CN103265022B - Method for spontaneously depositing three-dimensional graphene on conductive substrate - Google Patents

Abstract

The invention discloses a method for spontaneously depositing three-dimensional graphene on a conductive substrate, belonging to the field of functional materials. The steps of the method are as follows: the first step: prepare 8-20 mg/mL graphene oxide solution by oxidizing and exfoliating graphite; the second step: dilute the 8-20 mg/mL graphene oxide solution to make the concentration of the graphene oxide solution 0.5 ~ 3mg/mL; the third step: put the conductive substrate in the graphene oxide solution and let it stand, and take out the conductive substrate after reacting for 6 to 12 hours, and the three-dimensional graphene is deposited on the surface of the conductive substrate; the fourth step: the first The three-dimensional graphene obtained in the three steps is directly freeze-dried or washed and then freeze-dried to obtain dry porous functionalized three-dimensional graphene or pure dry porous three-dimensional graphene. The preparation process of the method is simple and environment-friendly, and the obtained three-dimensional graphene material has a three-dimensional and porous structure, and has the characteristics of large specific surface area and good flexibility.

Description

A method for spontaneous deposition of three-dimensional graphene on conductive substrates

technical field

The invention relates to a method for spontaneously depositing three-dimensional graphene on a conductive substrate, belonging to the field of functional materials.

Background technique

Graphene is a layered structure composed of six-membered rings of carbon bonded together. Because graphene has high electrical conductivity, large specific surface area, and good chemical stability, environmental stability and mechanical stability, it is widely used in photoelectric materials, photocatalytic materials, energy storage and conversion materials (fuel cells, Li batteries, etc. ), magnetic absorbing materials and other applications have attracted the attention of researchers at home and abroad.

At present, the method of preparing graphene in large quantities is to chemically reduce graphene oxide. At the same time, self-assembled three-dimensional graphene porous materials have a good effect on its application. However, the current preparation of graphene usually involves some harsh conditions, such as the heating reduction of hydrazine hydrate (N ₂ H ₄ ), the reduction of argon/hydrogen (Ar/H ₂ ) gas at a high temperature of 600–1000°C, the reduction of sodium borohydride (NaBH ₄ ) Reduction under alkaline conditions, reduction of acetic acid-hydroiodic acid (HAC-HI) solution at 80–120°C, reduction of sodium-ammonia (Na-NH ₃ ) solution in a dry ice bath. These reduction processes generally require the use of toxic chemical reagents, multiple cumbersome steps, and consume a considerable amount of time, and the obtained graphene is not completely reduced, and it is difficult to ensure that it is assembled into a three-dimensional porous structure. These have seriously affected Applications of graphene as devices.

Contents of the invention

In view of the shortcomings of the existing graphene preparation process, which is cumbersome, time-consuming, and involves toxic reagents, and the prepared graphene is not completely reduced, and it is difficult to ensure that it is assembled into a three-dimensional porous structure, the purpose of the present invention is to provide a conductive substrate. A method for spontaneously depositing three-dimensional graphene on the Internet. The preparation process of the method is simple, environmentally friendly, low in cost, and suitable for large-scale production. The three-dimensional graphene material prepared by the method is three-dimensional and porous, and has a large volume and high quality. Lightweight, large specific surface area, good flexibility.

The purpose of the present invention is achieved by the following technical solutions:

A method for spontaneously depositing three-dimensional graphene on a conductive substrate, the method steps are as follows:

Step 1: Prepare 8-20 mg/mL graphene oxide solution by oxidized exfoliated graphite method (Hummers method);

Step 2: Dilute the 8-20 mg/mL graphene oxide solution so that the concentration of the graphene oxide solution is 0.5-3 mg/mL;

The third step: put the conductive substrate in the graphene oxide solution prepared in the second step and let it stand, take out the conductive substrate after reacting for 6 to 12 hours, and the graphene oxide is reduced to obtain three-dimensional graphene, which is deposited on the surface of the conductive substrate , and the metal oxide is attached to the three-dimensional graphene;

The fourth step: directly freeze-dry the three-dimensional graphene obtained in the third step to obtain dry and porous functionalized three-dimensional graphene; or first clean off the metal oxide attached to the three-dimensional graphene obtained in the third step and then freeze Dry to obtain pure dry porous three-dimensional graphene;

The conductive base is one of the following six types, wherein:

The first is Zn, Fe, Al, Co or Cu (active metal);

The second is Ag, Pt or Au foil (inert metal) sprayed with Cu by vacuum sputtering;

The third is Cu foil with nanostructured Ag, Pt or Au deposited by chemical reaction;

The fourth type is Si wafer sprayed by vacuum sputtering;

The fifth type is conductive glass (ITO) with semi-surface vacuum sputtering Cu sputtering on the conductive surface;

The sixth is a Cu substrate with a graphene film;

Dilute in the second step and use water that reaches the purity of distilled water and above;

In the third step, when the conductive substrate is Al or Co, the resting temperature is 60° C.; when the conductive substrate is not Al or Co, the resting temperature is room temperature to 60° C.

Beneficial effect

(1) The present invention uses a simple and feasible method to prepare light weight, low density and functionalized three-dimensional graphene materials. Controllable and suitable for mass production.

(2) The raw material graphene oxide used in the present invention has mature synthesis technology, high quality, low cost, and can be mass-produced.

(3) The method of the present invention can not only deposit three-dimensional graphene on the surface of active metal Zn, Fe, Al, Co, Cu; it can also deposit on the surface of inert metal Ag, Pt, Au; non-metallic Si, graphene The surface of the film; and the surface of conductive glass (ITO), which greatly broadens the application range of 3D graphene.

(4) The three-dimensional graphene obtained by the method of the present invention has a three-dimensional and porous structure. It has the characteristics of large volume, light weight, large specific surface area, and good flexibility. It can be used as ultra-light materials, oil-absorbing materials, etc.

(5) The method of the present invention can easily synthesize functionalized graphene according to different substrate materials. These composite materials have good photoelectric response as photoelectric materials; as Li battery negative electrode materials, they can get rid of traditional non-conductive The linking agent has good cycle properties and a capacity beyond that of ordinary carbon materials. In addition, it can also be potentially applied to magnetic materials, wave-absorbing materials, and so on.

Description of drawings

Fig. 1 is the scanning electron micrograph after the direct lyophilization of the functionalized three-dimensional graphene obtained in embodiment 1;

Fig. 2 is the scanning electron micrograph after the three-dimensional graphene washing lyophilization that obtains in embodiment 2;

Fig. 3 is the transmission electron microscope figure after the direct freeze-drying of three-dimensional graphene obtained in embodiment 3;

Fig. 4 is the scanning electron micrograph after the three-dimensional graphene washing lyophilization that obtains in embodiment 8;

Fig. 5 is the scanning electron micrograph of the three-dimensional graphene obtained in embodiment 9 after washing and freeze-drying;

Fig. 6 is the scanning electron micrograph of the three-dimensional graphene obtained in embodiment 14 after washing and freeze-drying;

Fig. 7 is the capacity and efficiency test figure of the button battery obtained in embodiment 15;

8 is a photocurrent response test diagram of the three-dimensional graphene obtained in Example 16.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments, but is not limited thereto.

The dimensions of the conductive substrates in Examples 1-16 are 2 cm (length)×2 cm (width)×100 μm (height).

The process of preparing graphene oxide solution by Hummers method: take 3g of high-purity graphite powder, add 70mL of concentrated sulfuric acid, 1.5g of sodium nitrate, add 9g of potassium permanganate under ice bath and stirring conditions, and stir for half an hour , adjust the temperature to 35°C, keep it for half an hour, add 150mL of distilled water, adjust the temperature to 90°C, and keep it for 15 minutes, then add 500mL of distilled water, adjust the temperature to room temperature, stir for 1 hour, then let stand, After 1 hour, add 20 mL of hydrogen peroxide, then suction filter to obtain a solid, add 100 to 400 mL of water, and then centrifuge and wash to obtain a graphene oxide solution of 8 to 20 mg/mL.

Example 1

1. Prepare a 20 mg/mL graphene oxide solution using the oxidized exfoliated graphite method (Hummers method);

2. Dilute the 20mg/mL graphene oxide solution with distilled water so that the concentration of the graphene oxide solution is 3mg/mL;

3. Put the Zn conductive substrate in the graphene oxide solution prepared in the second step and let it stand at room temperature, take out the conductive substrate after reacting for 6 hours, the graphene oxide is reduced to obtain graphene, and deposit on the surface of the conductive substrate;

4. First immerse the graphene obtained in the previous step into liquid nitrogen to freeze, and then put it into a freeze dryer at -50°C to freeze-dry to obtain the product. The product is tested, and the ZnO can be seen from the X-ray powder diffraction test chart. The characteristic peaks (32°, 34°, 36°, 48°, 57°, 63°, 66°, 68° and 69°), and the characteristic peak of graphene oxide (10°) disappeared, and the graphene The characteristic peak (23°) indicates that graphene oxide has been reduced to graphene; combined with the scanning electron microscope test (Figure 1), it can be seen that the structure of graphene is a three-dimensional layered porous structure, that is, the product is a dried ZnO nanoparticle functionalized Porous 3D graphene.

Example 2

1. Prepare 8 mg/mL graphene oxide solution by using the oxidized exfoliated graphite method (Hummers method);

2. Dilute the 8mg/mL graphene oxide solution with distilled water so that the concentration of the graphene oxide solution is 0.5mg/mL;

3. Put the Fe conductive substrate in the graphene oxide solution prepared in the second step and let it stand at room temperature, take out the conductive substrate after reacting for 6 hours, graphene oxide is reduced to obtain graphene, and deposited on the surface of the conductive substrate;

4. After the graphene obtained in the previous step is washed with 100 mL of 2mol/L hydrochloric acid solution, the graphene is first immersed in liquid nitrogen to freeze, and then freeze-dried in a freeze-dryer at -50°C to obtain the product. The product is detected, and the characteristic peak (10°) of graphene oxide disappears through the X-ray powder diffraction test chart, and the characteristic peak (23°) of graphene appears, indicating that graphene oxide has been reduced to graphene, and there is no The characteristic peaks of metal oxides indicate the absence of metal oxides; combined with the scanning electron microscope test (Figure 2), it can be seen that the structure of graphene is a three-dimensional layered porous structure, that is, the product is dry, porous and pure three-dimensional graphene.

Example 3

1. Prepare a 14 mg/mL graphene oxide solution using the oxidized exfoliated graphite method (Hummers method);

2. Dilute the 14mg/mL graphene oxide solution with distilled water so that the concentration of the graphene oxide solution is 1.7mg/mL;

3. Put the Cu conductive substrate in the graphene oxide solution prepared in the second step and let it stand at 30°C. After reacting for 10 hours, take out the conductive substrate, and the graphene oxide is reduced to obtain graphene, which is deposited on the surface of the conductive substrate;

4. First immerse the graphene obtained in the previous step into liquid nitrogen to freeze, and then put it into a freeze dryer at -50°C to freeze-dry to obtain the product. The product is tested, and Cu can be seen from the X-ray powder diffraction test chart. The characteristic peaks of ₂ O (40°, 47°, 68°, 82° and 86°), and the characteristic peak of graphene oxide (10°) disappeared, and the characteristic peak of graphene (23°) appeared, indicating that graphite oxide Graphene has been reduced to graphene; combined with scanning electron microscopy and transmission electron microscopy (Figure 3), it can be seen that the structure of graphene is a three-dimensional layered porous structure, and the morphology of Cu ₂ O is 50nm particles, that is, the product is Cu ₂ O nanoparticles functionalized dry porous three-dimensional graphene.

Example 4

1. Prepare 8 mg/mL graphene oxide solution by using the oxidized exfoliated graphite method (Hummers method);

2. Dilute the 8mg/mL graphene oxide solution with distilled water so that the concentration of the graphene oxide solution is 0.5mg/mL;

3. Put the Al conductive substrate in the graphene oxide solution prepared in the second step and let it stand at 60°C. After reacting for 12 hours, take out the conductive substrate, and the graphene oxide is reduced to obtain graphene, which is deposited on the surface of the conductive substrate;

4. After the graphene obtained in the previous step is washed with 100 mL of 2mol/L hydrochloric acid solution, the graphene is first immersed in liquid nitrogen to freeze, and then freeze-dried in a freeze-dryer at -50°C to obtain the product. The product is detected, and the characteristic peak (10°) of graphene oxide disappears through the X-ray powder diffraction test chart, and the characteristic peak (23°) of graphene appears, indicating that graphene oxide has been reduced to graphene, and there is no The characteristic peaks of metal oxides indicate the absence of metal oxides; combined with scanning electron microscope images, it can be seen that the structure of graphene is a three-dimensional layered porous structure, that is, the product is dry, porous and pure three-dimensional graphene.

Example 5

1. Prepare 8 mg/mL graphene oxide solution by using the oxidized exfoliated graphite method (Hummers method);

2. Dilute the 8mg/mL graphene oxide solution with distilled water so that the concentration of the graphene oxide solution is 0.5mg/mL;

3. Put the Co conductive substrate in the graphene oxide solution prepared in the second step and let it stand at 60°C. After 12 hours of reaction, take out the conductive substrate, and the graphene oxide is reduced to obtain graphene, which is deposited on the surface of the conductive substrate;

4. After the graphene obtained in the previous step is washed with 100 mL of 2mol/L hydrochloric acid solution, the graphene is first immersed in liquid nitrogen to freeze, and then freeze-dried in a freeze-dryer at -50°C to obtain the product. The product is detected, and the characteristic peak (10°) of graphene oxide disappears through the X-ray powder diffraction test chart, and the characteristic peak (23°) of graphene appears, indicating that graphene oxide has been reduced to graphene, and there is no The characteristic peaks of metal oxides indicate the absence of metal oxides; combined with scanning electron microscope images, it can be seen that the structure of graphene is a three-dimensional layered porous structure, that is, the product is dry, porous and pure three-dimensional graphene.

Example 6

1. Prepare 8 mg/mL graphene oxide solution by using the oxidized exfoliated graphite method (Hummers method);

2. Dilute the 8mg/mL graphene oxide solution with distilled water so that the concentration of the graphene oxide solution is 0.5mg/mL;

3. Put the Ag conductive substrate sprayed with Cu by vacuum sputtering into the graphene oxide solution prepared in the second step and let it stand at 60°C. After reacting for 12 hours, take out the conductive substrate, and the graphene oxide is reduced to obtain graphene, which is deposited on The surface of the Ag conductive substrate;

4. After the graphene obtained in the previous step is washed with 100 mL of 2mol/L hydrochloric acid solution, the graphene is first immersed in liquid nitrogen to freeze, and then freeze-dried in a freeze-dryer at -50°C to obtain the product. The product is detected, and the characteristic peak (10°) of graphene oxide disappears through the X-ray powder diffraction test chart, and the characteristic peak (23°) of graphene appears, indicating that graphene oxide has been reduced to graphene, and there is no The characteristic peaks of metal oxides indicate the absence of metal oxides; combined with scanning electron microscope images, it can be seen that the structure of graphene is a three-dimensional layered porous structure, that is, the product is dry, porous and pure three-dimensional graphene.

Example 7

1. Prepare 8 mg/mL graphene oxide solution by using the oxidized exfoliated graphite method (Hummers method);

2. Dilute the 8mg/mL graphene oxide solution with distilled water so that the concentration of the graphene oxide solution is 0.5mg/mL;

3. Put the Pt conductive substrate sprayed with Cu by vacuum sputtering into the graphene oxide solution prepared in the second step and let it stand at 60°C. After reacting for 12 hours, take out the conductive substrate, and the graphene oxide is reduced to obtain graphene, which is deposited on the surface of the Pt conductive substrate;

4. After the graphene obtained in the previous step is washed with 100 mL of 2mol/L hydrochloric acid solution, the graphene is first immersed in liquid nitrogen to freeze, and then freeze-dried in a freeze-dryer at -50°C to obtain the product. The product is detected, and the characteristic peak (10°) of graphene oxide disappears through the X-ray powder diffraction test chart, and the characteristic peak (23°) of graphene appears, indicating that graphene oxide has been reduced to graphene, and there is no The characteristic peaks of metal oxides indicate the absence of metal oxides; combined with scanning electron microscope images, it can be seen that the structure of graphene is a three-dimensional layered porous structure, that is, the product is dry, porous and pure three-dimensional graphene.

Example 8

1. Prepare 8 mg/mL graphene oxide solution by using the oxidized exfoliated graphite method (Hummers method);

2. Dilute the 8mg/mL graphene oxide solution with distilled water so that the concentration of the graphene oxide solution is 0.5mg/mL;

3. Put the Au conductive substrate sprayed with Cu by vacuum sputtering into the graphene oxide solution prepared in the second step and let it stand at 60°C. After reacting for 12 hours, take out the conductive substrate, graphene oxide is reduced to obtain graphene, and deposited on the surface of the Au conductive substrate;

4. After the graphene obtained in the previous step is washed with 100 mL of 2mol/L hydrochloric acid solution, the graphene is first immersed in liquid nitrogen to freeze, and then freeze-dried in a freeze-dryer at -50°C to obtain the product. The product is detected, and the characteristic peak (10°) of graphene oxide disappears through the X-ray powder diffraction test chart, and the characteristic peak (23°) of graphene appears, indicating that graphene oxide has been reduced to graphene, and there is no The characteristic peaks of metal oxides indicate the absence of metal oxides; combined with the scanning electron microscope (Figure 4), it can be seen that the structure of graphene is a three-dimensional layered porous structure, that is, the product is dry, porous and pure three-dimensional graphene.

Example 9

1. Prepare 8 mg/mL graphene oxide solution by using the oxidized exfoliated graphite method (Hummers method);

2. Dilute the 8mg/mL graphene oxide solution with distilled water so that the concentration of the graphene oxide solution is 0.5mg/mL;

3. Add 0.01M AgNO ₃ dropwise on the Cu substrate, let it stand for one minute, and wash it with HCl solution. On the scanning electron microscope, it can be seen that the dendritic Ag nanostructure is deposited on the surface of the Cu conductive substrate, which will carry the Ag The nanostructured Cu substrate is placed in the graphene oxide solution prepared in the second step and left at room temperature, and the conductive substrate is taken out after 10 hours of reaction, and the graphene oxide is reduced to obtain graphene, which is deposited on the surface of the Ag conductive substrate;

4. After the graphene obtained in the previous step is washed with 100 mL of 2mol/L hydrochloric acid solution, the graphene is first immersed in liquid nitrogen to freeze, and then freeze-dried in a freeze-dryer at -50°C to obtain the product. The product is detected, and the characteristic peak (10°) of graphene oxide disappears through the X-ray powder diffraction test chart, and the characteristic peak (23°) of graphene appears, indicating that graphene oxide has been reduced to graphene, and there is no The characteristic peaks of metal oxides indicate the absence of metal oxides; combined with the scanning electron microscope (Figure 5), it can be seen that the structure of graphene is a three-dimensional layered porous structure, that is, dry, porous and pure three-dimensional graphene loaded on Ag nano the surface of the structure.

Example 10

1. Prepare 8 mg/mL graphene oxide solution by using the oxidized exfoliated graphite method (Hummers method);

2. Dilute the 8mg/mL graphene oxide solution with distilled water so that the concentration of the graphene oxide solution is 0.5mg/mL;

3. Add 0.01M HAuCl ₄ solution dropwise on the Cu substrate, let it stand for one minute, and wash it with HCl solution. It can be seen on the scanning electron microscope that Au nanoparticles are deposited on the surface of the Cu conductive substrate, and there will be Au nanoparticles Put the Cu conductive substrate in the graphene oxide solution prepared in the second step and let it stand at room temperature, take out the conductive substrate after reacting for 10 hours, graphene oxide is reduced to obtain graphene, and deposited on the surface of the Au conductive substrate;

4. After the graphene obtained in the previous step is washed with 100 mL of 2mol/L hydrochloric acid solution, the graphene is first immersed in liquid nitrogen to freeze, and then freeze-dried in a freeze-dryer at -50°C to obtain the product. The product is detected, and the characteristic peak (10°) of graphene oxide disappears through the X-ray powder diffraction test chart, and the characteristic peak (23°) of graphene appears, indicating that graphene oxide has been reduced to graphene, and there is no The characteristic peaks of metal oxides indicate the absence of metal oxides; combined with scanning electron microscope images, it can be seen that the structure of graphene is a three-dimensional layered porous structure, that is, dry, porous and pure three-dimensional graphene is supported on the surface of Au nanoparticles.

Example 11

1. Prepare 8 mg/mL graphene oxide solution by using the oxidized exfoliated graphite method (Hummers method);

2. Dilute the 8mg/mL graphene oxide solution with distilled water so that the concentration of the graphene oxide solution is 0.5mg/mL;

3. Add 0.01M H ₂ PtCl ₆ solution dropwise on the Cu substrate, let it stand for one minute, and wash it with HCl solution. It can be seen on the scanning electron microscope that Pt nanoparticles are deposited on the surface of the Cu conductive substrate. The Cu conductive substrate of the nanoparticles is placed in the graphene oxide solution prepared in the second step and left at room temperature, and the conductive substrate is taken out after 10 hours of reaction, and the graphene oxide is reduced to obtain graphene, which is deposited on the surface of the Pt conductive substrate;

4. After the graphene obtained in the previous step is washed with 100 mL of 2mol/L hydrochloric acid solution, the graphene is first immersed in liquid nitrogen to freeze, and then freeze-dried in a freeze-dryer at -50°C to obtain the product. The product is detected, and the characteristic peak (10°) of graphene oxide disappears through the X-ray powder diffraction test chart, and the characteristic peak (23°) of graphene appears, indicating that graphene oxide has been reduced to graphene, and there is no The characteristic peaks of metal oxides indicate the absence of metal oxides; combined with scanning electron microscope images, it can be seen that the structure of graphene is a three-dimensional layered porous structure, that is, dry, porous and pure three-dimensional graphene loaded on Pt nanoparticles is obtained. surface.

Example 12

1. Prepare 8 mg/mL graphene oxide solution by using the oxidized exfoliated graphite method (Hummers method);

2. Dilute the 8mg/mL graphene oxide solution with distilled water so that the concentration of the graphene oxide solution is 0.5mg/mL;

3. Put the Si conductive substrate sprayed with Cu by vacuum sputtering into the graphene oxide solution prepared in the second step and let it stand at 60°C. After reacting for 12 hours, take out the conductive substrate, and the graphene oxide is reduced to obtain graphene, which is deposited on the surface of the Si conductive substrate;

4. After the graphene obtained in the previous step is washed with 100 mL of 2mol/L hydrochloric acid solution, the graphene is first immersed in liquid nitrogen to freeze, and then freeze-dried in a freeze-dryer at -50°C to obtain the product. The product is detected, and the characteristic peak (10°) of graphene oxide disappears through the X-ray powder diffraction test chart, and the characteristic peak (23°) of graphene appears, indicating that graphene oxide has been reduced to graphene, and there is no The characteristic peaks of metal oxides indicate the absence of metal oxides; combined with scanning electron microscope images, it can be seen that the structure of graphene is a three-dimensional layered porous structure, that is, the product is dry, porous and pure three-dimensional graphene.

Example 13

1. Prepare 8 mg/mL graphene oxide solution by using the oxidized exfoliated graphite method (Hummers method);

2. Dilute the 8mg/mL graphene oxide solution with distilled water so that the concentration of the graphene oxide solution is 0.5mg/mL;

3. Put the ITO conductive substrate with half-surface vacuum sputtering and spraying Cu on the conductive surface into the graphene oxide solution prepared in the second step and let it stand at 60°C. After reacting for 12 hours, take out the conductive substrate, and the graphene oxide is reduced to obtain graphene. And deposited on the surface of the ITO conductive substrate;

4. After washing the graphene deposited on the surface of ITO obtained in the previous step with 100mL, 2mol/L hydrochloric acid solution, first immerse the graphene in liquid nitrogen to freeze, and then put it into a freeze dryer at -50°C for freeze drying That is to get the product, remove the graphene and Cu on the Cu-sprayed half-surface ITO, and test the remaining half-surface ITO deposited with graphene. The characteristic peak of graphene oxide (10°) can be seen through the X-ray powder diffraction test chart. disappears, and the characteristic peak of graphene (23°) appears, indicating that graphene oxide has been reduced to graphene, and there is no characteristic peak of metal oxide, indicating that there is no metal oxide; combined with scanning electron microscopy, it can be seen that graphene The structure is a three-dimensional layered porous structure, that is, the product is dry porous and pure three-dimensional graphene deposited on the surface of ITO.

Example 14

1. Prepare 8 mg/mL graphene oxide solution by using the oxidized exfoliated graphite method (Hummers method);

2. Dilute the 8mg/mL graphene oxide solution with distilled water so that the concentration of the graphene oxide solution is 0.5mg/mL;

3. Put the Cu conductive substrate in the graphene oxide solution prepared in the second step and let it stand at room temperature. After reacting for 10 hours, take out the conductive substrate, wash it, and dry it naturally at room temperature. The scanning electron microscope test shows that the graphene oxide is reduced. The obtained graphene shrinks into a film and attaches to the surface of the Cu conductive substrate during the normal temperature drying process;

4. Put the Cu conductive substrate with a layer of graphene film in the graphene oxide solution prepared in the second step and let it stand at room temperature. After 10 hours of reaction, take out the conductive substrate, and deposit a layer of graphene on the graphene film ;

5. Wash the graphene deposited on the surface of the graphene film obtained in the previous step with 100mL, 2mol/L hydrochloric acid solution, first immerse the graphene in liquid nitrogen to freeze, and then put it into a freeze dryer at -50°C The product is obtained by freeze-drying, and the product is detected. From the X-ray powder diffraction test chart, it can be seen that the characteristic peak (10°) of graphene oxide disappears, and the characteristic peak (23°) of graphene appears, indicating that graphene oxide has been It is reduced to graphene, and there is no characteristic peak of metal oxide, indicating that there is no metal oxide; combined with the scanning electron microscope (Figure 6), it can be seen that the structure of graphene is a three-dimensional layered porous structure, that is, the product is dry, porous and pure. The three-dimensional graphene is deposited on the surface of the graphene film.

Example 15

1. Prepare 8 mg/mL graphene oxide solution by using the oxidized exfoliated graphite method (Hummers method);

2. Dilute the 8mg/mL graphene oxide solution with distilled water so that the concentration of the graphene oxide solution is 0.5mg/mL;

3. Cut the Cu foil conductive substrate into a circle with a diameter of 1.6 cm, put it in the graphene oxide solution prepared in the second step and let it stand at room temperature. After 10 hours of reaction, take out the conductive substrate, and the graphene oxide is reduced to obtain graphene , and deposited on the surface of the conductive substrate;

4. After washing the graphene deposited on the Cu conductive substrate obtained in the previous step with 100mL, 2mol/L hydrochloric acid solution, first immerse the graphene in liquid nitrogen to freeze, and then put it into a freeze dryer at -50°C The product is obtained by freeze-drying, and the product is detected. From the X-ray powder diffraction test chart, it can be seen that the characteristic peak (10°) of graphene oxide disappears, and the characteristic peak (23°) of graphene appears, indicating that graphene oxide has been It is reduced to graphene, and there is no characteristic peak of metal oxide, indicating that there is no metal oxide; combined with scanning electron microscopy, it can be seen that the structure of graphene is a three-dimensional layered porous structure, that is, the product is supported on a circular Cu foil. Three-dimensional porous graphene on a substrate;

5. The three-dimensional porous graphene obtained in step 4 supported on the circular Cu foil conductive substrate was directly used as the negative electrode of the Li battery, and a button battery with a diameter of about 2 cm was assembled, and its capacity properties and cycle properties were tested. Tested at a current of 0.1A/g, the battery capacity is stable at 1076mAh/g, and when the current rises to 300mAh/g, the battery capacity is stable at 725mAh/g (Figure 7). From the rate test, the battery is stable at high current (20A/g) condition, the capacity can still reach 231mAh/g. The battery assembly process is completed in a glove box, and the test system is LAND CT2001A.

Example 16

1. Prepare 8 mg/mL graphene oxide solution by using the oxidized exfoliated graphite method (Hummers method);

2. Dilute the 8mg/mL graphene oxide solution with distilled water so that the concentration of the graphene oxide solution is 0.5mg/mL;

3. Put the Zn conductive substrate in the graphene oxide solution prepared in the second step and let it stand at room temperature, take out the conductive substrate after reacting for 6 hours, the graphene oxide is reduced to obtain graphene, and deposit on the surface of the conductive substrate;

4. First immerse the graphene obtained in the previous step into liquid nitrogen to freeze, and then put it into a freeze dryer at -50°C to freeze-dry to obtain the product. The product is tested, and the ZnO can be seen from the X-ray powder diffraction test chart. A series of characteristic peaks (32°, 34°, 36°, 48°, 57°, 63°, 66°, 68° and 69°), and the characteristic peak (10°) of graphene oxide disappeared, and graphene appeared The characteristic peak (23°) indicates that graphene oxide has been reduced to graphene; combined with the scanning electron microscope, it can be seen that the structure of graphene is a three-dimensional layered porous structure, that is, the product is a dry porous ZnO nanoparticle functionalized three-dimensional Graphene. Cut the freeze-dried graphene into a regular shape (rectangle: 0.4×0.8cm ² ) to test the photocurrent response. The photocurrent can reach 3 microamps (Figure 8). The test instrument is tested on a CHI760D electrochemical workstation, and the light source is a 100w incandescent lamp.

The present invention includes but is not limited to the above embodiments, and any equivalent replacement or partial improvement under the principle of the spirit of the present invention will be considered within the protection scope of the present invention.

Claims (1)

1. a method for spontaneously depositing three-dimensional graphene on conductive substrate, is characterized in that, described method step is as follows: The first step: prepare 8-20mg/mL graphene oxide solution by oxidizing and exfoliating graphite; Step 2: Dilute the 8-20 mg/mL graphene oxide solution so that the concentration of the graphene oxide solution is 1.7-3 mg/mL; The third step: put the conductive substrate in the graphene oxide solution prepared in the second step and let it stand, take out the conductive substrate after reacting for 6 to 12 hours, and the graphene oxide is reduced to obtain three-dimensional graphene, which is deposited on the surface of the conductive substrate ; The fourth step: directly freeze-dry the three-dimensional graphene obtained in the third step to obtain dry and porous functionalized three-dimensional graphene; or first clean off the metal oxide attached to the three-dimensional graphene obtained in the third step and then freeze Dry to obtain pure dry porous three-dimensional graphene; The conductive substrate is one of the following five types, wherein: The first is Ag, Pt or Au foil sprayed with Cu by vacuum sputtering; The second is Cu foil with nanostructured Ag, Pt or Au deposited by chemical reaction; The third type is Si wafer sprayed by vacuum sputtering; The fourth is conductive glass with half-surface vacuum sputtering Cu sputtering on the conductive surface; The fifth is a Cu substrate with a graphene film; Dilute in the second step and use water that reaches the purity of distilled water and above; The standing temperature in the third step is room temperature to 60°C.