IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
US-0015453
(2001-12-11)
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발명자
/ 주소 |
- Baker, R. Terry K.
- Rodriguez, Nelly M.
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출원인 / 주소 |
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대리인 / 주소 |
Kean, Miller, Hawthorne, D'Armond, McCowan &
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인용정보 |
피인용 횟수 :
6 인용 특허 :
9 |
초록
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A method for producing high yields of high-purity carbon nanostructures having uniform average widths narrower than conventional carbon nanostructures. The nanostructures are produced from unsupported catalytic metal powders. A dispersing agent, such as sodium chloride, is blended with the catalytic
A method for producing high yields of high-purity carbon nanostructures having uniform average widths narrower than conventional carbon nanostructures. The nanostructures are produced from unsupported catalytic metal powders. A dispersing agent, such as sodium chloride, is blended with the catalytic metal powders prior to milling to the desired catalytic size to prevent the powder particles from sintering.
대표청구항
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1. A method for producing a carbon nanostructure from an unsupported powdered metal catalyst, which method comprises:mixing a) one or more metal compounds selected from the group consisting of metal carbonates, metal nitrates, and metal hydroxides, wherein at least one of the metals is a Group VIII
1. A method for producing a carbon nanostructure from an unsupported powdered metal catalyst, which method comprises:mixing a) one or more metal compounds selected from the group consisting of metal carbonates, metal nitrates, and metal hydroxides, wherein at least one of the metals is a Group VIII metal, with b) one or more dispersing agents selected from the group consisting of alkaline halides, alkaline-earth halides, and metal oxides; calcining the resulting mixture at a temperature from about 200° C. to about 400° C. for an effective amount of time to convert at least the metal compound to its respective oxide; milling the calcined mixture for an effective amount of time to decrease the particles comprising the mixture to a predetermined size, wherein the dispersing agent, during milling, serves to keep the metal powder particles from agglomerating; treating the milled, calcined mixture of particles with hydrogen for an effective amount of time and temperature to chemically reduce at least a portion of the catalytic metal oxides to the metallic state; and decomposing a carbon-containing compound having up to about 8 carbon atoms in the presence of at least a portion of the reduced milled, calcined mixture of catalytic metal particles and discrete dispersing agent at a temperature from about 450° C. to about 800° C. 2. The method of claim 1 wherein the amount of dispersing agent used is from about 1 to 50 wt. %, based on the total amount of catalytic metal compound and dispersing agent.3. The method of clam 2 wherein the amount of dispersing agent used is from about 5 to 25 wt. %.4. The method of claim 3 wherein the amount of dispersing agent used is from about 5 to about 10 wt %.5. The method of claim 1 wherein the dispersing agent is an alkaline halide selected from the group consisting of sodium fluoride, sodium chloride, sodium bromide, potassium fluoride, potassium chloride, potassium bromide, lithium fluoride, and rubidium fluoride.6. The method of claim 5 wherein the dispersing agent is sodium chloride.7. The method of claim 1 wherein the dispersing agent is an alkaline-earth halide selected from the group consisting of calcium fluoride, calcium chloride, calcium bromide, magnesium fluoride, magnesium chloride, magnesium bromide, barium fluoride, barium chloride, barium bromide, strontium fluoride, strontium chloride and strontium bromide.8. The method of claim 1 wherein the dispersing agent is a metal oxide selected from the group consisting of magnesia, silica, alumina, titania, tungsten oxide, tantalum oxide, molybdenum oxide, lanthanum oxide, tellurium oxide, chromium oxide, niobium oxide and zirconium oxide.9. The method of claim 1 wherein the predetermined size is about 2.5 nm to about 100 nm.10. The method of claim 1 wherein the catalytic metal is a bimetallic comprised of iron and nickel.11. The method of claim 10 wherein the ratio of iron to nickel is from about 1:9 to about 9:1.12. The method of claim 11 wherein the ratio of iron to nickel is from about 3:7 to about 7:3.13. The method of claim 11 wherein CO is used as the carbon-containing compound and is decomposed in the presence of H2 wherein the ratio of CO to H2 is from about 95:5 to about 5:95.14. The method of claim 13 wherein the ratio of CO to H2 is from about 80:20 to about 20:80.15. The method of claim 11 wherein CO is used as the carbon-containing compound and is decomposed in the presence of H2 wherein the ratio of CO to H2 is from about 80:20 to about 20:80.16. The method of claim 1 wherein the catalytic metal is a multimetallic comprised of at least one Group VIII metal and at least one Group IB metal.17. The method of claim 16 wherein the catalytic metal is a bimetallic comprised of iron and copper.18. The method of claim 17 wherein the particle size of the bimetallic powder is from about 2.5 nanometer to about 1 micrometer.19. The method of claim 18 wherein the milled, calcined mixture of particles is treated with a mixture of hydrogen and helium wherein the ratio of hydrogen to helium is about 4 to 1.20. The method of claim 1 wherein the particle size of the catalytic metal powder is from about 0.5 nanometer to about 5 micrometer.21. The method of claim 1 wherein the dispersing agent is removed from the resulting carbon nanofibers.22. The method of claim 21 wherein the dispersing agent is removed from the resulting carbon nanofibers by dissolving the dispersing agent in a suitable solvent selected from the group consisting of water, dilute acid, or with a dilute alkali solution.23. The method of claim 7 wherein the alkaline-earth halide is selected from calcium chloride and magnesium chloride.
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