Catalyst article, method and use
AssigneeJohnson Matthey Public Limited Company
InventorsHai-Ying Chen, Eric Tyo
Life of this patent
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Abstract
A three-way catalyst article is provided for the treatment of exhaust gas from a positive ignition engine, the catalyst article comprising: a substrate having a first layer provided thereon, wherein a second layer is provided on the first layer, wherein the first layer comprises a first metal and a first alumina, and wherein the second layer comprises a second metal and a second alumina, wherein either (i) the first metal is Pd and the second metal is Rh; or (ii) the first metal is Rh and the second metal is Pd; and wherein at least one of the first and second aluminas comprises theta alumina.
Claims19
A three-way catalyst article for the treatment of exhaust gas from a positive ignition engine, the catalyst article comprising:
- a substrate having a first layer provided thereon, wherein a second layer is provided on the first layer,
- wherein the first layer comprises a first metal and a first alumina, and
- wherein the second layer comprises a second metal and a second alumina,
- wherein either (i) the first metal is Pd and the second metal is Rh;
- or (ii) the first metal is Rh and the second metal is Pd;
- wherein at least one of the first and second aluminas comprises theta alumina;
- and
- wherein the first alumina comprises theta alumina.
A three-way catalyst article for the treatment of exhaust gas from a positive ignition engine, the catalyst article comprising:
- a substrate having a first layer provided thereon, wherein a second layer is provided on the first layer,
- wherein the first layer comprises a first metal and a first alumina, and
- wherein the second layer comprises a second metal and a second alumina,
- wherein either (i) the first metal is Pd and the second metal is Rh;
- or (ii) the first metal is Rh and the second metal is Pd;
- wherein at least one of the first and second aluminas comprises theta alumina;
- and
- wherein the second alumina comprises gamma alumina.
A three-way catalyst article for the treatment of exhaust gas from a positive ignition engine, the catalyst article comprising:
- a substrate having a first layer provided thereon, wherein a second layer is provided on the first layer,
- wherein the first layer comprises a first metal and a first alumina, and
- wherein the second layer comprises a second metal and a second alumina,
- wherein either (i) the first metal is Pd and the second metal is Rh;
- or (ii) the first metal is Rh and the second metal is Pd;
- wherein at least one of the first and second aluminas comprises theta alumina;
- wherein the theta alumina is stabilised with one or more stabilising elements selected from the group consisting of La, Nd, Sr, Si, Ti, Zr, Ba, Ca and Ce;
- and
- wherein the one or more stabilising element are present in a total amount by weight of the alumina of from 0.1 to 5 wt %.
Dependencies are inferred from the claim text.