Catalyst system

Abstract

The present invention provides a catalyst system for treatment of an exhaust gas comprising: a first SCR catalyst comprising an iron (Fe) ion-exchanged molecular sieve having a ferrierite (FER) or MFI framework, wherein the first SCR catalyst is provided on or within a substrate; and a second SCR catalyst comprising vanadium, wherein the second SCR catalyst is provided on or within a substrate; wherein the first and second catalysts are arranged such that in use exhaust gas contacts the first SCR catalyst prior to contact with the second SCR catalyst. Also provided is an exhaust system, a method, use and vehicle incorporating or utilizing such a catalyst system.

Dependencies are inferred from the claim text.