Method for growing large-diameter carbon nanotube array on nickel net

Abstract

The invention discloses a method for growing a large-diameter carbon nanotube array on a nickel net, and belongs to the technical field of carbon nanomaterials. The method comprises the following steps: weighing citric acid and urea, and dissolving in a mixed solvent of absolute ethyl alcohol and water to obtain a precursor solution; baking and naturally cooling to obtain a blocky solid product derived from citric acid and urea; the preparation method comprises the following steps: grinding the raw materials into powder, uniformly laying the powder on the inner tube wall of a horizontally placed quartz test tube, placing a nickel net on the powder, placing the quartz test tube in a tubular furnace for high-temperature treatment, and naturally cooling to room temperature to obtain the large-tube-diameter carbon nanotube array growing on the nickel net. The method provided by the invention has the advantages of simple process and low cost, the prepared carbon nanotubes have the characteristics of large tube diameter and array distribution, the tube diameter can reach 200-700nm, and the carbon material is expected to be endowed with more possibilities in performance and application.

Description

Technical Field

[0001] The invention belongs to the technical field of nano carbon materials, and more specifically, relates to a method for growing a large-diameter carbon nano tube array on a nickel mesh. Background Art

[0002] Since its discovery in 1991, carbon nanotubes have become a research hotspot due to their excellent mechanical, electrical, thermal and chemical properties. As a one-dimensional tubular carbon nanomaterial, carbon nanotubes can be regarded as graphene sheets curled around the central axis at a certain spiral angle. According to the number of graphene sheets that constitute the tube wall, they can be divided into single-walled and multi-walled carbon nanotubes. Single-walled carbon nanotubes are made up of a layer of graphene sheets curled up, with a small diameter of about 0.4-3nm. Multi-walled carbon nanotubes are made up of multiple layers of graphene sheets curled up, with a spacing of 0.34±0.01nm between layers, and their diameter is generally 10-30nm. At present, the diameter of commercial carbon nanotubes is generally 10-60nm. There are few studies on carbon nanotubes with a diameter of more than 100nm, and there are almost no reports on carbon nanotubes with a diameter of up to 600nm. Studies have shown that the larger the diameter of carbon nanotubes, the larger the internal space, which is conducive to storing or transmitting more substances, thus showing unique advantages in the fields of energy storage, catalytic reactions, etc. In addition, large-diameter carbon nanotubes have stronger structural stability, which is conducive to improving the mechanical properties of materials.

[0003] According to the morphology of carbon nanotubes, carbon nanotubes can be divided into carbon nanotube arrays, bamboo-like carbon nanotubes, branched carbon nanotubes, spiral carbon nanotubes, etc. Carbon nanotube arrays are carbon nanotubes with basically consistent orientation, which is approximately perpendicular or parallel to the matrix. Compared with randomly distributed carbon nanotubes, carbon nanotube arrays have better mechanical, electrical and thermal properties and have been widely studied in the fields of electrochemical energy storage, sensors, thermal management, etc.

[0004] Based on this, the present invention proposes a method for growing a large diameter carbon nanotube array on a nickel mesh, which combines the characteristics of large diameter and array distribution, enriches the types of carbon nanotubes, and fills the current gap in the research and preparation of large diameter carbon nanotubes. Summary of the invention

[0005] In view of the problems existing in the above-mentioned prior art, the purpose of the present invention is to design and provide a method for growing a large diameter carbon nanotube array on a nickel mesh. The present invention has the advantages of simple process and low cost. The carbon nanotubes grow in the form of an array on the surface of the nickel fiber constituting the nickel mesh, and at the same time have the characteristics of large diameter and array distribution. The diameter can reach 700nm, which is expected to give carbon materials more performance and application possibilities.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In one aspect, the present invention provides a method for growing a large diameter carbon nanotube array on a nickel mesh, comprising the following steps:

[0008] (1) Weighing citric acid and urea, and dissolving them in a mixed solvent of anhydrous ethanol and water to obtain a precursor solution;

[0009] (2) calcining the precursor solution obtained in step (1) and cooling it naturally to obtain a block-like solid product derived from citric acid and urea;

[0010] (3) Grinding the blocky solid product obtained in step (2) into powder, taking the powder and evenly spreading it on the inner wall of a horizontally placed quartz test tube, taking a nickel mesh and placing it on the powder, placing it in a tube furnace for high-temperature treatment, and naturally cooling it to room temperature to obtain a large-diameter carbon nanotube array grown on the nickel mesh.

[0011] In the method for growing a large-diameter carbon nanotube array on a nickel mesh, the volume ratio of anhydrous ethanol to water in step (1) is 1.5 to 2:1;

[0012] Preferably, the volume ratio of anhydrous ethanol to water is 2:1;

[0013] The concentration of citric acid in the precursor solution is 0.45-0.6 mol / L, and the concentration of urea is 3.0-4.0 mol / L;

[0014] Preferably, the concentration of citric acid in the precursor solution is 0.52 mol / L, and the concentration of urea is 3.55 mol / L.

[0015] In the method for growing a large diameter carbon nanotube array on a nickel mesh, the calcination conditions in step (2) are: a temperature of 180 to 200° C. and a time of 12 to 18 hours;

[0016] Preferably, the calcination conditions are: temperature 180° C., time 15 hours.

[0017] In the method for growing a large-diameter carbon nanotube array on a nickel mesh, the particle size of the powder in step (3) is 2 to 15 μm;

[0018] The mass ratio of the powder to the nickel mesh is 2 to 8:1.

[0019] In the method for growing a large-diameter carbon nanotube array on a nickel mesh, the nickel mesh in step (3) is composed of nickel fibers.

[0020] In the method for growing a large-diameter carbon nanotube array on a nickel mesh, the high-temperature treatment method in step (3) is as follows: introducing N2 to expel the air in the tube furnace, stopping introducing N2, heating the furnace to 900-1000°C at a heating rate of 2.5-7.5°C / min, and keeping the temperature at 900-1000°C for 0.5-2 hours;

[0021] During the natural cooling process, N2 is introduced simultaneously;

[0022] Preferably, the high temperature treatment method is: introducing N2 or an inert gas to expel the air in the tube furnace, stopping the introduction of N2 or an inert gas, heating the temperature to 1000°C at a heating rate of 5°C / min, and keeping the temperature at 1000°C for 1 hour.

[0023] In a second aspect, the present invention provides a nickel mesh / large diameter carbon nanotube array composite material, which is prepared by the method described.

[0024] The nickel mesh / large-diameter carbon nanotube array composite material has a diameter of the large-diameter carbon nanotubes in the composite material of 300-700 nm.

[0025] In a third aspect, the present invention provides the use of the nickel mesh / large diameter carbon nanotube array composite material as an electrochemical material.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The diameter of the large-diameter array carbon nanotubes prepared by the present invention can reach 700 nm, which is far greater than the diameter of conventional carbon nanotubes. This allows the large-diameter carbon nanotubes of the present invention to have a larger internal space and stronger structural stability, providing new possibilities for improving the performance of composite materials. In addition, the internal space of the large-diameter carbon nanotubes can be used to store or transport more substances, such as gas, liquid or ions, thereby showing unique advantages in the fields of energy storage, catalytic reaction, etc.

[0028] (2) The large-diameter array carbon nanotubes prepared by the present invention grow in an array on the surface of the nickel fibers constituting the nickel mesh, forming a "forest"-like structure. This array structure not only enhances the interaction between the carbon nanotubes, but also makes the composite material show higher uniformity and isotropy on a macroscopic level, can conduct electrons and heat more effectively, and is conducive to improving the electrical conductivity and thermal conductivity of the composite material.

[0029] (3) The large-diameter array carbon nanotubes prepared by the present invention combine the characteristics of large diameter and array distribution. The relationship between their structure and physical properties is of great significance, and is expected to give carbon materials more possibilities in performance and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The scanning electron microscope images of the nickel mesh / large-diameter carbon nanotube array composite material prepared in Example 1 of the present invention are at magnifications of 500 times and 10,000 times respectively;

[0031] Figure 2 The scanning electron microscope photographs of the nickel mesh / large-diameter carbon nanotube array composite material prepared in Example 2 of the present invention are at magnifications of 222 times and 10,000 times, respectively;

[0032] Figure 3 These are scanning electron microscope photos of the nickel mesh / large-diameter carbon nanotube array composite material prepared in Example 3 of the present invention, with magnifications of 125 times and 5,000 times, respectively. DETAILED DESCRIPTION

[0033] The following are three embodiments of the present invention, which are further explanations of the present invention, but are not intended to limit the scope of the present invention. The present invention is further described in detail below in conjunction with the embodiments, and it is particularly noted that the raw materials used in the following embodiments can be derived from common commercial sources unless otherwise specified.

[0034] Embodiment 1:

[0035] A method for growing a large-diameter carbon nanotube array on a nickel mesh comprises the following steps:

[0036] (1) 30 mL of anhydrous ethanol and 15 mL of deionized water were measured and mixed as a solvent, 5 g of citric acid and 9.6 g of urea were dissolved, and the mixture was stirred with a magnetic stirrer until it became colorless and transparent to obtain a precursor solution.

[0037] (2) placing the beaker containing the precursor solution obtained in step (1) into a hydrothermal reactor, and then placing it in an oven, baking it at 180° C. for 15 hours and then cooling it naturally to obtain a block-like solid product derived from citric acid and urea.

[0038] (3) Grind the blocky solid product obtained in step (2) into a powder with a particle size of 2-15 μm using an agate mortar, and evenly spread 3 g of the powder on the wall of a horizontally placed quartz test tube, and then take 1 g of a nickel mesh and place it vertically on the powder;

[0039] (4) Place the quartz test tube in step (3) into a tube furnace, introduce N2 before heating to expel the air in the tube furnace, and after expelling the air, heat up to 1000°C at a heating rate of 5°C / min, and keep it at 1000°C for 1 hour. Stop introducing N2 during the heating and keeping period, and finally cool naturally to room temperature with the furnace. During the cooling period, introduce N2 to achieve the growth of large-diameter carbon nanotube arrays on the nickel mesh. The scanning electron microscope image of the prepared nickel mesh / large-diameter carbon nanotube array composite material is as follows: Figure 1As shown, the magnification of the upper and lower figures is 500 times and 10,000 times respectively. It can be seen that the diameter of the carbon nanotubes in the nickel mesh / large-diameter carbon nanotube array composite material is between 200 and 700 nm.

[0040] Embodiment 2:

[0041] A method for growing a large-diameter carbon nanotube array on a nickel mesh comprises the following steps:

[0042] (1) 30 mL of anhydrous ethanol and 15 mL of deionized water were measured and mixed as a solvent, 5 g of citric acid and 9.6 g of urea were dissolved, and the mixture was stirred with a magnetic stirrer until it became colorless and transparent to obtain a precursor solution.

[0043] (2) placing the beaker containing the precursor solution obtained in step (1) into a hydrothermal reactor, and then placing it in an oven, baking it at 180° C. for 15 hours and then cooling it naturally to obtain a block-like solid product derived from citric acid and urea.

[0044] (3) Grind the blocky solid product obtained in step (2) into a powder with a particle size of 2-15 μm using an agate mortar, and evenly spread 5 g of the powder on the wall of a horizontally placed quartz test tube (the inner diameter and tube length of the quartz test tube are 25 mm and 130 mm, respectively), and then take 1 g of a nickel mesh (with a diameter of 50 μm) and place it vertically on the powder;

[0045] (4) Place the quartz test tube in step (3) into a tube furnace, introduce N2 before heating to expel the air in the tube furnace, and after expelling the air, heat up to 1000°C at a heating rate of 5°C / min, and keep at 1000°C for 1 hour. Stop introducing N2 during the heating and keeping period, and finally cool naturally to room temperature with the furnace. During the cooling period, introduce N2 to achieve the growth of large-diameter carbon nanotube arrays on the nickel mesh. The scanning electron microscope photo of the prepared nickel mesh / large-diameter carbon nanotube array composite material is shown in FIG. Figure 2 As shown, the magnifications of the upper and lower figures are 222 and 10,000 times respectively. It can be seen that the diameter of the carbon nanotubes in the nickel mesh / large-diameter carbon nanotube array composite material is between 200 and 700 nm.

[0046] Embodiment 3:

[0047] A method for growing a large-diameter carbon nanotube array on a nickel mesh comprises the following steps:

[0048] (1) 30 mL of anhydrous ethanol and 15 mL of deionized water were measured and mixed as a solvent, 5 g of citric acid and 9.6 g of urea were dissolved, and the mixture was stirred with a magnetic stirrer until it became colorless and transparent to obtain a precursor solution.

[0049] (2) placing the beaker containing the precursor solution obtained in step (1) into a hydrothermal reactor, and then placing it in an oven, baking it at 180° C. for 15 hours and then cooling it naturally to obtain a block-like solid product derived from citric acid and urea.

[0050] (3) Grind the blocky solid product obtained in step (2) into a powder with a particle size of 2-15 μm using an agate mortar, and evenly spread 8 g of the powder on the wall of a horizontally placed quartz test tube, and then take 1 g of a nickel mesh and place it vertically on the powder;

[0051] (4) Place the quartz test tube in step (3) into a tube furnace, introduce N2 before heating to expel the air in the tube furnace, and after expelling the air, heat up to 1000°C at a heating rate of 5°C / min, and keep at 1000°C for 1 hour. Stop introducing N2 during the heating and keeping period, and finally cool naturally to room temperature with the furnace. During the cooling period, introduce N2 to achieve the growth of large-diameter carbon nanotube arrays on the nickel mesh. The scanning electron microscope photo of the prepared nickel mesh / large-diameter carbon nanotube array composite material is shown in FIG. Figure 3 As shown, the magnifications of the upper and lower figures are 125 and 5,000 times respectively. It can be seen that the diameter of the carbon nanotubes in the nickel mesh / large-diameter carbon nanotube array composite material is between 200 and 700 nm.

[0052] Based on the above three embodiments of the present invention, it can be concluded that the present invention provides a method for growing a large diameter carbon nanotube array on a nickel mesh, and the prepared carbon nanotubes grow uniformly and densely on the surface of the nickel fiber constituting the nickel mesh, and the growth direction is approximately perpendicular to the surface of the nickel fiber, presenting an array distribution. In addition, by measuring the diameter of the carbon nanotubes, it can be found that the diameter of the carbon nanotubes is between 200 and 700nm, which has the characteristics of a large diameter. By comparing the three embodiments, it is found that the mass ratio of the product powder of citric acid and urea used in Example 1 to the nickel mesh is small, and the length of the grown carbon nanotubes is significantly shorter. As the mass ratio increases, the length of the carbon nanotubes increases (such as Example 2). When the mass ratio reaches a certain value, the length tends to be stable (such as Example 2 and Example 3, the length of the carbon nanotubes is basically stable). It can be seen that as the mass ratio of the product powder of citric acid and urea to the nickel mesh increases, the length of the prepared carbon nanotubes increases accordingly. When the mass ratio of the product powder of citric acid and urea to the nickel mesh reaches a certain value, the length of the carbon nanotubes reaches a maximum value and tends to be stable.

[0053] The above description is only an exemplary embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims. The present invention will be further described below through the drawings and embodiments.

Claims

1. A method for growing a large diameter carbon nanotube array on a nickel mesh, characterized in that: The following steps are involved: (1) Weighing citric acid and urea, and dissolving them in a mixed solvent of anhydrous ethanol and water to obtain a precursor solution; (2) calcining the precursor solution obtained in step (1) and cooling it naturally to obtain a block-like solid product derived from citric acid and urea; (3) Grinding the blocky solid product obtained in step (2) into powder, taking the powder and evenly spreading it on the inner wall of a horizontally placed quartz test tube, taking a nickel mesh and placing it on the powder, placing it in a tube furnace for high-temperature treatment, and naturally cooling it to room temperature to obtain a large-diameter carbon nanotube array grown on the nickel mesh.

2. A method for growing a large diameter carbon nanotube array on a nickel mesh as claimed in claim 1, characterized in that: The volume ratio of anhydrous ethanol to water in step (1) is 1.5 to 2:1; Preferably, the volume ratio of anhydrous ethanol to water is 2:1; The concentration of citric acid in the precursor solution is 0.45-0.6 mol / L, and the concentration of urea is 3.0-4.0 mol / L; Preferably, the concentration of citric acid in the precursor solution is 0.52 mol / L, and the concentration of urea is 3.55 mol / L.

3. The method for growing a large diameter carbon nanotube array on a nickel mesh according to claim 1, characterized in that: The calcination conditions in step (2) are: temperature 180-200° C., time 12-18 hours; Preferably, the calcination conditions are: temperature 180° C., time 15 hours.

4. The method for growing a large diameter carbon nanotube array on a nickel mesh according to claim 1, characterized in that: The particle size of the powder in step (3) is 2 to 15 μm; The mass ratio of the powder to the nickel mesh is 2 to 8:

1.

5. The method for growing a large diameter carbon nanotube array on a nickel mesh according to claim 1, characterized in that: The nickel mesh described in step (3) is composed of nickel fibers.

6. The method for growing a large diameter carbon nanotube array on a nickel mesh as claimed in claim 1, characterized in that: The method of high temperature treatment in step (3) is as follows: introducing N2 or an inert gas to remove the air in the tube furnace, stopping introducing N2 or an inert gas, heating the furnace to 900-1000°C at a heating rate of 2.5-7.5°C / min, and keeping the temperature at 900-1000°C for 0.5-2 hours; During the natural cooling process, N2 or an inert gas is introduced simultaneously; Preferably, the high temperature treatment method is: introducing N2 or an inert gas to expel the air in the tube furnace, stopping the introduction of N2 or an inert gas, heating the temperature to 1000°C at a heating rate of 5°C / min, and keeping the temperature at 1000°C for 1 hour.

7. A nickel mesh / large diameter carbon nanotube array composite material, characterized in that: It is prepared by the method according to any one of claims 1 to 6.

8. The nickel mesh / large diameter carbon nanotube array composite material according to claim 7, characterized in that: The diameter of the large-diameter carbon nanotubes in the composite material is 200-700nm.

9. Use of the nickel mesh / large diameter carbon nanotube array composite material as claimed in claim 7 or 8 as an electrochemical material.

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