SELECTIVE CATALYTIC REDUCTION CATALYST SYSTEM

摘要

Described are SCR catalyst systems comprising a first SCR catalyst composition and a second SCR catalyst composition arranged in the system, the first SCR catalyst composition having a faster DeNOx response time when exposed to ammonia than the second catalyst composition and the second SCR catalyst composition has a higher steady state DeNOx performance than the first catalyst composition. The SCR catalyst systems are useful in methods and systems to catalyze the reduction of nitrogen oxides in the presence of a reductant.