| abstract |
A catalyst article for treating a combustion exhaust gas stream, the article comprising: a catalytically active substrate comprising one or more channels extending along its axial length through which, in use, combustion exhaust gas flows, the one or more channels have a first surface for contacting the combustion exhaust gas stream; 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 the first surface, wherein The first layer comprises an ammonia leakage catalyst composition comprising one or more platinum group metals supported on titania, silica-titania mixed oxide, Ce-Zr mixed oxide, or mixtures thereof , and a second layer is provided over at least a portion of the first layer and includes an SCR catalyst composition. |