| abstract |
An oxidation catalyst (5) for treating an exhaust gas produced by a stoichiometric natural gas (NG) engine, comprising a substrate and a catalytic material for oxidizing hydrocarbons (HC) Wherein the catalyst material comprises a molecular sieve and a platinum group metal (PGM) supported on the molecular sieve, wherein the molecular sieve has a framework comprising silicon, oxygen and optionally germanium. The first region (2) at the inlet of the catalyst is the zone containing the catalytic material for oxidizing the ammonia. At the outlet end of the catalyst, there is a second zone 3 which is a zone containing a catalytic material for oxidizing hydrocarbons. Both the first region and the second region are disposed directly on the substrate (1). The second zone 3 comprising the catalytic material for the oxidation of hydrocarbons may also be a zone arranged on the first layer 2 comprising a catalytic material for oxidizing ammonia. |