Selective catalytic reduction device

A selective catalytic reduction device for an exhaust gas treatment system of a vehicle, the selective catalytic reduction device comprising:

• a canister defining an interior, and having an inlet and an outlet, wherein the canister is configured to receive a flow of exhaust gas through the inlet, and discharge the flow of exhaust gas through the outlet;
• a substrate supported by the canister and disposed within the interior of the canister, wherein the substrate includes a porous flow through structure that is operable to allow the flow of exhaust gas to flow through the interior of the canister, from the inlet to the outlet;
• wherein the substrate includes a first portion, and a second portion disposed downstream of the first portion;
• wherein the first portion of the substrate defines a first volume, the second portion of the substrate defines a second volume, and the sum of the first volume and the second volume equals a total volume of the substrate, with the first volume defining between 15% and 25% of the total volume of the substrate, and with the second volume defining between 75% and 85% of the total volume of the substrate;
• a first selective catalytic reduction compound disposed on the first portion of the substrate;
• a second selective catalytic reduction compound disposed on the second portion of the substrate;
• wherein the first selective catalytic reduction compound includes an iron zeolite (Fe-Zeolite) compound;
• and
• wherein the second selective catalytic reduction compound includes a copper SAPO-34 compound.