Ammonia blocking catalyst designed to be the first in an SCR system

摘要

Catalyst articles comprising an ammonia slip catalyst (ASC) comprising a mixture of low ammonia storage platinum and a first SCR catalyst and a second catalyst such as a diesel oxidation catalyst, a diesel exothermic oxidation catalyst (DEC ), a NOX absorber, a selective catalytic reaction (catalyst) / passive NOX adsorber (SCR / PNA), a cold start catalyst (CSC) or a three way catalyst (TWC). The catalyst articles may further contain one or two additional SCR catalysts. The catalysts may be in one of several configurations. The catalytic articles are suitable for selective catalytic reduction (SCR) of NOX in exhaust gases and for reducing the amount of ammonia slip. Methods of using the catalytic articles in an SCR process in which the amount of ammonia slip is reduced are also described.