KR101563895B1 - Manufacturing method of graphene oxide nanopowder - Google Patents

Abstract

The present invention relates to a method for producing graphene nanopowder.
According to the present invention, by using a ball mill process and introducing a solvent including a carbonate and a hydroxyl group together with graphite powder in the ball mill process, a large amount of oxygen functional groups are introduced and the interlayer spacing becomes wide, Unlike the conventional method of producing graphene oxide, which is known as a graphene nano powder produced by the method of manufacturing a large amount of phosphorus nano powder and the graphene nano powder produced by the above manufacturing method, It is possible to manufacture graphene oxide by a simple method using a ball mill process and it is also economically advantageous since an additional process such as pickling is unnecessary. In addition, in the ball milling process, a large amount of oxygen functional groups are introduced by introducing a solvent including a carbonate and a hydroxyl group together with graphite, and a large amount of graphene powder having a nano-sized particle size can be produced.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for producing graphene nanopowder,

The present invention relates to a method for producing graphene nanopowder, and more particularly, to a method for manufacturing graphene nanopowder, which utilizes a ball milling process completely different from a conventional chemical stripping process, and a solvent including a carbonate and a hydroxyl group, The present invention relates to a method for mass-producing graphene nanoparticles having a nano-sized grain size with a large amount of functional groups introduced therebetween and a large gap between layers.

Graphene is a hexagonal, single-layer, two-dimensional structure composed of sp ² -bonding carbon atoms. Graphene, a complex of carbon atoms with a planar structure, is known to have a thickness of only 0.3 nm, which is only one carbon atom. Graphene has useful properties very different from other carbon isotopes such as carbon nanotubes and graphite. The most remarkable feature is that the electron movement speed is close to the speed of light and that it has an abnormal semi-integer quantum Hall effect on electrons and holes. In addition, the excellent properties of Graphene have been announced, including high electron mobility, high mechanical strength, electrical conductivity and optical transparency. In recent years, graphene production methods have been actively studied due to their excellent physical properties. Typical manufacturing methods of graphene include mechanical peeling, chemical manufacturing, and injection of a hydrocarbon-based gas onto a metal substrate, A chemical vapor deposition method is known. The mechanical peeling method is difficult to be applied commercially in various fields or a method of separating graphene using a separation method using an ultrasonic wave or a silicon structure. The chemical method is a method of synthesizing graphene through oxidation and reduction of graphite by a chemical method. It is necessary to use many chemicals in the process which is easiest to mass-produce or the process, and the process is also complicated and it is difficult to be applied commercially. Finally, it has been found that the chemical vapor deposition method solves the disadvantages of the conventional graphene manufacturing method and can be grown to a large area. However, the problem of additional formation of graphene side reaction oxides due to the dominant side reactions can not be solved, and the manufacturing process of the metal substrate is incidentally required, which requires an expensive process, low mass production efficiency and reproducibility This remains a drawback.

On the other hand, Korean Patent Laid-Open No. 10-2013-0105149 (a method for producing reduced graphene oxide) is known as a related art.

The present inventors have found that when a ball milling process is used in the production of graphene nanopowder, when a solvent containing a carbonate and a hydroxyl group is added together with graphite powder during the ball milling process, the grain size is greatly improved finally and uniform nano- The present invention has been completed by experimentally confirming that it is economically advantageous in comparison with conventional chemical exfoliation methods and owing to omission of additional processes and the like.

As a result, the object of the present invention is to utilize a ball mill process and introduce a carbonate and a hydroxyl group-containing solvent together with graphite powder in the ball mill process, thereby introducing a large amount of oxygen functional groups and increasing interlayer spacing. And a method for mass-producing fin nanopowder.

Another object of the present invention is to provide graphene nanopowder produced by the above-mentioned method.

In order to achieve the above object, the present invention provides a process for producing a carbon black powder, comprising the steps of: (1) mixing a solvent containing graphite powder, a carbonate and a hydroxyl group, followed by ball milling; and (2) (3) drying the graphene oxide prepared in the step (2); and (4) drying the graphene oxide prepared in the step (2). And (4) heat-treating the graphene oxide prepared in the step (3) in a reducing gas atmosphere.

In the step (1), the carbonate is mixed at 2 to 10 times the weight of the graphite powder.

In step (1), at least one carbonate selected from the group consisting of sodium hydrogencarbonate, ammonium hydrogencarbonate, sodium carbonate, ammonium carbonate, potassium carbonate, calcium carbonate and barium carbonate and distilled water, ethanol, methanol, And a solvent containing one or more kinds of hydroxyl groups selected from the group consisting of glycerin.

And then heat-treated at 300 to 2000 ° C for 1 to 6 hours in the step (4).

The present invention also provides graphene nanopowder produced by the above-described method.

According to the present invention, by using a ball mill process and introducing a solvent including a carbonate and a hydroxyl group together with graphite powder in the ball mill process, a large amount of oxygen functional groups are introduced and the interlayer spacing becomes wide, Unlike the conventional method of producing graphene oxide, which is known as a graphene nano powder produced by the method of manufacturing a large amount of phosphorus nano powder and the graphene nano powder produced by the above manufacturing method, It is possible to manufacture graphene oxide by a simple method using a ball mill process and it is also economically advantageous since an additional process such as pickling is unnecessary. In addition, a large amount of oxygen functional groups are introduced by introducing a solvent containing a carbonate and a hydroxyl group together with graphite in a ball mill process, and a large amount of graphene nano powder having a nano-sized grain size can be produced .

FIG. 1 is a graph showing particle size analysis of graphene nanopowder prepared by wet ball mill pulverization in the present invention.

Hereinafter, the present invention will be described in detail.

The present invention relates to a process for producing a magnetic powder, comprising the steps of (1) mixing a solvent containing graphite powder, a carbonate and a hydroxyl group, followed by ball milling, and (2) a solvent containing unreacted carbonate and unreacted hydroxyl groups after ball milling by the above step (1) (3) drying the graphene oxide prepared in the step (2); And (4) heat-treating the graphene oxide produced by the step (3) in a reducing gas atmosphere, and a graphene nanopowder produced by the manufacturing method .

The graphite powder used in the step (1) is obtained by crushing the size of the graphite flake (graphite flake) in a small size using a general crusher, and then pulverizing the particles filtered with a 50 mu m sieve using a wet ball mill crushing aid It is used for the production of graphene oxide. In this process, the smaller the particle size, the more efficient the physical and chemical functionalization of the graphite powder, thereby reducing the number of cycles of the ball milling process required in the wet ball mill grinding aid, thereby minimizing the time and cost consumption.

In the step (1), the process of simultaneously introducing the graphite powder, the carbonate and the hydroxyl group-enriched solvent (one or more selected from the group consisting of distilled water, ethanol, methanol, ethylene glycol and glycerin) As a method for maximizing the chemical functionalization reaction occurring in the process of manufacturing the graphene oxide, the area of contact with balls or beads into which the graphene oxide produced in the process of manufacturing is widened is widened as compared with the dry manufacturing method. It is effective in increasing the homogeneity of the graphene oxide nano powder and the particle size distribution can be made compact. This is possible because graphene oxide produced does not react to the solvents listed above. In addition, the introduced carbonates can provide carbon dioxide gas in addition to the physical peeling reaction occurring in the ball mill process, and thus it is possible to introduce a large amount of oxygen functional groups into the crushed graphite at the stage of producing graphene oxide. Such a carbonate may be selected from one or two or more selected from sodium hydrogen carbonate, ammonium hydrogen carbonate, sodium carbonate, ammonium carbonate, potassium carbonate, calcium carbonate, and barium carbonate. .

In addition, the kind and size of the ball and bead used in the step of preparing the graphene oxide using the wet ball mill pulverizing aid performed in the step (1) do not matter, but the material of the ball and bea and the jar should be unified. In addition, this process can not avoid the generation of abrasive particles due to abrasion of each ball and bead due to the strong physical collision which is necessarily accompanied by the ball mill process. For this reason, in the case of a commonly used SUS ball or SUS bead, an additional acid treatment process for removing SUS fine particles is necessarily required due to wear or wear of the SUS material or generation of separated particles. However, in the present invention, by using zirconia balls, beads and Jar suitable for pulverizing graphite powder, worn fine particles of zirconia generated by simple centrifugal separation can be easily removed. The size of the ball and the bead to be used is preferably 1 to 20 mm in a mixture of one kind or two or more kinds, and the amount of the ball and the bead is preferably used so as to be about 2/3 of the used container.

The ball mill used in the step (1) may be one of a jet mill ball mill, a vibrating ball mill, and a planetary ball mill. The ball mill may have a rpm of 100 To 500% by weight.

In the step of reducing graphene oxide in the high-temperature furnace in the step (4), the heat treatment temperature during reduction is in the range of 1 to 6 at an annealing temperature of 300 to 2000 ° C. in an inert atmosphere containing 1 to 10 wt. And then reducing the graphene oxide with graphene.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these examples are for illustrative purposes only and that the scope of the present invention is not construed as being limited by these examples.

Example 1 .

0.5 g of flaky graphite powder pulverized to 50 m or less and 5 g of sodium hydrogencarbonate were put into a zirconia kneader, and 70% of a ball having a diameter of 5 mm and the remaining 30% were prepared with a ball having a diameter of 10 mm, (The material of the ball used is unified with zirconia), and at the same time, ethylene glycol is added to the extent that the balls are locked. The ball mill reaction was carried out for 24 h at a rate of 300 rpm for 1 h. After the ball mill reaction, unreacted sodium hydrogencarbonate and ethylene glycol were washed with distilled water and the worn zirconia particles were removed using a centrifuge. The graphene oxide was then prepared by thoroughly drying at 160 DEG C for 24 hours using a filter and a vacuum oven.

In the next step, the prepared graphene oxide was heated to 1200 DEG C at a heating rate of 1 DEG C / min in an argon gas atmosphere containing 10% hydrogen gas using a tubular furnace, and then heat-treated for 5 hours, To prepare a reduced graphene nano powder.

Example 2.

0.5 g of platelet-shaped graphite powder pulverized to 50 탆 or less and 3 g of sodium hydrogencarbonate were put into a zirconia kneader, and 70% of a ball having a diameter of 5 mm and the remaining 30% were prepared with a ball having a diameter of 10 mm. (The material of the ball used is unified with zirconia), and at the same time, ethylene glycol is added to the extent that the balls are locked. The ball mill reaction was carried out for 24 h at a rate of 400 rpm for 1 h. After the ball mill reaction, unreacted sodium hydrogencarbonate and ethylene glycol were washed with distilled water and the worn zirconia particles were removed using a centrifuge. The graphene oxide was then prepared by thoroughly drying at 160 DEG C for 24 hours using a filter and a vacuum oven.

In the next step, the prepared graphene oxide was heated to 1500 DEG C at a rate of 1 DEG C / min in an argon gas atmosphere containing 5% hydrogen gas using a tubular furnace, and then heat-treated for 3 hours, To prepare a reduced graphene nano powder.

Example 3.

0.5 g of flaky graphite powder pulverized to 50 탆 or less and 5 g of sodium hydrogen carbonate were put into a zirconia kneader and 70% of a ball having a diameter of 3 mm and a remaining 30% thereof were prepared with a ball having a diameter of 10 mm. (The material of the balls used is unified with zirconia), and at the same time, ethylene glycol is added to the extent that the balls are locked. The ball mill reaction was carried out at a speed of 350 rpm for 1h for a total of 24 times. After the ball mill reaction, unreacted sodium hydrogencarbonate and ethylene glycol were washed with distilled water and the worn zirconia particles were removed using a centrifuge. The graphene oxide was then prepared by thoroughly drying at 160 DEG C for 24 hours using a filter and a vacuum oven.

In the next step, the prepared graphene oxide was heated to 1000 ° C at a rate of 1 ° C / min in an argon gas atmosphere containing 10% hydrogen gas using a tube-type furnace, and then heat-treated for 5 hours, To prepare a reduced graphene nano powder.

Example 4.

0.5 g of flaky graphite powder pulverized to 50 탆 or less and 5 g of sodium carbonate were charged into a zirconia sieve and 100% of a ball having a diameter of 5 mm was prepared and filled to a total volume of 2/3 of the sieve Zirconia), and at the same time, the methanol is put into the ball so that the ball is locked. The ball mill reaction was carried out at a speed of 400 rpm for 1h for a total of 24 times. After the ball mill reaction, unreacted sodium hydrogencarbonate and ethylene glycol were washed with distilled water and the worn zirconia particles were removed using a centrifuge. The graphene oxide was then prepared by thoroughly drying at 160 DEG C for 24 hours using a filter and a vacuum oven.

In the next step, the prepared graphene oxide was heated to 900 DEG C at a heating rate of 1 DEG C / min in an argon gas atmosphere containing 10% hydrogen gas using a tubular furnace, and then heat-treated for 5 hours, To prepare a reduced graphene nano powder.

Comparative Example 1

A ball having a diameter of 3 mm and containing the remaining 30% was prepared with a ball having a diameter of 10 mm and filled to a total volume of 2/3 (0.5 g of the graphite powder pulverized to 50 탆 or less (the material of the ball used was zirconia At the same time, ethylene glycol is injected enough to lock the ball. The ball mill reaction was carried out at a speed of 350 rpm for 1h for a total of 24 times. After the ball mill reaction, unreacted sodium hydrogencarbonate and ethylene glycol were washed with distilled water and the worn zirconia particles were removed using a centrifuge. The graphene oxide was then prepared by thoroughly drying at 160 DEG C for 24 hours using a filter and a vacuum oven.

In the next step, the prepared graphene oxide was heated to 1200 DEG C at a heating rate of 1 DEG C / min in an argon gas atmosphere containing 10% hydrogen gas using a tubular furnace, and then heat-treated for 5 hours, To prepare a reduced graphene nano powder.

[Table 1]

Having described specific portions of the present invention in detail, those skilled in the art will appreciate that these specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereby. something to do. Accordingly, the actual scope of the present invention will be defined by the appended claims and their equivalents.

Claims (5)

(1) mixing a solvent containing graphite powder, a carbonate, and a hydroxyl group, followed by ball milling;
(2) preparing graphene oxide by removing the solvent containing unreacted carbonate and unreacted hydroxyl groups after the ball mill treatment in the step (1);
(3) drying the graphene oxide produced by the step (2); And
(4) heat-treating the graphene oxide prepared in the step (3) in a reducing gas atmosphere.
The method according to claim 1,
Wherein the carbonate is mixed at 2 to 10 times the weight of the graphite powder in the step (1).
The method according to claim 1,
In step (1), at least one carbonate selected from the group consisting of sodium hydrogencarbonate, ammonium hydrogencarbonate, sodium carbonate, ammonium carbonate, potassium carbonate, calcium carbonate and barium carbonate and distilled water, ethanol, methanol, Glycerin, and a solvent containing at least one hydroxyl group selected from the group consisting of glycerin.
The method according to claim 1,
Wherein the heat treatment is performed at 300 to 2000 ° C for 1 to 6 hours in the step (4).
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