PALLADIUM SOLID SOLUTION CATAYST AND METHODS OF MAKING

• US 20130236380A1
• Filed: 08/08/2012
• Published: 09/12/2013
• Est. Priority Date: 08/10/2011
• Status: Active Grant

• Current Assignee: Clean Diesel Technologies, Inc.
• Original Assignee: Clean Diesel Technologies, Inc.
• Inventors: Golden, Stephen J., Hatfield, Randal, Pless, Jason D., Ngo, Johnny T.
• Granted Patent: US 9,012,353 B2
• Time in Patent Office: Days
• US Class Current: 423/213.2
• CPC Class Codes: B01D 2255/1023 Palladium
• CPC Class Codes: B01D 2255/1025 Rhodium
• CPC Class Codes: B01D 2255/204 Alkaline earth metals
• CPC Class Codes: B01D 2255/206 Rare earth metals
• CPC Class Codes: B01D 2255/2061 Yttrium
• CPC Class Codes: B01D 2255/2063 Lanthanum
• CPC Class Codes: B01D 2255/2065 Cerium
• CPC Class Codes: B01D 2255/2066 Praseodymium
• CPC Class Codes: B01D 2255/2068 Neodymium
• CPC Class Codes: B01D 2255/20715 Zirconium
• CPC Class Codes: B01D 2255/2073 Manganese
• CPC Class Codes: B01D 2255/20753 Nickel
• CPC Class Codes: B01D 2255/20761 Copper
• CPC Class Codes: B01D 2255/407 Zr-Ce mixed oxides
• CPC Class Codes: B01D 2255/908 O2-storage component incorporated in the catalyst
• CPC Class Codes: B01D 53/945 characterised by a specific catalyst
• CPC Class Codes: B01J 23/002 Mixed oxides other than spinels, e.g. perovskite
• CPC Class Codes: B01J 23/34 Manganese
• CPC Class Codes: B01J 23/44 Palladium
• CPC Class Codes: B01J 23/63 with rare earths or actinides
• CPC Class Codes: B01J 23/83 : with rare earths or actinides
• CPC Class Codes: B01J 2523/00 : Constitutive chemical elements of heterogeneous catalysts
• CPC Class Codes: B01J 2523/36 : Yttrium
• CPC Class Codes: B01J 2523/3712 : Cerium
• CPC Class Codes: B01J 2523/3725 : Neodymium
• CPC Class Codes: B01J 2523/48 : Zirconium
• CPC Class Codes: B01J 35/19 : Catalysts containing parts with different compositions
• CPC Class Codes: B01J 35/30 : characterised by their physical properties
• CPC Class Codes: B01J 35/396 : Distribution of the active metal ingredient
• CPC Class Codes: B01J 37/0036 : Grinding
• CPC Class Codes: B01J 37/0201 : Impregnation
• CPC Class Codes: B01J 37/0215 : Coating
• CPC Class Codes: B01J 37/0244 : Coatings comprising several layers
• CPC Class Codes: B01J 37/038 : to form slurries or suspensions, e.g. a washcoat
• CPC Class Codes: B01J 37/04 : Mixing B01J37/0009, B01J37/0018 take precedence
• CPC Class Codes: B01J 37/08 : Heat treatment B01J37/0009, B01J37/0018 take precedence
• CPC Class Codes: F01N 2510/0684 : having more than one coating layer, e.g. multi-layered coatings
• CPC Class Codes: F01N 2570/16 : Oxygen
• CPC Class Codes: F01N 3/101 : Three-way catalysts
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies

Abstract

Disclosed are three-way catalysts that are able to simultaneously convert nitrogen oxides, carbon monoxide, and hydrocarbons in exhaust gas emissions into less toxic compounds. Also disclosed are three-way catalyst formulations comprising palladium (Pd)-containing oxygen storage materials. In some embodiments, the three-way catalyst formulations of the invention do not contain rhodium. Further disclosed are improved methods for making Pd-containing oxygen storage materials. The relates to methods of making and using three-way catalyst formulations of the invention.

Claims

1. An oxygen storage material (OSM) comprising a metal oxide doped with at least one transition metal, wherein said transition metal and OSM are present as a solid solution.

2. The OSM of claim 1, wherein said OSM is a Ce-based oxygen storage material.

3. The OSM of claim 1, wherein said OSM is doped with about 0.5-10% of said transition metal.

4. The OSM of claim 1, wherein said transition metal is selected from the group consisting of:

Pd, Cu, Mn and Ni.

5. The OSM of claim 1, wherein said OSM comprises one or more of:

a. a SS Pd-IWCP OSM;

b. 30% CeO₂, 60% ZrO₂, 5% Nd₂O₃ and 5% Y₂O₃ or (30% CeO₂, 60% ZrO₂, 5% Nd₂O₃ and 5% Pr₆O₁₁).

6. A washcoat or overcoat comprising the oxygen storage material (OSM) of claim 1.

7. A catalyst system comprising:

a substrate and a washcoat,

wherein said washcoat comprises an oxygen storage material (OSM), and

wherein said OSM is an OSM of claim 1.

8. A catalyst system according to claim 7, wherein said overcoat comprises a support oxide, an OSM and a metal catalyst.

9. A catalyst system according to claim 7, further comprising an overcoat,

wherein said washcoat comprises a support oxide, an oxygen storage material (OSM) and a metal catalyst, and

wherein said overcoat comprises an OSM.

10. The catalyst system of claim 7, wherein said washcoat comprises platinum group metal (PGM) catalyst.

11. The catalyst system of claim 7, wherein the overcoat further comprises Ca, Sr, Ba or La.

12. The catalyst system of claim 7, wherein the washcoat or overcoat comprises Pd at a concentration of about 5-100 g/ft³ and said catalyst system is substantially free of Rh.

13. A method of making the oxygen storage material of claim 1, comprising:

1) adding an amount of transition metal salt to an aqueous slurry of milled OSM; and

2) adding an amount of base to generate an IWCP-OSM slurry.

14. A method of making a catalyst composition comprising an oxygen storage material of claim 1, comprising:

1) generating an IWCP-OSM slurry by;

a) adding an amount of transition metal salt to an aqueous slurry of milled OSM; and

b) adding an amount of base to generate an IWCP-OSM slurry;

2) generating a support oxide mixture by;

a) milling an amount of support oxide with acetic acid;

b) adding an amount of BaCO₃ or CaCO₃ and stirring to generate a support oxide mixture;

3) adding said support oxide mixture of

     2) to said IWCP-OSM slurry of

     1) and coating the resulting composition on to a washcoat; and

4) calcining the resulting mixture of

     3) to yield a catalyst composition.

15. A method of increasing oxygen flow through a catalyst system by utilizing an oxygen storage material (OSM) of claim 1 comprising a metal oxide doped with at least one transition metal,

wherein said OSM is present in the washcoat, overcoat, or both, and

wherein said transition metal and OSM are present as a solid solution.

16. A method of increasing the oxygen storage capacity of a catalyst system by utilizing an oxygen storage material (OSM) of claim 1 comprising a metal oxide doped with at least one transition metal,

wherein said OSM is present in the washcoat, overcoat, or both, and

wherein said transition metal and OSM are present as a solid solution.

17. A method of improving the lifetime of a platinum group metal (PGM) catalyst present in a catalyst system by utilizing an oxygen storage material (OSM) of claim 1 comprising a metal oxide doped with at least one transition metal,

wherein said OSM is present in the washcoat, overcoat, or both, and

wherein said transition metal and OSM are present as a solid solution.

18. A method of improving the light-off performance of a catalyst system by utilizing an oxygen storage material (OSM) of claim 1 comprising a metal oxide doped with at least one transition metal,

wherein said OSM is present in the washcoat, overcoat, or both, and

wherein said transition metal and OSM are present as a solid solution.

19. A method of reducing the amount of Rh present in a catalyst system while maintaining catalyst efficiency by utilizing an oxygen storage material (OSM) of claim 1 comprising a metal oxide doped with at least one transition metal,

wherein said OSM is present in the washcoat, overcoat, or both, and

wherein said transition metal and OSM are present as a solid solution.

20. A method of simultaneously converting a) nitrogen oxides to nitrogen and oxygen;

b) carbon monoxide to carbon dioxide; and

c) hydrocarbons to carbon dioxide and water present in exhaust gas emissions, comprising contacting said gas emissions with the catalyst system of claim 7.

21. A catalytic convertor system comprising the catalyst system of claim 7.

22. A close coupled catalytic converter comprising the oxygen storage material (OSM) of claim 1.

23. A catalyst system comprising:

a) an overcoat comprising an OSM and a Pd metal catalyst,

wherein said OSM comprises 30% CeO₂, 60% ZrO₂, 5% Nd₂O₃, and 5% Pr₆O₁₁ (% by weight),

and said overcoat comprises 5 g/ft³ of Pd; and

b) a washcoat comprising an OSM and a Pd metal catalyst,

wherein said OSM comprises 30% CeO₂, 60% ZrO₂, 5% Nd₂O₃ and 5% Y₂O₃ (% by weight),

and said washcoat comprises 15 g/ft³ of Pd.