Composite carbon film prepared by capturing carbon nanotubes based on graphene reduction process and method

Abstract

The invention belongs to the technical field of carbon film materials, and particularly relates to a composite carbon film prepared by capturing carbon nanotubes based on a graphene reduction process and a method. According to the invention, the driving force in the reduction process of the graphene oxide and the action bond between the graphene and the carbon nano tube are utilized to capture the carbon nano tube and bind the carbon nano tube between graphene sheet layers, and finally the composite carbon film is obtained. The carbon nanotubes of the prepared composite carbon film are distributed among graphene sheets to form a three-dimensional network structure, so that the composite carbon film has a very large specific surface area and can buffer a certain volume change or store a certain gas or liquid, graphene ensures uninterrupted transmission of electrons among fibers, and the performance of the composite carbon film is improved. And the overall mechanical strength of the composite carbon film is improved while the range of the carbon nanotubes is limited.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon thin film materials, and in particular relates to a composite carbon film and a method for preparing carbon nanotubes by capturing the carbon nanotubes during a graphene reduction process. Background Art

[0002] Carbon thin films, due to their excellent electrical, thermal, and mechanical properties, hold broad application prospects in a wide range of fields, including electronic devices, energy storage, and protective coatings. Graphene and carbon nanotubes, as typical carbon nanomaterials, each possess unique structures and outstanding properties. Combining them to form carbon thin films promises to combine the advantages of both, creating a synergistic effect and providing promising material solutions for a wide range of applications. For example, in terms of electrochemical performance, composite carbon films combine the high carrier mobility of graphene with the excellent conductivity of carbon nanotubes. As supercapacitor electrode materials, these composite carbon films can provide more charge storage sites and faster charge transfer pathways. Experimental studies have shown that compared to electrodes made from a single material, composite electrodes exhibit significantly higher capacitance and faster charge and discharge rates. In the field of electronic devices, composite carbon films have the potential to be used in the fabrication of high-performance field-effect transistors, reducing device resistance and improving electron transfer efficiency, thereby enhancing switching speed and overall performance. Regarding mechanical properties, the combination of graphene and carbon nanotubes significantly improves the mechanical properties of carbon films. Graphene offers high strength and toughness, while carbon nanotubes also possess excellent tensile strength and elastic modulus. After the two are combined, they show good flexibility and stretch resistance in the application of substrate materials for flexible electronic devices. For example, when preparing the substrate for flexible display screens, the composite carbon film can withstand repeated bending and stretching without significant performance degradation, greatly extending the service life of flexible electronic devices. In terms of thermal performance: the thermal conductivity of the composite carbon film has also been improved. In thermal management systems, such as heat dissipation materials for electronic devices, the composite carbon film can conduct heat more effectively. Since both graphene and carbon nanotubes have high thermal conductivity, the synergistic effect between them can build an efficient heat conduction channel, reduce thermal resistance, thereby improving heat dissipation efficiency and preventing electronic equipment from being damaged by overheating.

[0003] There are many methods for preparing composite carbon membranes, and literature reports mention various strategies. For example, a method combining hydrothermal reaction with freeze drying and hot pressing is used. First, graphene oxide and carbon nanotubes are mixed evenly in a solvent and subjected to hydrothermal reaction to obtain a hydrogel. Then, they are freeze dried to obtain an aerogel. Finally, they are hot pressed to form a film and annealed and heat treated. Some researchers have also obtained composite films mainly composed of carbon nanotubes and reduced graphene oxide by sequentially carbonizing and graphitizing carbon nanotube / graphene oxide composite films in a protective gas. However, these methods still have their own limitations, such as complex processes, the need for special reaction conditions and increased costs. The preparation process needs to be further simplified and the cost controlled. Therefore, it is of great research significance to develop a simple and easy method for preparing high-quality composite carbon membranes. Summary of the Invention

[0004] Based on the above technical problems, the purpose of the present invention is to provide a composite carbon film and method for preparing carbon nanotubes by capturing carbon nanotubes through a graphene reduction process.

[0005] To achieve the above object, the technical solution adopted by the present invention is: The present invention provides a method for preparing a composite carbon film by capturing carbon nanotubes during a graphene reduction process, comprising the following steps: mixing a graphene oxide aqueous solution and a carbon nanotube aqueous solution to obtain a mixed solution; The cleaned and dried metal foil was used as a reduction substrate and completely immersed in the mixed solution. After standing for 12 hours, it was taken out, washed and dried to obtain a metal foil with a composite carbon film coated surface; The metal foil with the composite carbon film coated on its surface was immersed in a dilute hydrochloric acid solution with a concentration of 0.2 mol / L for 30 minutes, after which the carbon film was taken out of the solution and washed, and then dried to obtain the composite carbon film.

[0006] The method provided by the present invention for preparing a composite carbon film by capturing carbon nanotubes during a graphene reduction process is simple and easy to implement, and can be self-propelled at room temperature and pressure, thereby significantly reducing manufacturing costs. The prepared composite carbon film has excellent mechanical strength and toughness, and can be repeatedly bent and folded.

[0007] Furthermore, the concentration of the graphene oxide aqueous solution and the carbon nanotube aqueous solution is 0.1 mg / ml.

[0008] Furthermore, the mass ratio of the graphene oxide aqueous solution to the carbon nanotube aqueous solution is 2:1.

[0009] Furthermore, the carbon nanotubes are single-walled carbon nanotubes.

[0010] Furthermore, the metal foil includes any one selected from aluminum foil, copper foil and nickel foil.

[0011] Furthermore, the drying condition is heating at 60° C. for 8 hours.

[0012] Furthermore, the thickness of the metal foil is 20 μm.

[0013] The present invention also provides a composite carbon film prepared by the method.

[0014] The present invention has the following beneficial effects: The method for preparing a composite carbon film by capturing carbon nanotubes during a graphene reduction process provided by the present invention can realize the capture of carbon nanotubes in a solution by graphene oxide at room temperature and pressure. As the graphene oxide is reduced by metal, a composite carbon film with graphene-bound carbon nanotubes between layers is finally obtained. This method does not require special reaction conditions such as heating and pressurization, has low cost, and has a simple operation process. It only requires a reduction reaction to generate the carbon film, and can realize large-area preparation of the composite carbon film through metal foil. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 These are electron microscope images of the composite carbon film prepared by method A, where A is a scanning electron microscope image at a magnification of 0.1K, and B is a scanning electron microscope image at a magnification of 20K.

[0016] Figure 2 These are electron microscope images of the composite carbon film prepared by method B, where A is a scanning electron microscope image at a magnification of 10K, and B is a scanning electron microscope image at a magnification of 30K.

[0017] Figure 3 These are electron microscope images of the composite carbon film prepared by method C, where A is a scanning electron microscope image at a magnification of 30K, and B is a scanning electron microscope image at a magnification of 10K.

[0018] Figure 4 These are electron microscope images of the composite carbon film prepared by method D, where A is a scanning electron microscope image at a magnification of 5K, and B is a scanning electron microscope image at a magnification of 30K. DETAILED DESCRIPTION

[0019] The present invention is described in detail below with reference to specific examples, but these examples should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the following examples are conventional means well known to those skilled in the art, and the materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained from commercial sources.

[0020] Graphene oxide was purchased from Dongguan Kelude New Energy Technology Co., Ltd., with the catalog number MA-LO-TW-000302. Single-walled carbon nanotubes were purchased from Dongguan Kelude New Energy Technology Co., Ltd., with the catalog number MA-EN-CO-001001. Multi-walled carbon nanotubes were purchased from Dongguan Kelude New Energy Technology Co., Ltd., with the catalog number MA-EN-CO-001401.

[0021] Example 1: A method for preparing a composite carbon film by capturing carbon nanotubes during a graphene reduction process.

[0022] 1. Experimental setup.

[0023] 1. Method A: A 20 μm-thick aluminum foil was used as the reduction substrate. The foil was washed with deionized water and then ethanol, followed by drying. A 0.1 mg / ml aqueous solution of graphene oxide and a 0.1 mg / ml aqueous solution of single-walled carbon nanotubes were prepared and mixed at a mass ratio of 2:1 to form a mixed solution. The aluminum foil was completely immersed in the mixed solution and allowed to stand at room temperature for 12 hours. Afterwards, the foil was removed and rinsed with deionized water. The foil was then placed in a vacuum drying oven and dried at 60°C for 8 hours to obtain a graphene / carbon nanotube composite carbon film-coated aluminum foil. The aluminum foil with the graphene / carbon nanotube composite carbon film-coated surface was then immersed in a 0.2 mol / L dilute hydrochloric acid solution. After 30 minutes, the carbon film was removed from the solution, rinsed with deionized water, and dried in a vacuum drying oven at 60°C for 8 hours to obtain the composite carbon film.

[0024] 2. Method B: A 20 μm-thick copper foil was used as the reduction substrate. The copper foil was washed with deionized water and then ethanol, followed by drying. A 0.1 mg / ml aqueous solution of graphene oxide and a 0.1 mg / ml aqueous solution of multi-walled carbon nanotubes were prepared and mixed at a mass ratio of 2:1 to form a mixed solution. The copper foil was completely immersed in the mixed solution and allowed to stand at room temperature for 12 hours. Afterwards, the solution was removed and rinsed with deionized water. The solution was then placed in a vacuum drying oven and dried at 60°C for 8 hours to obtain a graphene / carbon nanotube composite carbon film-coated copper foil. The graphene / carbon nanotube composite carbon film-coated copper foil was then immersed in a 0.2 mol / L dilute hydrochloric acid solution. After 30 minutes, the carbon film was removed from the solution, rinsed with deionized water, and dried in a vacuum drying oven at 60°C for 8 hours to obtain the composite carbon film.

[0025] 3. Method C: A 20 μm-thick aluminum foil was used as the reduction substrate. The foil was washed with deionized water and then ethanol, followed by drying. A 0.1 mg / ml aqueous solution of graphene oxide and a 0.2 mg / ml aqueous solution of single-walled carbon nanotubes were prepared and mixed at a mass ratio of 2:1 to form a mixed solution. The aluminum foil was completely immersed in the mixed solution and allowed to stand at room temperature for 12 hours. Afterwards, the foil was removed and rinsed with deionized water. The foil was then placed in a vacuum drying oven and dried at 60°C for 8 hours to obtain a graphene / carbon nanotube composite carbon film-coated aluminum foil. The aluminum foil with the graphene / carbon nanotube composite carbon film-coated surface was then immersed in a 0.2 mol / L dilute hydrochloric acid solution. After 30 minutes, the carbon film was removed from the solution, rinsed with deionized water, and placed in a vacuum drying oven at 60°C for 8 hours to obtain the composite carbon film.

[0026] 4. Method D: A 20 μm-thick nickel foil was used as the reduction substrate. The nickel foil was washed with deionized water and then ethanol, followed by drying. A 0.1 mg / ml aqueous solution of graphene oxide and a 0.2 mg / ml aqueous solution of single-walled carbon nanotubes were prepared and mixed at a mass ratio of 2:1 to form a mixed solution. The nickel foil was completely immersed in the mixed solution and allowed to stand at room temperature for 12 hours. After removal, it was rinsed with deionized water and then dried in a vacuum drying oven at 60°C for 8 hours to obtain a nickel foil coated with a graphene / carbon nanotube composite carbon film. The nickel foil coated with the graphene / carbon nanotube composite carbon film was then immersed in a 0.2 mol / L dilute hydrochloric acid solution. After 30 minutes, the carbon film was removed from the solution, rinsed with deionized water, and dried in a vacuum drying oven at 60°C for 8 hours to obtain the composite carbon film.

[0027] 2. Sample testing.

[0028] The composite carbon films prepared by methods A, B, C and D were observed for sample characterization parameters using a scanning electron microscope, and their performance parameters were tested using a flexible electronic tester.

[0029] 3. Experimental results.

[0030] The experimental results are as follows Figures 1 to 4 As shown in Table 1, from different test results, the influence of the concentrations of carbon nanotube solution and graphene oxide solution on the material properties is as follows: when the concentration of carbon nanotube solution is 0.1 mg / ml, the electrical conductivity and thermal conductivity of the material are relatively high; when the concentration of carbon nanotubes is fixed and the concentration of graphene oxide solution is increased to 0.2 mg / ml, the electrical conductivity and thermal conductivity decrease, which indicates that the addition of carbon nanotubes helps to improve the electrical conductivity of the composite film.

[0031] Effect of tube spacing on material properties: The tube spacing varies between 90 nm and 120 nm. As can be seen in Table 1, both electrical and thermal conductivity decrease with increasing tube spacing. This is because larger tube spacing increases the scattering of electrons and phonons, thereby reducing the material's electrical and thermal conductivity.

[0032] Flexibility testing results show that the material's flexibility varies with the concentration of carbon nanotubes and graphene oxide. The material exhibits even higher flexibility when treated with 0.2 mg / ml of graphene oxide. This is likely because the addition of a large amount of graphene oxide improves the material's toughness, enabling it to better withstand external forces.

[0033] Considering that the average data of method A and method B are better than those of method C and method D, and since the price of aluminum is much lower than that of copper, from the perspective of preparation cost, method A is finally determined to be the optimal experimental scheme.

[0034] Table 1: Flexible electronics test results Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

Claims

1. A method for preparing a composite carbon film by capturing carbon nanotubes during graphene reduction, characterized in that: The following steps are involved: mixing a graphene oxide aqueous solution and a carbon nanotube aqueous solution to obtain a mixed solution; The cleaned and dried metal foil is immersed in the mixed solution as a reducing substrate, left to stand, and then taken out, and the metal foil with a composite carbon film coated surface is obtained after cleaning and drying; The metal foil on the surface of the composite carbon film is immersed in a hydrochloric acid solution, the carbon film is taken out and washed, and then dried to obtain the composite carbon film.

2. The method for preparing a composite carbon film by capturing carbon nanotubes through a graphene reduction process according to claim 1, wherein: The concentration of the graphene oxide aqueous solution and the carbon nanotube aqueous solution is 0.1 mg / ml.

3. The method for preparing a composite carbon film by capturing carbon nanotubes through a graphene reduction process according to claim 2, wherein: The mass ratio of the graphene oxide aqueous solution to the carbon nanotube aqueous solution is 2:

1.

4. The method for preparing a composite carbon film by capturing carbon nanotubes through a graphene reduction process according to claim 1, wherein: The carbon nanotubes are single-walled carbon nanotubes.

5. The method for preparing a composite carbon film by capturing carbon nanotubes through a graphene reduction process according to claim 1, wherein: The metal foil is selected from any one of aluminum foil, copper foil and nickel foil.

6. The method for preparing a composite carbon film by capturing carbon nanotubes through a graphene reduction process according to claim 1, wherein: The drying condition is heating at 60° C. for 8 h.

7. The method for preparing a composite carbon film by capturing carbon nanotubes through a graphene reduction process according to claim 1, wherein: The thickness of the metal foil is 20 μm.

8. The method for preparing a composite carbon film by capturing carbon nanotubes through a graphene reduction process according to claim 1, wherein: The concentration of the hydrochloric acid solution is 0.2 mol / L.

9. A composite carbon film prepared by the method according to any one of claims 1 to 8.

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