초록 ▼

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 Aa-xBx MOb, in which A is a mixture of elements originally in the form of single phase mixed lanthanides collected from

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 Aa-xBx MOb, 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.

대표청구항 ▼

What is claimed is: 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 rep

What is claimed is: 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: description="In-line Formulae" end="lead"Aa-xBxMObdescription="In-line Formulae" end="tail" 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 Ln0.6Ca0. 4CoO3, Ln0.83Sr0.17MnO3, Ln0. 7Sr0.3CrO3, Ln0.6Ca0.4Fe0. 8Mn0.2O3, Ln0.8Sr0.2Mn0. 9Ni0.04Ru0.06O3, Ln0.8K0. 2Mn0.95Ru0.05O3, Ln0.7Sr0. 3Cr0.95Ru0.05O3, LnNiO3, Ln 2(Cu0.6Co0.2Ni0.2)O4, Ln0. 6Ca0.4Fe0.8Mn0.2O3, Ln0. 8Sr0.2Mn0.9Ni0.04Pd0.06O 3, Ln0.8Sr0.2Mn0.9Ni0.04Pt0. 06O3, Ln0.7Sr0.3Mn0.9Ni0. 04Ru0.06O3, LnMn0.5Cu0.5O 3, LnMn0.8Ni0.10Cu0.10O3, Ln 0.7Sr0.3Mn0.9Pd0.1O3, Ln0. 5Sr0.5Mn0.9Pd0.1O3, Ln0. 8Sr0.2MnO3, Ln0.5Sr0.5Mn0. 98Pd0.02O3, Ln0.8Sr0.2Mn0. 96Pd0.04O3, Ln0.5Sr0.5Mn0. 95Pt0.05O3, Ln0.8Sr0.2Mn0. 92Ni0.05Pd0.03O3, Ln0.8Sr0. 2Mn0.94Pt0.05Rh0.01O3, Ln0. 8Ba0.2Mn0.94Pd0.06O3, Ln0. 5Sr0.5Mn0.98Rh0.02O3, Ln0. 8Sr0.2Co0.9Ru0.1O3, Ln0. 8Sr0.2Mn0.9Ru0.1O3, Ln0. 5Sr0.5Mn0.95Pd0.05O3, Ln0. 5Sr0.5Mn0.95Ru0.05O3, and Ln 0.5Sr0.5MnO3, 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 300째 C. and 900째 C. 7. The method of claim 1, wherein said contacting is at a temperature between 500째 C. and 700째 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: description="In-line Formulae" end="lead"Aa-xBxMObdescription="In-line Formulae" end="tail" 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 300째 C. and 900째 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.