Emission control catalyst article with PGM-gradient architecture

An emission control catalyst article comprising:

• a substrate having a first inlet axial end and a second outlet axial end,
• a bottom washcoat layer comprising a platinum group metal coated on 60% to 100% length of the substrate from the first axial end to the second axial end, and
• a top washcoat layer comprising a platinum group metal coated on 60% to 100% length of the substrate from either the first axial or the second axial end of the substrate, wherein the top coat covers at least 60% of the length of the bottom washcoat layer,
• wherein at least a portion of the top washcoat layer comprises rhodium or a mixture of rhodium and platinum group metal(s) deposited within the washcoat layer(s) with a rhodium gradient, wherein the rhodium concentration in a top-most portion of the washcoat layer is at least two times higher compared to the rhodium concentration in a bottom-most portion of the washcoat layer,
• wherein a length of the portion of the top washcoat layer, the bottom washcoat layer or both washcoat layers ranges from 20%-100% of the substrate length,
• wherein the total platinum group metal loading deposited with a gradient is 30% to 95% of the total platinum group metal loading present in the washcoat layer, and
• wherein the top washcoat layer comprises uniformly deposited rhodium, a ratio of a total amount of the uniformly deposited rhodium within the top washcoat compared to an amount of the rhodium deposited by gradient ranges from 10:1 and 1:10.

An emission control catalyst article comprising:

• a substrate having a first inlet axial end and a second outlet axial end,
• a bottom washcoat layer comprising a platinum group metal coated on 60% to 100% length of the substrate from the first axial end to the second axial end, and
• a top washcoat layer comprising a platinum group metal (PGM) coated on 60% to 100% length of the substrate from either the first axial or the second axial end of the substrate, wherein the top washcoat covers at least 60% of the length of the bottom washcoat layer,
• wherein at least a portion of the top washcoat layer, the bottom washcoat layer or both washcoat layers comprises a platinum group metal deposited within the washcoat layer(s) with a platinum group metal gradient, wherein the PGM concentration in a top-most portion of the washcoat layer is at least two times higher compared to the PGM concentration in a bottom-most portion of the washcoat layer, and
• wherein a length of the portion of the top washcoat layer, the bottom washcoat layer or both washcoat layers ranges from 20%-100% of the substrate length;
• and
• wherein the platinum group metal gradient is formed by enriching a portion of the top washcoat layer, the bottom washcoat layer, or both the top washcoat layer and the bottom washcoat layer, which is essentially free of any platinum group metal, with a platinum group metal or a combination thereof.