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Method for removing carbon impurities in single-walled carbon nanotube

A single-walled carbon nanotube, carbon impurity technology, applied in nanotechnology, nanotechnology, nanotechnology for materials and surface science, etc., can solve the disadvantage of single-walled carbon nanotube application, loss of single-walled carbon nanotube, Carbon nanomaterial agglomeration and other problems, to achieve the effect of shortening the processing time, subsequent application is beneficial, and increasing the active surface

Active Publication Date: 2015-01-28
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

On the one hand, acid treatment (wet method) produces a lot of waste water that is not easy to handle, and at the same time, the carbon nanomaterials after washing will be agglomerated and difficult to disperse, which will affect the performance
On the other hand, the high-temperature oxidation method has poor selectivity and is not easy to control. While removing onion carbon nanoparticles and multi-walled carbon nanotube graphene, a large amount of single-walled carbon nanotubes will be lost.
Moreover, the thermal oxidation temperature of onion carbon nanoparticles and multi-wall carbon nanotubes is higher than that of single-wall carbon nanotubes, so it is not easy to completely remove them.
The above situation is unfavorable for the application of single-walled carbon nanotubes in transparent conductive displays and supercapacitors

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] The single-walled carbon nanotubes containing 50% multi-walled carbon nanotubes were ground with corundum balls, and the volume of the carbon product and the corundum balls was controlled to be 1:10, and ground for 20 hours. Transfer to a fixed-bed reactor, feed hydrogen at 850°C, control the weight space velocity of hydrogen to 0.1g / g carbon impurities / h, and treat at 0.3MPa (absolute pressure) for 72 hours. Then the gas flow rate was increased to 0.1m / s, and the treatment time was 0.5 hours. The multi-walled carbon nanotubes were separated from the single-walled carbon nanotubes by air classification and screening, and then cooled to room temperature. The mass fraction of single-walled carbon nanotubes in the product obtained for the first time is increased to 85%. Repeating the above steps, the mass fraction of single-walled carbon nanotubes in the product obtained for the second time increases to 95%. Repeating the above steps, the mass fraction of single-walled ca...

Embodiment 2

[0027] The single-walled carbon nanotubes containing 50% onion carbon nanoparticles were ground with boron nitride balls, and the volume of carbon products and boron nitride balls was controlled to be 10:1, and ground for 24 hours. Change to fluidized bed reactor, pass into 90% hydrogen and 10% argon (volume fraction) at 800 ℃, under the condition that the weight space velocity of control hydrogen is 10g / g carbon impurity / h, at 0.1MPa (absolute pressure) for 60 hours. Then the gas flow rate was increased to 0.01m / s, and the treatment time was 0.5 hours. The onion carbon nanoparticles and single-walled carbon nanotubes were separated by air classification and screening, and then cooled to room temperature. The mass fraction of single-walled carbon nanotubes in the product obtained for the first time is increased to 88%. Repeating the above steps, the mass fraction of single-walled carbon nanotubes in the product obtained for the second time increases to 96%. Repeating the abo...

Embodiment 3

[0029] The single-walled carbon nanotubes containing 5% onion carbon nanoparticles and 1% multi-walled carbon nanotubes were ground with boron nitride balls, and the volume of carbon products and boron nitride balls was controlled to be 1:2, and ground for 1 hour. Change over to fluidized bed reactor, pass into 50% hydrogen and 50% helium (volume fraction) at 480 ℃, plasma atmosphere, under the condition that the weight space velocity of control hydrogen is 5g / g carbon impurity / h, in 0.2MPa (absolute pressure) treatment for 48 hours. Then the gas flow rate was raised to 0.05m / s, and the treatment time was 0.3 hours, and the onion carbon nanoparticles, multi-walled carbon nanotubes and single-walled carbon nanotubes were separated, and then cooled to room temperature. The mass fraction of single-walled carbon nanotubes in the product obtained for the first time is increased to 97%. Repeating the above steps, the mass fraction of single-walled carbon nanotubes in the product ob...

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PUM

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Abstract

The invention discloses a method for removing carbon impurities in a single-walled carbon nanotube. The method comprises the following steps: mechanically grinding; carrying out high-temperature hydrogen or medium-temperature plasma hydrogen treatment; carrying out class screening on an air flow; and repeating the steps for two or three times. According to the method, the mass fraction of the carbon impurities in the single-walled carbon nanotube, namely onion carbon nanoparticles, a multiwalled carbon nanotube or amorphous carbon can be reduced from 50% to below 0.05%. Meanwhile, as the carbon impurities are fully treated by a dry method, the bulk structure of the single-walled carbon nanotube can be maintained, thereby providing a base for applications such as energy storage of a supercapacitor or transparent conductive display. The method has the advantages of being less in equipment, simple to operate, easy to repeat, easy for process amplification and low in cost.

Description

technical field [0001] The invention relates to the technical field of carbon impurities in single-wall carbon nanotubes, in particular to a method for removing carbon impurities in single-wall carbon nanotubes. Background technique [0002] Single-walled carbon nanotubes are nanomaterials with small diameter, large aspect ratio, large specific surface area, adjustable conductivity and semiconductor properties, and excellent mechanical strength. Conductive display materials, capacitor energy storage and other fields have extensive and important uses. [0003] Currently the most effective method for preparing single-walled carbon nanotubes is chemical vapor deposition. The principle is to use metal catalysts to crack carbon sources at higher temperatures. Due to the small diameter of single-walled carbon nanotubes, metal nanocatalysts with very small particle sizes must be used. But even so, carbon impurities such as onion carbon nanoparticles, multi-walled carbon nanotube...

Claims

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Application Information

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IPC IPC(8): C01B31/02B82Y30/00
Inventor 魏飞张兴华骞伟中张强
Owner TSINGHUA UNIV
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