Method and device for preparing nitrogen-doped carbon nanotubes by using microwave vapor deposition

Abstract

The invention discloses a method and device for preparing nitrogen-doped carbon nanotubes by using microwave vapor deposition. The method comprises the following steps that carbon nanotube powder is placed in a closed cavity, and the cavity is vacuumized; nitrogen gas is introduced to the cavity, the flow rate and air pressure of the nitrogen gas are adjusted, and meanwhile microwave irradiation is conducted to make the gas in the cavity absorb microwave energy and be excited to generate plasma; nitrogen atoms after plasma treatment can be doped into the surfaces and internal structures of carbon nanotubes to form the nitrogen-doped carbon nanotubes, and by controlling the microwave power and nitrogen doping time, the nitrogen carbon nanotubes with different nitrogen contents are obtained.A nitrogen gas source is subjected to plasma treatment by adopting a microwave plasma technology. Since the microwave power and the energy density are high and radical groups have high activity, thegas can be easily dissociated; the nitrogen carbon nanotubes prepared by means of the method are high in quality and purity and facilitates the test and characterization of ferromagnetic properties, optical properties and other properties, and prepared samples show good ferromagnetism.

Description

technical field [0001] The invention belongs to the technical field of nanometer materials, and in particular relates to a method for preparing nitrogen-doped carbon nanotubes by using microwave plasma chemical vapor deposition technology. Background technique [0002] Carbon nanotubes are seamless carbon nanotube one-dimensional nanomaterials formed by curling single-layer or multi-layer graphite sheets around the central axis at a certain helical angle. With the development of carbon nanotubes (CNTs) and carbon nanotubes doped with different types of elements, carbon nanotubes have attracted much attention due to their unique structure and excellent properties. When doped with different types of elements, The structure of the carbon nanotube hexacyclic ring will undergo certain changes to change or improve its performance. Carbon nanotube materials have a wide range of applications in electronic optical devices, electrochemistry, heat conduction and so on. Incorporating ...

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Problems solved by technology

[0003] Studies have shown that the diamagnetism of nitrogen-doped carbon nanotubes will decrease at the transition temperature of 910K and 1120K, but the related research results are not the same. The main reason is that the interior of the carbon nanotubes is a nanoscale hollow structure, but However, problems such as the small diameter of carbon nanotubes and many surface defects affect the practical application of carbon nanotubes.

There are many ways to prepare nitrogen and carbon nanotubes, most of which use chemical vapor deposition technology, but due to the difficulty in controlling the reaction time and degree of reaction, there are some impurity elements in the obtained product

Although the use of different nitrogen source substances, such as methane, nitrogen, etc., can effectively reduce other element impurity components in nitrogen-carbon nanotubes, the agglomeration of carbon nanotubes and carbon-containing components, as well as precursors and temperatures can affect the carbon Nitrogen doping amount of nanotubes and their ferromagnetism

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