material.