Purification method for obtaining high-purity carbon nano tube

A carbon nanotube and purification method technology, applied in nanotechnology, nanotechnology, nanostructure manufacturing and other directions, can solve the problems of harsh conditions, uneconomical, low crystalline graphite carbon impurity removal efficiency, etc., and achieves good stability and operating conditions. less demanding effects

Inactive Publication Date: 2010-07-21
PEKING UNIV
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Problems solved by technology

[0002] Single-walled carbon nanotubes have excellent physical and chemical properties, so they have potential application prospects in many fields such as aerospace, military affairs, and medicine, but how to remove a large amount of metal catalysts required in their production process under less harsh conditions As well as non-carbon tube carbon, it is still a difficult problem to obtain a large amount of high-purity single-walled carbon nanotubes
[0003] Modern carbon nanotube production technology has made great progress, especially the carbon nanotubes produced by the arc method have a high degree of graphitization, and their properties in all aspects are better than those produced by the CVD method, but the carbon nanotubes produced by the arc method The tubes contain a large amount of non-tube carbon impurities and residual metal catalyst impurities, which seriously hinder the application potential of carbon nanotubes in various fields.
[0004] The existing purification methods have limited purification effect on crude carbon nanotubes with high impurity content, which is mainly reflected in the low removal efficiency of crystalline graphite carbon impurities, so that it is difficult to completely remove the metal catalyst particles wrapped in it, which is mainly due to Since the chemical stability of crystalline graphitic carbon is higher than that of carbon nanotubes, neither liquid phase oxidation nor gas phase oxidation can completely and effectively remove crystalline carbon impurities.
[0005] Although there are currently some reported methods that can also obtain high-purity single-walled carbon nanotubes, the raw materials used are often samples with relatively low impurity content, which is not economical; in addition, the method of ultra-high temperature calcination under high vacuum conditions is adopted The conditions for obtaining high-purity single-walled nanotubes are very harsh, and it is difficult to realize and popularize; moreover, most methods are not suitable for the purification of a large number of samples (single processing capacity > 200mg), and with the application of single-walled carbon nanotubes With the continuous expansion of the industry, the demand for high-purity tubes is growing rapidly, so it is urgent to establish a purification process with mild conditions suitable for industrial mass production

Method used

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  • Purification method for obtaining high-purity carbon nano tube

Examples

Experimental program
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Effect test

Embodiment 1

[0035] Take 600mg of arc-produced SWNTs in 600ml of HNO 3 (2.6M) was refluxed for 6h, after vacuum filtration, the filter cake was dispersed in 600ml of HCl (6M) and refluxed for 12h, after vacuum filtration, the solid filter cake was washed to neutrality.

[0036] Remove the solid filter cake, ultrasonically disperse it in 100ml deionized water, and stir it properly to make it more uniform. Then the single-walled carbon nanotube aqueous solution was put into three 50ml plastic centrifuge tubes in equal portions, quick-frozen in liquid nitrogen, and dried into a fluffy flocculent solid product with freeze-drying equipment.

[0037] Then it was treated with water vapor at 900°C (Ar gas was bubbled in water at 98°C to carry water vapor, the flow rate was 100ml / min) for 2 hours. The single-walled carbon nanotubes treated with water vapor were then soaked in HCl (6M) overnight, filtered to remove acid, and washed with deionized water until neutral.

[0038] The electron micrograph...

Embodiment 2

[0042] Take 200mg of arc-produced double-walled carbon nanotubes in 100ml of HNO 3 (5.2M) backflow 12h, after decompression filtration, filter cake is dispersed in the H of 150ml 2 SO 4 (4M) was refluxed for 6 hours, and after vacuum filtration, the solid filter cake was washed to neutrality.

[0043] Remove the solid filter cake, ultrasonically disperse it in 100ml deionized water, and stir it properly to make it more uniform. Then the acid-oxidized double-walled carbon nanotube aqueous solution was packed into three 50ml plastic centrifuge tubes in equal portions, quick-frozen in liquid nitrogen, and dried into a fluffy flocculent solid product with freeze-drying equipment.

[0044] Then steam treatment at 900° C. (Ar gas flow rate 200 ml / min, bubbling in water at 90° C. to carry water vapor) for 4 hours. The steam-treated double-walled carbon nanotubes were then soaked in HCl (10M) for 24 hours, filtered to remove acid, and washed with deionized water until neutral.

[...

Embodiment 3

[0047] Get 1000mg of single-walled carbon nanotubes prepared by CVD, and process them according to the method of Example 1, but steps 1) and 2) use 1000ml hydrogen peroxide (mass concentration 15%) and 300ml HCl (10M) solutions respectively, and reflux treatment respectively 2h and 4h, and then filtered under reduced pressure, the filter cake was vacuum-dried and thoroughly ground for 6h to become a fluffy flocculent solid product.

[0048] It was then treated with water vapor (Ar gas flow rate 80ml / min in water at 98°C to carry water vapor) at 800°C for 4 hours. The single-walled carbon nanotubes treated with water vapor were then soaked in HCl (2M) for 6 hours, filtered to remove acid, and washed with deionized water until neutral.

[0049] Purified CVD single-walled carbon nanotubes: Raman spectroscopy I G / I D =42.4, thermogravimetric analysis purity: 90% (silicate is contained in the raw material).

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Abstract

The invention relates to the technical field of carbon nano materials, in particular to a purification method for obtaining a high-purity carbon nano tube. The method combines liquid-phase oxidation, acid treatment and gas-phase oxidation, and simultaneously and fully utilizes the fluffy technology to increase the pore space and the specific surface area in a sample, thereby greatly improving the treatment efficiency of eliminating graphite carbon impurities and preparing the high-purity carbon nano tube. The method is specially suitable for purifying single-walled carbon nano tubes prepared by an arc process, has good stability and low requirements on operation conditions and can carry out industrialized amplification; both the productivity and purity of the obtained products reach or exceed the best result reported by recent literatures; and in addition, the method can also be applied to purifying various carbon nano tubes produced by other methods, and the obtained high-purity carbon nano tube has wide usable range.

Description

technical field [0001] The invention relates to the technical field of carbon nanomaterials, in particular to a purification method for obtaining high-purity carbon nanotubes. Background technique [0002] Single-walled carbon nanotubes have excellent physical and chemical properties, so they have potential application prospects in many fields such as aerospace, military affairs, and medicine, but how to remove a large amount of metal catalysts required in their production process under less harsh conditions As well as non-carbon tube carbon, it is still a difficult problem to obtain a large amount of high-purity single-walled carbon nanotubes. [0003] Modern carbon nanotube production technology has made great progress, especially the carbon nanotubes produced by the arc method have a high degree of graphitization, and their properties in all aspects are better than those produced by the CVD method, but the carbon nanotubes produced by the arc method The tubes contain a l...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/02B82B3/00
Inventor 郭威孙红芳窦增培李鹤刘元方
Owner PEKING UNIV
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