Process for making single-wall carbon nanotubes utilizing refractory particles
First Claim
1. A method for producing single-wall carbon nanotubes comprising:
- (a) providing a transition metal catalyst precursor stream comprising a carrier gas and a transition metal catalyst precursor comprising at least one atom of at least one transition metal selected from the group consisting of Group VIb elements, Group VIIIb elements and combinations thereof, wherein the transition metal catalyst precursor stream is at a temperature below the decomposition temperature of the transition metal catalyst precursor;
(b) providing a refractory precursor stream comprising a carrier gas and a refractory precursor, wherein the refractory precursor is at a temperature below the thermolysis temperature of the refractory precursor;
(c) providing a carbon-containing feedstock gas stream at a temperature above the minimum single-wall carbon nanotube formation initiation temperature; and
(d) mixing the carbon-containing feedstock gas stream with the transition metal catalyst precursor stream and the refractory precursor stream to form a mixed gas stream, wherein (i) the transition metal catalyst precursor reaches a temperature above the decomposition temperature of the transition metal catalyst precursor, (ii) the refractory precursor reaches a temperature above which the thermolysis temperature of the refractory precursor and forms refractory particles, (iii) the temperature is sufficient to promote the initiation and growth of metal catalyst clusters on the refractory particles, and (iv) the temperature is sufficient to promote the initiation and growth of single-wall carbon nanotubes on the metal catalyst clusters and to form the single-wall carbon nanotubes in the mixed gas stream.
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Abstract
A continuous gas-phase method for producing single-wall carbon nanotubes at high catalyst productivity and high yield is disclosed. The method involves the use of a novel in-situ formed catalyst to initiate and grow single-wall carbon nanotubes using a carbon-containing feedstock in a high temperature and pressure process. The catalyst comprises in-situ-generated transition metal particles in contact with in-situ-generated refractory particles. The population of nucleating sites for single-wall carbon nanotubes is enhanced due to the ease of formation of a population of refractory particles. These, in turn, improve the nucleation and stability of the transition metal particles that grow on them. The larger number of transition metal particles translate into a larger number of sites for single-wall carbon nanotube production. The higher catalyst yields provide a means for obtaining higher purity single-wall carbon nanotubes.
81 Citations
52 Claims
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1. A method for producing single-wall carbon nanotubes comprising:
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(a) providing a transition metal catalyst precursor stream comprising a carrier gas and a transition metal catalyst precursor comprising at least one atom of at least one transition metal selected from the group consisting of Group VIb elements, Group VIIIb elements and combinations thereof, wherein the transition metal catalyst precursor stream is at a temperature below the decomposition temperature of the transition metal catalyst precursor;
(b) providing a refractory precursor stream comprising a carrier gas and a refractory precursor, wherein the refractory precursor is at a temperature below the thermolysis temperature of the refractory precursor;
(c) providing a carbon-containing feedstock gas stream at a temperature above the minimum single-wall carbon nanotube formation initiation temperature; and
(d) mixing the carbon-containing feedstock gas stream with the transition metal catalyst precursor stream and the refractory precursor stream to form a mixed gas stream, wherein (i) the transition metal catalyst precursor reaches a temperature above the decomposition temperature of the transition metal catalyst precursor, (ii) the refractory precursor reaches a temperature above which the thermolysis temperature of the refractory precursor and forms refractory particles, (iii) the temperature is sufficient to promote the initiation and growth of metal catalyst clusters on the refractory particles, and (iv) the temperature is sufficient to promote the initiation and growth of single-wall carbon nanotubes on the metal catalyst clusters and to form the single-wall carbon nanotubes in the mixed gas stream. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method for producing single-wall carbon nanotubes comprising:
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(a) providing a transition metal catalyst precursor stream comprising a carrier gas and a transition metal catalyst precursor comprising at least one atom of at least one transition metal selected from the group consisting of Group VIb elements, Group VIIIb elements and combinations thereof, wherein the transition metal catalyst precursor stream is at a temperature below the decomposition temperature of the transition metal catalyst precursor;
(b) providing a refractory precursor stream, comprising a carrier gas and a refractory precursor, (c) providing a refractory reactant stream comprising a refractory reactant compound capable of reacting with the refractory precursor to form a refractory material;
(d) providing a carbon-containing feedstock gas stream at a temperature above the minimum single-wall carbon nanotube formation initiation temperature; and
(e) mixing the carbon-containing feedstock gas stream with refractory precursor stream, the refractory reactant stream, and the transition catalyst precursor stream to form a mixed gas stream, wherein (i) the transition metal catalyst precursor reaches a temperature above the decomposition temperature of the transition metal catalyst precursor, (ii) the refractory precursor reacts with the refractory reactant to form refractory particles, (iii) the temperature is sufficient to promote the initiation and growth of metal catalyst clusters on the refractory particles, and (iv) the temperature is sufficient to promote the initiation and growth of single-wall carbon nanotubes on the metal catalyst clusters and to form the single-wall carbon nanotubes in the mixed gas stream. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
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48. A method for producing single-wall carbon nanotubes comprising:
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(a) providing a transition metal catalyst precursor stream comprising a carrier gas and a transition metal catalyst precursor, wherein the transition metal catalyst precursor stream is at a temperature below the transition metal catalyst precursor'"'"'s decomposition temperature;
(b) providing a refractory precursor stream comprising a carrier gas and a refractory precursor;
(c) providing a carbon-containing feedstock gas stream at a temperature above which formation of single-wall carbon nanotube formation can be initiated;
(d) mixing the carbon-containing feedstock gas stream with the transition metal catalyst precursor stream and the refractory precursor stream to form a mixed gas stream; and
(e) growing single-wall carbon nanotubes in the mixed stream. - View Dependent Claims (49, 50, 51, 52)
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Specification