US Patent 10179329 Combining SCR with PNA for low temperature emission control

A catalyst article comprises an SCR catalyst and a NOx adsorber catalyst, where each of these catalysts comprise a metal molecular sieve, each with a different metal. The catalyst article can be close coupled with other components to give a NOX performance advantage from cold start to a combined DOC and SCRF system. Higher NOX conversion is also shown in under-floor location due to NOx storage before SCR light off and selective NH3 slip control, allowing higher NH3 fill levels. Systems comprising the catalyst article and methods of using the catalyst article to give improved hydrocarbon and carbon monoxide control, as well as ammonia slip control, are described. The systems can include flow-through or wall-flow monoliths.