MULTI-LAYER TWC FORMULATIONS WITH OPTIMALIZED PGM LOADINGS

1 . A catalyst article for treating exhaust gas comprising:

a substrate comprising an inlet end, an outlet end with an axial length L;

a first catalytic region comprising a first palladium component;

a second catalytic region comprising a second rhodium component;

a third catalytic region comprising a third palladium component;

wherein the first catalytic region is adjacent to the second catalytic region; and

wherein the first palladium component and the second rhodium component have a weight ratio of from 3:1 to 19:1, based on element.

2 . The catalyst article of claim 1 wherein the first catalytic layer comprises 3-380 g/ft 3 of the first palladium component.

3 . The catalyst article of claim 1 , wherein the second catalytic layer comprises 1-20 g/ft 3 of the second rhodium component.

4 . The catalyst article of claim 1 , wherein the first catalytic region further comprises a first oxygen storage capacity (OSC) material, a first alkali or alkaline earth metal component, and/or a first inorganic oxide.

5 . The catalyst article of claim 4 , wherein the first OSC material is selected from the group consisting of cerium oxide, a ceria-zirconia mixed oxide, and an alumina-ceria-zirconia mixed oxide.

6 . The catalyst article of claim 4 , wherein the first alkali or alkaline earth metal is barium, strontium, or mixed oxides or composite oxide of barium and strontium.

7 . The catalyst article of claim 6 , wherein the first alkali or alkaline earth metal is loaded in an amount of 0.1 to 15 wt %, based on the total washcoat weight of the first catalytic region.

8 . The catalyst article of claim 4 , wherein the first inorganic oxide is selected from the group consisting of alumina, ceria, magnesia, silica, lanthanum, neodymium, praseodymium, yttrium oxides, and mixed oxides or composite oxides thereof.

9 . The catalyst article of claim 1 , wherein the second catalytic region further comprises a second OSC material and/or a second inorganic oxide.

10 . The catalyst article of claim 9 , wherein the second OSC material is selected from the group consisting of cerium oxide, a ceria-zirconia mixed oxide, and an alumina-ceria-zirconia mixed oxide.

11 . The catalyst article of claim 9 , wherein the second inorganic oxide is selected from the group consisting of alumina, ceria, magnesia, silica, lanthanum, neodymium, praseodymium, yttrium oxides, and mixed oxides or composite oxides thereof.

12 . The catalyst article of claim 1 , wherein the third catalytic region comprises 3-380 g/ft 3 of the third palladium component.

13 . The catalyst article of claim 1 , wherein the third catalytic region further comprises a third OSC material, a third alkali or alkaline earth metal component, and/or a third inorganic oxide.

14 . The catalyst article of claim 13 , wherein the third OSC material is selected from the group consisting of cerium oxide, a ceria-zirconia mixed oxide, and an alumina-ceria-zirconia mixed oxide.

15 . The catalyst article of claim 13 , wherein the third inorganic oxide is selected from the group consisting of alumina, ceria, magnesia, silica, lanthanum, neodymium, praseodymium, yttrium oxides, and mixed oxides or composite oxides thereof.

16 . The catalyst article of claim 13 , wherein the third alkali or alkaline earth metal is barium, strontium, or mixed oxides or composite oxide of barium and strontium.

17 . The catalyst article of claim 16 , wherein the third alkali or alkaline earth metal is loaded in an amount of 0.1 to 15 wt %, based on the total weight of the third catalytic region.

18 . The catalyst article of claim 1 , wherein the substrate is a flow-through monolith.

19 . An emission treatment system for treating a flow of a combustion exhaust gas comprising the catalyst article of claim 1 .

20 . A method of treating an exhaust gas from an internal combustion engine comprising contacting the exhaust gas with the catalyst article of claim 1 .