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

• US 20030198582A1
• Filed: 02/06/2003
• Published: 10/23/2003
• Est. Priority Date: 04/10/1996
• Status: Active Grant

• Current Assignee: Catalyst Health Solutions Incorporated (UnitedHealth Group Incorporated)
• Original Assignee: Catalyst Health Solutions Incorporated (UnitedHealth Group Incorporated)
• Inventors: Golden, Stephen J.
• Granted Patent: US 7,014,825 B2
• Time in Patent Office: Days
• US Class Current: 423/213.2
• CPC Class Codes: B01D 53/944 Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts three-way-catalysts [TWC] B01D53/9445
• 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 2523/3712 Cerium
• CPC Class Codes: B01J 2523/3718 Praseodymium
• CPC Class Codes: B01J 2523/3725 Neodymium
• 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: F01N 2370/02 : used in catalytic reactors
• CPC Class Codes: F01N 2510/06 : for exhaust purification, e.g. catalytic reaction
• CPC Class Codes: F01N 2610/02 : the substance being ammonia or urea
• CPC Class Codes: F01N 3/206 : Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents F01N3/2066 takes precedence
• CPC Class Codes: F01N 3/281 : Metallic honeycomb monoliths made of stacked or rolled sheets, foils or plates
• CPC Class Codes: F01N 3/2828 : Ceramic multi-channel monoliths, e.g. honeycombs
• CPC Class Codes: Y02A 50/20 : Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• 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 and methods of using them are 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 reduce nitrogen oxides, oxidize carbon monoxide, and oxidize hydrocarbons in an exhaust stream from a motor vehicle. Methods of such a use are provided.

Claims

1. A method of reducing nitrogen oxides, oxidizing carbon monoxide, and oxidizing hydrocarbons in an exhaust stream from a motor vehicle, said method comprising:

contacting the exhaust stream with a perovskite-type catalyst consisting essentially of a metal oxide composition represented by the general formula;

A<sub>a−

x</sub>B_xMO_b

wherein

A is a mixture of elements originally in the form of a single phase mixed lanthanide 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 22 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<

0.7.

2. The method of claim 1, wherein A comprises elements selected from the group consisting of lanthanides having an atomic number of from 57 to 71.

3. The method of claim 1, wherein B is selected from the group consisting of Ca, Sr, and K.

4. The method of claim 1, wherein M is selected from the group consisting of Fe, Mn, Co, Ni, Ru, Cr, and mixtures thereof.

5. The method of claim 1, wherein the perovskite-type catalyst is selected from the group consisting of Ln_0.6Ca_0.4CoO₃, Ln_0.83Sr_0.17MnO₃, Ln_0.7Sr_0.3CrO₃, Ln_0.6Ca_0.4Fe_0.8Mn_0.2O₃, Ln_0.8Sr_0.2Mn_0.9Ni_0.04Ru_0.06O₃, Ln_0.8K_0.2Mn_0.95Ru_0.05O₃, Ln_0.7Sr_0.3Cr_0.95Ru_0.05O₃, LnNiO₃, Ln₂(Cu_0.6Co_0.2Ni_0.2)O₄, Ln_0.6Ca_0.4Fe_0.8Mn_0.2O₃, Ln_0.8Sr_0.2Mn_0.9Ni_0.04Pd_0.06O₃, Ln_0.8Sr_0.2Mn_0.9Ni_0.04Pt_0.06O₃, Ln_0.7Sr_0.3Mn_0.9Ni_0.04Ru_0.06O₃, LnMn_0.5Cu_0.5O₃, LnMn_0.8Ni_0.10Cu_0.10O₃, Ln_0.7Sr_0.3Mn_0.9Pd_0.1O₃, Ln_0.5Sr_0.5Mn_0.9Pd_0.1O₃, Ln_0.8Sr_0.2MnO₃, Ln_0.5Sr_0.5Mn_0.98Pd_0.02O₃, Ln_0.8Sr_0.2Mn_0.96Pd_0.04O₃, Ln_0.5Sr_0.5Mn_0.95Pt_0.05O₃, Ln_0.8Sr_0.2Mn_0.92Ni_0.05Pd_0.03O₃, Ln_0.8Sr_0.2Mn_0.94Pt_0.05Rh_0.01O₃, Ln_0.8Ba_0.2Mn_0.94Pd_0.06O₃, Ln_0.5Sr_0.5Mn_0.98Rh_0.02O₃, Ln_0.8Sr_0.2Co_0.9Ru_0.1O₃, Ln_0.8Sr_0.2Mn_0.9Ru_0.1O₃, Ln_0.5Sr_0.5Mn_0.95Pd_0.05O₃, Ln_0.5Sr_0.5Mn_0.95Ru_0.05O₃, and Ln_0.5Sr_0.5MnO₃, where Ln is a mixture of lanthanides originally in the form of a single phase mixed lanthanide collected from bastnasite.

6. The method of claim 1, wherein said contacting is at a temperature between 300°

C. and 900°

C.

7. The method of claim 1, wherein said contacting is at a temperature between 500°

C. and 700°

C.

8. The method of claim 1, wherein said exhaust stream has a redox potential R that is in the range of between about 0.86 and about 1.17 during said contacting.

9. The method of claim 1, wherein said catalyst is supported on a structure.

10. The method of claim 9, wherein said structure is a honeycomb support.

11. The method of claim 10, wherein said honeycomb support is a ceramic honeycomb support or a metal honeycomb support.

12. The method of claim 9, wherein said structure is in a form of beads or pellets.

13. The method of claim 9, wherein a carrier material or a mixture of carrier materials is deposited onto the support structure, thereby forming a washcoat on the surface of the support structure.

14. The method of claim 13, wherein a solution of salts of element A and salts or oxides of elements B and M is impregnated into said washcoat.

15. The method of claim 14, wherein the impregnated washcoat is died and calcined to form the perovskite-type catalyst in the form of a dispersion.

16. The method of claim 1, wherein said perovskite-type catalyst is a three-way catalyst.

17. A method of purifying industrial process emissions containing hydrocarbons, carbon monoxide, and nitrogen oxides, the method comprising:

contacting said emissions with a perovskite-type catalyst, thereby purifying said emissions, said perovskite-type catalyst consisting essentially of a metal oxide composition represented by the general formula;

A<sub>a−

x</sub>B_xMO_b

wherein A is a mixture of elements originally in the form of a single phase mixed lanthanide 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 22 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<

0.7.

18. The method of claim 17, wherein purifying said exhaust gas comprises reducing the nitrogen oxides and oxidizing the carbon monoxide and hydrocarbons in the exhaust gas.

19. The method of claim 17, wherein said contacting is at a temperature between 300°

C. and 900°

C.

20. The method of claim 17, wherein the emissions have a redox potential R in the range of between about 0.86 and 1.17 during said contacting.