CN104386679A - Method for preparing graphene oxide and graphene - Google Patents

Abstract

The preparation method of graphene oxide and graphene comprises the following steps: the preparation method of graphene oxide: uniformly mix graphite raw material, solvent and oxidant, place in a closed reaction vessel, stir and react at 40-120°C for 0.5-6h, After decompression, suction filtration, and washing, vacuum-dry and grind the filtered matter, disperse the dried and ground product evenly in deionized water, add an oxidizing agent under acidic conditions, stir and react at 0-4°C for 1-4 hours, and heat up Stir and react at 20-40°C for 1-2 hours, separate and purify the reacted suspension, disperse in deionized water and spray dry to obtain graphene oxide; the preparation method of graphene: ultrasonically disperse graphene oxide in deionized water After adding a reducing agent for reduction reaction, the graphene is obtained by washing and drying.

Description

Graphene oxide and preparation method of graphene

technical field

The invention relates to the technical field of graphene, in particular to a method for preparing graphene oxide and a method for preparing graphene from graphene oxide. the

the

Background technique

Graphene is a two-dimensional carbon film with a thickness of only one atom. It is the only material composed of a single layer of atoms discovered so far. The chemical bonds between them are composed of sp2 hybrid orbitals, so graphene is very tenacious, and has excellent characteristics that other new materials do not have, such as bendability, strong electrical conductivity, good mechanical strength, and good light transmission. Graphene has extraordinary electrical conductivity, low resistivity, and electrons can migrate extremely efficiently, which is much higher than traditional conductors and semiconductors; electrons migrate in graphene without collisions between electrons and atoms, and can Greatly reduce energy loss; graphene has excellent light transmission, but is not breathable, can be used to develop a new generation of protective layer materials, and can be used to develop transparent electronic products and wearable electronic products. The preparation methods of graphene products are diverse, but there are some disadvantages, especially in the preparation process, it is difficult to control the product quality and yield. A slight change in the processing conditions in the production process, such as changes in temperature and time, will affect the quality and yield of the product. The efficiency has a great influence, so it is difficult to realize large-scale preparation. the

the

Contents of the invention

In view of the above-mentioned existing technical problems, the present invention provides a method for preparing graphene oxide and graphene with simple process and easy operation. The preparation conditions have relatively little influence on product quality and yield, and the product quality and yield are easy to control, suitable for Large-scale production. the

The technical scheme that the present invention takes to solve the problems of the technologies described above is: a kind of preparation method of graphene oxide and graphene, comprises the following steps:

a1. The preparation method of graphene oxide: mix the graphite raw material, solvent and oxidant evenly, place in a closed reaction container, stir and react at 40~120°C for 0.5~6h, depressurize, filter, and wash, and dry the filter in vacuum , Grinding.

a2. Secondary oxidation: uniformly disperse the dried product in deionized water, add an oxidizing agent under acidic conditions, stir and react at 0~4°C for 1~4h, raise the temperature to 20~40°C and stir for 1~2h, and put the reacted The suspension is separated and purified, dispersed in deionized water and spray-dried to obtain graphene oxide. the

b. The preparation method of graphene: ultrasonically disperse graphene oxide in deionized water, add a reducing agent for reduction reaction, wash and dry to obtain graphene. the

Preferably, the graphite raw material is flake graphite, graphite powder or expanded graphite. the

Preferably, the solvent is concentrated sulfuric acid, and the weight ratio of the concentrated sulfuric acid to the graphite raw material is 10-50:1. . the

As preferably, the oxidizing agent described in a1 is potassium permanganate, and the weight ratio of described potassium permanganate and graphite raw material is 3～8:1; Described in a2, the oxidizing agent is potassium permanganate and hydrogen peroxide, and the described The weight ratio of potassium permanganate and graphite raw material is 1～4:1, and the weight ratio of described hydrogen peroxide and graphite raw material is 5～10:1, and the weight ratio of deionized water and graphite raw material described in a2 is 100 ~1000:1. the

The separation and purification process described in a2 is: centrifugally settle the suspension at room temperature, remove the supernatant, add deionized water to the sediment and stir for 5-10 minutes, then carry out centrifugal sedimentation, remove the supernatant, and repeatedly add deionized In the process of water and centrifugation for 1~2 times, take the sediment and add absolute ethanol, stir for 5~10min, then carry out centrifugal sedimentation, take the sediment and repeat washing with absolute ethanol for 1~2 times, then dry the sediment. the

Preferably, the centrifugal speed is 4500~6000r/min, and the time is 3~8min. the

Preferably, the reducing agent is NaOH, KOH or hydrazine hydrate. the

Preferably, the mass ratio of reducing agent to graphene oxide is 1-4:1. the

Compared with the prior art, the technical solution of the present invention has the advantages: the present invention simultaneously provides graphene and a method for preparing graphene oxide as a raw material for preparing graphene, the process is simple and easy to operate, and the selection of raw and auxiliary materials is relatively common. It is suitable for large-scale production; in the preparation process of graphene oxide of the present invention, the graphite is oxidized and stripped deeply in the two oxidation processes; the separation and purification process can obtain graphite oxide with extremely high purity, and finally obtain high-quality graphene oxide and Graphene. the

the

Detailed ways

A preparation method of graphene oxide and graphene, comprising the following steps:

a1. Preparation of graphene oxide: Mix graphite raw materials, solvents and oxidants evenly, place in a closed reaction vessel, stir and react at 40-120°C for 0.5-6h, depressurize, filter with suction, and wash, vacuum-dry and grind the filtrate .

a2. Secondary oxidation: uniformly disperse the dried product in deionized water, add an oxidizing agent under acidic conditions, stir and react at 0~4°C for 1~4h, raise the temperature to 20~40°C and stir for 1~2h, and put the reacted The suspension is separated and purified, dispersed in deionized water and spray-dried to obtain graphene oxide. the

b. The preparation method of graphene: ultrasonically disperse graphene oxide in deionized water, add reducing agent for reduction reaction, wash and dry to obtain graphene. the

The process of preparing graphene oxide in the present invention is divided into two steps, including two oxidations, which can deeply oxidize and strip graphite. the

The graphite raw material can be flake graphite, graphite powder or expanded graphite, preferably expanded graphite or 30-1000 mesh graphite powder, because the structure of expanded graphite is loose and the particles of graphite powder are relatively fine, which is beneficial to the oxidation and exfoliation of graphite. the

The solvent is concentrated sulfuric acid, and the weight ratio of the concentrated sulfuric acid to the graphite raw material is 10-50:1. the

The oxidizing agent described in a1 is potassium permanganate, and the weight ratio of described potassium permanganate and graphite raw material is 3～8:1, and the oxidation action of potassium permanganate is very strong in the solution of the concentrated sulfuric acid, can more thoroughly oxidize Graphite; Oxidant described in a2 is potassium permanganate and hydrogen peroxide, and the weight ratio of described potassium permanganate and graphite raw material is 1～4:1, and the weight ratio of described hydrogen peroxide and graphite raw material is 5～ 10:1, the weight ratio of deionized water to graphite raw material mentioned in a2 is 100~1000:1. the

The specific process of secondary oxidation is: ultrasonically disperse the dried product in a small amount of deionized water, the weight ratio of deionized water to graphite raw material is 10~30:1, add hydrochloric acid or sulfuric acid to adjust the pH to less than 3, add high Potassium manganate was stirred and reacted at 0~4°C for 1~4h, hydrogen peroxide was added, the temperature was raised to 20~40°C, stirred and reacted for 1~2h, the reacted suspension was separated and purified, dispersed in deionized water and spray dried. the

The separation and purification process described in a2 is: centrifugally settle the suspension at room temperature, remove the supernatant, add deionized water to the sediment and stir for 5-10 minutes, then carry out centrifugal sedimentation, remove the supernatant, and repeatedly add deionized In the process of water and centrifugation for 1~2 times, take the sediment and add absolute ethanol, stir for 5~10min, then carry out centrifugal sedimentation, take the sediment and repeat washing with absolute ethanol for 1~2 times, then dry the sediment. the

The separation process can obtain graphite oxide solids with high purity, and the centrifugal washing with absolute ethanol can overcome the problems of difficult solid-liquid separation and incomplete washing in the water washing process. the

The centrifugal speed is 4500~6000r/min, and the time is 3~8min. the

The reducing agent is NaOH, KOH or hydrazine hydrate, and the mass ratio of reducing agent to graphene oxide is 1-4:1. the

Filter the solution after the reduction reaction, take the filtrate and heat it with microwave, cool and pickle after the treatment, wash and filter with water, and dry the filtrate to obtain graphene. the

A kind of graphene oxide of the present invention and the preparation method of graphene are described further below in conjunction with specific embodiment:

Example 1:

The preparation method of graphene oxide: take 1 part of graphite powder as graphite raw material, mix evenly with 10 parts of concentrated sulfuric acid and 3 parts of potassium permanganate, place in a closed reaction vessel, stir and react for 6 hours under the condition of heating in a water bath at 40 °C, and then After pressing, suction filtering and washing, the filtered matter is vacuum-dried and ground. Ultrasonic disperse the dry and ground product in 10 parts of deionized water, add hydrochloric acid to adjust the pH to less than 3, add 1 part of potassium permanganate and stir at 0°C for 4 hours, add 5 parts of hydrogen peroxide, heat up to 20°C and stir in a water bath After 2 hours, the reacted suspension was separated and purified, dispersed in deionized water and spray-dried to obtain graphene oxide, the above-mentioned parts are parts by weight.

The above process of separation and purification is as follows: centrifugally settle the suspension at room temperature, remove the supernatant, add deionized water to the sediment and stir for 5 minutes, then carry out centrifugal sedimentation, remove the supernatant, add deionized water repeatedly and During the centrifugation process once, take the sediment and add absolute ethanol, stir for 5 minutes, then carry out centrifugal sedimentation, take the sediment and repeat washing with absolute ethanol once, and then dry the sediment. The above centrifugation conditions are: 4500r/min, centrifugation for 3min. the

The preparation method of graphene: take 1 part of graphene oxide and ultrasonically disperse it in deionized water, add 1 part of reducing agent NaOH for reduction reaction, filter the solution after the reduction reaction, take the filtrate dry microwave heat treatment, cool the acid after treatment Washing, washing and filtering, and drying the filtrate is graphene. Said parts are parts by weight. the

Example 2:

The preparation method of graphene oxide: Take 1 part of flake graphite as the graphite raw material, mix it with 50 parts of concentrated sulfuric acid and 8 parts of potassium permanganate, put it in a closed reaction container, and stir it under the condition of 120 ℃ oil bath heating for 0.5h. After decompression, suction filtration and washing, the filtrate was vacuum-dried and ground. Ultrasonic disperse the dry and ground product in 30 parts of deionized water, add sulfuric acid to adjust the pH to less than 3, add 4 parts of potassium permanganate and stir at 4°C for 1 hour, add 10 parts of hydrogen peroxide, heat up to 40°C and stir in a water bath After 1 hour, the reacted suspension was separated and purified, dispersed in deionized water and spray-dried to obtain graphene oxide, the above-mentioned parts are parts by weight.

The above process of separation and purification is as follows: centrifugally settle the suspension at room temperature, remove the supernatant, add deionized water to the sediment and stir for 10 minutes, then carry out centrifugal sedimentation, remove the supernatant, repeatedly add deionized water and During the centrifugation process twice, take the sediment and add absolute ethanol, stir for 10 minutes, then carry out centrifugal sedimentation, take the sediment and wash twice with absolute ethanol, then dry the sediment. The above centrifugation conditions are: 6000r/min, centrifugation for 8min. the

The preparation method of graphene: take 1 part of graphene oxide and ultrasonically disperse it in deionized water, add 4 parts of reducing agent KOH for reduction reaction, filter the solution after the reduction reaction, take the filtrate dry microwave heat treatment, cool the acid after treatment Washing, washing and filtering, and drying the filtrate is graphene. Said parts are parts by weight. the

Example 3:

The preparation method of graphene oxide: take 1 part of expanded graphite as the graphite raw material, mix evenly with 30 parts of concentrated sulfuric acid and 5 parts of potassium permanganate, place in a closed reaction vessel, stir and react for 2 hours under the condition of heating in a water bath at 80 ° C, and after reducing After pressing, suction filtering and washing, the filtered matter is vacuum-dried and ground. Ultrasonic disperse the dry and ground product in 20 parts of deionized water, add sulfuric acid to adjust the pH to less than 3, add 3 parts of potassium permanganate and stir at 2°C for 2.5 hours, add 7 parts of hydrogen peroxide, heat up to 30°C and stir in a water bath After reacting for 2 hours, the reacted suspension was separated and purified, dispersed in deionized water and spray-dried to obtain graphene oxide, and the above-mentioned parts are parts by weight.

The above process of separation and purification is as follows: at room temperature, the suspension is subjected to centrifugal sedimentation, the supernatant is removed, deionized water is added to the sediment and stirred for 7 minutes, then centrifugal sedimentation is performed, the supernatant is removed, deionized water is added repeatedly and During the centrifugation process once, take the sediment and add absolute ethanol, stir for 9 minutes, then carry out centrifugal sedimentation, take the sediment and repeat the absolute ethanol washing twice, and then dry the sediment. The above centrifugation conditions are: 5200r/min, centrifugation for 7min. the

The preparation method of graphene: take 1 part of graphene oxide and ultrasonically disperse it in deionized water, add 3 parts of reducing agent hydrazine hydrate for reduction reaction, filter the solution after the reduction reaction, take the filtrate dry microwave heat treatment, cool after treatment Pickling, washing with water, filtration, and drying of the filtrate is graphene. Said parts are parts by weight. the

It should be noted that the examples and raw materials listed in the present invention are only methods and raw materials under more suitable conditions, and any simple modifications or modifications made without departing from the concept and principles of the present invention will fall within the scope of the present invention. within the scope of protection. the

Claims (8)

1. a preparation method for graphene oxide and Graphene, is characterized in that comprising the following steps:

A1. the preparation method of graphene oxide: graphite raw material, solvent and oxygenant are mixed, is placed in closed reaction vessel, stirring reaction 0.5 ~ 6h at 40 ~ 120 DEG C, after decompression, suction filtration, washing, by overanxious thing vacuum-drying, grinding;

A2. secondary oxidation: dried product is dispersed in deionized water, oxygenant is added under acidic conditions, in 0 ~ 4 DEG C of stirring reaction 1 ~ 4h, be warming up to 20 ~ 40 DEG C of stirring reaction 1 ~ 2h, by reacted suspension liquid separating-purifying, be scattered in spraying dry in deionized water and be graphene oxide;

B. the preparation method of Graphene: by graphene oxide ultrasonic disperse in deionized water, add after reductive agent carries out reduction reaction, washing drying treatment obtains Graphene.

2. the preparation method of a kind of graphene oxide according to claim 1 and Graphene, is characterized in that: described graphite raw material is crystalline flake graphite, Graphite Powder 99 or expanded graphite.

3. the preparation method of a kind of graphene oxide according to claim 1 and Graphene, is characterized in that: described solvent is the vitriol oil, and the weight ratio of the vitriol oil and graphite raw material is 10 ~ 50:1.

4. the preparation method of a kind of graphene oxide according to claim 1 and Graphene, is characterized in that: oxygenant described in a1 is potassium permanganate, and the weight ratio of described potassium permanganate and graphite raw material is 3 ~ 8:1; Oxygenant described in a2 is potassium permanganate and hydrogen peroxide, the weight ratio of described potassium permanganate and graphite raw material is 1 ~ 4:1, the weight ratio of described hydrogen peroxide and graphite raw material is the weight ratio of deionized water and graphite raw material described in 5 ~ 10:1, a2 is 100 ~ 1000:1.

5. the preparation method of a kind of graphene oxide according to claim 1 and Graphene, it is characterized in that: described in a2, separating-purifying process is: under room temperature, suspension liquid is carried out centrifugal settling, remove supernatant liquid, add deionized water in sediment and carry out centrifugal settling after stirring 5 ~ 10min, remove supernatant liquid, repeat to add deionized water and centrifugal process 1 ~ 2 time, get sediment and add dehydrated alcohol, after stirring 5 ~ 10min, carry out centrifugal settling, get after sediment repeats absolute ethanol washing 1 ~ 2 time, by sediment drying treatment.

6. the preparation method of a kind of graphene oxide according to claim 5 and Graphene, is characterized in that: described centrifugal rotational speed is 4500 ~ 6000r/min, and the time is 3 ~ 8min.

7. the preparation method of a kind of graphene oxide according to claim 1 and Graphene, is characterized in that: described reductive agent is NaOH, KOH or hydrazine hydrate.

8. a kind of graphene oxide according to claim 1 or 7 and the preparation method of Graphene, is characterized in that: the mass ratio of reductive agent and graphene oxide is 1 ~ 4:1.