CN108383115B

CN108383115B - Method for preparing high-quality graphene at normal temperature in large batch

Info

Publication number: CN108383115B
Application number: CN201810382328.2A
Authority: CN
Inventors: 张瑞军; 刘孟杰; 吴文玉
Original assignee: Yanshan University
Current assignee: Yanshan University
Priority date: 2018-04-26
Filing date: 2018-04-26
Publication date: 2020-07-28
Anticipated expiration: 2038-04-26
Also published as: CN108383115A

Abstract

A method for preparing high-quality graphene at normal temperature in large batch mainly comprises the following steps of: 1-20: uniformly ultrasonically mixing the raw materials in a ratio of 1-10 to prepare a mixed solution; according to the proportion of adding 0.05-0.5 g of graphite into every 5ml of mixed solution, uniformly stirring the graphite and the mixed solution, standing at normal temperature for 1-12 h, then washing with water to be neutral, and drying to obtain the graphene. The method realizes simultaneous implementation of four parts of oxidation, intercalation, puffing and stripping, and greatly simplifies the preparation process of the graphene; the whole preparation process can be finished at normal temperature without high temperature or irradiation, so that energy is saved; the whole process is simple to operate, labor force is saved, productivity is liberated, high-quality graphene can be prepared in a large batch, and a direction is provided for large-scale industrial production.

Description

Method for preparing high-quality graphene at normal temperature in large batch

Technical Field

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

Background

Graphene is a two-dimensional material with a single graphite layer, and is sp of carbon atoms²The cellular thin film formed by the hybridization mode has the advantages that graphene is the thinnest and the hardest nano material in the theory known at present, the graphene is almost completely transparent, and only absorbs 2.3% of light; the novel carbon material has high specific surface area and excellent electric and heat conductivity, the heat conductivity coefficient is as high as 5300W/(m.K), which is higher than that of carbon nano tube and diamond, and the electron mobility exceeds 15000cm at normal temperature²V.s, and is higher than carbon nanotubes or silicon crystals and has a resistivity of only about 10^-6Omega cm, lower than copper or silver, is the material with the smallest resistivity in the world. The graphene material presents a shale-like laminated layer on a macroscopic view; microscopically, unit cell atoms are arranged in a layer in a three-dimensional space in a plane, atoms in the layer are combined by covalent bonds, and atoms between the layers interact by Van der Waals force, so that the bonding effect between the atoms in the layer is far greater than the interaction between the atoms between the layers, and the graphene has a unique crystal structure and specific optical, electrical, acoustic and mechanical properties compared with compounds with other dimensions (0-dimensional fullerene, 1-dimensional carbon nanotube and 3-dimensional graphite). In the near future, graphene will be commercially applied in many fields such as catalysis, electronics, energy and the like. Scientists find that graphene has special physical effects and properties such as abnormal quantum hall effect and the like, and the graphene is generally considered to be finally substituted for silicon, so that the electronic industry is revolutionized again.

Since the few-layer graphene obtained by two scientists of manchester university in the united kingdom using a very simple mechanical separation method and acquired the nobel prize in physics, academic research and industrial demand for graphene have made high-yield, high-quality preparation of graphene particularly important. Generally, the methods for preparing graphene are: mechanical stripping, oxidation-reduction, liquid phase stripping, electrochemical methods, and the like, wherein the method of micro-mechanical stripping is a method of repeatedly stripping graphite by using photoresist through a mechanical means to obtain graphene, and the method is simple, but time-consuming, labor-consuming, poor in repeatability and difficult to accurately control; the most common method at present is an oxidation-reduction method, and the basic principle of the method is that strong protonic acid is used for treating graphite to form a graphite interlayer compound, then a strong oxidant is used for oxidation to form graphene oxide, and then a reducing agent is added in a reduction step to reduce the graphene oxide to obtain the graphene; also a commonly used method is the liquid phase exfoliation method, which uses a surfactant as an auxiliary of the ultrasonic means to exfoliate graphite, but this method requires a long time for ultrasonic treatment, the yield is low, typically 5%, and the size of the obtained graphene is small (typically ≦ 5 μm) due to severe damage to the graphite structure. The later washing of the surfactant on the graphene also makes the whole operation time and labor consuming, which is undoubtedly snow frosting for the big environment where the water resource is scarce at present.

Therefore, a technology capable of preparing high-quality graphene in large batch at normal temperature becomes an important part of research work of graphene researchers at home and abroad.

Disclosure of Invention

The invention aims to provide a method for preparing high-quality graphene in large batch at normal temperature, which is simple in process operation, does not need high temperature or irradiation and saves energy aiming at the defects of the technology.

The method comprises the following specific steps:

(1) concentrated sulfuric acid and peroxyacetic acid are mixed according to the volume ratio of 1-20: uniformly ultrasonically mixing the raw materials in a ratio of 1-10 to prepare a mixed solution;

(2) and (2) adding 0.05-0.5 g of graphite into every 5ml of mixed solution, uniformly stirring the graphite and the mixed solution obtained in the step (1), standing at normal temperature for 1-12 hours, then washing with water to be neutral, and drying to obtain the graphene.

The graphite is natural crystalline flake graphite with a particle size of 50-500 meshes.

Compared with the prior art, the invention has the following advantages:

1. the oxidation, intercalation, puffing and stripping are simultaneously carried out, and the preparation process of the graphene is greatly simplified.

2. The whole preparation process can be finished at normal temperature without high temperature or irradiation, thereby saving energy.

3. The whole process is simple to operate, labor force is saved, productivity is liberated, and high-quality graphene can be prepared in a large batch.

Drawings

Fig. 1 is a scanning electron microscope image of graphene prepared in example 1 of the present invention.

Fig. 2 is a transmission electron microscope image of graphene prepared in example 1 of the present invention.

Detailed Description

Example 1

5ml of 98% concentrated sulfuric acid and 5ml of 26% peracetic acid are mixed uniformly by ultrasonic to prepare a mixed solution, 0.1g of 50-mesh natural graphite is put into the mixed solution and stirred uniformly, then the mixed solution is kept stand for 12 hours at normal temperature, and then the mixed solution is washed to be neutral and dried to obtain graphene, wherein the number of layers of the obtained graphene is about 8.

As shown in fig. 1, the size of the obtained graphene is also relatively large and relatively transparent through high conversion from graphite to graphene.

As shown in fig. 2, it is further illustrated that the obtained graphene is relatively transparent and relatively thin.

Example 2

1ml of 98% concentrated sulfuric acid and 10ml of 26% peracetic acid are mixed uniformly by ultrasonic to prepare a mixed solution, 0.55g of 80-mesh natural graphite is put into the mixed solution and stirred, then the mixed solution is kept stand for 5 hours at normal temperature, and then the mixed solution is washed to be neutral and dried to obtain graphene, wherein the number of layers of the obtained graphene is about 15.

Example 3

The preparation method comprises the steps of ultrasonically mixing 20ml of 98% concentrated sulfuric acid and 10ml of 26% peracetic acid uniformly to prepare a mixed solution, placing 1g of 300-mesh natural graphite into the mixed solution, stirring, standing at normal temperature for 8 hours, washing with water to be neutral, and drying to obtain graphene, wherein the number of layers of the obtained graphene is about 25.

Example 4

The preparation method comprises the steps of ultrasonically mixing 15ml of 98% concentrated sulfuric acid and 1ml of 26% peracetic acid uniformly to prepare a mixed solution, placing 0.3g of 300-mesh natural graphite into the mixed solution, stirring, standing at normal temperature for 3 hours, washing with water to be neutral, and drying to obtain graphene, wherein the number of layers of the graphene is about 30.

Example 5

1ml of 98% concentrated sulfuric acid and 5ml of 26% peracetic acid are mixed uniformly by ultrasonic to prepare a mixed solution, 0.42g of 500-mesh natural graphite is put into the mixed solution and stirred, then the mixed solution is kept stand for 1 hour at normal temperature, and then the mixed solution is washed to be neutral and dried to obtain graphene, wherein the number of layers of the obtained graphene is about 20.

Example 6

The preparation method comprises the steps of uniformly mixing 20ml of 98% concentrated sulfuric acid and 1ml of 26% peracetic acid by ultrasonic waves to prepare a mixed solution, placing 1.68g of 100-mesh natural graphite into the mixed solution, stirring, standing at normal temperature for 9 hours, washing with water to be neutral, and drying to obtain graphene, wherein the number of layers of the obtained graphene is about 15.

Example 7

The preparation method comprises the steps of ultrasonically mixing 15ml of 98% concentrated sulfuric acid and 5ml of 26% peracetic acid uniformly to prepare a mixed solution, placing 2g of 50-mesh natural graphite into the mixed solution, stirring, standing at normal temperature for 12 hours, washing with water to be neutral, and drying to obtain graphene, wherein the number of layers of the obtained graphene is about 10.

Claims

1. A method for preparing high-quality graphene at normal temperature in large batch is characterized by comprising the following steps: which comprises the following steps:

(2) and (2) according to the proportion of adding 0.05-0.5 g of graphite into every 5ml of mixed solution, uniformly stirring the graphite and the mixed solution obtained in the step (1), standing at normal temperature for 1-12 h, then washing with water to be neutral, and drying to obtain the graphene.

2. The method for preparing high-quality graphene at normal temperature in large batch according to claim 1, wherein the method comprises the following steps: the graphite is natural crystalline flake graphite with a particle size of 50-500 meshes.