CN110835106A

CN110835106A - Preparation method of novel graphene material

Info

Publication number: CN110835106A
Application number: CN201810928997.5A
Authority: CN
Inventors: 何锦波
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-08-15
Filing date: 2018-08-15
Publication date: 2020-02-25

Abstract

The invention provides a preparation method of a novel graphene material, which comprises the following steps: preparing zeolite suspension of zeolite nanocrystals with the concentration of 50-100ppm, the pH value of 11-13 and the particle size of 50-80 nm; the method also comprises the steps of mixing the graphene oxide suspension with the concentration of 50-200ppm with the zeolite suspension to form a composite solution; the method also comprises the steps of treating the composite solution at the temperature of 15 ℃ by using a water bath method when the color of the composite solution is changed from brown yellow to dark brown, and adding a surfactant into a water bath at the temperature of 15 ℃; the method also comprises the steps of carrying out ultrasonic treatment on the composite solution for 5-30 minutes, and then taking out the composite solution from a water bath at 15 ℃, wherein the color of the composite solution is changed from dark brown to black; the method also comprises the step of further processing the composite solution into a novel graphene material with no more than 5 layers.

Description

Preparation method of novel graphene material

Technical Field

The invention relates to a preparation method of a novel graphene material, in particular to a method for preparing a novel graphene material which is good in electrical property, uniform in thickness, smooth in surface and strong in binding capacity with a matrix.

Background

In recent years, researches on graphene materials are becoming active in China, so that the production technology of the graphene materials is greatly developed. The graphene material has excellent mechanical properties, high thermal conductivity, high electron mobility and high specific surface area. However, the graphene material produced by the redox method is easily aggregated due to the change of temperature or pH value in the redox method and the subsequent extrusion process, so the specific surface area of the synthesized graphene material is significantly reduced, the electrical performance of the synthesized graphene material is also greatly affected, and the applicability of the graphene is reduced.

On the other hand, the traditional graphene material is often ten layers, has large thickness and is easy to generate defects. In addition, many graphene materials on the market have poor electrical properties, uneven thickness, rough surface and weak binding capacity with a substrate, and the applicability of the graphene materials is also influenced.

Therefore, it is necessary to search for a method for preparing a novel graphene material.

Graphene in the graphene material prepared by the invention is dispersed in a solution and can be mixed with a selected raw material to form a whole, so that the graphene composite material with enhanced performance can be prepared. The composite materials have excellent mechanical and electrical properties, are suitable for further processing, and have wide application prospects. In addition, zeolite has uniformly distributed pores and excellent heat and compression resistance, and a composite material formed by mixing graphene and zeolite, such as a graphene composite film, has higher structural stability than pure graphene. In addition, the three-dimensional structure of the zeolite can further improve the electron mobility of the graphene material, and is beneficial to oxidation-reduction reaction. The novel graphene material can be applied to super capacitors and sensors.

Disclosure of Invention

The present invention provides a method for manufacturing a novel material of few-layer graphene having better electrical properties, uniform thickness and smooth surface.

Such a method comprises: preparing a zeolite suspension having a concentration of zeolite crystals of 50-100ppm, wherein the nanocrystals of zeolite have a particle size of 50-80nm, and wherein the zeolite is suspended at a pH of 11-13.

The method further comprises: preparing a graphene oxide suspension containing graphene oxide with a concentration of 50-200 ppm.

The method further comprises: mixing the graphene oxide suspension according to the weight ratio of 1: 1-9: 1 to form a composite solution, and when the color of the composite solution changes from brown yellow to dark brown, the composite solution is converted into a water bath at 15 ℃.

The method further comprises: the surfactant was added to a water bath at 15 ℃.

The method further comprises: and adding a surfactant into the water bath at the temperature of 15 ℃, then carrying out ultrasonic treatment on the composite solution for 5-30 minutes, and removing the composite solution from the water bath at the temperature of 15 ℃ to change the color of the composite solution from dark brown to black.

The method further comprises: and atomizing the composite solution to form atomized liquid drops after the color of the composite solution is changed from dark brown to black.

The method further comprises: treating the atomized droplets with a plasma to charge the atomized droplets; and depositing charged atomized liquid drops on the substrate at the temperature of 150-350 ℃ to form a novel graphene material with less than or equal to 5 layers.

In the embodiment of the invention, alkali is added into the graphene oxide suspension, and the graphene oxide suspension containing the alkali is subjected to ultrasonic treatment at 50-90 ℃, so that the color of the composite solution is changed from brown yellow to dark brown, and the defects of partially reduced graphene oxide are prevented.

In the embodiment of the invention, the ultrasonic treatment is carried out on the composite solution at 50-90 ℃ for 12-24 hours, so that the color of the composite solution is changed from dark brown to black, and the defects of the reduced graphene oxide are further reduced.

In the examples of the present invention, 1-methyl-2-pyrrolidone, isopropyl alcohol (NMP), Propylene Glycol Methyl Ether (PGME), ethyl acetate or Methyl Ethyl Ketone (MEK) is used as the surfactant. These bases can reduce the number of layers of graphene.

In an embodiment of the present invention, a metal salt is added to the zeolite suspension to increase the specific capacitance of the graphene material. The metal salt is a salt containing gold, platinum, silver, copper or nickel to increase the specific capacity of the graphene material.

In an embodiment of the present invention, the reduced graphene suspension and the zeolite suspension are mixed together for 1 to 3 hours before adding the surfactant, in order to achieve the purpose of reducing the number of layers of graphene.

In an embodiment of the invention, a gas is used to carry the atomized droplets through the plasma. Thereby enhancing the bonding between the graphene material and the substrate, the gas being argon, helium or a mixed gas comprising argon and hydrogen to further reduce re-oxidation of graphene.

In the method for preparing the novel graphene material, alkaline zeolite suspension is added in the process of reducing graphene oxide into graphene, the alkaline zeolite suspension can be used as a reducing agent and can form zeolite nanocrystals between adjacent graphene layers in a composite solution, and then a surfactant is added in a water bath at 15 ℃, so that graphene oxide and the zeolite nanocrystals have a good dispersion effect in the composite solution, and the reduction rate of reducing the graphene oxide into the graphene is controlled; therefore, the prepared graphene material has fewer layers, so that the purpose of improving the electrical property of the graphene is achieved. Because the graphene material is formed by the composite solution of plasma enhanced atomization deposition, the zeolite nanocrystal is coated by the graphene, and the zeolite nanocrystal and the graphene jointly form a novel graphene material with smooth surface and uniform thickness, the applicability of the novel graphene material is improved. In addition, metal salt is added into the zeolite suspension, so that metal ions can enter zeolite nanocrystals, and the specific capacity of the novel graphene material is improved.

Drawings

The accompanying drawings are provided to more fully understand the relevant aspects of the present invention, and the material described in the present invention can be in various forms, including a flat, folded or multi-layer bent material, and the accompanying drawings do not limit the content of the present invention;

fig. 1 shows a 1000 × SEM image of graphene material from group B1;

fig. 2 shows a 100000 × SEM image of graphene material of group B1;

fig. 3 shows a cross-sectional SEM image of group B1 graphene materials;

fig. 4 shows a 1000 × SEM image of graphene material from group B2;

figure 5 shows a 50000 x SEM image of graphene material from group B2;

fig. 6 shows a cross-sectional SEM image of group B2 graphene materials;

FIG. 7 shows an FT-IR spectrum of graphene oxide;

FIG. 8 shows an FT-IR spectrum of graphene;

FIG. 9 shows a FT-IR spectrum of a zeolite;

FIG. 10 shows a FT-IR spectrum of a graphene material prepared according to the method of the present invention;

fig. 11 shows the results of the graphene materials of groups D1 and D5 using cyclic voltammetry.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

A method of preparing a graphene material includes:

(A) preparing a zeolite suspension containing zeolite nanocrystals at a concentration of 50-100ppm, wherein the zeolite nanocrystals have a particle size of 50-80nm and the pH of the zeolite suspension is 11-13;

(B) preparing a graphene oxide suspension containing graphene oxide with the concentration of 50-200 ppm;

(C) mixing the graphene oxide suspension according to the weight ratio of 01: 1-09: 1 to form a composite solution, and transferring the composite solution into a water bath at 15 ℃ when the color of the composite solution changes from brown yellow to dark brown;

(D) adding a surfactant into the composite solution in water bath at 15 ℃;

(E) carrying out ultrasonic treatment on the composite solution for 5-30 minutes after the step (D), and taking out the composite solution from a water bath at 15 ℃ to change the color of the composite solution from dark brown to black;

(F) atomizing the composite solution after step (E) to form atomized droplets;

(G) treating the atomized droplets with plasma to charge the atomized droplets;

(H) and depositing the charged atomized liquid drops on the substrate at the temperature of 150-350 ℃ to form no more than 5 layers of graphene materials.

In the present example, 16.04 g of tetramethylammonium hydroxide (TMAOH) was mixed with 25.35 g of pure water, 3.835 g of aluminum isopropoxide and 6.009 g of silica were added, and stirred for 24 hours to prepare a zeolite suspension. The zeolite suspension was then placed in a sealed vessel and reacted at 92 ℃ for 48 hours. The reaction product is centrifuged at a low speed (e.g., 3000 rpm for 30 min) to remove large particles precipitated, and then centrifuged at a high speed (e.g., 12000 rpm for 30 min) to further remove small particles from the supernatant. Thus, at a pH of about 11, about 20 ml of zeolite suspension can be prepared.

In the embodiment of the invention, the ion exchange capacity of zeolite is also utilized, and high-conductivity metal ions are introduced into the zeolite nanocrystals, so that the specific capacity of the graphene material can be improved. The metal ions may be selected from gold ions, platinum ions, silver ions, copper ions and nickel ions, which are readily recognized by a person of ordinary skill in the art, for example, the zeolite suspension may be added with a metal salt to enable the metal ions in the metal salt to enter the zeolite nanocrystals. In the present example, 1M aqueous silver nitrate solution was added to the zeolite suspension to achieve 0.3% by weight, and the silver nitrate zeolite mixed solution was suspended in a sealed plastic container, sonicated at 80 ℃ for 8 hours, placed in a dark place, and finally adjusted to pH 11 with ammonium solution.

In particular, the zeolite suspension in step (A)The suspension contains zeolite nanocrystal with particle size of 50-80nm, concentration of 50-100ppm, and pH value of 11-13; the zeolite nanocrystals may be aluminosilicate zeolites having the chemical formula: m_x/n[(AlO2)_x(SiO 2)_y].mH₂O, where x ≦ y. In this chemical formula, n represents the oxidation number of the cation M. The cation M is, but not limited to, an alkali metal, alkaline earth, rare earth, ammonia, or hydrogen ion.

The graphene oxide suspension in step (B) comprises graphene oxide in a concentration of 50-200ppm, and the graphene oxide suspension may be prepared by, but is not limited to, any method known in the art. For example: carbon source material (e.g., graphite) is first mixed with an oxidant and the oxidized carbon material is then filtered and washed. In the present example, 0.2g of graphite flake was mixed with 12ml of concentrated sulfuric acid by stirring in an ice bath for 1 hour, then 2g of potassium permanganate was added, the reaction mixture was stirred for a further hour, then stirred for 1 hour at 40 ℃, then 25 ml of pure water was added, the reaction mixture was transferred to a water bath at 95-98 ℃, after stirring for 15 min, hydrogen peroxide was added until no bubbles were present in the reaction mixture, the reaction mixture was centrifuged (12000 rpm, 15 min) before cooling, then washed to pH 4, and finally the reaction mixture was further sonicated (e.g. sonicated) until no distinct particles were present, thereby forming a graphene oxide suspension.

Next, step (C) is performed; in step (C), the graphene oxide is partially reduced (for example, reduced on a plane, the graphene oxide in the peripheral region is still oxidized), and since the graphene is brown in the oxidation state and black in the reduction state, the color of the graphene-containing suspension changes from brown to dark brown (for example, the color of the graphene suspension changes from PANTONE 124 to PANTONE 1405), which indicates that the surface functional groups of the graphene oxide begin to undergo a reduction reaction, and the reduction of the surface functional groups increases the intermolecular van der waals force, so that a plurality of reduction layers can begin to be formed on the surface of the graphene oxide. That is, a partially reduced graphene oxide is formed, which is also recognized by those skilled in the art.

The term "partially reduced graphene oxide" according to the present invention refers to a dark brown product obtained after a reduction reaction of graphene oxide before obtaining black graphene. The method comprises the following steps of adding a reducing agent into a graphene oxide suspension, wherein the reducing agent is suitable for reducing graphene oxide; for example, a basic compound, such as hydrazine, may interact with the pH of the zeolite suspension. Another method is to add a base to the zeolite suspension and then sonicate at 50-90C, the base can be lithium hydroxide, sodium hydroxide, potassium hydroxide or calcium hydroxide, the alkali metals are less harmful to the environment, the reduction rate is slower, defects in the partially reduced graphene oxide are not caused, and the reduction rate can be more easily controlled.

In the examples of the present invention, with tetramethylammonium hydroxide (TMAOH) in the zeolite suspension as the reducing agent, the graphene oxide suspension was first mixed in a ratio of 1: 1-9: 1 and zeolite suspension to form a composite solution, carrying out ultrasonic treatment on the composite suspension at 50 ℃ until the composite solution is changed from brown yellow to dark brown, wherein at the moment, in order to prevent the dark brown graphene in the composite solution from continuing to carry out reduction reaction with a reducing agent, the dark brown composite solution is changed into a 15 ℃ water bath, the water bath slows down the reduction rate of the dark brown graphene and the reducing agent in the composite solution, and when the temperature of the composite solution reaches 15 ℃, the dark brown can be kept without being changed.

To help explain and understand embodiments of the present invention, the reduced state of graphene may be defined by color, specifically, graphene oxide is referred to as "brown-yellow graphene", partially reduced graphene is referred to as "dark brown graphene", and further reduced graphene is referred to as "black graphene", the above color being defined by the TANTONE color band. For example, tan represents PANTONE 124, dark brown represents PANTONE 1405, and black represents PANTONE 4332X.

In step (D), the purpose is to add a surfactant to the dark brown complex solution. In one example of the present invention, 20 ml of 1-methyl-2-pyrrolidone (NMP) was added to the dark brown complex solution and placed in a 15 ℃ water bath. Theoretically, the dark brown graphene still has excellent suspension performance, and does not precipitate after centrifugation for 15 minutes at 10000 rpm, however, according to the method of the present invention, 1-methyl-2-pyrrolidone (NMP) is further used as a surfactant to further ensure that the dark brown graphene in the composite solution is kept in a suspended state, and provide a good dispersion effect for each component in the composite solution, and besides the 1-methyl-2-pyrrolidone (NMP) surfactant, isopropanol, Propylene Glycol Methyl Ether (PGME), ethyl acetate or Methyl Ethyl Ketone (MEK) is also used as a surfactant.

In the step (E), the dark brown composite solution is further reduced, and the composite solution in the step (D) contains a reducing agent to perform a reduction reaction, and the dark brown graphene is reduced to black graphene. In one example of the present invention, after the surfactant is added, the composite solution is subjected to ultrasonic treatment for 15 minutes to make the uneven color distribution of the dark brown graphene and the reducing agent in the composite solution tend to be uniform, after the composite solution is removed from the 15 ℃ water bath, the dark brown graphene in the dark brown composite solution continues to perform a reduction reaction with tetramethylammonium hydroxide (TMAOH), in one example of the present invention, the composite solution is removed from the 15 ℃ water bath, and is subjected to ultrasonic treatment at 80 ℃ for 24 hours to increase the reaction rate of the dark brown graphene and the reducing agent in the composite solution, so that the black graphene can be prepared by a complete reaction, and as the composite solution contains zeolite nanocrystals and incompletely reduced graphene, a weak attractive force similar to van der waals force is generated in the reduction reaction by the porous three-dimensional structure of the molecular sieve and the functional groups of graphene oxide, this avoids excessive aggregation of the dark brown graphene and subsequent formation of a multilayer structure due to too fast stacking in the reduction reaction. In addition, the surfactant in the composite solution is helpful for uniform dispersion of the dark brown graphene in the composite solution, so that the dark brown graphene is slowly and densely formed in the reduction reaction. The significance is that in order to improve the electrical property of the graphene material, the number of the synthesized graphene layers is not more than 5.

After step (E), step (F) is performed, i.e., the composite solution is atomized to form atomized droplets. The specific method is that after the composite solution is completely changed from dark brown to black, the partially reduced graphene is further reduced, and then the composite solution is atomized to form atomized liquid drops. After the composite solution is atomized, atomized droplets are formed by an atomizer, such as an ultrasonic oscillator or the like (using this method is also recognized by those skilled in the art), and when the atomized droplets are formed, the droplets with graphene surrounding zeolite nanocrystals forming a graphene sphere-like structure are formed.

Next, step (G) is performed in order to increase the conductivity of the atomized droplets after the atomized droplets are treated with plasma. Specifically, after the atomized liquid drops are subjected to plasma treatment, graphene is deposited on a substrate from a graphene material through plasma enhanced atomization deposition. For example, when the substrate temperature is 150-350 ℃, the atomized droplets are formed by inert gas (such as argon or helium) or mixed gas (such as Ar/H)₂The mixture of (a) and (b) is carried by the plasma and deposited on the substrate; through plasma treatment, the zeolite nanocrystals can be activated, the crosslinking between graphene and the zeolite nanocrystals is enhanced, and the adhesion between the graphene material and the matrix is enhanced. In the embodiment of the invention, the temperature of the substrate is 230 ℃, and plasma is generated after an atmospheric plasma system is applied with voltage of 60-90V; alternatively, a pulsed ac voltage may be used. In addition, in the embodiment of the invention, the liquid drops are atomized by using argon gas, the flow rate of the argon gas is set to be 6-10L/m, and meanwhile, the flow rate of the atomized liquid drops is about 60-100 ml/min, and the factors can be adjusted according to the requirements of graphene materials.

The graphene material prepared by the method disclosed by the invention is characterized in that the zeolite nanocrystals are surrounded by graphene, and the graphene and the zeolite nanocrystals are combined together to form the graphene material with a smooth surface, and the graphene material has the characteristics of few graphene layers and high density. The electrical property of the graphene material is improved through the characteristic; meanwhile, the graphene has the advantages of strong adhesive force with a matrix, smooth surface, improved electrical property and the like.

To demonstrate that the process of the invention can be prepared: the graphene material with the characteristics of zeolite nanocrystals and graphene has smooth surface and excellent electrical properties, and the following experiments are carried out:

(A) group experiment: comparison of graphene quality

In order to prove that the graphene material prepared by the method has fewer layers and fewer defects, the zeolite suspension and the graphene suspension which are preliminarily prepared by the method are directly adopted. After the zeolite suspension is added to the brown-yellow graphene oxide suspension, a composite solution containing dark brown partially-reduced graphene oxide is formed, then the dark brown composite solution is placed in a water bath at 15 ℃, then a surfactant is added, then the composite solution is removed from the water bath at 15 ℃, so that dark brown graphene in the composite solution is continuously subjected to reduction reaction with tetramethylammonium hydroxide (TMAOH) to form black graphene. As in group A1. Adding brown yellow graphene oxide, and then adding alkali to further reduce the mixture into black graphene. The zeolite suspension and surfactant were then added as in group a 2. The two sets of samples were again tested for light transmittance and reported in table 1 below:

since the light transmittance of graphene is related to the number of layers and the number of defects thereof, the higher the light transmittance, the smaller the number of layers and the number of defects. As can be seen from the data in table 1, in the a1 group, when the brown-yellow graphene is partially reduced to dark-brown graphene, the surfactant is added to the composite solution in the water bath at 15 ℃, and then the composite solution is removed from the water bath at 15 ℃ to continue the reduction reaction. The black graphene obtained from group a1 has a higher light transmittance, a smaller number of layers, and a smaller number of defects. In the A2 group, after the brown yellow graphene is further reduced, zeolite suspension and a surfactant are added, and the obtained graphene has low light transmittance, more layers and serious defects, so that the characteristics of few layers and few defects of the graphene material prepared by the method are well proved.

(B) Group experiment: morphology comparison of graphene materials

After preparation of the graphene oxide suspension and the zeolite suspension, the following procedure was carried out in a ratio of 07: 3 to form a composite solution containing dark brown graphene. And after ultrasonic treatment for 2 hours, adding 1-methyl-2-pyrrolidone (NMP) and uniformly dispersing the dark brown graphene in the composite solution. Then, the dark brown graphene in the composite solution continues to react with tetramethylammonium hydroxide (TMAOH) until the dark brown graphene is further reduced to black graphene. The composite solution is also used for preparing B1 graphene materials by a plasma enhanced atomization deposition method. The other graphene material is prepared by the same composite solution but adopting a spin coating method, namely B2 group;

please refer to the description of the drawings. Fig. 1 and 2 are 1000 × and 100000 × scanning electron microscope images of a graphene material of group B1, and fig. 3 is a cross-sectional SEM image of a graphene material of group B1. Further, fig. 4 and 5 in the drawing description are 1000 × and 50000 × scanning electron microscope images of a B2 group graphene material, and fig. 6 is a cross-sectional scanning electron microscope image of a B2 group graphene material. According to the images, the graphene material prepared by the method has a fine and smooth surface, and uniformly distributed particles can be seen in the enlarged image, which shows that the graphene material formed by combining the graphene and the zeolite nanocrystals is obvious in aggregation, rough in surface and uneven in thickness, so that the graphene material prepared by the spin coating method has the characteristics of uniform and smooth thickness

(C) Chemical property and composition analysis of graphene material

The graphene oxide suspension containing graphene oxide was directly regarded as group C1, the brown-yellow graphene oxide suspension was directly reduced to form a black graphene suspension was regarded as group C2, the zeolite suspension was regarded as group C3, and the composite solution of the above-mentioned group B1 was regarded as group C4. The infrared spectra of the graphene materials prepared by the plasma enhanced atomization deposition method from groups C1 to C4 are shown in FIGS. 7-10, and refer to FIGS. 7 and 8 (groups C1 and C2) illustrated in the drawings, which illustrate 1414 cm after the brown graphene is completely reduced to black graphene^-1The spectrum disappears at the maximum peak; FIG. 10 of the drawing illustration (i.e., set of C4 data) is contrasted with FIGS. 7-10 of the drawing illustration, where the data is representedAs can be seen, the peak value of the graphene material prepared by the method of the invention is 1620-^-1The peak value of the graphene is 500-700cm^-1The zeolite of (4). In addition, the method is characterized in that graphene oxide is completely reduced into graphene;

in addition, the invention further analyzes the graphene material of C4 group by using an Energy Dispersive Spectrometer (EDS), and finds that the carbon element is about 2.2 times of the silicon element, which is matched with the volume ratio of the graphene oxide suspension and the zeolite suspension. Thus, it can be appreciated that = the graphene and zeolite nanocrystals are combined together in volume ratio during formation of the atomized droplets to form a graphene material having a uniform distribution of graphene and zeolite nanocrystals, which readily demonstrates the characteristics of the graphene material prepared by the present invention.

(D) Analysis of electrical properties of graphene materials

First, taking black graphene (same as group C2) as group D1, a zeolite suspension (same as group C3) as group D2, a silver ion-containing zeolite suspension as group D3, a composite solution prepared according to the method of the present invention (same as group C4) as group D4, and the silver ion-containing composite solution produced from the method according to the present invention is regarded as group D5; groups D1 through D5 were then subjected to plasma enhanced atomized deposition forming materials. The specific capacitance of each group of materials was measured, with or without electrolyte (1M aqueous potassium hydroxide solution), and the data is recorded in table 2:

as can be seen from the data in the above table, the specific capacitance of the graphene material (group D4) produced according to the method of the present invention is close to that of black graphene (group D1), while the specific capacitance of the zeolite nanocrystals (group D3) to which silver ions are added is greater than that of pure zeolite nanocrystals (group D2); in addition, the graphene material prepared with the zeolite nanocrystals into which silver ions were introduced according to the method of the present invention (group D5) also further improved the electrical properties of the graphene material, thereby having a specific capacitance greater than that of the graphene material into which silver ions were not introduced according to the method of the present invention (group D4);

the invention also uses cyclic voltammetry to further analyze the materials of D1 group and D5 group, and the result is shown in the figure description FIG. 11, and as can be seen from FIG. 11, the current change of the graphene material (D5 group) prepared by the method of the invention is more stable than that of pure graphene (D1 group) in the range of-0.6 to-0.2V.

According to the preparation method for preparing the graphene material, the alkaline zeolite suspension is added in the process of reducing the graphene oxide into the graphene, the alkaline zeolite suspension can be used as a reducing agent and can promote the distribution of zeolite nanocrystals between two adjacent graphene layers in the composite solution, and the surfactant is added in a water bath at 15 ℃, so that the graphene oxide and the zeolite nanocrystals in the composite solution have a good dispersion effect, and the reduction rate of the graphene oxide into the graphene can be controlled. Therefore, the synthesized graphene has the characteristics of fewer layers and fewer defects, and the electrical property of the graphene is also improved.

In addition, in the method of the present invention, since the graphene material is formed from the composite solution by plasma enhanced atomization deposition, all of the graphene is surrounded by the zeolite. Therefore, the zeolite nanocrystals and the graphene can jointly form a graphene material with a smooth surface and uniform thickness, and the applicability of the graphene material is improved.

In addition, in the method of the present invention, since the metal salt is added to the zeolite suspension, metal ions can be introduced into the zeolite nanocrystals, thereby increasing the specific capacitance of the graphene material.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

Claims

1. A method for preparing a novel graphene material, the method comprising preparing a zeolite suspension containing zeolite nanocrystals at a concentration of 50-100ppm, wherein the zeolite nanocrystals have a particle size of 50-80nm and the zeolite suspension has a pH of 11-13; the method also comprises the steps of preparing a graphene oxide suspension containing graphene oxide with the concentration of 50-200 ppm; the method further comprises the step of mixing the graphene oxide suspension in a proportion of 1: 1-9: 1, mixing the zeolite suspension with the composite solution to form a composite solution, and transferring the composite solution to a water bath at 15 ℃ when the color of the composite solution is changed from brown yellow to dark brown; the method also comprises the steps of adding a surfactant into the composite solution in the water bath at 15 ℃; the method further comprises the steps of carrying out ultrasonic treatment on the composite solution for 5-30 minutes, and removing the composite solution from a water bath at 15 ℃; the method also comprises atomizing the composite solution to form atomized liquid drops, and treating the atomized liquid drops by using plasma to charge the atomized liquid drops; the method further comprises the step of depositing charged atomized liquid drops on the substrate at the temperature of 150-350 ℃ to form no more than 5 layers of novel graphene materials.

2. The method of preparing a novel graphene material according to claim 1, wherein: the composite solution of graphene oxide suspension and zeolite suspension is sonicated at 50-90 ℃ to change the color of the composite solution from brown-yellow to dark brown.

3. The method of preparing a novel graphene material according to claim 2, wherein: the composite solution formed by the graphene oxide suspension and the zeolite suspension is subjected to ultrasonic treatment at 50-90 ℃ for 12-24 hours, so that the color of the composite solution is changed from dark brown to black.

4. The method of preparing a novel graphene material according to claim 1, wherein: the surfactants used include: 1-methyl-2-pyrrolidone, isopropyl alcohol (NMP), Propylene Glycol Methyl Ether (PGME), ethyl acetate, or Methyl Ethyl Ketone (MEK), among others.

5. The method of preparing a novel graphene material according to claim 1, wherein: the zeolite suspension prepared also comprises a metal salt; is a salt composed of gold, platinum, silver, copper or nickel.

6. The method of preparing a novel graphene material according to claim 1, wherein: the composite solution of graphene oxide suspension and zeolite suspension was sonicated for 1-3 hours prior to addition of surfactant.

7. The method of preparing a novel graphene material according to claim 1, wherein: the atomized droplets are atomized by plasma using a gas to change the atomized droplets, the gas used being argon, helium or a mixed gas composed of argon and hydrogen.