High-purity helical carbon nanotubes and preparation method thereof

Abstract

The invention relates to high-purity helical carbon nanotubes and a preparation method thereof. The method comprises the following steps: (1) preparation of alpha-crystal-form nano iron oxide catalyst precursor: preparing the alpha-crystal-form nano iron oxide catalyst precursor by pre-precipitation in combination with a sol-gel process; and (2) preparation of high-purity helical carbon nanotubes: putting the alpha-crystal-form nano iron oxide catalyst precursor into a pipe furnace, reducing the alpha-crystal-form nano iron oxide catalyst precursor into a nano iron catalyst by an in-situ reduction process, introducing a carbon source and vapor as catalytic regulation aids, and keeping the temperature for 6-10 hours, thereby obtaining the igh-purity helical carbon nanotubes. The method is simple, safe and environment-friendly. The purity of the prepared helical carbon nanotubes is up to 99% or above, and the yield is up to 7709-8077 (g-HCNTs / g catalyst); and the product has uniform parameters (diameter, helical diameter, screw pitch and the like) and complete shape.

Description

technical field [0001] The invention relates to the field of preparation of micro-nano materials, in particular to a high-purity helical carbon nanotube and a preparation method thereof. Background technique [0002] Molecules with a helical structure have chirality, so that they have unique physical properties such as optics, electricity, and magnetism, and have broad application prospects in chiral separation, optoelectronic devices, and electromagnetic wave absorption; helical structures exist in nature and conform to The law of evolution in nature follows the law of thermodynamics, and the same is true for carbon nanotubes (helical carbon nanotubes HCNTs) with helical morphology. It can be expected that HCNTs can play an important role in micro-nano devices and modified polymer composites; however, the relevant The preparation technology of HCNTs is not mature. The main performance is that the size and uniformity of the catalyst are difficult to guarantee, the helical pu...

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Problems solved by technology

[0002] Molecules with a helical structure have chirality, so that they have unique physical properties such as optics, electricity, and magnetism, and have broad application prospects in chiral separation, optoelectronic devices, and electromagnetic wave absorption; helical structures exist in nature and conform to The law of evolution in nature follows the law of thermodynamics, and the same is true for carbon nanotubes (helical carbon nanotubes HCNTs) with helical morphology. It can be expected that HCNTs can play an important role in micro-nano devices and modified polymer composites; however, the relevant The preparation technology of HCNTs is not mature, the main performance is that the size and uniformity of the catalyst are difficult to guarantee, the helical purity of HCNTs is difficult to control, the yield is too low and the process is complicated, etc., which cannot meet people's requirements for applications.

[0003] At present, the preparation method of HCNTs is similar to that of carbon nanotubes (CNTs), mainly by chemical vapor deposition, but the helical purity of the product is not high, and the preparation of high-purity HCNTs is still very difficult, mainly because the catalyst particles The size and shape are difficult to control, resulting in low purity of the helical product; in the prior art, the main solution is usually to add a second component to the catalyst or introduce H during the catalytic growth process. 2 S, thiophene, etc. as growth aids can significantly improve the helical purity of the product, but this not only makes the preparation process of the catalyst more complicated, but also H 2 The introduction of toxic and polluting substances such as S and thiophene can also cause environmental problems

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