NO CATALYST FOR GASOLINE LEAN BURN ENGINES WITH IMPROVED NO OXIDATION ACTIVITY

摘要

The present invention is directed to a catalyst comprising a substrate and a catalyst coating, wherein the catalyst coating comprises two or more layers, wherein the layers comprise (a) at least one of Pt and / or Pd, layer; And (b) a second layer provided on the first layer, wherein the second layer comprises Pt; The first and second layers each comprising at least one particulate support material; At least one oxygen storage component (OSC) material; And at least one nitrogen oxide storage material comprising at least one element selected from the group of alkali and / or alkaline earth metals, wherein at least one of the alkaline and alkaline earth metals contained in said at least one nitrogen oxide storage material contained in said catalyst The total amount is in the range of 0.18 to 2.5 g / in ³ calculated as the alkali metal oxide M ₂ O and the alkaline earth metal oxide MO, respectively. The invention also relates to a process for the production of the catalyst and to a process for the treatment of an exhaust gas stream produced from a gas stream comprising nitric oxide, in particular an internal combustion engine.