Method of producing carbon nanotubes

a carbon nanotube and carbon nanotube technology, applied in the direction of catalyst regeneration/reactivation, physical/chemical process catalysts, metal/metal-oxide/metal-hydroxide catalysts, etc., can solve the problem that the method of growing swnts does not offer a means of controlling the chirality of swnt produced

Inactive Publication Date: 2010-09-23
HONDA MOTOR CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0013]A method of preparing cylindrical carbon structures by providing a catalyst component on a substrate and a carbon component, and contacting the catalyst component and the carbon component to produce a first cylindrical carbon structu

Problems solved by technology

The total amount of SWNT that could be grown by prior methods of growing SWNT using metal catalysts was limited by the build-up and coating of the metal catalyst with a layer composed of, among other compounds, amorphous carbon and metal carbides.
Additionally, the methods of growing the SWNTs did not offer means of controlling the chirality of the SWNT produced.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0043]Ferric nitrate (Fe(NO3)3.9H2O) can be dissolved in 2-propanol at an approximate concentration of 100 μg / mL, and stirred for 15 minutes. A previously prepared silicon dioxide substrate can then be immersed into the iron solution for 15 seconds, rinsed in hexane, and dried in air.

[0044]The substrate with the catalyst can then be placed in a tube furnace and reduced under a helium / hydrogen (60 / 40) gas flow (200 sccm) at 500 C for one hour. The He / H2 gas mixture can then be replaced with Ar gas, and the temperature increased to 750 C. Once the higher temperature is reached, then methane gas can be added at a flow rate of 20 sccm for 15 minutes, after which time the furnace is cooled to room temperature under a flow of argon. An atomic force microscopy (“AFM”) image can be obtained of the nanotubes.

[0045]The resulting supported iron nanoparticles with nanotubes can be cleaned by exposing the sample to a dry air flow (100 sccm) at a temperature of 200 C for thirty minutes.

[0046]The ...

example 2

[0049]Ferric nitrate (Fe(NO3)3.9H2O) and ammonium molybdate ((NH4)6Mo7O24.4H2O) at a 1:0.17 Fe:Mo molar ratio can be dissolved in methanol, and then mixed with a methanol suspension of alumina. The suspension can be deposited, drop wise, onto a previously prepared silicon dioxide substrate, and then dried in air.

[0050]The substrate with the bimetallic catalyst can then be placed in a tube furnace and reduced under a helium / hydrogen (60 / 40) gas flow (200 sccm) at 500 C for one hour. The He / H2 gas mixture can then be replaced with Ar gas, and the temperature increased to 750 C. Once the higher temperature is reached, then methane gas can be added at a flow rate of 20 sccm for 15 minutes, after which time the furnace is cooled to room temperature under a flow of argon. An atomic force microscopy (“AFM”) image can be obtained of the nanotubes.

[0051]The supported iron / molybdenum nanoparticles with nanotubes can be cleaned by exposing the sample to a dry air flow (100 sccm) at a temperatu...

example 3

[0055]Ferric nitrate (Fe(NO3)3.9H2O) can be dissolved in methanol at an approximate concentration of 150 μg / mL, and then mixed with a methanol suspension of alumina. The alumina can have a BET surface area of 150 m2 / g. The iron and alumina suspension can be deposited, drop wise, onto a previously prepared silicon dioxide substrate, and then dried in air.

[0056]The substrate with the catalyst can then be placed in a tube furnace and reduced under a helium / hydrogen (60 / 40) gas flow (200 sccm) at 500 C for one hour. The He / H2 gas mixture can then be replaced with Ar gas, and the temperature increased to 750 C. Once the higher temperature is reached, then methane gas can be added at a flow rate of 20 sccm for 15 minutes, after which time the furnace is cooled to room temperature under a flow of argon. An atomic force microscopy (“AFM”) image can be obtained of the nanotubes.

[0057]The supported iron nanoparticles with nanotubes can be cleaned by exposing the sample to a dry air flow (100 ...

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Abstract

The present teachings are directed to methods of preparing cylindrical carbon structures, specifically single-walled carbon nanotubes, with a desired chirality. The methods include the steps of providing a catalyst component on a substrate and a carbon component, contacting the catalyst component and the carbon component to produce a cylindrical carbon structure. Then, no longer providing the carbon component and determining the chirality of the cylindrical carbon structure. The catalyst component is then cleaned and the process is repeated until the cylindrical carbon structure fulfills a desired characteristic, such as, length. The chirality of the single-walled carbon nanotube grown, after cleaning of the catalyst component, has the same chirality as the initially produced nanotube.

Description

BACKGROUND[0001]1. Field of the Invention[0002]The present teachings relate to methods of producing carbon nanotubes from initially produced nanotubes so that the subsequently produced nanotubes have the same chirality as the initially produced nanotubes.[0003]2. Discussion of the Related Art[0004]The desire to produce cylindrical carbon structures, specifically carbon nanotubes, and more specifically, single-walled carbon nanotubes (hereinafter “SWNT”), with a specific chirality has been an unfilled desire since it was realized that the chirality of the nanotube influences or controls numerous nanotube properties.[0005]Smalley et al. have described a method of “cloning” SWNT grown by a CVD based method by growing SWNT fibers with open ends, reductively docking nanosized transition metal particles to the open ends of the SWNT fibers and restarting growth of the SWNT on the exposed metal particles. The SWNT growth from the docked nanocatalysts is said to have the same diameter and ch...

Claims

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Application Information

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IPC IPC(8): D01F9/12
CPCB01J21/04C01P2004/13B01J23/28B01J23/462B01J23/74B01J23/745B01J23/881B01J23/94B01J37/0203B01J37/0234B01J38/12B82Y30/00B82Y40/00C01B31/0233C01B2202/02C01B2202/04C01B2202/06B01J21/08Y02P20/584C01B32/162
InventorHARUTYUNYAN, AVETIK
OwnerHONDA MOTOR CO LTD