Perovskite-type metal oxide compounds and methods of making and using thereof

• US 6,372,686 B1
• Filed: 11/10/2000
• Issued: 04/16/2002
• Est. Priority Date: 04/10/1996
• Status: Expired due to Term

• Current Assignee: Catalyst Health Solutions Incorporated (UnitedHealth Group Incorporated)
• Original Assignee: Catalyst Health Solutions Incorporated (UnitedHealth Group Incorporated)
• Inventors: Golden, Stephen J.
• Primary Examiner(s): Griffin, Steven P.
• Assistant Examiner(s): Nguyen, Cam N.
• Application Number:
  US09/710,378
• Time in Patent Office: 522 Days
• Field of Search: 502/302, 502/305, 502/313, 502/314, 502/315, 502/324, 502/325, 502/326, 502/328, 502/337, 502/339, 502/340, 502/349, 502/353, 502/304, 423/263
• US Class Current: 502/302
• 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 23/83 with rare earths or actinides
• CPC Class Codes: B01J 23/8892 Manganese
• CPC Class Codes: B01J 2523/00 Constitutive chemical elements of heterogeneous catalysts
• CPC Class Codes: B01J 2523/13 Potassium
• CPC Class Codes: B01J 2523/17 Copper
• CPC Class Codes: B01J 2523/23 Calcium
• CPC Class Codes: B01J 2523/24 Strontium
• CPC Class Codes: B01J 2523/25 Barium
• CPC Class Codes: B01J 2523/3706 Lanthanum
• CPC Class Codes: B01J 2523/67 Chromium
• CPC Class Codes: B01J 2523/72 Manganese
• CPC Class Codes: B01J 2523/821 Ruthenium
• CPC Class Codes: B01J 2523/822 Rhodium
• CPC Class Codes: B01J 2523/824 Palladium
• CPC Class Codes: B01J 2523/828 Platinum
• CPC Class Codes: B01J 2523/842 Iron
• CPC Class Codes: B01J 2523/845 Cobalt
• CPC Class Codes: B01J 2523/847 Nickel
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies
• CPC Class Codes: Y10S 502/525 : Perovskite

Abstract

Perovskite-type catalyst consists essentially of a metal oxide composition is provided. The metal oxide composition is represented by the general formula A_a-xB_xMO_b, in which A is a mixture of elements originally in the form of single phase mixed lanthanides collected from bastnasite; B is a divalent or monovalent cation; M is at least one element selected from the group consisting of elements of an atomic number of from 23 to 30, 40 to 51, and 73 to 80; a is 1 or 2; b is 3 when a is 1 or b is 4 when a is 2; and x is a number defined by 0≦x<0.5. Methods of making and using the perovskite-type catalysts are also provided. The perovskite-type catalyst may be used to make a catalytic converter. Methods of making a catalytic converter are also provided.

Claims

1. A method of making a catalytic converter comprising the steps of:

(a) providing a perovkite-type catalyst comprising a metal oxide composition represented by the general formula;

2. The method of making a catalytic converter of claim 1, wherein the perovskite-type catalyst is in a bulk form.

3. The method of making a catalytic converter of claim 2, which further comprises the steps of providing a carrier powder and mixing the carrier powder into the stable slurry suspension of step (c).

4. The method of making a catalytic converter of claim 3, wherein the carrier powder is an inert powder.

5. The method of making a catalytic converter of claim 4, wherein the inert powder is a gamma-alumina powder, a ceria-based powder, or a mixture thereof.

6. The method of making a catalytic converter of claim 3, wherein the carrier powder is selected from the group consisting of titania, silica, gamma alumina, alpha alumina, ceria, zirconia, ceria-zirconia, and mixtures thereof.

7. The method of claim 3, wherein the bulk perovskite-type catalyst and the carrier powder is slurry deposited onto the support as a layer of washcoat.

8. The method of making a catalytic converter of claim 7 further comprising the steps of:

(a) forming a homogeneous solution of a single phase mixed lanthanide salt of element A collected from bastnasite and respective salts or oxides of elements B and M, wherein the ratio of A;

B;

M is the ratio represented by the general formula;

9. The method of making a catalytic converter of claim 8, wherein the perovskite-type metal oxide deposited on the pre-coated support may be the same or different from the bulk perovskite-type catalyst contained in the pre-coated support.

10. The method of claim 9, wherein the perovskite-type metal oxide has a formula Ln_0.5Sr_0.5Mn_0.98Pd_0.02O₃, and the bulk perovskite-type catalyst has a formula Ln_0.8Sr_0.2Mn_0.9O₃.

11. The method of making a catalytic converter of claim 10, wherein the carrier is a mixture of ceria-zirconia and gamma alumina powders.

12. The method of making a catalytic converter of claim 7 further comprising the steps of:

(a) forming a homogeneous solution of a salt of a catalyst;

(b) impregnating the solution onto washcoat of the support; and

(c) calcining said support impregnated with said solution for forming the catalyst on the support.

13. The method of making a catalytic converter of claim 12, wherein the solution contains single base, noble metals, or a binary mixture thereof.

14. The method of making a catalytic converter of claim 13, wherein the single base metal is selected from a group consisting of metallic elements with atomic numbers 3-4, 11-15, 19-32, 37-43, 48-52, 56-75, and 80-83.

15. The method of making a catalytic converter of claim 13, wherein the noble metal is selected from a group consisting of elements with atomic numbers 44, 45, 46, 47, 76, 77, 78 and 79.

16. The method of making a catalytic converter of claim 13, wherein the binary mixture is a mixture of two single bases, a single base and a noble metal, or two noble metals.

17. The method of making a catalytic converter of claim 13, wherein the catalyst solution has the cation ratio Sr₂Pd_0.1.

18. The method of making a catalytic converter of claim 1, wherein the perovskite-type catalyst is in a form of dispersion.

19. The method of making a catalytic converter of claim 18, wherein the dispersion form of the perovskite-type catalyst is formed by the steps of:

(a) forming a homogeneous solution of a single phase mixed lanthanide salt of element A collected from bastnasite and respective salts or oxides of elements B and M, wherein the ratio of A;

B;

M is the ratio represented by the general formula;

20. The method of making a catalytic converter of claim 19, wherein the carrier powder is selected from a group consisting of titania, silica, gamma alumina, alpha alumina, ceria, zirconia, ceria-zirconia, and mixtures thereof.

21. The method of claim 1, wherein the support is in the form of beads or pellets.

22. The method of claim 21, wherein the support is made of a carrier material.

23. The method of claim 22, wherein the carrier material is selected from the group consisting of aluminas, titania, and silica.

24. The method of claim 1, wherein the support structure is a honeycomb support.

25. The method of claim 24, wherein the honeycomb support is a ceramic honeycomb support.

26. The method of claim 24, wherein the honeycomb support is a metal honeycomb support.

27. A method of making a catalytic converter comprising the steps of:

(a) providing a carrier powder;

(b) providing a support;

(c) depositing the carrier powder to the surface of the support for forming a washcoat on the surface of the support;

(d) forming a homogeneous solution of a single phase mixed lanthanide salt of element A collected from bastnasite and respective salts or oxides of elements B and M, wherein the ratio of A;

B;

M is the ratio represented by the general formula;

28. The method of claim 27, wherein the carrier powder is selected from a group consisting of titania, silica, gamma-alumina, alpha-alumina, ceria, zirconia, ceria-zirconia, ceria doped with rare-earths, alkaline earths, and transition metals.

29. The method of claim 27, wherein the washcoat comprises ceria-zirconia.

30. The method of claim 29, wherein the washcoat further comprises up to 10 parts of alumina by weight per part of ceria-zirconia.