WO2016175484A1

WO2016175484A1 - Method for increasing reactivity of two-dimensional material having layered structure and method for preparing graphene oxide by means of same

Info

Publication number: WO2016175484A1
Application number: PCT/KR2016/003931
Authority: WO
Inventors: 양우석; 박원규
Original assignee: 전자부품연구원
Priority date: 2015-04-27
Filing date: 2016-04-15
Publication date: 2016-11-03
Also published as: KR20160127885A

Abstract

Disclosed is a method for increasing the reactivity of a two-dimensional material having a layered structure and a method for preparing graphene oxide by means of same, the method in which a product, for which quality controlling is possible, can be obtained in a short time. A method for increasing the reactivity of an environment-friendly two-dimensional material having a layered structure, according to an embodiment of the present invention, is a method for increasing the reactivity of a two-dimensional material by means of applying stress to a two-dimensional material having a layered structure and comprises a stress applying step for applying pressure to an end portion of a first layer of a two-dimensional material and an end portion of a second layer that is adjacent to the first layer, thereby enabling the distance between the end portions of the first layer and second layer to be greater than an average interlayer distance.

Description

Method for increasing the reactivity of a two-dimensional layer of a layered structure and a method for producing graphene oxide using the same

The present invention relates to a method for increasing the reactivity of a two-dimensional material of the layered structure and a method for producing graphene oxide using the same, and more particularly, to increase the reactivity of the two-dimensional material of the layered structure to obtain a product capable of quality control in a short time It relates to a method and a method for producing graphene oxide using the same.

Graphite has a structure in which graphene, a plate-shaped two-dimensional sheet in which carbon atoms are formed in a hexagonal shape, is stacked. Graphite has the advantages of excellent electrical strength and thermal conductivity, excellent mechanical strength, high elasticity, high transparency, energy storage materials such as secondary batteries, fuel cells, supercapacitors, filtration membranes, chemical detectors, transparent electrodes, etc. It can be used in a variety of applications such as.

Graphene, which is produced by oxidizing graphite, separating it into several layers, and then reducing it, also has excellent physical properties such as high thermal conductivity, high current transfer capability, and excellent rigidity, so that nanoscale electric and electronic devices and nanosensors It is evaluated to be applied to various fields such as optoelectronic devices and high performance composite materials.

Graphene can generally be produced through chemical vapor deposition (CVD), chemical synthesis (oxidation / reduction of graphite) and the like. Since the announcement that it is possible to produce graphene by the mechanical peeling method known as the Scotch tape method, many technologies have been researched and developed.

Among these methods, a chemical synthesis method capable of producing a graphene at a relatively low cost as well as mass production by a top-down method is known as the most realistic and convenient method.

In the chemical synthesis method, graphite is oxidized with strong acid, dispersed and exfoliated with graphene oxide (GO), and then GO is reduced by heat treatment to reduce graphene oxide (rGO). ) In other words, graphene oxide is a raw material of graphene, which is a key starting material for the graphene-based industry.

However, in the traditional method of preparing graphene oxide using a chemical synthesis method as described above (known as the Hummer's method, Hummer's method), the interlayer chemical reaction is induced because the interlayer distance of graphite is very narrow at 0.34 nm. It takes a long time (about 2 to 5 days) to manufacture a competitive graphene oxide is practically difficult.

In order to shorten the manufacturing time, a method of adjusting the reaction rate through strong acid and temperature control has been proposed, but in this case, an environmental problem caused by an increase in waste acid solution and a cost for treating them have increased.

This problem is because, in the case of an interlayer compound such as graphite, since the distance between layers is very narrow, it is difficult to insert the reactant for reaction between layers. Is requested.

The present invention has been made to solve the above problems, an object of the present invention, a method for increasing the reactivity of the layered two-dimensional material to obtain a product capable of quality control in a short time and the production of graphene oxide using the same In providing a method.

According to an aspect of the present invention, a method of increasing the reactivity of a two-dimensional material having a layered structure is a method of increasing the reactivity of the two-dimensional material by applying stress to the two-dimensional material having a layered structure. Stressing an end portion and an end portion of the second layer adjacent to the first layer such that the interlayer distance at the ends of the first layer and the second layer is greater than the average interlayer distance.

The increase in reactivity may be due to an increase in the interlaminar penetration rate of the reactant with the two-dimensional material due to the increase of the interlayer distance at the end.

Stress can be imparted by applying two or more different flows of fluid to two-dimensional materials.

In addition, stress can be imparted to a two-dimensional material by applying a first fluid flow and a double fluid flow having a second fluid flow, which is a fluid flow in a direction different from the first fluid flow.

The dual fluid flow may be a vortex in a ring pair arrangement or may be a Taylor Vortex.

Taylor vortices can be generated in a Couet-Taylor reactor that includes fluid with a rotation of at least one of the inner cylinder and the inner cylinder, including inner cylinders and inner cylinders having the same center and different diameters.

Polar solvents may be added to the Kuet-Taylor reactor, which may be water, acetone, chloroform, isopropanol, cyclohexanone, N-methyl pyrrolidone, N, N-thimethylacetamide, dimethylformamide, or ethanol. , Methanol, hexane and toluene.

Further water may be introduced through the inlet at a different position from the inlet into which the polar solvent is introduced. In addition, ultrasonic waves may also be applied to the Kuet-Taylor reactor.

When stress is applied to a two-dimensional material having a layered structure, vortices may also form inside the layered structure.

Vortex inside the layered structure may be formed by applying a bubble inside the layered structure.

The two-dimensional material having a layered structure may be at least one of graphite, graphite oxide, hexagonal boron nitride (hBN) and transition metal chalcogenide, and the transition metal chalcogenide may be tungsten sulfide (WS ₂ ) and molybdenum sulfide. It may be at least one of (MoS ₂ ).

According to another aspect of the present invention, graphite oxide is introduced into a Kuet-Taylor reactor in which Taylor vortex is formed to stress the end of the first layer of graphite oxide and the end of the second layer adjacent to the first layer, thereby providing a first There is provided a method for producing graphene oxide comprising the step of peeling with graphene oxide so that the interlayer distance at the end of the layer and the second layer is greater than the average interlayer distance. Here, the exfoliated graphene oxide has an average size of 100 nm to 100 μm, and may have a 1 to 10 layer structure.

As described above, according to the embodiments of the present invention, it is possible to increase the reactivity of the two-dimensional material having a layered structure to significantly shorten the reaction time.

According to the present invention, when the reactivity of a two-dimensional material having a layered structure is increased by using the Cuet-Taylor reactor, the mass production process can be performed, and the continuous process is possible, thereby reducing the process cost and reducing the process time. Due to this, the amount of reactant and sewage waste water can be minimized, which is advantageous in terms of cost savings and environmentally beneficial effects.

In addition, it is possible to control the size and number of layers of the monolayer material generated by adding a polar solvent and an ultrasonic process, thereby obtaining a product of a desired quality.

In addition, when the graphene oxide is prepared from graphite oxide using the method for increasing reactivity according to the present invention, there is an effect of obtaining a homogeneous size of graphene oxide with a large area in a short time.

1 is a view schematically illustrating stressing a two-dimensional material having a layered structure according to an embodiment of the present invention.

FIG. 2 is a view showing penetration of a reactant into a two-dimensional material having a layered structure before stress is applied, and FIG. 3 is a view showing penetration of a reactant into a two-dimensional material having a layered structure after stress is applied. One drawing.

4 is a diagram illustrating a Kuet-Taylor reactor for stressing a two-dimensional material having a layered structure according to another embodiment of the present invention.

FIG. 5 is a diagram schematically illustrating a fluid flow in the Kuet-Taylor reactor of FIG. 4.

FIG. 6 illustrates a Queet-Taylor reactor in accordance with another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art. In the accompanying drawings, there may be a component having a specific pattern or having a predetermined thickness, but this is for convenience of description or distinction. It is not limited only.

1 is a view schematically showing stressing a two-dimensional material having a layered structure according to an embodiment of the present invention, Figure 2 is a reaction material to the two-dimensional material having a layered structure before the stress is applied 3 is a diagram illustrating penetration, and FIG. 3 is a diagram illustrating penetration of a reactant into a two-dimensional material having a layered structure after stress is applied.

The method of increasing the reactivity of a layered two-dimensional material according to the present invention is a method of increasing the reactivity in a layered material, wherein the layered two-dimensional material is graphite, graphite oxide, hexagonal boron nitride ( hBN) and the transition metal chalcogenide compound.

Transition Metal Dichalcogenides (TMDs) are compounds composed of at least one Group 16 (chalcogen) element and at least one electropositive element. Examples of chalcogen elements include S, Se, and Te. Examples of positive electrode elements include Ti, Hf, Zr, V, Nb, Ta, Mo, W, Tc, Re, Pd, and Pt. have. The transition metal chalcogenide compound is a two-dimensional material having a layered structure and having a layered structure that can be separated into a single layer. The transition metal chalcogen compound is a structure in which a single layer is surrounded by a chalcogen atom layer on both sides, and three atomic layers constitute a single layer and show semiconductor characteristics. It is a material.

The transition metal chalcogen compound may be, for example, at least one of tungsten sulfide (WS2) and molybdenum sulfide (MoS2).

Referring to FIG. 1, a two-dimensional material having a layered structure is composed of several layers. The layered structure is formed when the bonding force between molecules and atoms in the layer and the bonding force between layers are different. The two-dimensional material having a layered structure may be used for various purposes, but may be used as such, but may be used by inserting another compound between layers, or by converting it into another material by reacting it with a reactant such as an oxidizing agent or a reducing agent. Alternatively, the layered structure may be broken and the layered structure may be used by peeling a plurality of layered layers into flakes having layers of 1 to 10 layers.

The method for increasing the reactivity of a two-dimensional material of a layered structure according to the present invention increases the reactivity of the two-dimensional material by stressing the two-dimensional material having a layered structure. To this end, it is possible to stress the end of the two-dimensional material having a layered structure. Referring to FIG. 1, one of several layers of a two-dimensional material 100 having a layered structure is called a first layer 110, and a layer adjacent to the first layer 110 is referred to as a second layer 120. Let's say When stress S is applied to the ends of the first layer 110 and the second layer 120, the interlayer distance d2 at the ends of the first layer 110 and the second layer 120 is the average interlayer distance. It becomes larger than (d1).

Accordingly, the interlayer penetration rate of the two-dimensional material 100 having the layered structure and the reactant may increase due to the increase in the interlayer distance d2 between the ends. In FIG. 2, the penetration rate of the reactant 230 to penetrate between the first layer 210 and the second layer 220 of the two-dimensional material having the layered structure without stress is the layered structure in FIG. 3. The penetration rate of the reactant 330 to penetrate between the first layer 310 and the second layer 320 of the two-dimensional material having a layered structure after stress is applied to the two-dimensional material is inevitably smaller. This is because the interlayer distance between the first layer 310 and the second layer 320 is widened in FIG. 3, so that the reactant 330 easily penetrates.

In order to increase the reactivity of the layered two-dimensional material, stress can be applied, which stress can be applied by applying two or more different directions of fluid flow to the layered two-dimensional material. In the case of applying the fluid flow in one direction, since the two-dimensional material having a layered structure moves together with the flow of the fluid, no stress is applied, and stress is applied only when two or more fluid flows flowing in different directions exist. .

In particular, in order to increase the reactivity of the two-dimensional material having a layered structure, stress is applied to the two-dimensional material by applying a double fluid flow having a first fluid flow and a second fluid flow which is a fluid flow in a direction different from that of the first fluid flow. Can be given. FIG. 4 illustrates a Kuet-Taylor reactor for stressing a two-dimensional material having a layered structure in accordance with the present invention, and FIG. 5 schematically illustrates the fluid flow in the Kuet-Taylor reactor of FIG. One drawing.

The Couette-Taylor reactor 400 is a device that uses a spiral vortex called Taylor vortex. The inner cylinder 410 rotates when the fluid flows between two cylinders having the same center. Fluid flows in the direction of rotation. At this time, the fluid present in the inner cylinder 410 by the centrifugal force and Coriolis force (force) to the direction of the outer cylinder 420 is generated, and as the rotational speed increases gradually becomes unstable and regular along the axial direction And vortices of ring pair arrays rotating in opposite directions are formed. This helical vortex imparts shear stress to the layered two-dimensional material, which stresses parallel to each layer of the layered two-dimensional material, making each layer open more easily. Since the reactants can easily penetrate through the gaps as shown in FIG. 3, each layer of the two-dimensional material having a layered structure can easily react.

When a dispersion in which a two-dimensional material having a layered structure is dispersed is introduced into the inlet In in the Kuet-Taylor reactor 400, the dispersion flows in a different direction from the first fluid flow 431 according to the rotation of the inner cylinder 410. The second fluid flow 432 is formed so that the double fluid flow 430 is applied to the two-dimensional material having a layered structure. Accordingly, the two-dimensional material having a layered structure increases reactivity, reacts with the reactants, or collapses the layered structure to be converted into a smaller number of layers and discharged to the outlet.

In more detail, the dual fluid flow 430 may be a vortex 530 of a ring pair array, as shown in FIG. 5, which is called Taylor Vortex. The flow direction of the first fluid flow 531 and the flow direction of the second fluid flow 532 formed between the inner cylinder 510 and the outer cylinder 520 are different from each other, and thereby the reactivity of the two-dimensional material having a layered structure. This is to be increased.

FIG. 6 illustrates a Queet-Taylor reactor in accordance with another embodiment of the present invention. When stress is applied to a two-dimensional material having a two-dimensional water layer structure having a layered structure, vortices may be formed inside the layered structure. Vortex inside the layered structure may be formed by applying a bubble inside the layered structure.

To this end, a polar solvent may be added to the Kuet-Taylor reactor 600. The polar solvent may be at least one of water, acetone, chloroform, isopropanol, cyclohexanone, N-methyl pyrrolidone, N, N-thimethylacetamide, dimethylformamide, ethanol, methanol, hexane and toluene.

Water or intercalation material may be further introduced through the inlet 640 at a location different from that of the polar solvent. Intercalants include K, Cs, NaK ₂ , K / THF, CIF ₃ , ICI, IBr, FeCl ₃ , Li / Pc, N-butyl lithium, H ₂ SO ₄ , eutectic salt, CSA, H ₂ O ₂ or an ionic liquid. Accordingly, the polar solvent and the additionally introduced water or intercalation material generate bubbles between the layers of the two-dimensional material having a layered structure, and the bubbles can be further opened between the layers, so that a state similar to that in which additional stress is applied is generated. Can further increase the reactivity.

In addition, the tip sonicator 650 may be further positioned so that ultrasonic waves may also be applied to the Kuet-taylor reactor 600. In the case of applying the ultrasonic wave, a product having a more homogeneous size can be obtained when the two-dimensional material having a layered structure is peeled off.

According to another aspect of the present invention, graphite oxide is introduced into a Kuet-Taylor reactor in which Taylor vortex is formed to stress the end of the first layer of graphite oxide and the end of the second layer adjacent to the first layer, thereby providing a first There is provided a graphene oxide manufacturing method comprising the step of peeling the graphene oxide so that the interlayer distance at the end of the layer and the second layer is greater than the average interlayer distance. This embodiment is a method of manufacturing graphene oxide by peeling graphite oxide, by applying stress to the graphite oxide, a two-dimensional material having the above-described layered structure to increase the graphite oxide interlayer distance, and eventually to be peeled off with graphene oxide do. Since the detailed stress applying method is as described above, a description thereof will be omitted.

Conventionally, graphene oxide is exfoliated from graphite oxide using an ultrasonic wave or a chemical substance. In this case, it is difficult to obtain graphene oxide with a large area due to the force applied to the entire surface of the graphite oxide due to the ultrasonic wave. In particular, large area graphene oxide of 10 µm or more could not be obtained. According to the production method as in the present invention, since a stress is applied to the end of the layer of graphite oxide, a larger area of graphene oxide can be obtained. Here, the exfoliated graphene oxide may have a large area as compared with a 1-10 layer structure having an average size of 100 nm to 100 μm.

As described above, in the present invention, the graphite oxide may be separated into graphene oxide by using a Kuet-Taylor reactor, and when ultrasonic waves are additionally applied by using the tip sonicator 650 as shown in FIG. Since the size of the area of graphene oxide can be controlled, it is possible to obtain a large-area graphene oxide of uniform size.

When the graphite is oxidized and the graphite oxide obtained therefrom is peeled off to prepare graphene oxide, graphene oxide may be obtained by using a method of increasing the reactivity of a two-dimensional material having a layered structure according to the present invention. That is, when oxidizing the graphite, it is possible to stress the end of the layers to increase the reactivity with the oxidizing agent, thereby obtaining the graphite oxide in a short time. In addition, stress may be applied to the ends of the layers of the obtained graphite oxide to exfoliate it to obtain graphene oxide. When stressing is performed through the Kuet-Taylor reactor, the two Kuet-Taylor reactors are connected to each other, and then graphite is added together with the oxidant to the first Kuet-Taylor reactor, and when the graphite is oxidized, the oxide is A large area of homogeneous graphene oxide can be obtained in a short time from graphite by being put into a Cuet-Taylor reactor.

While the above has been shown and described with respect to preferred embodiments of the present invention, the present invention is not limited to the specific embodiments described above, it is usually in the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

Claims

As a method of increasing the reactivity of the two-dimensional material by applying stress to the two-dimensional material having a layered structure,

Stressing the end of the first layer of the two-dimensional material and the end of the second layer adjacent to the first layer such that the interlayer distance at the ends of the first layer and the second layer is greater than the average interlayer distance. Stressing step; increase the reactivity of the two-dimensional material of the layered structure comprising a.
The method of claim 1,

The increase in reactivity is

The method of increasing the reactivity of the two-dimensional material of the layered structure, which increases the interlayer penetration rate of the reactant material with the two-dimensional material by increasing the interlayer distance at the end.
The method of claim 1,

The stress is

The method of increasing the reactivity of the two-dimensional material of the layered structure that is given by applying a fluid flow in two or more different directions to the two-dimensional material.
The method of claim 1,

The stress is

And applying a double fluid flow having a first fluid flow and a second fluid flow having a second fluid flow in a direction different from the first fluid flow to the two-dimensional material.
The method of claim 4, wherein

The double fluid flow, Taylor Vortex (Taylor Vortex) is a method of increasing the reactivity of the layered two-dimensional material.
The method of claim 5,

The taylor vortex,

A two-dimensional layered structure of a layered structure, including an inner cylinder and an inner cylinder having the same center and having a diameter, which is generated in a Kuet-Taylor reactor that flows fluid upon rotation of at least one of the inner cylinder and the inner cylinder How to increase the reactivity of a substance.
The method of claim 6,

A method of increasing the reactivity of a two-dimensional material of a layered structure, characterized in that the polar solvent is introduced into the Kuet-Taylor reactor.
The method of claim 7, wherein

The polar solvent is at least one of water, acetone, chloroform, isopropanol, cyclohexanone, N-methyl pyrrolidone, N, N- dimethylacetamide, dimethylformamide, ethanol, methanol, hexane and toluene Method for increasing the reactivity of the two-dimensional material of the layered structure.
The method of claim 7, wherein

Method for increasing the reactivity of the two-dimensional material of the layered structure, characterized in that the water or the intercalation material is introduced through the inlet of the position different from the inlet in which the polar solvent is introduced.
The method of claim 7, wherein

The method of increasing the reactivity of the two-dimensional material of the layered structure, characterized in that the ultrasonic applied to the Kuet-Taylor reactor.
The method of claim 1,

Method for increasing the reactivity of the two-dimensional material of the layered structure, characterized in that the vortex is formed inside the layered structure.
The method of claim 1,

The two-dimensional material having the layered structure,

A method of increasing the reactivity of a layered two-dimensional material of at least one of graphite, graphite oxide, hexagonal boron nitride (hBN) and transition metal chalcogenide.
Graphite oxide is introduced into a Kuet-Taylor reactor in which Taylor vortex is formed, and stress is applied to the end of the first layer of graphite oxide and the end of the second layer adjacent to the first layer, thereby providing the first layer and the second layer. A step of peeling with graphene oxide so that the interlayer distance at the end of the layer is greater than the average interlayer distance; Graphene oxide manufacturing method comprising a.
The method of claim 13,

The exfoliated graphene oxide is a graphene oxide production method, characterized in that the average size of 100 nm to 100 ㎛.
The method of claim 13,

The exfoliated graphene oxide is a graphene oxide manufacturing method, characterized in that 1 to 10 layer structure.