Ammonia oxidation catalyst
AssigneeJohnson Matthey Public Limited Company
InventorsPAUL JOSEPH ANDERSEN, KEVIN DOURA
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Abstract
A catalyst article for treating an emission gas is provided comprising (a) a first catalyst layer having a plurality of consecutive sub-layers, wherein each sub-layer includes vanadium on a first refractory metal oxide support selected from alumina, titania, zirconia, ceria, silica, and mixtures of these; (b) a second catalyst layer comprising one or more noble metals disposed on a second refractory metal oxide support; and (c) a substrate, wherein the first and second catalyst layers are on and/or within the substrate.
Claims23
A catalyst article for treating an emission gas comprising:
- a. a first catalyst layer having a plurality of consecutive sub-layers, wherein each sub-layer includes vanadium on a first refractory metal oxide support selected from alumina, titania, zirconia, ceria, silica, and mixtures of these;
- b. a second catalyst layer comprising one or more noble metals disposed on a second refractory metal oxide support;
- and
- c. a substrate,
- wherein the first and second catalyst layers are on and/or within the substrate.
A method for preparing a catalyst article comprising:
- a. coating a substrate with a bottom catalyst layer comprising noble metal on a second refractory metal oxide support;
- b. coating said substrate with a top catalyst sub-layer comprising vanadia on a first refractory metal oxide support;
- and
- c. subsequent to step (b), coating said substrate with a consecutive catalyst top sub-layer comprising said vanadia on said first refractory metal oxide support,
- wherein said top sub-layers are applied over said bottom layer.
The method of claim 18, further comprising the step of calcining the catalyst article coated with the bottom layer and the top sub-layers at a temperature of about 400-600° C. for about 1-10 hours.
A catalyst article prepared by a process comprising the steps of:
- a. coating a substrate with a bottom catalyst layer comprising noble metal on a second refractory metal oxide support;
- b. coating said substrate with a top catalyst sub-layer comprising vanadia on a first refractory metal oxide support;
- and
- c. subsequent to step (b), coating said substrate with a consecutive catalyst top sub-layer comprising said vanadia on said first refractory metal oxide support,
- wherein said top sub-layers are applied over said bottom layer.
Dependencies are inferred from the claim text.