Three-dimensional porous graphene thin film material, preparation method therefor and use thereof

Abstract

A method for preparing a three-dimensional porous graphene thin film material, comprising the following steps: (1) bonding opposing sides of two glass sheets together by using a double-sided adhesive polyimide tape; (2) preparing a graphene oxide solution, putting the graphene oxide solution into a hydrothermal kettle, impregnating the bonded glass sheets with the graphene oxide solution, and performing evacuation to a vacuum to enable the graphene oxide solution to fully enter an interlayer between the glass sheets; and (3) performing a solvothermal reaction, then allowing the reaction solution to naturally cool, peeling off the two layers of glass sheets, then cleaning and drying the glass sheets, further performing high-temperature annealing treatment on the obtained three-dimensional porous graphene thin film material, and adjusting the thickness of the three-dimensional graphene thin film by adjusting the thickness of the double-sided adhesive polyimide tape. Provided are a three-dimensional porous graphene thin film prepared by the method and a use thereof. A porous graphene thin film having a uniform and controllable thickness is prepared by using a confined solvothermal method, so that accurate control of the thickness and the pore size is achieved.

Description

A three-dimensional porous graphene film material, preparation method and application thereof Technical Field

[0001] The present invention belongs to the technical field of thin film preparation, and in particular relates to a three-dimensional porous graphene thin film material, a preparation method and applications thereof. Background Art

[0002] Graphene is an emerging two-dimensional material in which carbon atoms are completely connected by covalent bonds and are tightly packed together. Tests have shown that the strength limit of graphene can reach 42 N / m, its tensile strength can reach 125 GPa, and its elastic modulus is 1.1 TPa. In addition, a single layer of graphene has good light transmittance. For the visible light region, the absorbance of the graphene sheet is only 2.3%. The thermal conductivity of graphene at room temperature reaches 3000 W m -1 K −1 , the electron mobility at room temperature is 250,000 cm 2 V -1 s -1 , the conductivity is also 10 6 S / m, is the material with the highest room temperature conductivity. In order to apply graphene to macroscopic fields, it is necessary to prepare graphene-based macroscopic materials, including one-dimensional fibers, two-dimensional films, and three-dimensional graphene foams.

[0003] Currently, methods such as chemical vapor deposition and solvothermal self-assembly can be used to prepare three-dimensional graphene. The resulting materials exhibit excellent mechanical stability, high specific surface area, and excellent electrical and thermal conductivity, and are widely used in optoelectronics, energy, sensing, catalysis, and other fields. Solvothermal self-assembly involves subjecting a graphene oxide solution to high temperature and high pressure to condense and crosslink its surface oxygen-containing functional groups, resulting in a three-dimensional porous structure. Graphene oxide is amphiphilic 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. Technical issues

[0004] Currently, graphene foam produced by solvothermal methods is limited by the shape of the solvothermal reactor, typically resulting in a cylindrical block of material. Laser cutting into specific shapes makes it difficult to precisely control parameters such as thickness and size, and it is also difficult to directly form a three-dimensional porous film structure. Furthermore, graphene foam itself has weak structural integrity and poor mechanical properties. While its porous surface facilitates efficient light absorption, it also hinders contact with electrodes or other materials. Technical Solutions

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

[0006] To achieve the above object, the present invention adopts the following technical solutions:

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

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

[0009] (2) Prepare graphene oxide (GO) solution, put it into a hydrothermal kettle, immerse the glued glass pieces in it, evacuate the solution and let it stand for a period of time to allow the GO solution to fully penetrate into the glass interlayer;

[0010] (3) Carry out solvent thermal reaction, then cool naturally to room temperature, carefully peel off the double-layer glass sheet, wash 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 three-dimensional porous graphene film material with a substrate, and finally undergo 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 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 100-2000 μm, and the thickness can be precisely controlled by stacking and pasting multiple layers of tape.

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

[0014] Furthermore, the solvent of the solvothermal process in step (3) is selected from one or a mixture of two 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.

[0015] Furthermore, the additives for 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 hydrogen bonds in the solvothermal process and achieve effective cross-linking of the three-dimensional graphene structure.

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

[0017] Furthermore, after the solvent thermal reaction in step (3), the double-layer glass sheet is peeled off and repeatedly washed with ethanol and water.

[0018] Furthermore, the substrate for wet transfer in step (3) includes a rigid substrate such as a silicon wafer, a quartz wafer, a glass sheet, or an acrylic plate, or a flexible substrate such as polyvinyl alcohol (PVA), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), a paper sheet, or a textile material, and is vacuum dried after transfer at a vacuum drying temperature of 50-150°C and a drying time of 6-48 h.

[0019] Furthermore, in step (3), high temperature annealing is performed in an inert atmosphere at a temperature of 400-2000°C for a time of 1-12 h.

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

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

[0022] The present invention can be used to prepare porous graphene films with uniform and adjustable thickness through a confined solvent thermal method, can achieve precise control of thickness and pore size, can prepare self-supporting films or transfer them to a variety of rigid or flexible substrates, has strong compatibility, and has broad application prospects in surface catalysis, photoelectric detection, electromagnetic shielding and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG1 is a diagram of a confined solvothermal reaction device.

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

[0025] FIG3 is a photograph of a self-supporting porous graphene film obtained by freeze drying.

[0026] FIG4 is a cross-sectional SEM image of a porous graphene film.

[0027] FIG5 is a graph showing the transmittance of porous graphene films of different thicknesses. Modes for Carrying Out the Invention

[0028] Example 1

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

[0030] Use polyimide double-sided tape to stick the two sides of the two glass pieces together. The single layer of polyimide double-sided tape is 100 microns, and 3 layers are pasted with a total thickness of 300 microns. Prepare 60 ml of 1 mg / ml single-layer graphene oxide aqueous solution, add it to a 100 ml hydrothermal kettle, immerse the double-layer glass pieces in the solution, evacuate and let it stand for 10 minutes, put the hydrothermal kettle into an oven for solvent thermal reaction at 180 ° C for 12 hours, and then naturally cool to room temperature. Peel off the glass pieces, take out the middle film, wash it with ethanol and water several times, and then freeze-dry it. Anneal it at 800 ° C 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 film material comprises the following steps:

[0033] Use polyimide double-sided tape to stick the two sides of the two glass pieces together. The single layer of polyimide double-sided tape is 100 microns, and two layers are pasted with a total thickness of 200 microns. Prepare 60 ml of 0.5 mg / ml single-layer graphene oxide ethanol solution, add it to a 100 ml hydrothermal kettle, immerse the double-layer glass piece in the solution, vacuum it and let it stand for 10 minutes, put the hydrothermal kettle into an oven for solvent thermal reaction at 150 ° C for 8 hours, and then cool it naturally to room temperature. Peel off the glass piece, take out the middle film, wash it with ethanol several times, and use a quartz slice to fish it out. After drying at 80 ° C, anneal it at 500 ° C 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 film material comprises the following steps:

[0036] Use polyimide double-sided tape to stick the two sides of the two glass pieces together. The single layer of polyimide double-sided tape is 100 microns, and two layers are pasted with a total thickness of 200 microns. Prepare 60 ml of a 2 mg / ml single-layer graphene oxide ethanol and water mixed solution (volume ratio 1:1), add it to a 100 ml hydrothermal kettle, immerse the double-layer glass piece in the solution, vacuum it and let it stand for 10 minutes, put the hydrothermal kettle into an oven for solvent thermal reaction at 160 ° C for 12 hours, and then cool it naturally to room temperature. Peel off the glass piece, take out the middle film, wash it with ethanol several times, fish it out with PET film, and dry it at 60 ° C to obtain a three-dimensional porous graphene film material on a flexible PET substrate.

[0037] This invention uses a confined solvothermal reaction method to produce uniform, thickness-adjustable three-dimensional porous graphene films. The apparatus is shown in Figure 1. Glass sheets are bonded together using polyimide double-sided tape and 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 precisely controlled (Figures 2 and 3). SEM cross-sectional images also reveal a three-dimensional cross-linked network structure between the graphene sheets, with no apparent accumulation between the sheets (Figure 4). The porous graphene film exhibits a porous macrostructure while retaining graphene's intrinsic properties. The resulting three-dimensional graphene film is translucent and can be transferred to any substrate via wet transfer. The prepared 3DG-100 μm has a transmittance of approximately 40% in the visible region and approximately 50% in the near-infrared region (Figure 5). 3DG-200 μm has a transmittance of over 20% in the infrared region and approximately 10-20% in the visible light region. This new porous graphene film has broad application prospects in areas such as surface catalysis and photoelectric detection.

Claims

1. A method for preparing a three-dimensional porous graphene film material, characterized in that: The following steps are involved: (1) Use polyimide double-sided tape to stick the two sides of the two glass sheets together; (2) Prepare a graphene oxide (GO) solution, put it into a hydrothermal reactor, immerse the glued glass pieces in it, evacuate the solution and let it stand for a period of time to allow the GO solution to fully enter the glass interlayer; (3) Carry out a solvent thermal reaction, then cool naturally to room temperature, carefully peel off the double-layer glass sheet, wash it with ethanol and water, and then freeze-dry it to obtain a self-supporting three-dimensional porous graphene film material, or directly wet transfer it to a rigid or flexible substrate, dry it to obtain a three-dimensional porous graphene film material with a substrate, and finally undergo 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 a three-dimensional porous graphene film material according to claim 1, characterized in that: The glass sheet in step (1) has a thickness of 0.2-3 mm and a smooth surface.

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

4. The method for preparing the three-dimensional porous graphene film material according to claim 1, characterized in that: The graphene oxide described in step (2) is a single-layer graphene oxide or a multi-layer (2-10 layers) graphene oxide, preferably a single-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 film material according to claim 1, characterized in that: The solvent of the solvothermal process in step (3) is selected from one or a mixture of two 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 volume of the solvent. The use of the acidic additive can effectively enhance the hydrogen bonding in the solvothermal process and realize the effective crosslinking of the three-dimensional graphene structure.

6. The method for preparing the three-dimensional porous graphene film material according to claim 1, characterized in that: In step (3), the solvent thermal reaction temperature is 80-200 ºC, and the reaction time is 5-24 h. After the solvent thermal reaction, the double-layer glass sheet is peeled off and repeatedly washed with ethanol and water.

7. The method for preparing the three-dimensional porous graphene film material according to claim 1, characterized in that: The substrate for wet transfer in step (3) includes a rigid substrate such as a silicon wafer, a quartz wafer, a glass wafer, an acrylic plate, or a flexible substrate such as polyvinyl alcohol (PVA), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), a paper sheet, or a textile material. After the transfer, the substrate is vacuum dried at a temperature of 50-150°C for a drying time of 6-48 hours. High temperature annealing is carried out in an inert atmosphere at a temperature of 400-2000 ºC for 1-12 h.

8. The method for preparing the three-dimensional porous graphene film material according to claim 1, characterized in that: The thickness of the self-supporting three-dimensional porous graphene film material obtained by freeze-drying in step (3) is 100-2000 microns, and the thickness of the three-dimensional porous graphene film material after wet transfer is 3-1000 microns.

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

10. An application 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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