阅读说明：本技术 一种电解法制备石墨烯的制备方法 (Preparation method for preparing graphene by electrolytic method ) 是由 赵宁 于 2019-08-15 设计创作，主要内容包括：本发明公开了一种电解法制备石墨烯的制备方法,采用高纯石墨板为此电解制备法的阴阳极,一个阴极石墨板与一个阳极石墨板构成一个电解,配制浓度为0.6%的磷酸氢二铵水溶液,加入电解池中使溶液的体积占容器体积的80%,将高纯石墨板作为电解池的阴阳极放入电解池中,高纯石墨电极板上连接导线,阳极连接12V直流电源的正极,阴极连接12V直流电源的负极,进行电解反应。本发明中,其制备石墨烯的成本较低,并且工艺简单,能够实现快速高效的制备石墨烯,便于大规模工业化生产,其次对比与市场上采用氧化还原法制备石墨烯,品质更高,保证石墨烯的性能,并且利用此电解法制备出的石墨烯1-10层的产量占总产量的68%,10-20层石墨烯的产量占总产量的32%。(The invention discloses a preparation method for preparing graphene by an electrolytic method, which adopts a high-purity graphite plate as a cathode and an anode of the electrolytic preparation method, wherein a cathode graphite plate and an anode graphite plate form electrolysis, a diammonium hydrogen phosphate aqueous solution with the concentration of 0.6% is prepared, the solution is added into an electrolytic cell to enable the volume of the solution to account for 80% of the volume of a container, the high-purity graphite plate is used as the cathode and the anode of the electrolytic cell and is placed into the electrolytic cell, a lead is connected to the high-purity graphite electrode plate, the anode is connected with the anode of a 12V direct current power supply, and the cathode is connected with the cathode of the 12V direct current power supply. According to the invention, the cost for preparing graphene is low, the process is simple, the graphene can be quickly and efficiently prepared, the large-scale industrial production is facilitated, the quality is higher compared with that of the graphene prepared by adopting a redox method in the market, the performance of the graphene is ensured, the yield of 1-10 layers of graphene prepared by utilizing the electrolytic method accounts for 68% of the total yield, and the yield of 10-20 layers of graphene accounts for 32% of the total yield.)

1. A preparation method for preparing graphene by an electrolytic method is characterized by comprising the following steps:

adopting a high-purity graphite plate as a cathode and an anode of the electrolytic preparation method, wherein one cathode graphite plate and one anode graphite plate form an electrolysis;

preparing a diammonium hydrogen phosphate aqueous solution with the concentration of 0.6%, and adding the diammonium hydrogen phosphate aqueous solution into an electrolytic cell to enable the volume of the solution to account for 80% of the volume of the container;

putting a high-purity graphite plate serving as a cathode and an anode of an electrolytic cell into the electrolytic cell, adjusting the position of an electrode to ensure that electrolyte completely submerges a graphite electrode plate, connecting a lead on the high-purity graphite electrode plate, connecting the anode with the anode of a 12V direct-current power supply, and connecting the cathode with the cathode of the 12V direct-current power supply to perform an electrolytic reaction;

after 3-5 hours, the black graphite flakes flake off from the anode graphite rod like onion skin, bubbles are continuously generated on the cathode graphite rod in the whole electrolysis process, and the cathode graphite rod is not corroded and is intact;

after the reaction is finished, washing the obtained black product with distilled water;

removing some large graphite blocks by using a centrifugal machine, and drying the left black powdery solid for 6-10 hours in a drying oven at 60 ℃;

and then ground into uniform powder with an agate mortar to obtain a large amount of product.

2. The method for preparing graphene by electrolysis according to claim 1, wherein the direct current power supply in the step (3) is obtained by connecting a transformer to a common civil alternating current power supply.

3. The method for preparing graphene by electrolysis according to claim 1, wherein the temperature of the whole electrolysis system is kept not higher than 35 ℃ during the electrolysis in step (3).

4. The method for preparing graphene by electrolysis according to claim 1, wherein multiple groups of high-purity graphite plates can be used in parallel, each parallel group can be separately placed in a respective electrolytic cell, or each parallel group can be placed in the same electrolytic cell, and an insulating interlayer with the thickness of 25cm needs to be additionally arranged between each group, a single group of electrode plates is connected to a direct current power supply through a lead, and multiple groups of electrode plates need to be connected to the direct current power supply in parallel through leads.

5. The method for preparing graphene by electrolysis according to claim 1, wherein the high-purity graphite plate is used as a cathode and an anode, and the high-purity graphite electrode plate can be in various shapes.

6. The method for preparing graphene by electrolysis according to claim 1, wherein the voltage between the cathode and the anode during the electrolysis in step (2) is 10V, 12V, 14V, 16V, 18V, 20V, 22V.

Technical Field

The invention relates to the technical field of graphene preparation, in particular to a preparation method for preparing graphene by an electrolytic method.

Background

Graphene is a single-layer two-dimensional honeycomb lattice structure carbon nanomaterial, the basic structure of the graphene is the most stable six-membered carbon ring in an organic material, carbon atoms are hybridized by sp2 to form delta bonds with surrounding carbon atoms respectively, the rest p electron orbit of the outermost layer of the carbon atoms is perpendicular to a graphene sheet layer to form a large pi bond, the theoretical thickness of the graphene is only 0.335nm, and the graphene is the thinnest in a known material in the nature, so the theoretical specific surface area of the graphene is extremely large. In 2016, the new national standard provides that the graphene is called as a graphene sheet with less than 10 sheets and the graphene nano sheet with more than 10 sheets. The graphene has excellent mechanical property and electrical property, and has wide application prospect in the fields of electronics, optics, magnetism, biology and the like for preparing the graphene by a graphite raw ore electrolytic method. There is not only one preparation method of graphene, but there are mainly four methods in terms of the current situation: micro mechanical lift-off, silicon carbide epitaxial growth, Chemical Vapor Deposition (CVD), and redox.

The microcomputer peeling method is the earliest method for preparing graphene, high-orientation pyrolytic graphite is torn off for multiple times by using an adhesive tape, the obtained adhesive tape with graphite flakes is adhered to a target substrate such as a silicon wafer, and finally the adhesive tape is removed by using solvents such as acetone, so that single-layer graphene and few-layer graphene are obtained on the substrate such as the silicon wafer. Although the graphene prepared by the method is high in quality, the preparation method is tedious and time-consuming, the period is long, and large-scale production cannot be realized.

The silicon carbide epitaxial growth method is that under the ultrahigh vacuum environment and high temperature, silicon atoms in a silicon carbide substrate are sublimated by heating, the surface of the left C-rich carbon atoms is graphitized, and the graphene layer is formed by reconstruction. The method has the advantages of complex process, higher experimental requirement and high cost, and is not suitable for industrial large-scale production.

The redox method is to oxidize graphite by means of ultrasound or high-speed centrifugation to obtain graphene oxide dispersed in a solution, and then to reduce the graphene oxide to obtain single-layer or multi-layer graphene. The method relates to the processes of oxidation reaction, reduction reaction and the like, the finally obtained graphene still contains oxygen-containing functional groups which are partially complete in reaction, and the existence of the functional groups can destroy the electronic structure of graphene sheet layers, so that the performance of the graphene is influenced.

Chemical Vapor Deposition (CVD) is a method of growing graphene by pyrolysis on the surface of a substrate using a carbon-containing compound such as methane as a carbon source. Although the graphene material prepared by the method has a large size, the number of layers of the prepared graphene is difficult to control, the application of the graphene is limited, and the cost is high, so that the large-scale production is difficult.

Disclosure of Invention

The invention aims to solve the defects in the prior art, and provides a preparation method for preparing graphene by an electrolytic method.

In order to achieve the purpose, the invention adopts the following technical scheme: a preparation method for preparing graphene by an electrolytic method comprises the following steps:

(1) adopting a high-purity graphite plate as a cathode and an anode of the electrolytic preparation method, wherein one cathode graphite plate and one anode graphite plate form an electrolysis;

(2) preparing a diammonium hydrogen phosphate aqueous solution with the concentration of 0.6%, and adding the diammonium hydrogen phosphate aqueous solution into an electrolytic cell to enable the volume of the solution to account for 80% of the volume of the container;

(3) putting a high-purity graphite plate serving as a cathode and an anode of an electrolytic cell into the electrolytic cell, adjusting the position of an electrode to ensure that electrolyte completely submerges a graphite electrode plate, connecting a lead on the high-purity graphite electrode plate, connecting the anode with the anode of a 12V direct-current power supply, and connecting the cathode with the cathode of the 12V direct-current power supply to perform an electrolytic reaction;

(4) after 3-5 hours, the black graphite flakes flake off from the anode graphite rod like onion skin, bubbles are continuously generated on the cathode graphite rod in the whole electrolysis process, and the cathode graphite rod is not corroded and is intact;

(5) after the reaction is finished, washing the obtained black product with distilled water;

(6) removing some large graphite blocks by using a centrifugal machine, and drying the left black powdery solid for 6-10 hours in a drying oven at 60 ℃;

(7) and then ground into uniform powder with an agate mortar to obtain a large amount of product.

As a further description of the above technical solution:

and (4) the direct current power supply in the step (3) can be obtained by connecting a transformer with a common civil alternating current power supply.

As a further description of the above technical solution:

the temperature of the whole electrolytic system is kept to be not higher than 35 ℃ in the electrolytic process in the step (3);

as a further description of the above technical solution:

multiple groups of high-purity graphite plates can be used in parallel, each parallel group can be independently arranged in a respective electrolytic cell, each parallel group can also be arranged in the same electrolytic cell, at the moment, an insulating interlayer with the thickness of 25cm needs to be additionally arranged among the groups, a single group of electrode plates is connected to a direct current power supply through a lead, and multiple groups of electrode plates need to be connected to the direct current power supply in parallel through the lead.

As a further description of the above technical solution:

the high-purity graphite plate is used as a cathode and an anode, and the high-purity graphite electrode plate can be in various shapes.

As a further description of the above technical solution:

the voltage between the cathode and the anode during the electrolysis in the step (2) can be 10V, 12V, 14V, 16V, 18V, 20V and 22V.

Advantageous effects

The invention provides a preparation method for preparing graphene by an electrolytic method, which has the following beneficial effects:

compared with a microcomputer stripping method, a silicon carbide epitaxial growth method or a chemical vapor deposition method which are used in the current market, the method for preparing the graphene by the electrolysis method has the advantages that the cost for preparing the graphene is lower, the process is simple, the graphene can be quickly and efficiently prepared, the large-scale industrial production is facilitated, the quality is higher compared with that of the graphene prepared by an oxidation-reduction method in the market, the performance of the graphene is guaranteed, 0.6% diammonium hydrogen phosphate aqueous solution is adopted as an electrolysis system, the volume of the solution accounts for 80% of the volume of a container after the solution is added into an electrolytic cell, compared with the traditional method that a sulfuric acid solution with the concentration of 30% -50% is adopted as an electrolyte to supply power, the problem that the graphene oxide has many structural defects due to strong oxidation energy of the sulfuric acid solution with the concentration of 30% -50% in a bed body is solved, and the sp2 hybrid structure of the graphene is seriously damaged due to the defects is solved, thereby influencing the subsequent use of the graphene, increasing the yield of the prepared graphene and ensuring higher purity of the prepared graphene.

Drawings

Fig. 1 is a structural diagram of a preparation method of graphene prepared by an electrolytic method according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.