CN103073009B - Anionic clay/graphene nanocomposite material and preparation method thereof - Google Patents

Abstract

The invention belongs to the field of nanocomposite materials, and discloses an anionic clay/graphene nanocomposite material and a preparation method thereof. The preparation method of the anionic clay/graphene nanocomposite material comprises the following steps: (1) preparation of delaminated anionic clay colloids; (2) preparation of delaminated negatively charged graphene colloids; (3) anionic clay/graphene colloids Graphene via the preparation of nanocomposites. The anionic clay/graphene nanocomposite material prepared by the present invention breaks the traditional combination of semiconductor and graphene, makes the semiconductor and graphene fully and effectively combined, maximizes the functions of the two materials, and then improves the photoelectricity of the semiconductor material performance.

Description

Anionic clay/graphene nanocomposite material and preparation method thereof

technical field

The invention belongs to the field of nanocomposite materials, relates to a nanocomposite material, in particular to an anionic clay/graphene nanocomposite material and a preparation method thereof.

Background technique

Anionic clay is a porous material with a large specific surface area, which can be artificially synthesized as a layered material according to specific functional requirements. With Zn, Ti and other elements as the main body, anionic clay can be designed as a semiconductor material with light function, and then some transition metal elements are added to adjust the bandgap width, so that it has a good response in the visible light range. After the photofunctional anionic clay semiconductor material is combined with graphene, graphene can not only act as a photoacceptor, but also quickly transport electrons, so that photogenerated electrons and photogenerated holes can be effectively separated and transferred, thereby improving the semiconductor material. The photoelectric performance makes the nanocomposite material widely used in many fields such as photocatalytic cracking of water to produce hydrogen and oxygen, photocatalytic degradation of organic pollutants, photovoltaic cells, and solar cells. At the same time, the nanocomposite material can also be used as a super adsorbent.

At present, there have been some reports on the composite materials of semiconductor and graphene. The preparation methods mainly focus on growing semiconductor particles on the surface of graphene or growing graphene on the surface of semiconductor, but these methods cannot fully combine graphene and semiconductor materials. , so that the advantages of graphene's fast electron transport cannot be effectively utilized. Therefore, it is necessary to break the traditional combination method and find a new combination method of semiconductor and graphene, so that the semiconductor material and graphene can be fully and effectively combined. Some nano-research centers in Japan and South Korea have reported that two semiconductor materials with different charges can be combined through layer-by-layer self-assembly by layer-by-layer method. Anionic clay is a layered material with positively charged laminates, and the thickness of the laminates is about 0.5nm, while graphite can be oxidized or further carboxylated to obtain delaminated, negatively charged graphene oxide, and its sheets The thickness is about 0.8-1.2nm. Anionic clay and graphene oxide, two layered materials with opposite electrical properties, are made into a colloidal solution, and after mixing, the monomolecular layer of anionic clay and monomolecular layer of graphene oxide are self-assembled layer by layer to form anion Clay/graphene oxide nanocomposites. Then reduce the graphene oxide with hydrazine hydrate to obtain an anionic clay/graphene nanocomposite material. This composite material breaks the traditional way of combining semiconductor and graphene, so that the semiconductor and graphene can be fully and effectively combined to maximize the Play the functions of the two materials, and then improve the photoelectric performance of the semiconductor material.

Contents of the invention

The object of the present invention is to provide a kind of preparation method of anionic clay/graphene nanocomposite material.

Another object of the present invention is to provide an anionic clay/graphene nanocomposite material prepared by the above preparation method. The anionic clay/graphene nanocomposite material is a composite material with a sandwich structure.

The object of the present invention is achieved through the following technical solutions:

A preparation method of anion clay/graphene nanocomposite material, comprises the following steps:

(1) Preparation of delaminated anionic clay colloid: Take 0.1-10 g of anionic clay, add it to 1 L of pure formamide solution, and stir to obtain a delaminated anionic clay colloid solution with a concentration of 0.1-10 g/L;

(2) Preparation of delaminated negatively charged graphene colloid: Take 5g of negatively charged graphene powder and add it to 500mL pure formamide liquid, stir to obtain delaminated negatively charged graphene colloid with a concentration of 1g/L solution;

(3) Preparation of anionic clay/graphene via nanocomposites: In an Ar atmosphere, during stirring, add the delaminated anionic clay colloid solution dropwise to the delaminated negatively charged graphene colloid solution, so that The mass ratio of the delaminated anionic clay colloid to the delaminated negatively charged graphene colloid is 0.2:1 to 20:1; stirring treatment, the flocculent precipitate is obtained, and the flocculent precipitate is centrifugally washed with absolute ethanol, and vacuum-dried. To obtain anion clay/negatively charged graphene composite material, grind and sieve to obtain anion clay/negatively charged graphene composite material powder; add 2mL hydrazine hydrate to 1g of anion clay/negatively charged graphene composite material powder React for 1-5 hours, reduce, and vacuum-dry to obtain anionic clay/graphene nanocomposite material, grind and pass through a 200-mesh sieve to obtain anionic clay/graphene composite material powder.

The preparation steps of the anionic clay described in step (1) are: mix divalent metal salt and trivalent metal salt, add deionized water, stir until the metal salt dissolves, and record it as solution A; take cyclohexamethylene tetra amine, add deionized water, stir until it dissolves, add HNO ₃ solution dropwise, adjust the pH to 2-5, and record it as solution B; mix solution A and solution B in equal volume, add NaNO ₃ , shake well, and sonicate, Obtain a clarified mixed solution; reflux the mixed solution for 24-48 hours to obtain a light green turbid liquid, centrifuge after cooling, wash the supernatant until the pH is 6.5-8.0, dry the obtained precipitate, grind, and sieve to obtain anionic clay;

Wherein, the divalent metal salt is Zn(NO ₃ ) ₂ ·6H ₂ O with an amount of 0.04-0.048 mol, and Ni(NO ₃ ) ₂ ·6H ₂ O with an amount of 0.012-0.02 mol; The molar ratio of the divalent metal salt Zn ²⁺ : Ni ²⁺ is 2:1 to 4:1; the trivalent metal salt is Al(NO ₃ ) ₃ with a substance amount of 0.02mol; the The molar ratio of divalent metals to trivalent metals is 3:1; the added amount of the deionized water is 125mL; the amount of the hexamethylenetetramine is 0.125mol; the HNO ₃ The molar concentration of the solution is 1.0mol/L; the added amount of the _NaNO3 is 5g; the ultrasonic treatment is at 50KHZ for 10-20min; the reflux temperature is 100°C; the cooling The temperature is 20-30°C; the rotational speed of the centrifuge is 6000-8000rpm, and the time is 10-20min; the sieving is through a 200-mesh sieve.

The stirring described in the step (1) is at 20-30° C. for 5-10 days.

The negatively charged graphene described in the step (2) is graphene oxide or carboxyl graphene; the stirring is carried out at 20-30° C. for 5-10 days.

Wherein, the preparation method of graphene oxide is as follows: add 5g graphene powder into 100mL concentrated sulfuric acid, stir at 4°C, add _2.5gNaNO3 and _15.0gKMnO4 during the stirring process, stir for 90min, then transfer to the medium temperature process, Stir for 30-40min, turn to high temperature stage, add deionized water, stir for 20-30min, wash once with H ₂ O ₂ solution, then wash with HCl solution until no white precipitate is formed, dry the white precipitate in vacuum to obtain graphite oxide Graphene, ground, and sieved to obtain graphene oxide powder.

Wherein, the temperature of the middle temperature process is 30-40°C; the temperature of the high-temperature stage is 80-90°C; the amount of deionized water added is 200mL; the concentration of the H ₂ O ₂ solution 30%; the concentration of the HCl solution is 5%; the sieve is 200 mesh sieve.

The preparation method of the carboxylated graphene is as follows: adding the graphene oxide powder into the NaOH solution, then dripping into the chloroacetic acid solution, stirring, after the reaction is completed, centrifugally washing with deionized water, and vacuum-drying the obtained precipitate, That is, carboxylated graphene is obtained, ground, sieved, and carboxylated graphene powder.

Wherein, the quality of the graphene oxide is 2g; the concentration of the NaOH solution is 1.0mmol/L, and the volume is 100mL; the concentration of the chloroacetic acid solution is 1.0mmol/L, and the volume is 20mL; the The stirring time is 2 hours; the number of times of washing with deionized water is 5 times; the rotation speed of the centrifugation is 6000 rpm, and the time is 10 minutes; the sieving is 200-mesh sieve.

The time of the stirring treatment described in step (3) is 2-6 hours; the number of times of washing with absolute ethanol is 3-5 times, the speed of centrifugation is 6000-8000rpm, and the time is 10-20min; The vacuum drying temperature is 60-80°C; the sieving is 200 mesh sieve.

The anionic clay/graphene nanocomposite material prepared by the above-mentioned preparation method, the anionic clay/graphene nanocomposite material is formed by stacking monomolecular layer anionic clay and monomolecular layer graphene with a sandwich Structural composite materials.

The principle of the present invention is that two kinds of semiconductor materials with different electrical properties can be combined together through layer-by-layer self-assembly by layer-by-layer method. Anionic clay is a layered material with positively charged layers, and its layer thickness is about 0.5nm, while graphite can be oxidized or further carboxylated to obtain delaminated, negatively charged graphene, and its layer thickness About 0.8 ~ 1.2nm. Anionic clay and negatively charged graphene, two layered materials with opposite electrical properties, are made into a colloidal solution, and after mixing, the monomolecular anionic clay and monomolecular graphene oxide are self-assembled layer by layer through electrostatic interaction. Formation of anionic clay/graphene oxide nanocomposites. The graphene oxide is then reduced with hydrazine hydrate to obtain an anionic clay/graphene nanocomposite material.

Advantages of the present invention compared with the prior art: Currently, the composite materials used in cracking water to produce hydrogen under visible light generally need to be doped with noble metal elements, such as Ag-doped nano-TiO ₂ , Pt-doped nano-TiO ₂ , etc., the doping of these noble metals It is to effectively transport electrons and reduce the recombination probability of photogenerated electrons and photogenerated holes. However, noble metal doping costs are high, and the ability to transport electrons is far inferior to that of lower-cost graphene. The present invention provides a method for preparing an anionic clay/graphene nanocomposite material that can be applied to cracking water to produce hydrogen under visible light. Composite materials that can maximize the combination of anionic clay and graphene.

Description of drawings

Figure 1. Schematic diagram of the preparation method for anionic clay/graphene nanocomposites.

Fig. 2. is the XRD pattern of the anionic clay prepared in Example 1.

Fig. 3. is the TEM image of the carboxylated graphene prepared in embodiment 1.

Figure 4. The TEM image of the anionic clay/graphene nanocomposite prepared in Example 1.

Figure 5. High-definition TEM and schematic diagram of the cross-section of the anionic clay/graphene nanocomposite.

Figure 6. Solid UV-vis spectral scans: (a) anionic clay; (b) anionic clay/graphene nanocomposite.

Detailed ways

The present invention will be further described in detail below with reference to the examples and drawings, but the implementation of the present invention is not limited thereto.

Example 1

(1) Preparation of anionic clay: Weigh 11.90g (0.040mol) Zn(NO ₃ ) ₂ ·6H ₂ O, 5.82g (0.020mol) Ni(NO ₃ ) ₂ ·6H ₂ O, 7.50g (0.020mol) )Al(NO ₃ ) ₃ , put in a 300mL beaker, add 125mL deionized water, stir until the solid is completely dissolved, and record it as solution A. In solution A, the molar ratio of divalent metal to trivalent metal (Zn ²⁺ + Ni ²⁺ ):Al ³⁺ =3:1, where Zn ²⁺ :Ni ²⁺ =2:1. Weigh 17.50g (0.125mol) cyclohexamethylenetetramine, put it in a 300mL beaker, add 125mL deionized water, stir until the solid is completely dissolved, then add 1.0mol/L _HNO3 solution dropwise to lower the pH to 2 , recorded as solution B.

Mix the above A and B solutions in a 500mL two-necked test flask with medium volume, add 5.00g NaNO ₃ and shake well, then place the two test flasks in a 50kHz ultrasonic scrubber for 10min to obtain a clear mixed solution.

Put the two test flasks into the electric heating device and reflux at 100°C for 24 hours to obtain a light green suspension. After cooling to 25°C, centrifuge with deionized water at 6,000 rpm for 10 minutes to wash the supernatant until the pH of the supernatant reaches 6.5. The resulting precipitate is frozen. Dry, grind after drying, and pass through a 200-mesh sieve to obtain anionic clay. The XRD pattern of the prepared anionic clay can be seen in Figure 2, which is characterized by a sharp peak around 2θ=10°.

(2) Preparation of delaminated anionic clay colloid: Take 1.0 g of the prepared anionic clay, add it to 1.0 L of pure formamide liquid, stir at 20°C for 5 days, and obtain a delaminated anionic clay colloid with a concentration of 1.0 g/L Anionic clay colloid solution. The Tyndall effect can be used to judge whether a colloidal solution has formed.

(3) Preparation of graphene oxide: graphene oxide was prepared by the improved Hummers method. The preparation steps are as follows: add 5.0g graphene powder (purchased from Shanghai Aladdin Company) into 100mL concentrated H ₂ SO ₄ , stir at 4°C, add 2.5g NaNO ₃ and 15.0g KMnO ₄ during the stirring process, and stir After 90 minutes, turn to the medium temperature process (35°C), stir at medium temperature for 30 minutes, then switch to the high temperature stage (80°C), then add 200mL deionized water, and stir for 30 minutes at the high temperature stage. After the reaction, wash once with 30% H ₂ O ₂ solution, then wash with 5% HCL solution until no white precipitate is formed, then dry the white precipitate in vacuum to obtain graphene oxide, grind it through 200 mesh for later use, and obtain graphene oxide Graphene powder.

(4) Preparation of delaminated graphene oxide colloidal solution: Take 0.5g of the prepared graphene oxide powder and add it to 500mL of pure formamide liquid, stir at 20°C for 7 days to obtain a layer with a concentration of 1.0g/L isolated graphene oxide colloidal solution. The Tyndall effect can be used to judge whether a colloidal solution has formed.

(5) Preparation of anionic clay/graphene nanocomposites: transfer the obtained 500mL delaminated graphene oxide colloidal solution to a 3L round bottom flask, and add 1.0 L of delaminated anionic clay colloidal solution, so that the mass ratio of delaminated anionic clay to delaminated graphene oxide is 2:1, stirred for 2 hours, and a flocculent precipitate was obtained.

The flocculent precipitate obtained was centrifuged and washed 3 times with pure ethanol at a centrifugal speed of 6000rpm, and the obtained precipitate was vacuum-dried at 60°C to obtain an anionic clay/graphene oxide composite material, which was then ground to 100 mesh to obtain anionic clay/graphene oxide olefin composite material powder.

Take 1.0 g of the obtained anionic clay/graphene oxide composite powder, add 2.0 mL of hydrazine hydrate to react for 1 h, make it reduced, and dry it in vacuum at 60°C to obtain anionic clay/graphene nanocomposite material, and then grind it through 200 meshes, The schematic diagram of the preparation method of the powdered anionic clay/graphene nanocomposite material obtained by the anionic clay/graphene nanocomposite material is shown in FIG. 1 .

Example 2

(1) Preparation of anionic clay: Weigh 11.90g (0.040mol) Zn(NO ₃ ) ₂ ·6H ₂ O, 5.82g (0.020mol) Ni(NO ₃ ) ₂ ·6H ₂ O, 7.50g (0.020mol) )Al(NO ₃ ) ₃ , put in a 300mL beaker, add 125mL deionized water, stir until the solid is completely dissolved, and record it as solution A. In solution A, the molar ratio of divalent metal to trivalent metal (Zn ²⁺ + Ni ²⁺ ):Al ³⁺ =3:1, where Zn ²⁺ :Ni ²⁺ =2:1. Weigh 17.50g (0.125mol) cyclohexamethylenetetramine, put it in a 300mL beaker, add 125mL deionized water, stir until the solid is completely dissolved, then add 1.0mol/L _HNO3 solution dropwise to lower the pH to 5 , recorded as solution B.

Mix the above A and B solutions in a 500mL two-necked test flask with medium volume, add 5.00g NaNO ₃ and shake well, then place the two test flasks in a 50kHz ultrasonic scrubber for 10min to obtain a clear mixed solution.

Put the two test flasks into the electric heating device and reflux at 100°C for 48 hours to obtain a light green suspension. After cooling to 20°C, wash with deionized water at 8,000 rpm for 20 minutes until the pH of the supernatant reaches 8.0 , The resulting precipitate is freeze-dried, ground after drying, and passed through a 200-mesh sieve to obtain anionic clay.

(2) Preparation of delaminated anionic clay colloid: Take 0.1g of the prepared anionic clay, add it to 1.0L of pure formamide liquid, stir at 25°C for 10 days, and obtain a delaminated anionic clay with a concentration of 0.1g/L Anionic clay colloid solution. The Tyndall effect can be used to judge whether a colloidal solution has formed.

(3) Preparation of carboxylated graphene: Graphene oxide was prepared by the improved Hummers method. The preparation steps are as follows: add 5.0g graphene powder (purchased from Shanghai Aladdin Company) to 100mL concentrated H ₂ SO ₄ and stir at 4°C. During the stirring process, add 2.5g NaNO ₃ and 15.0g KMnO ₄ , stir for 90min and then turn to Enter the medium temperature process, the temperature is controlled at 35°C, stir for 30 minutes and then transfer to the high temperature stage, the temperature is controlled at 80°C, then add 200mL deionized water, and stir for 30 minutes. After the reaction, wash once with 30% H ₂ O ₂ solution, and then wash with 5% HCL solution until no white precipitate is formed. Vacuum-dry the white precipitate to obtain graphene oxide, and grind it through 200 mesh to obtain graphene oxide powder. Weigh 2.0g of the prepared graphene oxide powder, add it to 100mL NaOH solution with a concentration of 1.0mmol/L, then drop in 20mL of chloroacetic acid solution with a concentration of 1.0mmol/L, stir for 2h, after the reaction is over, rinse with deionized water Centrifuge at 6000 rpm for 10 min, wash and centrifuge 5 times, then vacuum-dry the obtained precipitate to obtain carboxylated graphene, and grind to 200 mesh to obtain carboxylated graphene powder.

(4) Add 0.5 g of the prepared carboxylated graphene into 500 mL of pure formamide liquid, and stir at 25 °C for 10 days to obtain a delaminated carboxylated graphene colloidal solution with a concentration of 1.0 g/L. The Tyndall effect can be used to judge whether a colloidal solution has formed. The TEM image of its delaminated carboxylated graphene colloid can be seen in Figure 3.

(5) Preparation of anionic clay/graphene nanocomposites: transfer the obtained 500mL delaminated carboxylated graphene colloidal solution to a 3L round bottom flask, and dropwise 1.0 L of delaminated anionic clay colloidal solution was added so that the mass ratio of delaminated anionic clay to delaminated carboxylated graphene was 1:5, and stirred for 6 hours to obtain a flocculent precipitate.

The flocculent precipitate obtained was centrifuged and washed 4 times with pure ethanol at a centrifugal speed of 8000rpm, and the obtained precipitate was vacuum-dried at 70°C to obtain an anionic clay/carboxylated graphene composite material, which was then ground to 100 mesh to obtain anionic clay/carboxylated graphene Graphene composite material powder.

Take 1.0 g of the obtained anionic clay/carboxylated graphene composite powder, add 2.0 mL of hydrazine hydrate to react for 3 hours, make it reduced, and dry it in vacuum at 70°C to obtain anionic clay/graphene nanocomposite material, and then grind it through 200 mesh , to obtain the powder of anionic clay/graphene nanocomposite material, its TEM image can be referred to Fig. 4 and Fig. 5, and the solid UV-vis spectrum scanning figure of its anionic clay and anionic clay/graphene nanocomposite material can refer to Fig. 6.

Example 3

(1) Preparation of anionic clay: weigh 13.38g (0.045mol) Zn(NO ₃ ) ₂ 6H ₂ O, 4.36g (0.015mol) Ni(NO ₃ ) ₂ 6H ₂ O, 7.50g (0.02mol) Al(NO ₃ ) ₃ , put in a 300mL beaker, add 125mL deionized water, stir until the solid is completely dissolved, and record it as solution A. In solution A, the molar ratio of divalent metal to trivalent metal (Zn ²⁺ +Ni ²⁺ ):Al ³⁺ =3:1, where Zn ²⁺ :Ni ²⁺ =3:1. Weigh 17.50g (0.125mol) cyclohexamethylenetetramine, put it in a 300mL beaker, add 125mL deionized water, stir until the solid is completely dissolved, then add 1.0mol/L _HNO3 solution dropwise to lower the pH to 2.5 , recorded as solution B. Mix the above-mentioned A and B solutions in a 500mL two-necked test flask with medium volume, add 5.00g NaNO ₃ and shake well, then place the flask in a 50kHz ultrasonic scrubber for 20min to obtain a clear mixed solution.

Put the two test flasks into the electric heating device and reflux at 100°C for 36 hours to obtain a light green suspension. After cooling to 30°C, centrifuge with deionized water at 6,000 rpm for 10 minutes and wash the supernatant until the pH reaches 7. The obtained precipitate is freeze-dried, ground after drying, and passed through a 200-mesh sieve to obtain anionic clay.

(2) Preparation of delaminated anionic clay colloid: Take 10g of the prepared anionic clay, add it to 1.0L of pure formamide liquid, stir at 30°C for 7 days, and obtain delaminated anionic clay with a concentration of 10g/L colloidal solution. The Tyndall effect can be used to judge whether a colloidal solution has formed.

(3) Preparation of graphene oxide: graphene oxide was prepared by the improved Hummers method. The preparation steps are as follows: add 5.0g graphene powder (purchased from Shanghai Aladdin Company) to 100mL concentrated H ₂ SO ₄ and stir at 4°C. During the stirring process, add 2.5g NaNO ₃ and 15.0g KMnO ₄ , stir for 90min and then turn to Enter the medium temperature process, the temperature is controlled at 30°C, stir for 40 minutes and then turn to the high temperature stage, the temperature is controlled at 85°C, then add 200mL deionized water, and stir for 25 minutes. After the reaction, wash once with 30% H ₂ O ₂ solution, and then wash with 5% HCL solution until no white precipitate is formed. Vacuum-dry the white precipitate to obtain graphene oxide, and grind it through 200 mesh for later use to obtain graphene oxide powder.

(4) Add 0.5 g of the prepared graphene oxide into 500 mL of pure formamide liquid, and stir at 30° C. for 5 days to obtain a delaminated graphene oxide colloidal solution with a concentration of 1.0 g/L. The Tyndall effect can be used to judge whether a colloidal solution has formed.

(5) Preparation of anionic clay/graphene nanocomposites: transfer the obtained 500mL delaminated graphene oxide colloidal solution to a 3L round bottom flask, and add 1.0 L of anionic clay colloid solution, so that the mass ratio of delaminated anionic clay to delaminated graphene oxide is 20:1, stirred for 4 hours, and a flocculent precipitate was obtained.

Wash the obtained flocculent precipitate by centrifugation with pure ethanol for 5 times at a centrifugal speed of 5000rpm, and vacuum-dry the obtained precipitate at 80°C to obtain an anionic clay/graphene oxide composite material, which is then ground to 100 meshes to obtain anionic clay/graphene oxide olefin composite material powder.

Take 1.0 g of the obtained anionic clay/graphene oxide composite powder, add 2.0 mL of hydrazine hydrate to react for 1 h, make it reduced, and dry it in vacuum at 80°C to obtain the anionic clay/graphene nanocomposite material, which is then ground to 200 meshes, The powder of the anionic clay/graphene nanocomposite material is obtained.

Example 4

(1) Preparation of anionic clay: Weigh 14.28g (0.048mol) Zn(NO ₃ ) ₂ ·6H ₂ O, 3.49g (0.012mol) Ni(NO ₃ ) ₂ ·6H ₂ O, 7.50g (0.02mol) )Al(NO ₃ ) ₃ , put in a 300mL beaker, add 125mL deionized water, stir until the solid is completely dissolved, and record it as solution A. In solution A, the molar ratio of divalent metal to trivalent metal (Zn ²⁺ + Ni ²⁺ ):Al ³⁺ =3:1, where Zn ²⁺ :Ni ²⁺ =4:1. Weigh 17.50g (0.125mol) cyclohexamethylenetetramine, put it in a 300mL beaker, add 125mL deionized water, stir until the solid is completely dissolved, then add 1.0mol/L _HNO3 solution dropwise to lower the pH to 2.5 , recorded as solution B.

Mix the above-mentioned A and B solutions in a 500mL two-necked test flask with medium volume, add 5.00g NaNO ₃ and shake well, then place the flask in a 50kHz ultrasonic scrubber for 10min to obtain a clear mixed solution.

Put the two test flasks into the electric heating device and reflux at 100°C for 48 hours to obtain a light green suspension. After cooling to 25°C, centrifuge at 6,000 rpm for 10 minutes to wash the supernatant until the pH reaches 8.0. The resulting precipitate is frozen. Dry, grind after drying, and pass through a 200-mesh sieve to obtain anionic clay.

(2) Preparation of delaminated anionic clay colloid: Take 1.0 g of the prepared anionic clay, add it to 1.0 L of pure formamide liquid, stir at 25°C for 10 days, and obtain delaminated anion with a concentration of 1 g/L Clay colloid solution. The Tyndall effect can be used to judge whether a colloidal solution has formed.

(3) Preparation of graphene oxide: graphene oxide was prepared by the improved Hummers method. The preparation steps are as follows: add 5.0g graphene powder (purchased from Shanghai Aladdin Company) to 100mL concentrated H ₂ SO ₄ and stir at 4°C. During the stirring process, add 2.5g NaNO ₃ and 15.0g KMnO ₄ , stir for 90min and then turn to Enter the medium temperature process, the temperature is controlled at 40°C, stir for 25 minutes and then turn to the high temperature stage, the temperature is controlled at 90°C, then add 200mL deionized water, and stir for 20 minutes. After the reaction, wash once with 30% H ₂ O ₂ solution, and then wash with 5% HCL solution until no white precipitate is formed. Vacuum-dry the white precipitate to obtain graphene oxide, and grind it through 200 mesh for later use to obtain graphene oxide powder.

(4) Add 0.5 g of the prepared graphene oxide into 500 mL of pure formamide liquid, stir at 25°C for 7 days, and obtain a delaminated graphene oxide colloidal solution with a concentration of 1.0 g/L. The Tyndall effect can be used to judge whether a colloidal solution has formed.

(5) Preparation of anionic clay/graphene nanocomposites: transfer the obtained 500mL delaminated graphene oxide colloidal solution to a 3L round bottom flask, and add 1.0 L of delaminated anionic clay colloidal solution, so that the mass ratio of anionic clay to delaminated graphene oxide is 2:1, stirred for 2 hours, and a flocculent precipitate was obtained.

The obtained flocculent precipitate was centrifuged and washed 3 times with pure ethanol at a centrifugal speed of 6000rpm, and the obtained precipitate was vacuum-dried at 60°C to obtain an anionic clay/carboxylated graphene composite material, which was then ground to 100 mesh to obtain anionic clay/carboxylated graphene Graphene composite material powder.

Take 1.0 g of the obtained anionic clay/graphene oxide composite powder, add 2.0 mL of hydrazine hydrate to react for 5 hours, make it reduced, and dry it in vacuum at 60°C to obtain anionic clay/graphene nanocomposite material, and then grind it through 200 meshes, The powder of the anionic clay/graphene nanocomposite material is obtained.

As can be seen from the accompanying drawings: the anionic clay/graphene nanocomposite material prepared by the present invention has realized the composite material that the anionic clay of the monomolecular layer and the graphene layer of the monomolecular layer are superimposed to form a sandwich structure, which can maximize Combining anionic clay with graphene.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (10)

1. a preparation method for anionic clay/graphene nanocomposite material, is characterized in that: comprise the following steps:

(1) preparation of the anionic clay colloidal solution of leafing: get anionic clay 0.1～10g, join in the pure formamide soln of 1L, stir, obtaining concentration is the anionic clay colloidal solution of the leafing of 0.1～10g/L;

(2) preparation of the electronegative Graphene colloidal solution of leafing: get the electronegative graphene powder of 0.5g and join in the pure methane amide liquid of 500mL, stir, obtaining concentration is the electronegative Graphene colloidal solution of the leafing of 1g/L;

(3) preparation of anionic clay/graphene nanocomposite material: under the atmosphere of Ar, in the process stirring, the anionic clay colloidal solution of leafing is dropped in the electronegative Graphene colloidal solution of leafing, making the mass ratio of the anionic clay colloid of leafing and the electronegative Graphene colloid of leafing is 0.2:1～20:1, stir process, obtain flocks, with dehydrated alcohol by flocks centrifuge washing, vacuum-drying, obtain anionic clay/electronegative graphene composite material, grind, sieve, obtain anionic clay/electronegative graphene composite material powder, add 2mL hydrazine hydrate and react 1～5h to 1g anionic clay/electronegative graphene composite material powder, reduction, vacuum-drying, obtain anionic clay/graphene nanocomposite material, grind, cross 200 mesh sieves, obtain anionic clay/Graphene complex material powder.

2. preparation method according to claim 1, it is characterized in that: the preparation process of the anionic clay described in step (1) is: get divalent metal salt and trivalent metal salt and mix, add deionized water, be stirred to metal-salt and dissolve, be designated as solution A; Get urotropin, add deionized water, be stirred to it and dissolve, drip HNO ₃solution, regulating pH is 2～5, is designated as solution B; Solution A is mixed with solution B equal-volume, add NaNO ₃, shaking up, supersound process, obtains clarifying mixing solutions; Mixing solutions backflow 24～48h, obtains light green turbid solution, cooling rear centrifugal, and washing supernatant liquor is 6.5～8.0 to pH, and institute is precipitated dry, grinds, and sieves, and obtains anionic clay;

Stirring described in step (1) is at 20～30 DEG C, to stir 5～10 days.

3. preparation method according to claim 1, is characterized in that: the electronegative Graphene described in step (2) is graphene oxide or carboxyl Graphene; Described stirring is at 20～30 DEG C, to stir 5～10 days.

4. preparation method according to claim 1, is characterized in that: the time of the described stir process described in step (3) is 2～6h; Described absolute ethanol washing number of times is 3～5 times, and centrifugal rotating speed is 6000～8000rpm, and the time is 10～20min; Described vacuum drying temperature is 60～80 DEG C; Described sieving was 200 mesh sieves.

5. preparation method according to claim 2, is characterized in that: described divalent metal salt is that amount of substance is the Zn (NO of 0.04～0.048mol ₃) ₂6H ₂ni (the NO that O, amount of substance are 0.012～0.02mol ₃) ₂6H ₂o; Described divalent metal salt mol ratio Zn ²⁺: Ni ²⁺for 2:1～4:1; Described trivalent metal salt is that amount of substance is the Al (NO of 0.02mol ₃) ₃; Described divalent metal and the mol ratio of trivalent metal are 3:1; The add-on of described deionized water is 125mL; The amount of substance of described urotropin is 0.125mol; Described HNO ₃the volumetric molar concentration of solution is 1.0mol/L; Described NaNO ₃add-on be 5g; Described supersound process is to process 10～20min under 50KHz; The temperature of described backflow is 100 DEG C; Described cooling temperature is 20～30 DEG C; Described centrifugal rotating speed is 6000～8000rpm, and the time is 10～20min; Described sieving was 200 object sieves.

6. preparation method according to claim 3, it is characterized in that: the preparation method of described carboxylated Graphene is: graphene oxide powder is joined in NaOH solution, splash into again chloroacetic acid solution, stir, after reaction finishes, use deionized water centrifuge washing, again gained is precipitated to vacuum-drying, obtain carboxylated Graphene, grind, sieve, obtain carboxylated graphene powder.

7. according to the preparation method described in claim 3 or 6, it is characterized in that: the preparation process of described graphene oxide is: 5g graphene powder is joined in the 100mL vitriol oil, stir at 4 DEG C, in whipping process, add 2.5gNaNO ₃with 15.0g KMnO ₄, after stirring 90min, proceed to middle temperature process, stir 30～40min, proceed to hot stage, add deionized water, stir 20～30min, use H ₂o ₂solution washing once, then with HCl solution washing to without white precipitate generate, by white precipitate vacuum-drying, obtain graphene oxide, grind, sieve, obtain graphene oxide powder.

8. preparation method according to claim 6, is characterized in that: described graphene oxide quality is 2g; The concentration of described NaOH solution is 1.0mmol/L, and volume is 100mL; The concentration of described chloroacetic acid solution is 1.0mmol/L, and volume is 20mL; Described churning time is 2h; Described deionized water wash number of times is 5 times; Described centrifugal rotating speed is 6000rpm, and the time is 10min; Described sieving was 200 object sieves.

9. preparation method according to claim 7, is characterized in that: the temperature of described middle temperature process is 30～40 DEG C; The temperature of described hot stage is 80～90 DEG C; The add-on of described deionized water is 200mL; Described H ₂o ₂the concentration of solution is 30%; The concentration of described HCl solution is 5%; Described sieving was 200 mesh sieves.

10. anionic clay/the graphene nanocomposite material being prepared by the preparation method described in claim 1～9 any one, is characterized in that: this anionic clay/graphene nanocomposite material is by the anionic clay of unimolecular layer and the Graphene of the monoatomic layer matrix material with sandwich structure forming that is layering.