CN105217621A - A kind of graphene oxide preparation method of size uniformity - Google Patents

Abstract

The invention discloses a method for preparing graphene oxide with uniform size. Firstly, pre-oxidized graphene oxide is prepared through the action of graphite and an oxidizing agent. After increasing the oxidation degree of graphite powder, the obtained pre-oxidized Graphene is further oxidized to prepare graphene oxide with uniform size. The method is simple to operate, has a high degree of oxidation, is environmentally friendly, and the prepared graphene oxide has a uniform size.

Description

A kind of preparation method of graphene oxide with uniform size

technical field

The invention belongs to the field of graphene oxide preparation, in particular to a method for preparing graphene oxide with uniform size.

Background technique

Since the existence of graphene was discovered, scientists have been paying great attention to it. Graphene is the thinnest and toughest material discovered so far, and it also has extraordinary electrical and thermal conductivity. Due to the excellent properties of graphene, it plays a huge role in many fields such as electrochemistry and biomedicine.

The preparation of graphene is of great significance to the study of graphene properties. At present, the chemical graphite oxide reduction method is the most effective method for preparing graphene, which has the advantages of low experimental requirements and high quality graphene, and is widely used in the preparation of graphene. Among them, the preparation of graphene oxide is a crucial link in the chemical graphite oxide reduction method, and the preparation of graphene oxide determines the quality of reduced graphene. At present, the preparation of graphene oxide with uniform size plays an important role in the research of graphene oxide properties and the preparation of reduced graphene.

The current methods for preparing graphene oxide mainly include Brodie, Staudenmaier and Hummers methods. The Brodie method requires multiple oxidation treatments to increase the degree of oxidation, the reaction time is relatively long, and because perchlorate is used as the oxidizing agent, it is more dangerous, and more toxic gases will be produced during the reaction; the Staudenmaier method The disadvantage is that the reaction time is long, the degree of oxidation is low, and multiple oxidation treatments are required; the Hummers method uses concentrated sulfuric acid and nitrate system, uses permanganate as the oxidant, and undergoes low temperature (below 5°C), medium temperature (35°C About) and high temperature (about 98 ° C) three reaction stages to prepare graphite oxide, the prepared graphene oxide has a high degree of oxidation but still has the disadvantages of different sizes of graphene oxide.

Contents of the invention

In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a method for preparing graphene oxide with uniform size.

For this reason, the present invention adopts following technical scheme, a kind of size-uniform graphene oxide preparation method is characterized in that taking the following steps:

A) React 2~4g of graphite powder with 3~6g of potassium dithionate, 3~6g of phosphorus pentoxide and 12~ ^24mL of concentrated sulfuric acid in the reactor, and stir for 4~6 Hour, to form dark blue solution, obtain pre-oxidized graphite after cooling, suction filtration, drying;

B) Take 2~4g of graphite oxide prepared in step A) in a three-necked flask, add 25~50g of potassium permanganate gradually under the condition of an ice-water bath with 150~300mL of concentrated sulfuric acid solution, and stir for 2~4 Hour;

C) Put the three-necked flask in the above step B) into an oil bath, raise the temperature to 35~40 ^o C, stir for 0.5~2 hours, continue stirring and add 30wt% hydrogen peroxide and deionized water according to the volume ratio of 1:15 The mixed solution; suction filtration, washed once with 4 mL of dilute hydrochloric acid and deionized water with a mass fraction of 10%, centrifuged, and dried to obtain the first oxidized graphene oxide;

D) Mix 2~4g of graphene oxide prepared in step C) with 50~100mL of concentrated sulfuric acid solution in the three-necked flask again under the condition of ice-water bath, gradually add 8~16g of KMnO ₄ , stir for 1~2 Hour;

E) Put the three-necked flask in the above step D) into an oil bath, raise the temperature to 40 ^o C, stir for 1~2 hours, then continue to heat up to 90 ^o C, stir for 1~2 hours, continue to stir and according to the volume ratio Add a mixed solution of 30wt% hydrogen peroxide and deionized water at a ratio of 1:7, continue to stir for 6 to 8 hours, cool down, filter with suction, wash twice with 4mL of dilute hydrochloric acid with a mass fraction of 10% and deionized water, and centrifuge. After drying, graphene oxide with uniform size was obtained.

The method first prepares pre-oxidized graphene oxide through the action of graphite and oxidizing agent, increases the oxidation degree of graphite powder, and then continues to further oxidize the obtained pre-oxidized graphene oxide to prepare graphene oxide with uniform size . The method is simple to operate, has a high degree of oxidation, is environmentally friendly, and the prepared graphene oxide has a uniform size.

detailed description

Embodiment 1 takes the following steps:

A) React 2g of graphite powder with 3g of potassium dithionate, 3g of phosphorus pentoxide and 12mL of concentrated sulfuric acid in a reactor, stir for 4 hours in a water bath at 80 ^o C until a dark blue solution is formed, cool, Obtain pre-oxidized graphite after suction filtration and drying;

B) Take 2 g of graphite oxide prepared in step A) in a three-necked flask, add 25 g of potassium permanganate gradually with 150 mL of concentrated sulfuric acid solution under the condition of an ice-water bath, and stir for 2 hours;

C) Transfer the three-necked flask in the above step B) into an oil bath, heat up to 35 ^o C, stir for 2 hours, continue stirring and add a mixed solution of 30wt% hydrogen peroxide and deionized water according to the volume ratio of 1:15; Suction filtration, washed once with 4 mL of dilute hydrochloric acid with a mass fraction of 10% and deionized water, centrifuged, and dried to obtain the first oxidized graphene oxide;

D) Mix 2 g of graphene oxide prepared in step C) with 50 mL of concentrated sulfuric acid solution in a three-necked flask again under the condition of an ice-water bath, gradually add 8 g of KMnO ₄ , and stir for 1 hour;

E) Put the three-necked flask in the above step D) into an oil bath, raise the temperature to 40 ^o C, stir for 1 hour, then continue to heat up to 90 ^o C, after stirring for 1 hour, continue to stir and follow the volume ratio of 1:7 Add a mixed solution of 30wt% hydrogen peroxide and deionized water, continue to stir for 6 hours, cool down, filter with suction, wash twice with 4mL of dilute hydrochloric acid with a mass fraction of 10% and deionized water, centrifuge, and dry to obtain a uniform size. Graphene oxide.

Embodiment 2 takes the following steps:

A) React 3g of graphite powder with 4.5g of potassium dithionate, 4.5g of phosphorus pentoxide and 18mL of concentrated sulfuric acid in the reactor, and stir for 5 hours under 80 ^o C water bath conditions until a dark blue solution is formed. Obtain pre-oxidized graphite after cooling, suction filtration and drying;

B) Take 3g of the prepared graphite oxide in step A) in a three-necked flask, add 40g of potassium permanganate gradually with 250mL of concentrated sulfuric acid solution under the condition of an ice-water bath, and stir for 3 hours;

C) Transfer the three-necked flask in the above step B) to an oil bath, heat up to 37 ^o C, stir for 1 hour, continue stirring and add a mixed solution of 30wt% hydrogen peroxide and deionized water according to the volume ratio of 1:15; Suction filtration, washed once with 4 mL of dilute hydrochloric acid with a mass fraction of 10% and deionized water, centrifuged, and dried to obtain the first oxidized graphene oxide;

D) Mix 3 g of graphene oxide prepared in step C) with 75 mL of concentrated sulfuric acid solution in a three-necked flask again under the condition of an ice-water bath, gradually add 12 g of KMnO ₄ , and stir for 1.5 hours;

E) Put the three-necked flask in the above step D) into an oil bath, heat up to 40 ^o C, stir for 1.5 hours, then continue to heat up to 90 ^o C, stir for 1.5 hours, continue stirring and according to the volume ratio of 1:7 Add a mixed solution of 30wt% hydrogen peroxide and deionized water, continue to stir for 7 hours, cool down, filter with suction, wash twice with 4mL of dilute hydrochloric acid with a mass fraction of 10% and deionized water, centrifuge, and dry to obtain a uniform size Graphene oxide.

Embodiment 3 takes the following steps:

A) React 4g of graphite powder with 6g of potassium dithionate, 6g of phosphorus pentoxide and 24mL of concentrated sulfuric acid in the reactor, and stir for 6 hours at 80 ^° C in a water bath until a dark blue solution is formed, cool, Obtain pre-oxidized graphite after suction filtration and drying;

B) Take 4g of the prepared graphite oxide in step A) in a three-necked flask, add 50g of potassium permanganate gradually with 300mL of concentrated sulfuric acid solution under the condition of an ice-water bath, and stir for 4 hours;

C) Transfer the three-necked flask in the above step B) to an oil bath, heat up to 40 ^o C, stir for 0.5 hours, continue stirring and add a mixed solution of 30wt% hydrogen peroxide and deionized water according to the volume ratio of 1:15; Suction filtration, washed once with 4 mL of dilute hydrochloric acid with a mass fraction of 10% and deionized water, centrifuged, and dried to obtain the first oxidized graphene oxide;

D) Mix 4 g of graphene oxide prepared in step C) with 100 mL of concentrated sulfuric acid solution in a three-necked flask again under the condition of an ice-water bath, gradually add 8 to 16 g of KMnO ₄ , and stir for 2 hours;

E) Put the three-necked flask in the above step D) into an oil bath, raise the temperature to 40 ^o C, stir for 2 hours, then continue to heat up to 90 ^o C, after stirring for 2 hours, continue to stir and follow the volume ratio of 1:7 Add a mixed solution of 30wt% hydrogen peroxide and deionized water, continue to stir for 8 hours, cool down, filter with suction, wash twice with 4mL of dilute hydrochloric acid with a mass fraction of 10% and deionized water, centrifuge, and dry to obtain a uniform size. Graphene oxide.

The protection scope of the present invention is not limited to the above several embodiments, therefore, any technical solution formed by simple numerical replacement etc. constitutes a specific embodiment of the present invention and forms the protection scope of the present invention.

Claims (1)

1. a method for preparing graphene oxide with uniform size, characterized in that it takes the following steps: A) React 2~4g of graphite powder with 3~6g of potassium dithionate, 3~6g of phosphorus pentoxide and 12~ ^24mL of concentrated sulfuric acid in the reactor, and stir for 4~6 Hour, to form dark blue solution, obtain pre-oxidized graphite after cooling, suction filtration, drying; B) Take 2~4g of graphite oxide prepared in step A) in a three-necked flask, add 25~50g of potassium permanganate gradually under the condition of an ice-water bath with 150~300mL of concentrated sulfuric acid solution, and stir for 2~4 Hour; C) Put the three-necked flask in the above step B) into an oil bath, raise the temperature to 35~40 ^o C, stir for 0.5~2 hours, continue stirring and add 30wt% hydrogen peroxide and deionized water according to the volume ratio of 1:15 The mixed solution; suction filtration, washed once with 4 mL of dilute hydrochloric acid and deionized water with a mass fraction of 10%, centrifuged, and dried to obtain the first oxidized graphene oxide; D) Mix 2~4g of graphene oxide prepared in step C) with 50~100mL of concentrated sulfuric acid solution in the three-necked flask again under the condition of ice-water bath, gradually add 8~16g of KMnO ₄ , stir for 1~2 Hour; E) Put the three-necked flask in the above step D) into an oil bath, raise the temperature to 40 ^o C, stir for 1~2 hours, then continue to heat up to 90 ^o C, stir for 1~2 hours, continue to stir and according to the volume ratio Add a mixed solution of 30wt% hydrogen peroxide and deionized water at a ratio of 1:7, continue to stir for 6 to 8 hours, cool down, filter with suction, wash twice with 4mL of dilute hydrochloric acid with a mass fraction of 10% and deionized water, and centrifuge. After drying, graphene oxide with uniform size was obtained.