Single-wall carbon nanotubes from high pressure CO

• US 7,204,970 B2
• Filed: 12/08/2003
• Issued: 04/17/2007
• Est. Priority Date: 11/03/1998
• Status: Expired due to Fees

• Current Assignee: Rice University
• Original Assignee: Rice University
• Inventors: Smalley, Richard E., Nikolaev, Pavel, Colbert, Daniel T., Smith, Ken A., Bronikowski, Michael J., Rohmund, Frank, Bradley, Robert K.
• Primary Examiner(s): Hendrickson; Stuart L.
• Assistant Examiner(s): Fiorito; James
• Application Number:
  US10/730,630
• Publication Number:
  US 20040223901A1
• Time in Patent Office: 1,226 Days
• Field of Search: 977/750, 977/751, 423/447.2, 423/447.3
• US Class Current: 423/447.2
• CPC Class Codes: B01J 19/121 Coherent waves, e.g. laser beams lasers per se H01S3/00
• CPC Class Codes: B01J 19/26 Nozzle-type reactors, i.e. the distribution of the initial reactants within the reactor is effected by their introduction or injection through nozzles
• CPC Class Codes: B01J 2219/0875 Gas
• CPC Class Codes: B01J 3/04 Pressure vessels, e.g. autoclaves
• CPC Class Codes: B01J 3/042 in the form of a tube
• CPC Class Codes: B01J 4/002 Nozzle-type elements nozzle-type reactors B01J19/26
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C01B 2202/02 Single-walled nanotubes
• CPC Class Codes: C01B 2202/36 Diameter
• CPC Class Codes: C01B 32/162 characterised by catalysts
• CPC Class Codes: D01F 9/1278 Carbon monoxide
• CPC Class Codes: Y10S 977/75 Single-walled
• CPC Class Codes: Y10S 977/751 with specified chirality and/or electrical conductivity
• CPC Class Codes: Y10S 977/843 Gas phase catalytic growth, i.e. chemical vapor deposition
• CPC Class Codes: Y10S 977/845 Purification or separation of fullerenes or nanotubes
• CPC Class Codes: Y10S 977/951 Laser
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

The present invention discloses the process of supplying high pressure (e.g., 30 atmospheres) CO that has been preheated (e.g., to about 1000° C.) and a catalyst precursor gas (e.g., Fe(CO)₅) in CO that is kept below the catalyst precursor decomposition temperature to a mixing zone. In this mixing zone, the catalyst precursor is rapidly heated to a temperature that results in (1) precursor decomposition, (2) formation of active catalyst metal atom clusters of the appropriate size, and (3) favorable growth of SWNTs on the catalyst clusters. Preferably a catalyst cluster nucleation agency is employed to enable rapid reaction of the catalyst precursor gas to form many small, active catalyst particles instead of a few large, inactive ones. Such nucleation agencies can include auxiliary metal precursors that cluster more rapidly than the primary catalyst, or through provision of additional energy inputs (e.g., from a pulsed or CW laser) directed precisely at the region where cluster formation is desired. Under these conditions SWNTs nucleate and grow according to the Boudouard reaction. The SWNTs thus formed may be recovered directly or passed through a growth and annealing zone maintained at an elevated temperature (e.g., 1000° C.) in which tubes may continue to grow and coalesce into ropes.

Claims

1. A composition of matter comprising single wall carbon nanotubes wherein at least 95% of said single wall carbon nanotubes have a diameter in the range of 0.6 nm to 0.8 nm.

2. The composition of matter of claim 1, wherein said single wall carbon nanotubes are aggregated as ropes.

3. The composition of matter of claim 1, wherein said single wail carbon nanotubes comprise (5,5) single wall carbon nanotubes.

4. A product made by a process comprising:

(a) providing a gas stream comprising CO at superatmospheric pressure;

(b) providing a gaseous catalyst precursor stream comprising a gaseous catalyst precursor comprising atoms of a transition metal selected from the group consisting of Group VI metals, Group VIII metals and mixtures thereof, said gaseous catalyst precursor stream being provided at a temperature below the decomposition temperature of said catalyst precursor;

(c) heating said gas stream comprising CO to a temperature that is at least above the decomposition temperature of said catalyst precursor and is sufficient to form single wall carbon nanotubes;

(d) mixing said heated gas stream comprising CO with said gaseous catalyst precursor stream into a reaction mixture in a mixing zone to rapidly heat said catalyst precursor to a temperature that is

(i) above the decomposition temperature of said catalyst precursor,

(ii) sufficient to promote the formation of catalyst metal atom clusters and

(iii) sufficient to promote the initiation and growth of single wall carbon nanotubes; and

(e) forming solid products comprising the single wall carbon nanotubes that are in a resulting gaseous stream, wherein at least 99% of atoms of the solid products are atoms of the single wall carbon nanotubes.

5. A product made by a process comprising:

(a) providing a gas stream comprising CO at superatmospheric pressure;

(b) providing a gaseous catalyst precursor stream comprising a gaseous catalyst precursor comprising atoms of a transition metal selected from the group consisting of Group VI metals, Group VIII metals and mixtures thereof, said gaseous catalyst precursor stream being provided at a temperature below the decomposition temperature of said catalyst precursor;

(c) heating said gas stream comprising CO to a temperature that is at least above the decomposition temperature of said catalyst precursor and is sufficient to form single wall carbon nanotubes;

(d) mixing said heated gas stream comprising CO with said gaseous catalyst precursor stream into a reaction mixture in a mixing zone to rapidly heat said catalyst precursor to a temperature that is

(i) above the decomposition temperature of said catalyst precursor;

(ii) sufficient to promote the formation of catalyst metal atom clusters and

(iii) sufficient to promote the initiation and growth of single wall carbon nanotubes; and

(e) forming solid products comprising the single wall carbon nanotubes that are in a resulting gaseous stream, wherein at least 95% of said single wall carbon nanotubes have a diameter in the range of 0.6 nm to 0.8 nm.

6. A product made by a process comprising:

(a) providing a CO gas stream comprising CO, wherein said CO gas stream is at a superatmospheric pressure;

(b) providing a gaseous catalyst precursor stream comprising a catalyst precursor;

(c) mixing the CO gas stream and the gaseous catalyst precursor stream to form a reaction mixture, wherein said mixing step occurs under reaction conditions to form single wall carbon nanotubes; and

(d) reacting said reaction mixture to form carbon products in tubular form, wherein at least 99% atom % of the carbon products in tubular form are single wall carbon nanotubes.

7. The product of claim 6, wherein at least 75% of said single wall carbon nanotubes have a diameter in the range of 0.6 nm to 0.8 nm.

8. The product of claim 6, wherein at least 95% of said single wall carbon nanotubes have a diameter in the range of 0.6 nm to 0.8 nm.