| 摘要 |
A catalyst article having an extruded support having a plurality of channels, and a single layer coating or a bi-layer coating on the support. The single layer coating contains a blend of platinum on a support with low ammonia storage and a 1st for selective catalytic reduction (SCR) catalyst. The bi-layer coating has a bottom layer of a blend of Pt on a support and a 1st SCR catalyst, and the top layer is a 2nd SCR catalyst. The extruded support may contain a third SCR catalyst. The low ammonia storage support may be a silica or zeolite. The 1st SCR catalyst can either be a Cu-SCR or Fe-SCR catalyst. The 2nd SCR catalyst may also contain a base metal promoter such as Ce-Zr or MnO2.The catalytic articles are useful for SCR of NOx in exhaust gases and can be used to provide an improvement in N2 yield from NH3. Methods of using the catalytic articles in an SCR process, where the amount of ammonia slip is reduced, are also described. The application also relates to an exhaust system, engine and vehicle. |
