Catalyst for abating a nitrogen oxide, method for preparing the same, and catalyst system for abating a nitrogen oxide

Patent metadata

Field	Value
Publication number	US-9821293-B2
Application number	US-201414562015-A
Country	US
Kind code	B2
Filing date	Dec 5, 2014
Priority date	Apr 24, 2014
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

A catalyst for abating a nitrogen oxide includes: a honeycomb substrate including a plurality of cell passages partitioned by a cell barrier rib; and a coating layer positioned on the internal side of the cell passages. The coating layer includes a support including Mg-substituted alumina (MgAl 2 O 4 ), ceria (Ce), and a composite ceria; and Ba and a noble metal catalyst selected from the group consisting of Pt, Pd, Rh and combinations thereof, which are supported on the support. Also provided is a catalyst system for abating a nitrogen oxide includes the coating layer.

First claim

What is claimed is:

1. A catalyst for abating a nitrogen oxide, comprising:
a honeycomb substrate comprising a plurality of cell passages partitioned with a cell barrier rib; and
a coating layer positioned on the internal side of the cell passages,
wherein the coating layer comprises,
a support comprising Mg-substituted alumina (MgAl 2 O 4 ), ceria (CeO 2 ) and a composite ceria; and Ba and a noble metal catalyst selected from the group consisting of Pt, Pd, Rh and combinations thereof supported on the support,
wherein an amount of 50 to 70 wt % of the total of the Ba is supported on the Mg-substituted alumina (MgAl 2 O 4 ), an amount of 30 to 50 wt % of the total amount of the Ba is supported on the ceria (CeO 2 ), and an amount less than or equal to 20 wt % of the total amount of the Ba is supported on the composite ceria.

2. The catalyst of claim 1 , wherein the noble metal catalyst comprises:
the Pt in an amount of 80 to 90 wt % based on the total weight of the noble metal catalyst;
the Pd in an amount of 5 to 10 wt % based on the total weight of the noble metal catalyst; and
the Rh in an amount of 5 to 10 wt % based on the total weight of the noble metal catalyst.

3. The catalyst of claim 1 , wherein an amount of 10 to 25 wt % of the total amount the Pt is supported on the ceria.

4. The catalyst of claim 1 , wherein the noble metal catalyst supported on the Mg-substituted alumina (MgAl 2 O 4 ) is a Pt/Pd alloy, and the Pt/Pd alloy is supported in an amount of 30 to 50 wt % of the total amount of the Pt and in an amount of 80 to 100 wt % of the total amount of the Pd.

5. The catalyst of claim 1 , wherein noble metal catalyst supported on the composite ceria is a Pt and Rh combination, and the Pt and Rh combination is supported in an amount of 40 to 60 wt % of the total amount of the Pt and in an amount of 80 to 100 wt % of the total amount of the Rh.

6. The catalyst of claim 1 , wherein the coating layer comprises:
the Mg-substituted alumina (MgAl 2 O 4 ) in an amount of 20 to 40 wt % based on the total weight of the coating layer;
the ceria (CeO 2 ) in an amount of 20 to 40 wt % based on the total weight of the coating layer;
the composite ceria in an amount of 20 to 40 wt % based on the total weight of the coating layer;
the Ba in an amount of 5 to 15 wt % based on the total weight of the coating layer; and
the noble metal catalyst in an amount of less than or equal to 1.5 wt % based on the total weight of the coating layer.

7. The catalyst of claim 1 , wherein the coating layer consists essentially of:
the Mg-substituted alumina (MgAl 2 O 4 ) in an amount of 20 to 40 wt % based on the total weight of the coating layer;
the ceria (CeO 2 ) in an amount of 20 to 40 wt % based on the total weight of the coating layer;
the composite ceria in an amount of 20 to 40 wt % based on the total weight of the coating layer;
the Ba in an amount of 5 to 15 wt % based on the total weight of the coating layer; and
the noble metal catalyst in an amount of less than or equal to 1.5 wt % based on the total weight of the coating layer.

8. The catalyst of claim 1 , wherein the Mg-substituted alumina (MgAl 2 O 4 ) is formed in a spinel structure.

9. The catalyst of claim 1 , wherein the composite ceria is a mixture of CeO 2 and at least one oxide selected from the group consisting of Al, Si, La, Pr, Zr, Nd and combinations thereof.

10. The catalyst of claim 9 , wherein the composite ceria comprises:
the CeO 2 in an amount of 60 to 90 wt %; and at least one oxide selected from the group consisting of Al, Si, La, Pr, Zr, Nd and combinations thereof in an amount of 10 to 40 wt %, based on the total weight of the composite ceria.

11. The catalyst of claim 1 , wherein the Mg-substituted alumina (MgAl 2 O 4 ) has an average particle diameter ranging from 7 to 15 μm.

12. The catalyst of claim 1 , wherein the ceria (CeO 2 ) has an average particle diameter ranging from 2 to 7 μm.

13. The catalyst of claim 1 , wherein the composite ceria has an average particle diameter ranging from 2 to 7 μm.

14. A catalyst system for abating a nitrogen oxide comprising a nitrogen oxide in exhaust gas and the catalyst for abating the nitrogen oxide of claim 1 by intercalating the nitrogen oxide.

15. The catalyst system of claim 14 , which is operated in a lean-burn engine having a theoretical air-fuel (A/F) ratio of greater than or equal to 14.7:1.

16. A vehicle comprising a catalyst of claim 1 for use to abate nitrogen oxide in exhaust gas.

Assignees

• Hyundai Motor Co Ltd
• Hyundai Motor Corp

Inventors

• Jung Chang-Ho

Classifications

• B01J2523/822

  Rhodium · CPC title

• B01J2523/824

  Palladium · CPC title

• B01J2523/828

  Platinum · CPC title

• B01J2523/25

  Barium · CPC title

• B01J35/40

  characterised by dimensions, e.g. grain size (in a colloidal state B01J35/23; crystallite size B01J35/77) · CPC title