Graphene and hydrotalcite composite material and preparation method thereof

Abstract

The invention relates to the technical field of material preparation, and particularly discloses a graphene and hydrotalcite composite material and a preparation method thereof.The preparation method comprises the steps that graphite is delaminated to prepare a graphene oxide solution, then the graphene oxide solution, a metal salt solution and an organic ligand solution are mixed and stirred in sequence, standing and processing are conducted, and then a GO and MOF composite material is obtained; and finally, putting the graphene-hydrotalcite composite material into a polar solvent mixed solution containing nitrate, etching and converting at room temperature, washing, and drying to obtain the graphene-hydrotalcite composite material. The preparation method is mild in condition and can be completed at normal temperature and normal pressure, the two-dimensional flaky hydrotalcite in the prepared composite material is arranged on the surface of the graphene in an array mode, the composite material has a unique structure and excellent performance, many defects of a traditional high-temperature and high-pressure preparation technology are overcome, and the composite material has great application potential in the fields of electrochemistry and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of material preparation, and particularly relates to a graphene@layered double hydroxide composite material and a preparation method thereof. Background Art

[0002] Layered-double hydroxides (LDHs), as a class of layered double metal hydroxides, exhibit good application potential in electrochemistry fields such as water electrolysis, supercapacitors, and batteries due to their rich chemical composition and easily adjustable properties. However, there are problems and challenges such as insufficient conductivity and slow electrochemical kinetics, which limit their further application and development.

[0003] In recent years, to improve the performance of LDHs, researchers have adopted various methods. Among them, preparing graphene@LDHs composite materials by loading LDHs on conductive graphene is an effective approach. In this way, the conductivity and stability of LDHs materials are significantly improved, thereby improving their electrochemical properties. However, most of the traditional methods for preparing such composite materials require high-temperature and high-pressure conditions, which not only lead to complex processes, high energy consumption costs, but also have problems such as potential safety hazards and environmental unfriendliness.

[0004] Therefore, it is of great practical significance to develop a simple, efficient, and mild-condition preparation method to obtain graphene@layered double hydroxide composite materials with excellent performance. Summary of the Invention

[0005] To solve the above problems, the present invention provides a graphene@layered double hydroxide composite material and a preparation method thereof. The preparation method is simple to operate, mild in conditions, highly universal, and safe. It can successfully prepare graphene@layered double hydroxide composite materials with specific morphologies and excellent electrochemical properties under normal temperature and pressure, meeting the requirements for high-performance materials in fields such as energy and environmental protection.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides a preparation method of a graphene@layered double hydroxide composite material, comprising the following steps:

[0008] (1) Exfoliate graphite to obtain a graphene oxide solution, and respectively prepare a metal salt solution and an organic ligand solution; after mixing and stirring the graphene oxide solution with the metal salt solution, then add the organic ligand solution and mix and stir to obtain a mixed solution of GO; let it stand for a period of time, and then centrifuge, wash, and dry to obtain a GO@MOF composite material;

[0009] (2) Add the GO@MOF composite material obtained in step (1) to a mixed solution of a polar solvent mixed with nitrate, and perform etching conversion at room temperature. The product is centrifugally washed with the polar solvent and dried to obtain a graphene@hydrotalcite composite material.

[0010] Further, in the step (1), when the mixing and stirring time of the graphene oxide solution and the metal salt solution is 0.5 h to 24 h, the mixing and stirring time of adding the organic ligand solution is 0.5 h to 24 h, and the standing time is 0.5 h to 72 h.

[0011] Further, in the step (2), the etching conversion time is 0.5 h to 24 h.

[0012] Further, in the step (2), in the mixed solution of GO, the concentration of the metal salt is 0.1 mol / L to 10 mol / L, and the molar ratio of the organic ligand to the metal salt is 1 to 100:1.

[0013] Further, in the step (2), the concentration of the GO@MOF composite material is 0.1 g / L to 10 g / L, and the total concentration of the polar solvent mixed solution mixed with nitrate is 1 g / L to 10 g / L.

[0014] Further, the metal salt is one or more of zinc nitrate, zinc acetate, zinc chloride, zinc sulfate, cobalt nitrate, cobalt acetate, cobalt chloride, cobalt sulfate, nickel nitrate, nickel acetate, nickel chloride, nickel sulfate, copper nitrate, copper acetate, copper chloride, copper sulfate, iron nitrate, iron acetate, iron chloride, and iron sulfate.

[0015] Further, the organic ligand is one or more of 2-methylimidazole, 1-methylimidazole, 2-nitroimidazole, benzimidazole, 5-nitrobenzimidazole, terephthalic acid, amino-terephthalic acid, biphenyldicarboxylic acid, trimesic acid, and amino-trimesic acid.

[0016] Further, the polar solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, formamide, methanol, ethanol, ethylene glycol, propanol, isopropanol, glycerol, chloromethane, dichloromethane, trichloromethane, chloroform, and deionized water.

[0017] Further, the nitrate is a strong acid and weak base salt. Preferably, the nitrate includes but is not limited to at least one of nickel nitrate, cobalt nitrate, iron nitrate, copper nitrate, and magnesium nitrate.

[0018] The present invention also provides a graphene@hydrotalcite composite material, which is prepared by the above preparation method, and the morphology of the graphene@hydrotalcite composite material is that hydrotalcite with a two-dimensional sheet-like morphology and arranged in an array is distributed on the surface of graphene.

[0019] The beneficial effects of the present invention are as follows:

[0020] (1) The preparation method of the present invention can be completed under normal temperature and pressure conditions. Compared with the traditional high-temperature and high-pressure preparation method, it does not require expensive high-temperature and high-pressure equipment and complex safety protection facilities, significantly reducing equipment investment and operating costs. At the same time, it reduces energy consumption, having prominent economic benefits and environmental protection advantages. For example, in large-scale industrial production, it can greatly reduce production costs, improve production efficiency, and reduce the pressure on the environment.

[0021] (2) The present invention realizes the in-situ growth of metal-organic framework materials (MOFs) on the surface of graphene by utilizing the oxygen-containing functional groups on the surface of graphene oxide, providing good nucleation sites and growth guidance for the subsequent growth of hydrotalcite, enabling hydrotalcite to grow in an array-like manner with a two-dimensional sheet-like morphology on the surface of graphene. This unique structure effectively solves the problem of easy agglomeration of graphene, and at the same time significantly improves the dispersibility of hydrotalcite, giving full play to the synergistic effect of the two, making the composite material have excellent electrochemical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 It is the transmission electron microscope image of the GO@MOF composite material in Embodiment 1 of the present invention;

[0024] Figure 2 It is the X-ray diffraction pattern of the GO@MOF composite material in Embodiment 1 of the present invention;

[0025] Figure 3 It is the transmission electron microscope image of the graphene@hydrotalcite composite material in Embodiment 1 of the present invention;

[0026] Figure 4 It is the transmission electron microscope image of the graphene@hydrotalcite composite material in Embodiment 2 of the present invention;

[0027] Figure 5 It is the transmission electron microscope image of the graphene@hydrotalcite composite material in Embodiment 3 of the present invention;

[0028] Figure 6 It is the X-ray diffraction pattern of the graphene@hydrotalcite composite material in Embodiment 3 of the present invention;

[0029] Figure 7This is the electrochemical performance diagram of the graphene@hydrotalcite composite material in Example 3 of the present invention; Detailed implementation manners

[0030] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

[0031] Example 1

[0032] A preparation method of a graphene@hydrotalcite composite material includes the following steps:

[0033] 1) Preparation of graphene oxide solution:

[0034] Using the improved Hummer method, under mechanical stirring, add 1 g of graphite to a 250 mL flask containing 108 mL of sulfuric acid and 12 mL of phosphoric acid. Under ice-water bath cooling, slowly add 3 g of potassium permanganate in batches, and stir at room temperature for 3 days. Then add 10 mL of 30% hydrogen peroxide to stop further oxidation. After 1 hour, add 100 mL of deionized water and continue stirring for 1 hour. After the system cools to room temperature, centrifuge the product, wash it 5 times with 1 M dilute hydrochloric acid to remove metal impurities, and then wash the product with deionized water until the pH is 5, and ultrasonically disperse it to finally obtain a graphene oxide solution.

[0035] 2) Preparation of GO@MOF composite material:

[0036] Dissolve Co(NO 3 ) 2 ·6H 2 O (450 mg) in 5 mL of deionized water, stir until the solution is clear to make a metal salt solution; dissolve 2-methylimidazole (5.5 g) in 10 mL of deionized water, stir until the solution is clear to make an organic ligand solution. Take 10 mL of graphene oxide solution and mix it with 5 mL of metal salt solution and stir for 1 hour, then add the organic ligand solution and continue stirring for 6 hours to obtain a GO mixed solution. In the GO mixed solution, the concentration of the metal salt solution is 0.31 mol / L, and the molar ratio of the organic ligand solution to the metal salt solution is 51.4:1. Let the obtained GO mixed solution stand for 24 hours, centrifuge to separate the solid, and wash it three times by centrifugation with deionized water. After drying, obtain the GO@MOF composite material.

[0037] 3) Preparation of graphene@hydrotalcite composite material

[0038] The obtained GO@MOF composite material (50 mg) was first dispersed in 30 mL of ethanol, and then a mixed solution of polar solvents (2 mL of methanol and 8 mL of ethanol) containing Ni(NO 3 ) 2 ·6H 2 O (25 mg) was added. Among them, the concentration of the GO@MOF composite material was 1.25 g / L, and the total concentration of the mixed solution of polar solvents mixed with nitrate was about 2.5 g / L. After stirring for 1 hour, the system was allowed to stand overnight, the product was centrifuged, washed three times by centrifugation with ethanol and methanol respectively, and then dried in an oven at 80 °C to obtain the graphene@layered double hydroxide composite material.

[0039] Performance testing:

[0040] (1) Morphology and structure characterization of the GO@MOF composite material.

[0041] Figure 1 Shown is the transmission electron microscope image of the GO@MOF composite material. From this image, the composite structure of GO and MOF can be clearly observed, and the growth of MOF on the surface of GO can be visually presented, which provides extremely important microscopic structural basis for the subsequent etching conversion to prepare the graphene@layered double hydroxide composite material and helps to deeply understand the formation process of the composite material.

[0042] Figure 2 Shown is the X-ray diffraction pattern of the GO@MOF composite material. By analyzing this pattern, the crystal structure of the GO@MOF composite material can be accurately determined and its phase composition can be clarified.

[0043] (2) Morphology characterization of the graphene@layered double hydroxide composite material.

[0044] Figure 3 Shown is the X-ray diffraction pattern of the graphene@layered double hydroxide composite material. It can be clearly seen from the figure that due to the insufficient amount of nitrate during the etching conversion process, the MOF was not completely etched, the size of the layered double hydroxide flakes grown on the surface of GO was small, and the distribution was relatively sparse. By comparing with samples prepared with different amounts of nitrate, the influence law of the amount of nitrate on the growth of layered double hydroxide can be effectively studied.

[0045] Example 2

[0046] A preparation method of a graphene@layered double hydroxide composite material, comprising the following steps:

[0047] 1) Preparation of graphene oxide solution: The same as in Example 1

[0048] 2) Preparation of GO@MOF composite material: The same as in Example 1

[0049] 3) Preparation of graphene@layered double hydroxide composite material

[0050] The obtained GO@MOF composite material (50 mg) was first dispersed in 30 mL of ethanol, and then a mixed solution of polar solvents (2 mL of methanol and 8 mL of ethanol) dissolved with Ni(NO 3 ) 2 ·6H 2 O (50 mg) was added. Among them, the concentration of the GO@MOF composite material was 1.25 g / L, and the total concentration of the mixed solution of polar solvents mixed with nitrate was about 5 g / L. After stirring for 1 hour, the system was allowed to stand overnight, the product was centrifuged and separated, and then centrifuged and washed three times with ethanol and methanol respectively. Subsequently, it was placed in an oven at 80 °C to dry, and a graphene@layered double hydroxide composite material was obtained.

[0051] Performance detection:

[0052] Figure 4 Shown is the X-ray diffraction pattern of the graphene@layered double hydroxide composite material, which also shows the growth of layered double hydroxide on the surface of GO. It can be found from it that as the amount of nitrate increases, the size of the layered double hydroxide flakes on the surface of GO increases, and the distribution density also increases, further verifying the key role of the amount of nitrate in the etching conversion process.

[0053] Example 3

[0054] A preparation method of a graphene@layered double hydroxide composite material, comprising the following steps:

[0055] 1) Preparation of graphene oxide solution: The same as in Example 1

[0056] 2) Preparation of GO@MOF composite material: The same as in Example 1

[0057] 3) Preparation of graphene@layered double hydroxide composite material

[0058] The obtained GO@MOF composite material (50 mg) was first dispersed in 30 mL of ethanol, and then a mixed solution of polar solvents (2 mL of methanol and 8 mL of ethanol) dissolved with Ni(NO 3 ) 2 ·6H 2 O (100 mg) was added. Among them, the concentration of the GO@MOF composite material was 1.25 g / L, and the total concentration of the mixed solution of polar solvents mixed with nitrate was about 10 g / L. After stirring for 1 hour, the system was allowed to stand overnight, the product was centrifuged and separated, and then centrifuged and washed three times with ethanol and methanol respectively. Subsequently, it was placed in an oven at 80 °C to dry, and a graphene@layered double hydroxide composite material was obtained.

[0059] Performance detection: Morphology, structure characterization and performance testing were carried out on the graphene@layered double hydroxide composite material.

[0060] Figure 5Shown is the transmission electron microscopy image of the graphene@hydrotalcite composite material. In this image, it can be clearly seen that when the amount of nitrate is sufficient, the MOF is completely etched, and large-sized hydrotalcite sheets grow on the surface of GO, presenting a good two-dimensional sheet-like morphology with an array growth feature and uniform distribution, fully indicating that the growth of hydrotalcite on the surface of graphene can be effectively controlled by the method of the present invention;

[0061] Figure 6 Shown is the X-ray diffraction pattern of the graphene@hydrotalcite composite material. By analyzing this pattern, the crystal structure of the graphene@hydrotalcite composite material can be accurately determined;

[0062] Figure 7 Shown is the electrochemical performance graph of the graphene@hydrotalcite composite material. It can be seen from the graph that after a long-term charge-discharge test, the electrochemical performance of this graphene@hydrotalcite composite material shows no attenuation, intuitively demonstrating that the graphene@hydrotalcite composite material prepared by the present invention has excellent electrochemical stability, highlighting the advantages and application potential of the method of the present invention, and providing strong support for its application in the electrochemical field.

[0063] Example 4

[0064] A preparation method of a graphene@hydrotalcite composite material includes the following steps:

[0065] 1) Preparation of graphene oxide solution: The same as in Example 1

[0066] 2) Preparation of GO@MOF composite material:

[0067] Prepare a copper nitrate solution with a concentration of 0.1 mol / L as the metal salt solution, and a trimesic acid solution as the organic ligand solution. Mix the graphene oxide solution and the copper nitrate solution and stir for 0.5 hours, then add the organic ligand solution and continue to stir for 0.5 hours. The molar ratio of the organic ligand solution to the copper nitrate solution is 1:1. Let the obtained mixed solution stand for 0.5 hours, centrifuge, wash with deionized water, and dry to obtain the GO@MOF composite material.

[0068] 3) Preparation of graphene@hydrotalcite composite material

[0069] Add the GO@MOF composite material into an N,N-dimethylacetamide mixed solution (total concentration of 1 g / L) containing magnesium nitrate (as nitrate) at a concentration of 0.1 g / L, and etch and transform at room temperature for 0.5 hours. Centrifuge and separate the product, wash it three times by centrifugation with N,N-dimethylacetamide, and then place it in an 80-degree Celsius oven to dry to obtain the graphene@hydrotalcite composite material.

[0070] Example 5

[0071] A preparation method of a graphene@hydrotalcite composite material, comprising the following steps:

[0072] 1) Preparation of graphene oxide solution: The same as in Example 1

[0073] 2) Preparation of GO@MOF composite material:

[0074] Prepare a zinc nitrate solution with a concentration of 10 mol / L as the metal salt solution, and a benzimidazole solution as the organic ligand solution. Mix the graphene oxide solution and the zinc nitrate solution and stir for 24 hours, then add the organic ligand solution and continue to stir for 24 hours. The molar ratio of the organic ligand solution to the zinc nitrate solution is 100:1. Let the obtained mixed solution stand for 72 hours, centrifuge, wash with methanol, and dry to obtain the GO@MOF composite material.

[0075] 3) Preparation of graphene@hydrotalcite composite material

[0076] Add the GO@MOF composite material to a mixed solution of chloromethane and dichloromethane (total concentration of 10 g / L) containing iron nitrate (as nitrate) at a concentration of 10 g / L, and etch and transform at room temperature for 24 hours. Centrifuge and separate the product, wash it three times by centrifugation with chloromethane and dichloromethane respectively, and then dry it in an oven at 80 °C to obtain the graphene@hydrotalcite composite material.

[0077] Example 6

[0078] A preparation method of a graphene@hydrotalcite composite material, comprising the following steps:

[0079] 1) Preparation of graphene oxide solution: Using the mechanical exfoliation method, place graphite in a ball mill and ball mill at a certain rotation speed for 8 hours, then disperse the product in N,N-dimethylformamide and perform ultrasonic treatment for 6 hours, and centrifuge to obtain the graphene oxide solution.

[0080] 2) Preparation of GO@MOF composite material:

[0081] Prepare a zinc nitrate solution with a concentration of 3 mol / L as the metal salt solution, and an amino-terephthalic acid solution as the organic ligand solution. Mix the graphene oxide solution and the zinc nitrate solution and stir for 10 hours, then add the organic ligand solution and continue to stir for 8 hours. The molar ratio of the organic ligand solution to the zinc nitrate solution is 50:1. Let the obtained mixed solution stand for 36 hours, centrifuge, wash with deionized water, and dry to obtain the GO@MOF composite material.

[0082] 3) Preparation of graphene@hydrotalcite composite material

[0083] The GO@MOF composite material was added to an ethylene glycol solution containing copper nitrate (as the nitrate) at a concentration of 3 g / L (total concentration 4 g / L), and etched and transformed at room temperature for 12 hours. The product was centrifugally washed with ethylene glycol and dried to obtain the graphene@hydrotalcite composite material.

[0084] Example 7

[0085] A method for preparing a graphene@hydrotalcite composite material, comprising the following steps:

[0086] 1) Preparation of graphene oxide solution: By the liquid-phase exfoliation method, graphite was dispersed in dichloromethane, an appropriate amount of surfactant was added, and ultrasonic treatment was carried out for 12 hours, followed by centrifugal separation to obtain the graphene oxide solution.

[0087] 2) Preparation of GO@MOF composite material:

[0088] A ferric chloride solution (concentration 8 mol / L) was prepared as the metal salt solution, and a trimesic acid solution was used as the organic ligand solution. The graphene oxide solution was mixed and stirred with the ferric chloride solution for 5 hours, the trimesic acid solution was added and stirring continued for 6 hours. The molar ratio of the ferric chloride solution to the trimesic acid solution was 80:1. It was left standing for 24 hours, centrifuged, washed with ethanol, and dried to obtain the GO@MOF composite material.

[0089] 3) Preparation of graphene@hydrotalcite composite material

[0090] The GO@MOF composite material was added to a glycerol solution containing ferric nitrate (as the nitrate) at a concentration of 2 g / L (total concentration 6 g / L), and etched and transformed at room temperature for 6 hours. The product was centrifugally washed with glycerol and dried to obtain the graphene@hydrotalcite composite material.

[0091] Comparative Example 1

[0092] In this comparative example, the graphene@hydrotalcite composite material was prepared by the traditional hydrothermal method, the reaction temperature was 180 °C, the reaction time was 12 hours, and other conditions were the same as in Example 1.

[0093] Result: For the composite material obtained by the traditional method, the hydrotalcite had a larger size.

[0094] Comparative Example 2

[0095] In this comparative example, the preparation step of the GO@MOF composite material was not carried out, and graphene oxide was directly mixed with the hydrotalcite precursor, and other conditions were the same as in Example 1.

[0096] Result: The composite material of graphene and hydrotalcite could not be obtained.

[0097] Comparative Example 3

[0098] In this comparative example, the nitrate in the preparation of the graphene@layered double hydroxide composite material in step (3) is a salt of a weak base and a non-strong acid (such as sodium chloride), and other conditions are the same as those in Example 1.

[0099] Result: This method needs to utilize the hydrolysis of the salt of a strong acid and a weak base to release trace hydrogen ions, so as to etch the MOF precursor. If a salt of a non-strong acid and a weak base is used, the MOF cannot be converted into layered double hydroxide, and the target product cannot be obtained.

[0100] The following conclusions can be drawn from the above examples:

[0101] In the present invention, graphene oxide (GO) solution is obtained by exfoliating graphite, and then it is added to the MOF growth solution. Using the oxygen-containing functional groups on the surface of GO as anchor points, MOF is grown in-situ to obtain a GO@MOF composite material. Then, the obtained GO@MOF composite material is added to a mixed solution of a polar solvent of mixed nitrates for etching conversion, and layered double hydroxide grows in an array in the form of two-dimensional flakes on the surface of graphene, and finally a graphene@layered double hydroxide composite material with excellent electrochemical performance can be obtained.

[0102] The present invention has been further described with the aid of specific examples above. However, it should be understood that the specific description here should not be construed as a limitation on the essence and scope of the present invention. Various modifications made by those of ordinary skill in the art to the above examples after reading this specification all fall within the scope protected by the present invention.

Claims

1. A method for preparing a graphene@hydrotalcite composite material, characterized in that: The following steps are involved: (1) exfoliating graphite to obtain a graphene oxide solution, and preparing a metal salt solution and an organic ligand solution respectively; mixing the graphene oxide solution with the metal salt solution, and then adding the organic ligand solution to mix and stir to obtain a mixed solution of GO; After standing for a period of time, the mixture was centrifuged, washed and dried to obtain the GO@MOF composite material; (2) adding the GO@MOF composite material obtained in step (1) to a mixed solution of a polar solvent mixed with nitrate, performing etching conversion at room temperature, centrifugally washing the product with a polar solvent, and drying to obtain a graphene@hydrotalcite composite material.

2. The method for preparing the graphene@hydrotalcite composite material according to claim 1, characterized in that: In the step (1), when the mixing and stirring time of the graphene oxide solution and the metal salt solution is 0.5h to 24h, the mixing and stirring time of adding the organic ligand solution is 0.5h to 24h, and the standing time is 0.5h to 72h.

3. The method for preparing the graphene@hydrotalcite composite material according to claim 1, characterized in that: In the step (2), the etching conversion time is 0.5h to 24h.

4. The method for preparing the graphene@hydrotalcite composite material according to claim 1, characterized in that: In the step (1), in the mixed solution of GO, the concentration of the metal salt is 0.1 mol / L to 10 mol / L, and the molar ratio of the organic ligand to the metal salt is 1 to 100:

1.

5. The method for preparing the graphene@hydrotalcite composite material according to claim 1, characterized in that: In the step (2), the concentration of the GO@MOF composite material is 0.1 g / L to 10 g / L, and the total concentration of the polar solvent mixed solution mixed with nitrate is 1 g / L to 10 g / L.

6. The method for preparing the graphene@hydrotalcite composite material according to claim 1, characterized in that: The metal salt is one or more of zinc nitrate, zinc acetate, zinc chloride, zinc sulfate, cobalt nitrate, cobalt acetate, cobalt chloride, cobalt sulfate, nickel nitrate, nickel acetate, nickel chloride, nickel sulfate, copper nitrate, copper acetate, copper chloride, copper sulfate, ferric nitrate, ferric acetate, ferric chloride, and ferric sulfate.

7. The method for preparing the graphene@hydrotalcite composite material according to claim 1, characterized in that: The organic ligand is one or more of 2-methylimidazole, 1-methylimidazole, 2-nitroimidazole, benzimidazole, 5-nitrobenzimidazole, terephthalic acid, aminoterephthalic acid, biphenyl dicarboxylic acid, trimesic acid, and aminotrimesic acid.

8. The method for preparing the graphene@hydrotalcite composite material according to claim 1, characterized in that: The polar solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, formamide, methanol, ethanol, ethylene glycol, propanol, isopropanol, glycerol, chloroform, dichloromethane, chloroform, chloroform, and deionized water.

9. The method for preparing the graphene@hydrotalcite composite material according to claim 1, characterized in that: The nitrate is a strong acid and weak alkaline salt.

10. A graphene@hydrotalcite composite material, characterized in that: The graphene@hydrotalcite composite material is prepared by the preparation method according to any one of claims 1 to 9, and the morphology of the graphene@hydrotalcite composite material is hydrotalcite with two-dimensional flaky morphology distributed on the surface of graphene and arranged in an array.

Images