阅读说明：本技术 一种石墨烯的制备方法 (Preparation method of graphene ) 是由 王帅 袁瑞 丁玉洁 于 2020-12-10 设计创作，主要内容包括：本发明属于碳材料技术领域,公开了一种石墨烯的制备方法。该方法包括以下步骤：(1)将纤维素、催化剂和造孔剂溶解,得混合液；(2)将步骤(1)制得的混合液加热反应,分离,得到固体物；(3)将步骤(2)制得的固体物于真空下碳化处理,然后除催化剂,分离得固体,即为所述石墨烯；所述催化剂为可溶性铁盐。(1)本发明采用纤维素作为原料,在铁盐催化剂和造孔剂的作用下,生成含碳聚合物,然后含碳聚合物经高温分解成碳,最后形成具有二维片状结构石墨烯；该方法使生物质材料得到合理利用,有利于资源循环利用和环境保护；且该制备方法的工序简单、对设备要求低,适合工业化大规模生产和应用。(The invention belongs to the technical field of carbon materials, and discloses a preparation method of graphene. The method comprises the following steps: (1) dissolving cellulose, a catalyst and a pore-forming agent to obtain a mixed solution; (2) heating the mixed solution prepared in the step (1) for reaction, and separating to obtain a solid; (3) carbonizing the solid prepared in the step (2) in vacuum, then removing the catalyst, and separating to obtain a solid, namely the graphene; the catalyst is soluble iron salt. (1) The method comprises the steps of adopting cellulose as a raw material, generating a carbon-containing polymer under the action of an iron salt catalyst and a pore-forming agent, and decomposing the carbon-containing polymer into carbon at high temperature to finally form graphene with a two-dimensional sheet structure; the method reasonably utilizes the biomass material, and is beneficial to resource recycling and environmental protection; and the preparation method has simple process and low requirement on equipment, and is suitable for industrial large-scale production and application.)

1. A preparation method of graphene is characterized by comprising the following steps:

(1) dissolving cellulose, a catalyst and a pore-forming agent to obtain a mixed solution;

(2) heating the mixed solution prepared in the step (1) for reaction, and separating to obtain a solid;

(3) carbonizing the solid prepared in the step (2) in vacuum, removing the catalyst, and separating to obtain a solid, namely the graphene; the catalyst is soluble iron salt.

2. The method of claim 1, wherein the soluble ferric salt is selected from at least one of ferric trichloride, ferric sulfate, or ferric nitrate.

3. The method according to claim 1, wherein the purity of the cellulose in the step (1) is more than 97%.

4. The preparation method according to claim 1, wherein in the step (1), the pore former is a zinc salt.

5. The method of claim 4, wherein the pore-forming agent is zinc chloride.

6. The production method according to claim 1, wherein in the step (2), the heating reaction is an oil bath reaction; the temperature of the oil bath reaction is 70-90 ℃, and the time of the oil bath reaction is 1-5 h.

7. The method as set forth in claim 1, wherein in the step (3), the carbonization treatment is carried out by raising the temperature to 650-1000 ℃ at a temperature raising rate of 3-15 ℃/min in an atmosphere of a protective gas, and then maintaining the temperature for 0.5-5 hours.

8. The method according to claim 1, wherein in the step (3), the catalyst removal is carried out by acidification with an acid.

9. The method according to claim 8, wherein the acid is present at a concentration of 1 to 5 mol/L.

10. Use of the preparation method of any one of claims 1 to 9 for preparing graphene from biomass.

Technical Field

The invention belongs to the technical field of carbon materials, and particularly relates to a preparation method of graphene.

Background

Graphene is the thinnest, the hardest and the strongest novel nano material in the world, and has the highest electrical and thermal conductivity, since the mode of mechanical stripping is brought out in 2004, the graphene becomes a global research and development hotspot, and the graphene is also known as the king of new materials. At present, graphene has been developed and used in a variety of fields such as adsorption, catalysis, biomedicine and electrochemistry, and has great development potential.

Graphene materials prepared from biomass have been widely used in the fields of electronics, information, energy, materials, and the like. China is a big agricultural country and has great potential as a biomass raw material of biomass energy. Most of biomass is simply incinerated and discarded at present, so that the environment is seriously polluted, and a large amount of renewable resources are wasted. Therefore, the reasonable and efficient utilization of the good biomass energy can not only relieve the current energy crisis, but also create higher commercial value to improve the living standard of people. In recent years, some researchers are continuously researching methods for preparing graphene by using cellulose as a carbon source, but the existing methods still have the problems of complex process, high requirement on equipment, incapability of preparing high-purity and high-quality graphene and the like.

Therefore, it is desirable to provide a method for preparing high-quality graphene with a simple process.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art described above. Therefore, the preparation method of the graphene is simple and easy to operate, has low requirements on equipment, and can be used for preparing high-quality graphene.

The invention conception of the invention is as follows: under the action of an iron salt catalyst and a pore-forming agent, cellulose is subjected to oil bath reaction to generate a carbon-containing polymer serving as a precursor, the carbon-containing polymer is decomposed into carbon at high temperature, iron is formed after the iron salt catalyst is reduced, and the carbon is further catalyzed to form graphene, so that high-quality graphene is obtained.

A preparation method of graphene comprises the following steps:

(1) dissolving cellulose, a catalyst and a pore-forming agent to obtain a mixed solution;

(2) heating the mixed solution prepared in the step (1) for reaction, and separating to obtain a solid;

(3) carbonizing the solid prepared in the step (2) in vacuum, removing the catalyst, and separating to obtain a solid, namely the graphene; the catalyst is soluble iron salt.

Preferably, the soluble iron salt is selected from at least one of ferric chloride, ferric sulfate or ferric nitrate.

Preferably, in step (1), the purity of the cellulose is greater than 97%; further preferably, the purity of the cellulose in step (1) is greater than 98%.

Preferably, in the step (1), the pore-forming agent is zinc salt; more preferably, the pore-forming agent is zinc chloride. The zinc chloride plays a role in stripping and pore-forming in the reaction process.

Preferably, in the step (2), the heating reaction is an oil bath reaction, and the temperature of the oil bath reaction is 70-90 ℃; the oil bath reaction time is 1-5 h; further preferably, the temperature of the oil bath reaction is 75-85 ℃; the reaction time of the oil bath is 2-4 h. The oil selected in the oil bath reaction is nontoxic and pollution-free oil, such as glycerol. The reaction is safer by adopting an oil bath, so that the danger caused by the water being dried in the water bath is avoided.

Preferably, in the step (3), the temperature of the carbonization treatment is raised to 650-1000 ℃ at a temperature raising speed of 3-15 ℃/min in a protective gas atmosphere, and the temperature is maintained for 0.5-5 hours; preferably, the carbonization treatment in step (3) is carried out by heating to 700-900 ℃ at a heating rate of 5-10 ℃/min in an atmosphere of protective gas, and then keeping the temperature for 0.5-3 hours.

The protective gas is an inert gas, such as nitrogen or argon.

Preferably, in the step (3), the catalyst is removed by acidification for 10-20h with acid at 50-80 ℃.

Further preferably, the acid is selected from sulfuric acid or/and hydrochloric acid.

Preferably, the concentration of the acid is 1-5 mol/L; further preferably, the concentration of the acid is 1 to 3 mol/L.

Specifically, the preparation method of the graphene comprises the following steps:

(1) preparing a catalyst solution, adding cellulose and a pore-forming agent, and dissolving in water to obtain a mixed solution;

(2) carrying out oil bath reaction on the mixed solution prepared in the step (1) at 70-90 ℃ for 1-5 hours, carrying out suction filtration on the reacted solution, and drying at 70-100 ℃ to obtain a solid;

(3) placing the solid prepared in the step (2) in a vacuum tube furnace, heating to 650-1000 ℃ at a heating rate of 3-15 ℃/min in the atmosphere of protective gas, then preserving heat for 0.5-5 hours, then naturally cooling, and taking out solid powder; and (3) placing the solid powder in acid at 50-80 ℃, stirring to remove iron particles, performing suction filtration to obtain a solid, and placing the solid product obtained by reaction at 60-85 ℃ for drying.

Graphene prepared by the method is of a two-dimensional sheet structure.

The preparation method is applied to preparation of graphene by using biomass.

Compared with the prior art, the invention has the following beneficial effects:

(1) the method comprises the steps of adopting cellulose as a raw material, generating a carbon-containing polymer under the action of an iron salt catalyst and a pore-forming agent, and decomposing the carbon-containing polymer into carbon at high temperature to finally form graphene with a two-dimensional sheet structure; the iron salt catalyst firstly catalyzes cellulose to form carbon polymer, then is reduced at high temperature to form iron, the iron further catalyzes carbon to form graphene, and finally is removed through acidification treatment. In the process, the ferric salt is used as a catalyst for the two reactions, so that other catalysts or reactants are not added, impurities are reduced, the purity of the obtained graphene is not lower than 95%, and the quality is high.

(2) The method adopts the cellulose as the raw material to prepare the graphene, so that the biomass material (cellulose) is reasonably utilized, and the resource recycling and the environmental protection are facilitated.

(3) The preparation method has the advantages of simple process, easy operation, low cost and low equipment requirement, and is suitable for industrial large-scale production and application.

Drawings

Fig. 1 is a transmission electron micrograph of graphene prepared in example 1.

Detailed Description

In order to make the technical solutions of the present invention more apparent to those skilled in the art, the following examples are given for illustration. It should be noted that the following examples are not intended to limit the scope of the claimed invention.

The starting materials, reagents or apparatuses used in the following examples are conventionally commercially available or can be obtained by conventionally known methods, unless otherwise specified.

Example 1

A preparation method of graphene comprises the following steps: firstly, preparing 50mL of 3mol/L ferric trichloride solution in a beaker, uniformly stirring the solution to be used as a catalyst solution, then taking 3 g of cellulose (with the purity of 99 percent) and 9 g of zinc chloride, adding the cellulose and the zinc chloride into the prepared ferric trichloride catalyst solution, dissolving the solution in 160mL of water, carrying out an oil bath reaction at 80 ℃ for 2 hours, carrying out suction filtration on the solution after the reaction, drying the solution at 100 ℃, then placing the dried powder in a vacuum tube furnace for carbonization heat treatment, and heating the powder to 900 ℃ at the heating rate of 5 ℃/min in a nitrogen atmosphere to calcine the powder for 1 hour. Naturally cooling, taking out solid powder, putting the powder into dilute hydrochloric acid, carrying out acidification treatment at 60 ℃, stirring to remove iron particles, carrying out acidification treatment and stirring for 17 hours, wherein the concentration of the dilute hydrochloric acid is 3mol/L, carrying out suction filtration by a suction filtration instrument to obtain a solid, and drying a solid product obtained by reaction at 70 ℃ to obtain the graphene. The purity of the graphene is 96%.

The graphene prepared in this example was observed by a field emission transmission electron microscope, and the result is shown in fig. 1. As can be seen from fig. 1, the graphene prepared in this example has a two-dimensional sheet structure with a thickness of about 2 nm.

Example 2

A preparation method of graphene comprises the following steps: firstly, preparing 50mL of 2.5mol/L ferric nitrate solution in a beaker, uniformly stirring the solution to be used as a catalyst solution, then taking 3 g of cellulose (with the purity of 98 percent) and 9 g of zinc chloride to be added into the prepared ferric trichloride catalyst solution, dissolving the solution in 160mL of water, carrying out reaction for 3 hours by using an 80 ℃ oil bath, carrying out suction filtration on the solution after the reaction and drying the solution at 90 ℃, then placing the dried powder in a vacuum tube furnace for carbonization heat treatment, and heating the powder to 800 ℃ at the heating rate of 5 ℃/min in nitrogen atmosphere to calcine for 2 hours. Naturally cooling, taking out solid powder, putting the powder into dilute hydrochloric acid, carrying out acidification treatment at 70 ℃, stirring to remove iron particles, carrying out acidification treatment and stirring for 15 hours, wherein the concentration of the dilute hydrochloric acid is 3mol/L, carrying out suction filtration by a suction filtration instrument to obtain a solid, and drying a solid product obtained by reaction at 70 ℃ to obtain the graphene. The purity of the graphene was 95%.

Example 3:

a preparation method of graphene comprises the following steps: firstly, preparing 50mL of 2mol/L ferric trichloride solution in a beaker, uniformly stirring the solution to be used as a catalyst solution, then taking 3 g of cellulose (with the purity of 99 percent) and 9 g of zinc chloride to be added into the prepared ferric trichloride catalyst solution, dissolving the solution in 160mL of water, carrying out an oil bath reaction at 80 ℃ for 4 hours, carrying out suction filtration on the solution after the reaction and drying the solution at 80 ℃, then placing the dried powder in a vacuum tube furnace for carbonization heat treatment, and heating the powder to 900 ℃ at the heating rate of 5 ℃/min in a nitrogen atmosphere to calcine the powder for 3 hours. Naturally cooling, taking out solid powder, putting the powder into dilute hydrochloric acid, carrying out acidification treatment at 50 ℃, stirring to remove iron particles, carrying out acidification treatment and stirring for 13 hours, wherein the concentration of dilute sulfuric acid is 3mol/L, carrying out suction filtration by a suction filtration instrument to obtain a solid, and drying a solid product obtained by reaction at 70 ℃ to obtain the graphene. The purity of the graphene was 95%.

Example 4:

a preparation method of graphene comprises the following steps: firstly, preparing 50mL of 3mol/L ferric trichloride solution in a beaker, uniformly stirring the solution to be used as a catalyst solution, then taking 3 g of cellulose (with the purity of 98 percent) and 9 g of zinc chloride to be added into the prepared ferric trichloride catalyst solution, dissolving the solution in 160mL of water, carrying out reaction for 2 hours by using an 80 ℃ oil bath, carrying out suction filtration on the solution after the reaction and drying the solution at the temperature of 100 ℃, then placing the dried powder in a vacuum tube furnace for carbonization heat treatment, and heating the powder to 1000 ℃ at the heating rate of 10 ℃/min in nitrogen atmosphere to calcine for 2 hours. Naturally cooling, taking out solid powder, putting the powder into dilute hydrochloric acid, carrying out acidification treatment at 60 ℃, stirring to remove iron particles, carrying out acidification treatment and stirring for 17 hours, wherein the concentration of the dilute hydrochloric acid is 2mol/L, carrying out suction filtration by a suction filtration instrument to obtain a solid, and drying a solid product obtained by reaction at 70 ℃ to obtain the graphene. The purity of the graphene was 95%.

Example 5:

a preparation method of graphene comprises the following steps: firstly, preparing 50mL of 3mol/L ferric trichloride solution in a beaker, uniformly stirring the solution to be used as a catalyst solution, then taking 3 g of cellulose (with the purity of 98 percent) and 9 g of zinc chloride to be added into the prepared ferric trichloride catalyst solution, dissolving the solution in 160mL of water, carrying out reaction for 3 hours by using an 80 ℃ oil bath, carrying out suction filtration on the solution after the reaction and drying the solution at the temperature of 100 ℃, then placing the dried powder in a vacuum tube furnace for carbonization heat treatment, and heating the powder to 700 ℃ at the heating rate of 10 ℃/min in nitrogen atmosphere to calcine for 3 hours. Naturally cooling, taking out solid powder, putting the powder into dilute hydrochloric acid, carrying out acidification treatment at 70 ℃, stirring to remove iron particles, carrying out acidification treatment and stirring for 15 hours, wherein the concentration of the dilute hydrochloric acid is 2mol/L, carrying out suction filtration by a suction filtration instrument to obtain a solid, and drying a solid product obtained by reaction at 70 ℃ to obtain the graphene. The purity of the graphene was 95%.

Example 6:

a preparation method of graphene comprises the following steps: firstly, preparing 50mL of 3mol/L ferric trichloride solution in a beaker, uniformly stirring the solution to be used as a catalyst solution, then taking 3 g of cellulose (with the purity of 99 percent) and 9 g of zinc chloride, adding the cellulose and the zinc chloride into the prepared ferric trichloride catalyst solution, dissolving the solution in 160mL of water, carrying out an oil bath reaction at 80 ℃ for 4 hours, carrying out suction filtration on the solution after the reaction, drying the solution at 100 ℃, then placing the dried powder in a vacuum tube furnace for carbonization heat treatment, and heating the powder to 700 ℃ at the heating rate of 10 ℃/min in nitrogen atmosphere to calcine the powder for 3 hours. Naturally cooling, taking out solid powder, putting the powder into dilute hydrochloric acid, carrying out acidification treatment at 80 ℃, stirring to remove iron particles, carrying out acidification treatment and stirring for 13 hours, wherein the concentration of the dilute hydrochloric acid is 2mol/L, carrying out suction filtration by a suction filtration instrument to obtain a solid, and drying a solid product obtained by reaction at 70 ℃ to obtain the graphene. The purity of the graphene was 95%.