Three-dimensional porous graphene film material, preparation method and application thereof

Abstract

The application discloses a preparation method of a three-dimensional porous graphene film material, which comprises the following steps: (1) using a polyimide double-sided adhesive tape to stick two sides of two glass sheets together; (2) preparing a graphene oxide solution, loading the graphene oxide solution into a hydrothermal kettle, immersing the glass sheets into the graphene oxide solution, and vacuumizing to make the GO solution fully enter the interlayer of the glass; (3) performing a solvothermal reaction, naturally cooling, peeling off the double-layer glass sheets, then cleaning and drying, and performing high-temperature annealing treatment on the obtained three-dimensional porous graphene film material; and by adjusting the thickness of the polyimide double-sided adhesive tape, the thickness of the three-dimensional graphene film can be adjusted. The application can be used for preparing a porous graphene film with uniform and adjustable thickness by using a confined solvothermal method, and the thickness and pore size can be accurately controlled, so that the application has wide application prospects in the fields of surface catalysis, photoelectric detection, electromagnetic shielding and the like.

Description

Technical Field

[0001] This invention belongs to the field of thin film preparation technology, specifically relating to a three-dimensional porous graphene thin film material, its preparation method, and its application. Background Technology

[0002] Graphene is an emerging two-dimensional material in which carbon atoms are entirely connected by covalent bonds and are tightly packed together. Tests have shown that graphene has a tensile strength of up to 42 N / m, a tensile strength of up to 125 GPa, and an elastic modulus of 1.1 TPa. Furthermore, monolayer graphene exhibits excellent light transmittance; in the visible light region, the absorbance of a graphene sheet is only 2.3%. Graphene also has a thermal conductivity of 3000 W / m at room temperature. -1 K -1 The electron mobility at room temperature is 250,000 cm⁻¹. 2 V -1 s -1 The conductivity is also 10. 6 S / m is currently the highest room-temperature conductivity value for a material. To apply graphene to macroscopic applications, it is necessary to prepare graphene-based macroscopic materials, including one-dimensional fibers, two-dimensional films, and three-dimensional graphene foams.

[0003] Currently, chemical vapor deposition (CVD) and solvothermal self-assembly methods can be used to prepare three-dimensional graphene. The resulting materials exhibit good mechanical stability, high specific surface area, and excellent electrical and thermal conductivity, making them widely applicable in optoelectronics, energy, sensing, and catalysis. Solvothermal self-assembly involves placing a graphene oxide solution in a high-temperature, high-pressure environment, causing the oxygen-containing functional groups on its surface to condense and cross-link, resulting in a three-dimensional porous structure. Graphene oxide possesses amphiphilic properties and can be stably dispersed in solvents such as water, ethanol, and ethylene glycol. The resulting three-dimensional graphene retains the structure and properties of single-layer graphene.

[0004] Currently, graphene foam materials prepared by the solvothermal method are limited by the shape of the solvothermal reactor, generally resulting in cylindrical bulk materials that are then laser-cut into specific shapes. It is difficult to precisely control parameters such as thickness and size, and it is also difficult to directly form three-dimensional porous film structures. Moreover, graphene foam itself has weak structure and poor mechanical properties. Although its porous surface is conducive to efficient light absorption, it can also affect its contact with electrodes or other materials. Summary of the Invention

[0005] The present invention provides a method for preparing three-dimensional porous graphene film materials, so as to achieve uniform and controllable preparation of porous graphene film materials.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for preparing a three-dimensional porous graphene thin film material includes the following steps:

[0008] (1) Use polyimide double-sided tape to stick the two sides of the two glass plates together;

[0009] (2) Prepare graphene oxide (GO) solution, put it into a hydrothermal reactor, immerse the glued glass slide in it, vacuum and let it stand for a period of time to allow the GO solution to fully enter the glass interlayer.

[0010] (3) Perform a solvothermal reaction, then cool naturally to room temperature, carefully peel off the double-layer glass sheet, clean it with ethanol and water, and then freeze-dry it to obtain a self-supporting three-dimensional porous graphene film material, or directly transfer it to a rigid or flexible substrate by wet method, dry it to obtain a substrate three-dimensional porous graphene film material, and finally perform high-temperature annealing treatment. By adjusting the thickness of the polyimide double-sided tape, the thickness of the obtained three-dimensional graphene film can be precisely controlled.

[0011] Furthermore, the glass sheet mentioned in step (1) has a thickness of 0.2-3 mm and a smooth surface.

[0012] Furthermore, the thickness of the polyimide double-sided tape in step (1) is 100-2000μm, and the thickness can be precisely controlled by stacking and pasting multiple layers of tape.

[0013] Further, the graphene oxide mentioned in step (2) is single-layer graphene oxide or multi-layer (2-10 layers) graphene oxide, preferably single-layer graphene oxide; the concentration of graphene oxide in the graphene oxide solution is 0.2-10 mg / mL.

[0014] Furthermore, the solvent in the solvothermal process of step (3) is selected from one or more of the following in any proportion: water, methanol, ethanol, ethylene glycol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, N,N-dimethylformamide, tetrahydrofuran, and acetone.

[0015] Furthermore, the additives in the solvothermal process in step (3) are selected from one or more of sulfuric acid, nitric acid, hydrochloric acid, and phosphoric acid, and the addition ratio is 0.01%-2% of the solvent volume. The use of acidic additives can effectively enhance the hydrogen bonds in the solvothermal process and achieve effective cross-linking of the three-dimensional graphene structure.

[0016] Furthermore, in step (3), the solvothermal reaction temperature is 80-200℃, and the reaction time is 5-24h.

[0017] Furthermore, after the solvothermal reaction described in step (3), the double-layered glass slides are peeled off and repeatedly cleaned with ethanol and water.

[0018] Furthermore, the substrates for wet transfer in step (3) include rigid substrates such as silicon wafers, quartz wafers, glass sheets, and acrylic sheets, or flexible substrates such as polyvinyl alcohol (PVA), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), paper sheets, and textile materials. After transfer, vacuum drying is performed at a temperature of 50-150℃ for 6-48 hours.

[0019] Furthermore, in step (3), the high-temperature annealing is carried out in an inert atmosphere, with an annealing temperature of 400-2000℃ and a time of 1-12h.

[0020] Furthermore, the thickness of the self-supporting three-dimensional porous graphene film material obtained by freeze-drying in step (3) is 100-2000 micrometers, and the thickness of the three-dimensional porous graphene film material after wet transfer is 3-1000 micrometers.

[0021] Compared with the prior art, the present invention has the following technical advantages:

[0022] This invention utilizes a confined solvothermal method to prepare porous graphene films with uniform and tunable thickness. It enables precise control over thickness and pore size, and can be used to prepare self-supporting films or transfer them to various rigid or flexible substrates. It exhibits strong compatibility and has broad application prospects in fields such as surface catalysis, photoelectric detection, and electromagnetic shielding. Attached Figure Description

[0023] Figure 1 This is a diagram of a confined solvothermal reaction apparatus.

[0024] Figure 2 This is a photograph of a porous graphene film transferred onto a quartz plate.

[0025] Figure 3 This is a photograph of a self-supporting porous graphene film obtained by freeze-drying.

[0026] Figure 4 This is a cross-sectional SEM image of a porous graphene film.

[0027] Figure 5 This is a transmittance diagram of porous graphene films of different thicknesses. Detailed Implementation

[0028] Example 1

[0029] A method for preparing a three-dimensional porous graphene thin film material includes the following steps:

[0030] Two glass sheets were bonded together using polyimide double-sided tape, with each layer being 100 micrometers thick. Three layers were bonded together, totaling 300 micrometers in thickness. A 60ml solution of 1mg / ml monolayer graphene oxide was prepared and added to a 100ml hydrothermal reactor. The double-layer glass sheets were immersed in the solution, and the mixture was vacuumed and allowed to stand for 10 minutes. The hydrothermal reactor was then placed in an oven for a solvothermal reaction at 180℃ for 12 hours. After that, the mixture was allowed to cool naturally to room temperature. The glass sheets were then peeled off, and the inner film was removed. The film was washed multiple times with ethanol and water, then freeze-dried and annealed at 800℃ for 1 hour to obtain a self-supporting three-dimensional porous graphene film material.

[0031] Example 2

[0032] A method for preparing a three-dimensional porous graphene thin film material includes the following steps:

[0033] Two glass sheets were bonded together using polyimide double-sided tape, with each layer being 100 micrometers thick. Two layers were bonded together, totaling 200 micrometers in thickness. A 60ml solution of 0.5mg / ml single-layer graphene oxide in ethanol was prepared and added to a 100ml hydrothermal reactor. The double-layer glass sheets were immersed in the solution, and the reactor was vacuumed and allowed to stand for 10 minutes. The hydrothermal reactor was then placed in an oven for a solvothermal reaction at 150℃ for 8 hours. After that, the reactor was allowed to cool naturally to room temperature. The glass sheets were then peeled off, and the middle film was removed. The film was washed multiple times with ethanol and then retrieved using a quartz plate. After drying at 80℃, the film was annealed at 500℃ for 1 hour to obtain a three-dimensional porous graphene film material on a quartz substrate.

[0034] Example 3

[0035] A method for preparing a three-dimensional porous graphene thin film material includes the following steps:

[0036] Two glass sheets were bonded together using polyimide double-sided tape, with each layer being 100 micrometers thick. Two layers were bonded together, totaling 200 micrometers in thickness. A 60ml solution of 2mg / ml single-layer graphene oxide in ethanol and water (volume ratio 1:1) was prepared and added to a 100ml hydrothermal reactor. The double-layer glass sheets were immersed in the solution, and the mixture was vacuumed and allowed to stand for 10 minutes. The hydrothermal reactor was then placed in an oven for a solvothermal reaction at 160℃ for 12 hours. After that, the mixture was allowed to cool naturally to room temperature. The glass sheets were then peeled off, and the middle film was removed. The film was washed multiple times with ethanol, retrieved using a PET film, and dried at 60℃ to obtain a three-dimensional porous graphene film material on a flexible PET substrate.

[0037] This invention utilizes a confined solvothermal reaction method to prepare uniform, three-dimensional porous graphene thin film materials with adjustable thickness. The apparatus is as follows: Figure 1As shown, glass sheets are bonded together using polyimide double-sided adhesive and then placed in a hydrothermal reactor along with graphene oxide for a solvothermal reaction. By adjusting the number of adhesive layers, the thickness of the resulting three-dimensional graphene film can be controlled relatively precisely. Figure 2 3). The SEM cross-sectional images also show that the graphene sheets exhibit a three-dimensional cross-linked network structure, with no obvious stacking between the graphene sheets. Figure 4 Porous graphene films possess both a porous macroscopic structure and retain the intrinsic properties of graphene. The prepared three-dimensional graphene films are semi-transparent and can be transferred to any substrate using a wet transfer method. The prepared 3DG-100μm film has a transmittance of approximately 40% in the visible light region and approximately 50% in the near-infrared region. Figure 5 3DG-200μm has a transmittance of over 20% in the infrared region and about 10-20% in the visible light region. This novel porous graphene film has broad application prospects in fields such as surface catalysis and photoelectric detection.

Claims

1. A method for preparing a three-dimensional porous graphene film material, characterized in that, Includes the following steps: (1) Use polyimide double-sided tape to stick the two sides of the two glass plates together; (2) Prepare graphene oxide (GO) solution, put it into a hydrothermal reactor, immerse the glued glass slide in it, vacuum and let it stand for a period of time to allow the GO solution to fully enter the glass interlayer. (3) Perform a solvothermal reaction, then cool naturally to room temperature, carefully peel off the double-layer glass sheet, clean it with ethanol and water, and then freeze-dry it to obtain a self-supporting three-dimensional porous graphene film material, or directly transfer it to a rigid or flexible substrate by wet method, dry it to obtain a substrate three-dimensional porous graphene film material, and finally perform high-temperature annealing treatment. By adjusting the thickness of the polyimide double-sided tape, the thickness of the obtained three-dimensional graphene film can be precisely controlled.

2. The method for preparing the three-dimensional porous graphene thin film material according to claim 1, characterized in that, The glass sheet mentioned in step (1) has a thickness of 0.2-3 mm and a smooth surface.

3. The method of claim 1, wherein the three-dimensional porous graphene film material is prepared by the steps of: The thickness of the polyimide double-sided tape mentioned in step (1) is 100-2000 μm. The thickness can be precisely controlled by stacking and pasting multiple layers of tape.

4. The method of claim 1, wherein the three-dimensional porous graphene film material is prepared by the steps of: The graphene oxide mentioned in step (2) is single-layer graphene oxide or multi-layer graphene oxide; the concentration of graphene oxide in the graphene oxide solution is 0.2-10 mg / mL.

5. The method for preparing the three-dimensional porous graphene thin film material according to claim 1, characterized in that, In step (3), the solvent for the solvothermal process is selected from one or more of water, methanol, ethanol, ethylene glycol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, N,N-dimethylformamide, tetrahydrofuran and acetone in any proportion; the additive is selected from one or more of sulfuric acid, nitric acid, hydrochloric acid and phosphoric acid, and the addition ratio is 0.01%-2% of the solvent volume. The use of acidic additives effectively enhances the hydrogen bonds in the solvothermal process and realizes the effective cross-linking of the three-dimensional graphene structure.

6. The method of claim 1, wherein the three-dimensional porous graphene film material is prepared by the steps of: The temperature for the solvothermal reaction in step (3) is 80-200 ºC and the reaction time is 5-24 h. After the solvothermal reaction, the double-layered glass slides are peeled off and repeatedly cleaned with ethanol and water.

7. The method for preparing the three-dimensional porous graphene thin film material according to claim 1, characterized in that, In step (3), the substrates for wet transfer include rigid substrates such as silicon wafers, quartz wafers, glass sheets, and acrylic sheets, or flexible substrates such as PVA, PET, PI, PEN, paper sheets, and textile materials. After transfer, vacuum drying is performed at a temperature of 50-150 ºC for 6-48 h. High-temperature annealing is carried out in an inert atmosphere at a temperature of 400-2000 ºC for 1-12 h.

8. The method of claim 1, wherein the three-dimensional porous graphene film material is prepared by the steps of: The thickness of the self-supporting three-dimensional porous graphene film material obtained by freeze drying in step (3) is 100-2000 micrometers, and the thickness of the three-dimensional porous graphene film material after wet transfer is 3-1000 micrometers.

9. A three-dimensional porous graphene thin film material prepared by the method according to any one of claims 1-8.

10. Use of the three-dimensional porous graphene film material according to claim 9, characterized in that, Applications include surface catalysis, photoelectric detection, and electromagnetic shielding.

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