CN114380286B

CN114380286B - Needle-like carbon nanotube for encapsulating magnetic particles and preparation method thereof

Info

Publication number: CN114380286B
Application number: CN202210031336.9A
Authority: CN
Inventors: 李雪爱; 李越; 唐慧敏; 王海燕
Original assignee: Yanshan University
Current assignee: Yanshan University
Priority date: 2022-01-12
Filing date: 2022-01-12
Publication date: 2023-06-30
Anticipated expiration: 2042-01-12
Also published as: CN114380286A

Abstract

The invention belongs to the technical field of composite materials, in particular to a needle-shaped carbon nanotube for encapsulating magnetic particles and a preparation method thereof. The carbon nanotube of the present invention has needle shape, and features that the carbon nanotube has thick end of 140-220 nm diameter and thin end of 35-65 nm diameter, and the needle shape carbon nanotube has length of 1.5-4.0 micron and magnetic particle packed inside. The preparation method comprises the following steps: dissolving a catalyst precursor ferric salt in a solvent, adding a carbon source, stirring, evaporating the solvent to obtain a mixture powder of the catalyst and the carbon source, heating the mixture to a set temperature in a flowing inert atmosphere, and preserving the temperature for a certain time at the set temperature to obtain black powder which is needle-shaped carbon nano tubes for encapsulating magnetic particles, wherein the morphology of the carbon nano tubes can be regulated and controlled by changing the gas flow rate, the preserving temperature and the mass ratio of the catalyst to the carbon source in the heating and preserving processes.

Description

Needle-like carbon nanotube for encapsulating magnetic particles and preparation method thereof

Technical Field

The invention belongs to the technical field of composite materials, in particular to the technical field of carbon nanotube preparation, and particularly relates to a needle-shaped carbon nanotube for encapsulating magnetic particles and a preparation method thereof.

Background

The carbon nano tube is a one-dimensional nano material, has excellent mechanical property, chemical stability, electrical conductivity and thermal conductivity, and an ideal structure plays an important role in the fields of mechanics, electricity, heat and the like, and has wide application prospect in the fields of materiality, chemistry, biology, physics or some interdisciplines, and the carbon nano tube can be particularly suitable for optical sensors, electrode materials, flat panel displays, wave absorbing materials and the like. In order to further improve the performance of the carbon nanotubes, researchers prepare the carbon nanotubes with different forms by various methods, important achievements are obtained in a plurality of fields, and how to use a preparation method with simple steps and low cost to realize the controllable growth of the carbon nanotubes is a key to pushing the carbon nanotubes to diversified application.

Current carbon nanotube fabrication methods include arc discharge, laser ablation, chemical vapor deposition, and the like. In the arc discharge method, high-purity graphene is used as a cathode and an anode, when arc discharge occurs between the two electrodes, the generated high temperature gasifies the anode, carbon decomposed by gasification forms rings to finally form carbon nanotubes, and the carbon nanotubes are deposited on the cathode, but the method is complicated, the purity of the generated carbon nanotubes is extremely low, and the generated carbon nanotubes are not suitable for large-scale mass production due to the fact that subsequent purification treatment is required. The laser ablation method is characterized in that a graphene target is bombarded by a laser beam, and the gasified graphene target is deposited on the surface of a conical water-cooled copper tube under the carrying of inert atmosphere to form the carbon nano tube. The chemical vapor deposition method is a method which is relatively more applied at present, a layer of catalyst substrate is deposited firstly, then gas serving as a carbon source is introduced, the carbon source gas is decomposed and contacted with the catalyst by utilizing high temperature, and the carbon nano tube is produced by catalysis.

Disclosure of Invention

In order to solve the defects in the prior art, the invention provides a needle-shaped carbon nano tube for encapsulating magnetic particles and a preparation method thereof, and the adopted technical scheme is as follows:

the needle-shaped carbon nanotube for encapsulating magnetic particles has needle shape, length of 1.5-4.0 μm, thick end and thin end, diameter of thick end is 140-220 nm, diameter of thin end is 35-65 nm, and magnetic particles are encapsulated in the needle-shaped carbon nanotube.

Further, the magnetic particles are ellipsoidal, and the particle size length of the magnetic particles is 250-400 nm;

further, the particle size width of the magnetic particles is 130-210 nm;

further, the magnetic particles are Fe and/or Fe ₃ C。

The preparation process of needle-shaped carbon nanotube with encapsulated magnetic particle includes the following steps:

(1) Dissolving a catalyst precursor ferric salt in a solvent, adding a carbon source, stirring, and evaporating the solvent to obtain a mixture powder;

(2) And (3) heating the mixture powder in the step (1) to a set temperature in an inert gas flowing atmosphere, and preserving heat to obtain black powder, namely the needle-shaped carbon nano tube for encapsulating the magnetic particles.

Further, the mass ratio of the catalyst precursor iron salt to the carbon source in the step (1) is 5: 4-4: 5, a step of;

further, the mass-volume ratio of the catalyst precursor ferric salt to the solvent is 1:10-1:50 g/mL.

Further, in step (1) the catalyst precursor iron salt is selected from iron trichloride hexahydrate and/or iron acetylacetonate;

further, the carbon source is selected from melamine;

further, the solvent is selected from ethanol and/or deionized water.

Further, the inert gas in step (2) is selected from nitrogen or argon.

Further, the inert gas flow rate in the step (2) is 60-300 mL/min.

Further, the temperature rising rate of the heat preservation in the step (2) is 5-10 ℃/min.

Further, the heat preservation temperature in the step (2) is 700-950 ℃;

further, the heat preservation time is 3-6 h.

Further, in the step (1), the dissolution temperature of the catalyst precursor ferric salt dissolved in the solvent is 40-80 ℃;

further, the evaporating temperature is 40-80 ℃.

The beneficial effects obtained by the invention are as follows:

(1) The invention discloses a needle-shaped carbon nano tube for encapsulating magnetic particles, which has needle-shaped morphology and thick ends and thin ends, wherein the length of the needle-shaped carbon nano tube is 1.5-4.0 mu m, the diameter of the thick ends is 140-220 nm, the diameter of the thin ends is 35-65 nm, and the thick ends are encapsulated with the magnetic particles. The specific forming process is as follows: firstly, iron ions in iron salt are reduced into iron to serve as a catalytic center, carbon-containing gas decomposed by a carbon source grows on the surface of a catalyst to form an initial carbon nano tube, because the gas flow rate is large, the size of the catalyst center particle formed initially is small, the initial carbon nano tube is a fine end, at high temperature, magnetic particles are mutually gathered and become larger in size due to an Ostwald ripening mechanism, the diameter of the catalyzed carbon nano tube becomes larger along with the magnetic particle, and thus the needle-shaped carbon nano tube with a thick end and a fine end is formed.

(2) The invention provides a preparation method of needle-shaped carbon nano tubes for packaging magnetic particles, which comprises the steps of heating and dissolving catalyst precursor ferric salt in a solvent, adding a carbon source, stirring, evaporating the solvent to obtain mixture powder, heating and preserving heat under an inert gas flowing atmosphere to obtain black powder which is the needle-shaped carbon nano tubes, and adopting cheap and easily obtained catalyst precursor ferric salt and the carbon source to obtain the needle-shaped carbon nano tubes for packaging the magnetic particles through simple mixing and heat preservation treatment under the inert gas flowing atmosphere.

Drawings

FIG. 1 is a scanning electron microscope image of needle-like carbon nanotubes encapsulating magnetic particles obtained in example 19;

FIG. 2 is a transmission electron microscope image of the acicular carbon nanotubes encapsulating magnetic particles obtained in example 19;

FIG. 3 is an X-ray diffraction pattern of acicular carbon nanotubes encapsulating magnetic particles obtained in example 19;

FIG. 4 shows the hysteresis loop at room temperature of acicular carbon nanotubes encapsulating magnetic particles obtained in example 19;

FIG. 5 is a graph showing the absorption of acicular carbon nanotubes encapsulating magnetic particles obtained in example 19.

Examples

For a clearer understanding of the present invention, the present invention will now be further described with reference to the following examples and drawings. The examples are for illustration only and are not intended to limit the invention in any way. In the examples, each of the starting reagent materials is commercially available, and the experimental methods without specifying the specific conditions are conventional methods and conventional conditions well known in the art, or according to the conditions recommended by the instrument manufacturer.

Example 1

(1) Weighing 3.0g of ferric trichloride hexahydrate, dissolving in 30mL of ethanol solution, placing in an oil bath at 60 ℃, adding 3.0g of melamine after the ferric trichloride hexahydrate is completely dissolved, magnetically stirring and fully mixing, and drying the mixture in a baking oven at 60 ℃ for 24 hours to obtain orange powder;

(2) Placing the orange powder prepared in the step (1) into a container, placing into a temperature control area of a tube furnace, heating to 700 ℃ at a heating rate of 5 ℃/min under a nitrogen atmosphere (gas flow rate of 60 mL/min), preserving heat for 3 hours, and cooling to room temperature to obtain black powder, namely the needle-shaped carbon nano tube.

Example 2

This example differs from example 1 in that ferric trichloride hexahydrate in step (1) was used instead of ferric acetylacetonate, and the other steps and parameters were the same as in example 1.

Example 3

This example differs from example 1 in that the ethanol solution in step (1) was changed to deionized water, and the other steps and parameters were the same as in example 1.

Example 4

This example differs from example 1 in that the amount of ferric trichloride hexahydrate used in step (1) was 2.4g, and the other steps and parameters were the same as in example 1.

Example 5

This example differs from example 1 in that the melamine content in step (1) is 2.4g, the other steps and parameters being the same as in example 1.

Example 6

This example differs from example 1 in that the nitrogen in step (2) is changed to argon, and the other steps and parameters are the same as in example 1.

Example 7

This example differs from example 1 in that the gas flow rate in step (2) was 100mL/min, and the other steps and parameters were the same as in example 1.

Example 8

This example differs from example 1 in that the gas flow rate in step (2) was 150mL/min, and the other steps and parameters were the same as in example 1.

Example 9

This example differs from example 1 in that the gas flow rate in step (2) was 200mL/min, and the other steps and parameters were the same as in example 1.

Example 10

This example differs from example 1 in that the gas flow rate in step (2) was 250mL/min, and the other steps and parameters were the same as in example 1.

Example 11

This example differs from example 1 in that the gas flow rate in step (2) was 300mL/min, and the other steps and parameters were the same as in example 1.

Example 12

The difference between this example and example 1 is that the temperature rise rate in step (2) was 6 ℃/min, the temperature of the incubation was 900 ℃, and the other steps and parameters were the same as in example 1.

Example 13

The difference between this example and example 1 is that the temperature rise rate in step (2) was 10℃per minute, the holding temperature was 950℃and the other steps and parameters were the same as in example 1.

Example 14

This example differs from example 2 in that the heating to 800℃is performed in step (2), and the other steps and parameters are the same as in example 2.

Example 15

This example differs from example 3 in that the heating to 800℃in step (2) is performed, and the other steps and parameters are the same as in example 3.

Example 16

This example differs from example 4 in that the heating to 800℃in step (2) is performed, and the other steps and parameters are the same as in example 4.

Example 17

This example differs from example 5 in that the heating to 800℃in step (2) is performed, and the other steps and parameters are the same as in example 5.

Example 18

This example differs from example 6 in that the heating to 800℃in step (2) is performed, and the other steps and parameters are the same as in example 6.

Example 19

This example differs from example 7 in that the heating to 800℃in step (2) is performed, and the other steps and parameters are the same as in example 7.

Example 20

The difference between this example and example 1 is that the holding time in step (2) is 4h, and the other steps and parameters are the same as those in example 1.

Example 21

The difference between this example and example 1 is that the holding time in step (2) is 5h, and the other steps and parameters are the same as those in example 1.

Example 22

The difference between this example and example 1 is that the heat retention time in step (2) was 6 hours, the heat retention temperature was 800 ℃, and the other steps and parameters were the same as in example 1.

As can be seen from FIGS. 1 and 2, the needle-like carbon nanotubes obtained in example 19, which encapsulate magnetic particles, had a uniform morphology, an average length of about 3. Mu.m, an average particle size of about 330nm, an average particle size of about 170nm, an average diameter of about 185nm at the thick end of the carbon nanotube, and an average diameter of about 46nm at the thin end of the carbon nanotube.

As can be seen from FIG. 3, the X-ray diffraction peaks of the needle-shaped carbon nanotubes detect Fe and Fe ₃ Characteristic peak of C, peak at 26 ° position is assigned to C.

It can be seen from FIG. 4 that the saturation magnetization and coercive force of the obtained needle-like carbon nanotubes were 50.57emu/g and 140O, respectively.

From fig. 5, it can be seen that the effective absorption bandwidth of the obtained needle-shaped carbon nanotubes for electromagnetic waves reaches 5.20GHz, and the effective absorption of electromagnetic waves in the frequency range of 15-18GHz can be realized.

It should be apparent that the above embodiments are merely examples for clarity of illustration and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary or exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the invention.

Claims

1. The needle-shaped carbon nano tube for encapsulating the magnetic particles is characterized in that the needle-shaped carbon nano tube for encapsulating the magnetic particles is needle-shaped, has a length of 1.5-4.0 mu m and has a thick end and a thin end, the diameter of the thick end is 140-220 nm, the diameter of the thin end is 35-65 nm, and the magnetic particles are encapsulated in the needle-shaped carbon nano tube;

the magnetic particles are ellipsoidal, and the particle size length of the magnetic particles is 250-400 nm;

the particle size width of the magnetic particles is 130-210 nm;

the magnetic particles are Fe and/or Fe ₃ C。

2. The method for preparing the needle-shaped carbon nano tube for encapsulating the magnetic particles as claimed in claim 1, which is characterized by comprising the following specific steps:

the mass ratio of the catalyst precursor ferric salt to the carbon source is 5:4~4:5, a step of;

the mass volume ratio of the catalyst precursor ferric salt to the solvent is 1:10-1:50 g/mL;

the catalyst precursor ferric salt is selected from ferric trichloride hexahydrate and/or ferric acetylacetonate;

the carbon source is selected from melamine;

the solvent is selected from ethanol and/or deionized water;

(2) Heating the mixture powder in the step (1) to a set temperature in an inert gas flowing atmosphere and preserving heat to obtain black powder, namely the needle-shaped carbon nano tube for encapsulating the magnetic particles;

the flow speed of the inert gas is 60-300 mL/min;

the temperature rising rate of the heat preservation is 5-10 ℃/min;

the heat preservation temperature is 700-950 ℃;

the heat preservation time is 3-6 hours.

3. The method of claim 2, wherein the inert gas in step (2) is selected from nitrogen and argon.

4. The preparation method according to claim 2, wherein the dissolution temperature of the catalyst precursor ferric salt dissolved in the solvent in the step (1) is 40-80 ℃;

the evaporating temperature is 40-80 ℃.