阅读说明：本技术 一种氟化石墨烯的制备方法 (Preparation method of fluorinated graphene ) 是由 王建兴 刘才超 魏鹏亮 杨志鹏 白俊 于 2020-07-22 设计创作，主要内容包括：本发明涉及材料领域,具体涉及一种氟化石墨烯的制备方法,包括以下步骤：S1.将膨胀石墨进行机械剥离处理得到多层结构石墨烯；S2.将步骤S1得到的多层石墨烯进行氟化处理；S3.将步骤S2得到的氟化多层结构石墨烯再通过机械剥离处理,即得到氟化石墨烯。本发明所使用的石墨烯片层制备方法为机械剥离法,制备过程无污染,无废料产生。相比于直接剥离氟化石墨制备氟化石墨烯,本技术工艺为先剥离石墨成为多片层石墨烯再进行后续处理,剥离过程更容易实现,且剥离的片层更完整、均匀。相比于直接对石墨烯或氧化石墨烯进行氟化处理,本技术为先对多片层的石墨微片进行氟化,氟化容易、效率高,且氟化过程较安全。(The invention relates to the field of materials, and particularly relates to a preparation method of fluorinated graphene, which comprises the following steps: s1, mechanically stripping expanded graphite to obtain multilayer graphene; s2, carrying out fluorination treatment on the multilayer graphene obtained in the step S1; and S3, mechanically stripping the fluorinated graphene with the multilayer structure obtained in the step S2 to obtain the fluorinated graphene. The graphene sheet layer preparation method used by the invention is a mechanical stripping method, and the preparation process is pollution-free and generates no waste materials. Compared with the method for preparing the fluorinated graphene by directly stripping the fluorinated graphite, the technical process comprises the steps of firstly stripping the graphite to form multi-layer graphene and then carrying out subsequent treatment, the stripping process is easier to realize, and the stripped layers are more complete and uniform. Compared with the method for directly fluorinating graphene or graphene oxide, the method is used for fluorinating the multi-lamellar graphite microchip firstly, and is easy to fluorinate, high in efficiency and safer in fluorination process.)

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

s1, mechanically stripping expanded graphite to obtain multilayer graphene;

s2, carrying out fluorination treatment on the multilayer graphene obtained in the step S1;

preparing fluorinated multilayer graphene by reacting the multilayer graphene obtained in the step S1 with a fluorine-containing substance;

and S3, mechanically stripping the fluorinated graphene with the multilayer structure obtained in the step S2 to obtain the fluorinated graphene.

2. The method for preparing fluorinated graphene according to claim 1, wherein the mechanical exfoliation treatment in step S1 specifically comprises the following steps: mixing the expanded graphite with the dispersion liquid A, adding 40-80 mL of the dispersion liquid A into each milligram of the expanded graphite, and carrying out ultrasonic treatment at the temperature of 30-50 ℃ and the frequency of 150-180 Hz for 20-40 min.

3. The method for preparing fluorinated graphene according to claim 2, wherein the dispersion liquid A is a mixture of ethanol, water and isopropanol in a volume ratio of 1: 3-5: 1-3.

4. The method for preparing fluorinated graphene according to claim 1, wherein the mechanical exfoliation treatment of the fluorinated graphene with a multilayer structure in the step S3 includes the following specific steps: and (4) mixing the fluorinated multilayer-structure graphene obtained in the step (S2) with the dispersion liquid B, adding 90-120 mL of dispersant B into each milligram of fluorinated multilayer-structure graphene, and carrying out ultrasonic treatment at the temperature of 30-50 ℃ and the frequency of 150-180 Hz for 1-3 h.

5. The method for preparing fluorinated graphene according to claim 4, wherein the dispersion liquid B is a mixture of DMF and THF in a volume ratio of 1: 1 to 3.

6. The method for preparing fluorinated graphene according to claim 3, wherein the volume ratio of the ethanol to the water to the isopropanol is 1: 4: 2.

7. The method for preparing fluorinated graphene according to claim 5, wherein the volume ratio of DMF to THF is 1: 2.

8. The method for preparing fluorinated graphene according to claim 1, wherein the reaction of the multilayer-structured graphene with the fluorine-containing substance is carried out at a temperature of 200-600 ℃ for 3-7 hours by mixing the multilayer-structured graphene with a gas mixture of an inert gas and a gas phase fluorinating agent in a molar ratio of (3-5) to 1.

9. The method for producing fluorinated graphene according to claim 8, further characterized in that,the gas phase fluorinating agent comprises: f₂、NF₃、SF₄、XeF₂One or a combination of both.

10. The method for preparing fluorinated graphene according to claim 8, wherein the inert gas and the gas phase fluorinating agent are in a molar ratio of 4: 1.

Technical Field

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

Technical Field

Since the first successful preparation of fluorinated graphene by the group of the project Geim in 2010 and the detailed description of the structure and properties of fluorinated graphene in the accompanying table article, fluorinated graphene has attracted extensive attention of scientific researchers as a member of graphene family, the fluorinated graphene retains the honeycomb-shaped carbon-carbon skeleton of graphene, and fluorine atoms and carbon atoms act in a covalent bond form, so that the fluorinated graphene not only has ultrahigh specific surface area, high Young modulus, high breaking strength and excellent chemical properties, but also has unique physical and chemical properties. In many high-tech areas such as: hydrogen storage materials, sensors, ultra-efficient solar cells, composite materials, biomedicine, aerospace and the like show excellent application prospects. However, the preparation of high-quality fluorinated graphene materials with few defects is still a research hotspot problem to be solved urgently.

The common preparation method of fluorinated graphene comprises the following steps: the graphite fluoride is used as a raw material and is prepared by direct stripping, liquid phase stripping, ion stripping and other modes. Although the preparation of fluorinated graphene is achieved by exfoliation of graphite fluoride as in patent nos. CN 108584933 a and CN 108002367 a, which are theorized to produce high-purity and few-defect fluorinated graphene, graphite is hard after fluorination, difficult to exfoliate, low in yield, and time-consuming and labor-consuming in practice. The prepared fluorinated graphene has uneven quality and uneven lamellar distribution, and the overall performance of the fluorinated graphene is greatly reduced compared with that of a thin layer. The other method is to directly fluorinate graphene or graphene oxide to prepare fluorinated graphene. For example, patent CN 107879328A, etc. is to prepare fluorinated graphene by adding hydrofluoric acid and concentrated nitric acid to a graphene oxide solution and performing fluorination under certain conditions. The fluorination process is difficult because the graphene has a large specific surface area. Graphene oxide is expensive, fluorinated graphene prepared by fluorination of graphene oxide has many defects, and the fluorination process is seriously polluted. And the fluorocarbon ratio of the product is difficult to control through the direct fluorination preparation process of the graphene. Therefore, it is necessary to develop a more scientific preparation process of fluorinated graphene.

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provides a preparation method of fluorinated graphene.

The purpose of the invention is realized by the following technical scheme:

a preparation method of fluorinated graphene comprises the following steps:

s1, mechanically stripping expanded graphite to obtain multilayer graphene;

s2, carrying out fluorination treatment on the multilayer graphene obtained in the step S1;

preparing fluorinated multilayer graphene by reacting the multilayer graphene obtained in the step S1 with a fluorine-containing substance;

and S3, mechanically stripping the fluorinated graphene with the multilayer structure obtained in the step S2 to obtain the fluorinated graphene.

The preparation method of the fluorinated graphene comprises the steps of firstly obtaining the graphene with the multilayer structure by a mechanical stripping method, and then carrying out fluorination treatment on the graphene with the multilayer structure. Compared with the method for directly fluorinating expanded graphite, the graphene with the multilayer structure is easier to fluorinate, the fluorination degree is higher, and the fluorinated graphene with the multilayer structure is obtained. Finally, the fluorinated graphene with a single layer or a small number of layers can be obtained through mechanical stripping, and the finally obtained fluorinated graphene is better in stability.

The above-mentioned mechanical peeling methods may be various, for example: ball milling, sand milling, shearing, emulsifying, homogenizing, etc. or combination of multiple methods. Preferably, ultrasonic exfoliation is used.

Preferably, the mechanical stripping treatment in step S1 includes the specific steps of: mixing the expanded graphite with the dispersion liquid A, adding 40-80 mL of the dispersion liquid A into each milligram of the expanded graphite, and carrying out ultrasonic treatment at the temperature of 30-50 ℃ and the frequency of 150-180 Hz for 20-40 min.

Preferably, the dispersion liquid A is formed by mixing ethanol, water and isopropanol according to the volume ratio of 1 to (3-5) to (1-3).

Preferably, the mechanical exfoliation treatment of the fluorinated multilayer graphene in step S3 includes the specific steps of: and (4) mixing the fluorinated multilayer-structure graphene obtained in the step (S2) with the dispersion liquid B, adding 90-120 mL of dispersant B into each milligram of fluorinated multilayer-structure graphene, and carrying out ultrasonic treatment at the temperature of 30-50 ℃ and the frequency of 150-180 Hz for 1-3 h.

Preferably, the dispersion liquid B is formed by mixing N-N-Dimethylformamide (DMF) and Tetrahydrofuran (THF) according to the volume ratio of 1: 1-3.

Preferably, the volume ratio of the ethanol, the water and the isopropanol is 1: 4: 2.

Preferably, the volume ratio of DMF to THF is 1: 2.

Preferably, the multilayer structure graphene and the fluorine-containing substance react to form a mixed gas of the multilayer structure graphene and an inert gas and a gas phase fluorinating agent according to a molar ratio of (3-5) to 1, and the reaction time is 3-7 hours at a temperature of 200-600 ℃.

Preferably, the gas phase fluorinating agent comprises: f₂、NF₃、SF₄、XeF₂One or a combination of both.

Preferably, the inert gas and the gas phase fluorinating agent are in a molar ratio of 4: 1.

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

according to the method for fluorinating graphene, provided by the invention, graphite is firstly formed into a multi-layer graphene structure through a liquid phase stripping method, then the multi-layer graphene is subjected to fluorination treatment, and finally the prepared multi-layer graphene fluoride is mechanically stripped again, so that the graphene fluoride is successfully prepared. The graphene sheet layer preparation method used by the invention is a mechanical stripping method, and the preparation process is pollution-free and generates no waste materials. Compared with the method for preparing the fluorinated graphene by directly stripping the fluorinated graphite, the technical process comprises the steps of firstly stripping the graphite to form multi-layer graphene and then carrying out subsequent treatment, the stripping process is easier to realize, and the stripped layers are more complete and uniform. Compared with the method for directly fluorinating graphene or graphene oxide, the method is used for fluorinating the multi-lamellar graphite microchip firstly, and is easy to fluorinate, high in efficiency and safer in fluorination process.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below with reference to specific examples and comparative examples. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.

Unless otherwise specified, the devices used in this example are all conventional experimental devices, the materials and reagents used are commercially available, and the experimental methods without specific descriptions are also conventional experimental methods.