ZONED TWC CATALYSTS FOR GASOLINE ENGINE EXHAUST GAS TREATMENTS

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 beginning at the inlet end and extending for less than the axial length L, wherein the first catalytic region comprises a first platinum group metal (PGM) component, a first inorganic oxide, and an optional first oxygen storage capacity (OSC) material;

a second catalytic region beginning at the outlet end and extending for less than the axial length L, wherein the second catalytic region comprises a second PGM component, an optional second inorganic oxide, and a second OSC material; and

a third catalytic region;

wherein the weight ratio of the first inorganic oxide to the optional first OSC material is greater than 1:1.

2 . The catalyst article of claim 1 , wherein the first catalytic region extends for 20 to 90 percent of the axial length L.

3 . The catalyst article of claim 1 , wherein the second catalytic region extends for 20 to 90 percent of the axial length L.

4 . The catalyst article of claim 1 , wherein the weight ratio of the first inorganic oxide to the optional first OSC material is at least 2:1.

5 . The catalyst article of claim 1 , wherein the weight ratio of the optional second inorganic oxide to the second OSC material is less than 1:1.

6 . The catalyst article of claim 5 , wherein the weight ratio of the optional second inorganic oxide to the second OSC material is no more than 1:2.

7 . The catalyst article of claim 1 , wherein the third catalytic region extends for 100 percent of the axial length L.

8 . The catalyst article of claim 1 , wherein the third catalytic region extends for less than 100 percent of the axial length L.

9 . The catalyst article of claim 1 , wherein the first PGM component is Pd, Pt, Rh, or a combination thereof.

10 . The catalyst article of claim 1 , wherein the optional first 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 1 , 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.

12 . The catalyst article of claim 1 , wherein the second PGM component is Pd, Pt, Rh, or a combination thereof.

13 . The catalyst article of claim 1 , 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.

14 . The catalyst article of claim 1 , wherein the optional 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.

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

16 . The catalyst article of claim 1 , wherein the first catalytic region is supported/deposited directly on the substrate.

17 . The catalyst article of claim 1 , wherein the second catalytic region is supported/deposited directly on the substrate.

18 . The catalyst article of claim 1 , wherein the third catalytic region is supported/deposited directly on the substrate.

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 .