Zoned configuration for oxidation catalyst combinations

An exhaust gas treatment system comprising:

• a first oxidation catalyst component for the abatement of HC and CO, wherein said first oxidation catalyst component comprises a first catalyst composition disposed onto a carrier substrate, wherein said first catalyst composition comprises a platinum group metal component impregnated into a refractory oxide material;
• a selective catalytic reduction (SCR) component for the abatement of NOx, wherein said SCR component comprises a second catalyst composition disposed onto a carrier substrate, wherein said second catalyst composition comprises a metal ion-exchanged molecular sieve;
• a second oxidation catalyst component for the abatement of CO, wherein said second oxidation catalyst component comprises a third catalyst composition disposed onto a carrier substrate, wherein said third catalyst composition comprises a platinum group metal component impregnated into an oxygen storage component wherein the platinum group metal component is palladium and the oxygen storage component is ceria;
• and
• wherein the first catalyst component is located downstream of an internal combustion engine, wherein the SCR component is located downstream of the first oxidation catalyst component, and wherein the second oxidation catalyst component is located downstream of the SCR component.