CATALYTIC PRODUCT WITH AN ACTIVE SCR SUBSTRATE, AN AMMONIA PROSCOCK CATALYST LAYER AND SCR LAYER FOR USE IN THE EXHAUST TREATMENT SYSTEM

摘要

A catalyst article for treating a flow of a combustion exhaust gas comprises: a catalytically active substrate comprising one or more channels extending along an axial length thereof through which, in use, a combustion exhaust gas flows, the one or more channels having a first surface for contacting a flow of combustion exhaust gas; wherein the substrate is formed of an extruded vanadium-containing SCR catalyst material, wherein a first layer is provided on at least a portion of said first surface, wherein the first layer comprises an ammonia slip catalyst composition comprising one or more platinum group metals supported on titania, a silica-titania mixed oxide, a Ce-Zr mixed oxide, or a mixture thereof, and a second layer is provided on at least a portion of the first layer and comprises an SCR catalyst composition.