| 摘要 |
<p>A method to produce a NOx trap composition, and its use in a NOx trap and in an exhaust system for internal combustion engines, is disclosed. The NOx trap composition is produced by heating an iron-containing zeolite in thepresence of an inert gas and an organic compound (e.g. polyethylene oxide) to produce a reductively calcined iron/zeolite. A palladium compound is then added to the reductively calcined iron/zeolite, and the resulting Pd-Fe/zeolite is then calcined at 400 to 600°C in the presence of an oxygen-containing gas to produce the NOx trap composition. The NOx trap composition shows low temperature NO capacity below 200°C, as well as an additional NO storage temperature window in the 200 to 250°C range, and is useful as a cold start catalyst.</p> |
