KR20200131408A - Functional Graphene Fiber and fabricating method of the same - Google Patents

Abstract

A method for producing functional graphene fibers is provided. The method of producing the functional graphene fibers includes the steps of: preparing a source solution in which a graphene oxide sheet is dispersed; spinning the source solution in a coagulation bath containing a coagulant and a functional material including a metal to produce graphene oxide fibers having a surface provided with the functional material; and heat-treating the graphene oxide fibers having a surface provided with the functional material to produce graphene fibers having a surface provided with a functional particle reduced from the functional material.

Description

Functional graphene fiber and its manufacturing method. {Functional Graphene Fiber and fabricating method of the same}

The present invention relates to a functional graphene fiber and a method for manufacturing the same, and more specifically, to a functional graphene fiber for producing graphene fibers through reduction after spinning a source solution in which a graphene oxide sheet is dispersed in a coagulation bath. will be.

Graphene is the most outstanding material among the existing materials with various characteristics such as strength, thermal conductivity, and electron mobility. Accordingly, it is applied to various fields such as displays, secondary batteries, solar cells, automobiles, and lighting, and is recognized as a strategic core material that will drive the growth of related industries, and technology for commercializing graphene is receiving a lot of interest.

In recent years, in order to apply the useful mechanical and electrical properties of graphene to various industrial fields, studies on various processes for obtaining graphene oxide from graphite raw materials have been actively conducted.

For example, in Korean Patent Publication KR20140045851A (application number: KR20120112103A, Co., Ltd.: grapheneol), forming a first reaction product including graphene oxide by oxidizing graphite using an acid, the first reaction product The acid is easily separated from the graphene oxide product within a relatively short time through the steps of recovering the acid from and by oxidizing graphite using the recovered acid to form a recycling reaction product containing graphene oxide. And, a technology for producing graphene oxide that can reduce the disposal rate of toxic process by-products such as acids is disclosed.

In addition, various studies have been conducted on graphene composite fibers with improved mechanical properties and electrical conductivity, as well as process characteristics such as a simplified process and reduced process cost.

Korean patent publication publication KR20140045851A

One technical problem to be solved by the present invention is to provide a functional graphene fiber with improved mechanical properties and a method for manufacturing the same.

Another technical problem to be solved by the present invention is to provide a functional graphene fiber with a simplified process and a method for manufacturing the same.

Another technical problem to be solved by the present invention is to provide a functional graphene fiber with improved gas sensing efficiency and a manufacturing method thereof.

The technical problem to be solved by the present invention is not limited to the above.

In order to solve the above technical problems, the present invention provides a method of manufacturing a functional graphene fiber.

According to an embodiment, the method of manufacturing the functional graphene fiber comprises: preparing a source solution in which a graphene oxide sheet is dispersed, in a coagulation bath containing a functional material including a metal and a coagulant. Spinning a source solution to prepare a graphene oxide fiber having a surface provided with the functional material, and heat treatment of the graphene oxide fiber having a surface provided with the functional material, so that the functional particles having reduced the functional material are Including the step of preparing a graphene fiber having a provided surface, depending on the heat treatment temperature of the graphene oxide fiber, the functional particles may include those having metal particles or metal oxide particles.

According to an embodiment, the heat treatment temperature of the graphene oxide fiber may include a temperature greater than 500°C and less than 800°C.

According to an embodiment, in the step of manufacturing the graphene fiber, it may include controlling the heat treatment heating rate of the graphene oxide fiber to control the size and number of the functional particles.

According to an embodiment, the heat treatment heating rate of the graphene oxide fiber may be greater than 14°C/min and less than 16°C/min.

According to an embodiment, the graphene oxide sheet may include a plurality of holes.

According to an embodiment, in the graphene fiber manufacturing step, when the graphene oxide fiber is heat-treated, oxygen removed from the graphene oxide fiber is transferred to the outside of the graphene oxide fiber through the pores. It may include discharged.

According to an embodiment, the metal is copper (Cu), nickel (Ni), cobalt (Co), manganese (Mn), zinc (Zn), iron (Fe), aluminum (Al), or palladium (Pd) It may include any one of.

According to an embodiment, the functional material is CuCl ₂ , CuSO ₄ , CuSO ₄ NH ₄ , NiCl ₂ , NiSO ₄ , Cobalt nitrate, Cobalt acetate, MnCl ₂ , MnNO ₃ , ZnCl ₂ , FeCl ₃ , AlCl ₃ , or It may contain any one of PdCl ₂ .

According to an embodiment, the step of manufacturing the graphene fiber may include heat-treating the graphene oxide fiber, and quenching the heat-treated graphene oxide fiber.

In order to solve the above technical problems, the present invention provides a functional graphene fiber.

According to an embodiment, the graphene fibers are graphene fibers extending in one direction by agglomeration of a plurality of reduced graphene oxide sheets, and are disposed on the graphene fibers, and reduced graphene oxide and first energy It may include functional particles including a metal having a level difference and a metal oxide having a second energy level difference greater than the first energy level difference.

According to an embodiment, the metal may include copper (Cu), and the metal oxide may include copper oxide (Cu ₂ O).

According to an embodiment, the metal may include nickel (Ni), and the metal oxide may include nickel oxide (NiO).

According to an embodiment, the graphene fiber may include a plurality of holes.

In order to solve the above-described technical problems, the present invention provides a gas sensor.

According to an embodiment, the gas sensor may include a substrate, a catalyst layer disposed on the substrate and including a functional graphene fiber according to the embodiments, and an electrode disposed on the catalyst layer.

The method of manufacturing a functional graphene fiber according to an embodiment of the present invention includes preparing a source solution in which a graphene oxide sheet is dispersed, spinning the source solution in a coagulation bath including a functional material including a metal and a coagulant, Preparing a graphene oxide fiber having a surface provided with the functional material, and heat treatment of the graphene oxide fiber having a surface provided with the functional material, so that the graphene having a surface provided with the functional particles reduced with the functional material Including the step of manufacturing a fiber, depending on the heat treatment temperature of the graphene oxide fiber, the functional particles may include those having metal particles or metal oxide particles. Accordingly, as a simple method of controlling the heat treatment temperature, various functional graphene fibers that can be applied depending on the application can be easily manufactured.

In addition, in the case of a gas sensor including a functional graphene fiber according to an embodiment of the present invention, the adsorption efficiency and desorption efficiency of the target gas may be improved, so that the target gas sensing ability may be improved.

1 is a flow chart illustrating a method of manufacturing a functional graphene fiber according to an embodiment of the present invention.
2 is a view showing a manufacturing process of a functional graphene fiber according to an embodiment of the present invention.
3 is a diagram illustrating a heat treatment process of graphene oxide fibers during the manufacturing process of functional graphene fibers according to an embodiment of the present invention.
4 is a view showing a functional graphene fiber according to an embodiment of the present invention.
5 is a view showing the energy level of functional particles included in the functional graphene fiber according to an embodiment of the present invention.
6 is a view showing a gas sensor including a functional graphene fiber according to an embodiment of the present invention.
7 and 8 are photographs of functional graphene fibers according to Example 1 of the present invention.
9 and 10 are photographs of functional graphene fibers according to Example 2 of the present invention.
11 to 13 are photographs of graphene oxide fibers formed in the manufacturing process of functional graphene fibers according to Example 1 of the present invention.
14 to 16 are photographs of functional graphene fibers according to Example 1 prepared by heat treatment at a temperature of 750°C.
17 to 19 are graphs showing changes in the composition of functional particles included in the functional graphene fiber according to Example 1 of the present invention according to the heat treatment temperature.
20 to 22 are graphs showing changes in the composition of functional particles included in the functional graphene fiber according to Example 2 of the present invention according to the heat treatment temperature.
23 to 25 are photographs comparing changes in functional particles included in the functional graphene fiber according to Example 1 of the present invention according to the heat treatment heating rate.
26 is a graph comparing changes in functional particles included in the functional graphene fiber according to Example 1 of the present invention according to the heat treatment heating rate.
27 is a graph comparing the change in properties of functional graphene fibers according to embodiments of the present invention.
28 is a photograph of graphene oxide fibers according to Comparative Example 1 and graphene fibers according to Comparative Example 2 of the present invention.
29 is a photograph of graphene oxide fibers according to Example 5 and graphene fibers according to Example 6 of the present invention.
30 is a graph comparing the mechanical properties of graphene oxide fibers and graphene fibers according to Examples and Comparative Examples of the present invention.
31 and 32 are graphs comparing mechanical properties of graphene oxide fibers according to Comparative Examples 1 and 5 of the present invention.
33 is a graph comparing mechanical properties with graphene fibers and conventional high strength fibers according to Example 6 of the present invention.
34 and 35 are photographs of functional graphene fibers according to Example 7 of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical idea of the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art.

In the present specification, when a component is referred to as being on another component, it means that it may be formed directly on the other component or that a third component may be interposed between them. In addition, in the drawings, thicknesses of films and regions are exaggerated for effective description of technical content.

In addition, in various embodiments of the present specification, terms such as first, second, and third are used to describe various components, but these components should not be limited by these terms. These terms are only used to distinguish one component from another component. Accordingly, what is referred to as a first component in one embodiment may be referred to as a second component in another embodiment. Each embodiment described and illustrated herein also includes its complementary embodiment. In addition, in the present specification,'and/or' is used to mean including at least one of the elements listed before and after.

In the specification, expressions in the singular include plural expressions unless the context clearly indicates otherwise. In addition, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, elements, or a combination of the features described in the specification, and one or more other features, numbers, steps, and configurations It is not to be understood as excluding the possibility of the presence or addition of elements or combinations thereof. In addition, in the present specification, "connection" is used to include both indirectly connecting a plurality of constituent elements and direct connecting.

Further, in the following description of the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

1 is a flow chart illustrating a method of manufacturing a functional graphene fiber according to an embodiment of the present invention, Figure 2 is a view showing a manufacturing process of the functional graphene fiber according to an embodiment of the present invention, Figure 3 is the present invention A diagram showing a heat treatment process of graphene oxide fibers during a manufacturing process of a functional graphene fiber according to an embodiment of the present invention, FIG. 4 is a view showing a functional graphene fiber according to an embodiment of the present invention, and FIG. It is a view showing the energy level of the functional particles included in the functional graphene fiber according to an embodiment, Figure 6 is a view showing a gas sensor including the functional graphene fiber according to an embodiment of the present invention.

1 to 4, a source solution 10 in which a graphene oxide sheet is dispersed is prepared (S100). The source solution 10 may be prepared by adding the graphene oxide sheet to a solvent. According to an embodiment, the solvent may be water (H ₂ O). According to another embodiment, the solvent may be an organic solvent. For example, the organic solvent is dimethyl sulfoxide (DMSO), ethylene glycol, N-methyl-2-piperidone (n-methyl-2-pyrrolidone, NMP), dimethylformamide , DMF) may be any one of.

The source solution 10 is spun in the coagulation bath bt, so that the graphene oxide fibers 30 may be manufactured (S200). According to an embodiment, in the manufacturing step of the graphene oxide fiber 30, the source solution 10 is spun into the coagulation bath bt to form a preliminary graphene oxide fiber 20, and the By drying the preliminary graphene oxide fiber 20, it may include the step of preparing the graphene oxide fiber 30. That is, after the source solution 10 is spun in the coagulation bath (bt) to form the preliminary graphene oxide fiber 20, as the preliminary graphene oxide fiber 20 is dried, the graphene oxide fiber 30 can be manufactured.

According to an embodiment, the source solution 10 may be radiated into the coagulation bath bt through a syringe sy. According to an embodiment, the coagulation bath bt may contain a coagulant and a functional material. For example, the coagulant may include methanol. For example, the functional material may include metal and metal ions. The metal may include any one of copper (Cu), nickel (Ni), cobalt (Co), manganese (Mn), zinc (Zn), iron (Fe), aluminum (Al), or palladium (Pd). I can. Specifically, the functional material is CuCl ₂ , CuSO ₄ , CuSO ₄ NH ₄ , NiCl ₂ , NiSO ₄ , Cobalt nitrate, Cobalt acetate, MnCl ₂ , MnNO ₃ , ZnCl ₂ , FeCl ₃ , AlCl ₃ , or PdCl ₂ It can contain either. Hereinafter, in describing a method of manufacturing a functional graphene fiber according to an embodiment of the present invention, a case where the functional material contains CuCl ₂ is described as an example.

As described above, as the coagulation bath bt includes the functional material and the coagulant, the preliminary graphene oxide fiber 20 may include the functional material and the coagulant. Specifically, the functional material may be provided on the surface of the preliminary graphene oxide fiber 20. Alternatively, the coagulant may penetrate into the preliminary graphene oxide fiber 20.

In the process of drying the preliminary graphene oxide fiber 20, the coagulant may be evaporated. Accordingly, the preliminary graphene oxide fiber 20 is solidified, so that the graphene oxide fiber 30 may be manufactured. According to an embodiment, the graphene oxide fiber 30 may have a structure in which a plurality of graphene oxide sheets are aggregated to extend in one direction.

In addition, the functional material may be oxidized while the preliminary graphene oxide fiber 20 is dried. Accordingly, the graphene oxide fiber 30 may have a surface provided with an oxidized functional material. For example, when the functional material is CuCl ₂ , the graphene oxide fiber 30 may have a surface provided with CuClO ₄ in which CuCl _{2, which} is the functional material, is oxidized.

Alternatively, the functional material may remain as it is while the preliminary graphene oxide fiber 20 is dried. For example, when the functional material is NiCl ₂ , the graphene oxide fiber 30 may have a surface provided with the functional material NiCl ₂ .

The graphene oxide fiber 30 may be wound. According to an embodiment, the graphene oxide fiber 30 may be separated from the coagulation bath bt by a guide roller (gr) and come out to the outside, and may be attached to a winding roller (not shown). Can be wound by

The graphene oxide fiber 30 is heat treated, so that a functional graphene fiber 40 may be manufactured (S300). When the graphene oxide fiber 30 is heat-treated, the graphene oxide fiber 30 and the functional material may be reduced. According to an embodiment, when the graphene oxide fibers 30 are reduced, graphene fibers GF may be formed. The graphene fibers GF may have a structure in which a plurality of reduced graphene oxide sheets are aggregated to extend in one direction. According to an embodiment, when the functional material is reduced, functional particles FP may be formed.

As a result, when the graphene oxide fiber 30 having a surface provided with the functional material is heat treated, the graphene fiber GF having a surface provided with the functional particle GP may be prepared. Accordingly, the functional graphene fiber 40 according to the embodiment may be manufactured. Specifically, as shown in FIG. 3, when the graphene oxide fiber 30 having a surface provided with CuClO ₄ is heat treated, CO ₂ , CO, and HCl in the graphene oxide fiber 30 are removed. Can be. Accordingly, the functional material is reduced to functional particles, the functional graphene fiber 40 can be produced.

According to an embodiment, depending on the heat treatment temperature of the graphene oxide fiber 30, the functional particles FP may have metal particles or metal oxide particles. That is, according to the heat treatment temperature of the graphene oxide fiber 30, the functional particles FP may include metal particles. In contrast, according to the heat treatment temperature of the graphene oxide fiber 30, the functional particles FP may include metal oxide particles. In contrast, according to the heat treatment temperature of the graphene oxide fiber 30, the functional particles FP may have both metal oxide particles and the metal particles.

For example, when the heat treatment temperature of the graphene oxide fiber 30 is 0° C. to less than 500° C., the functional particles FP may have metal oxide particles. Specifically, when the heat treatment temperature of the graphene oxide fiber 30 is 0°C to 250°C, the functional particles FP may include CuO particles. In contrast, when the heat treatment temperature of the graphene oxide fiber 30 is 250°C to 500°C, the functional particles FP may include Cu ₂ O particles.

For another example, when the heat treatment temperature of the graphene oxide fiber 30 is more than 500°C and less than 800°C, the functional particles FP may have both metal oxide particles and metal particles. Specifically, when the heat treatment temperature of the graphene oxide fiber 30 is more than 500° C. and less than 800° C., the functional particles FP may have both Cu ₂ O particles and Cu particles.

In the case of the prior art for reducing metal oxides to metals, an environment in which an inert gas is provided at a high temperature of 1400°C or higher has been required. However, in the method of manufacturing a functional graphene fiber according to an embodiment of the present invention, carbon of graphene may serve as a catalyst for metal oxide reduction in the process of heat treatment of the graphene oxide fiber 30. Accordingly, the metal oxide contained in the functional particles may be reduced at a relatively low temperature (more than 500°C and less than 800°C) compared to the prior art. As a result, graphene fibers including metals and metal oxides can be easily manufactured through a relatively simplified process. In addition, by not using a noble metal such as platinum (Pt), but using a general-purpose metal such as copper (Cu), it is possible to obtain an economic advantage.

For another example, when the heat treatment temperature of the graphene oxide fiber 30 is 800° C. or higher, the functional particles FP may have metal particles. Specifically, when the heat treatment temperature of the graphene oxide fiber 30 is 800°C or higher, the functional particles FP may have Cu particles.

After the graphene oxide fiber 30 is heat-treated, the heat-treated graphene oxide fiber 30 may be quenched. For example, the heat-treated graphene oxide fiber 30 may be cooled at a rate of -10°C/min in an argon (Ar) atmosphere. Unlike the above, when the cooling rate of the heat-treated graphene oxide fiber 30 is relatively slow, the size of the functional particles FP may be increased. In this case, there may be a problem in that the properties of the graphene fiber due to the functional particles (FP) are deteriorated.

According to an embodiment, by controlling the heat treatment heating rate of the graphene oxide fiber 30, it is possible to control the size and number of the functional particles (FP). Specifically, the heat treatment heating rate of the graphene oxide fiber 30 may be controlled to be greater than 14°C/min and less than 16°C/min. In this case, the size of the functional particles FP may be relatively small, and the number of the functional particles FP may be relatively increased. Accordingly, the functional graphene fiber 40 may have improved characteristics according to the functional particle FP.

The functional graphene fiber 40 according to the embodiment may be used in various applications depending on the type of the functional material. For example, the functional graphene fiber 40 may be used in various applications such as energy storage, EMI materials, electrical conductive wire, and gas sensors.

Specifically, when the functional material includes copper (Cu) or nickel (Ni) as described above, the functional graphene fiber 40 according to the embodiment may be used as a catalyst layer of a gas sensor. Hereinafter, a gas sensor including the functional graphene fiber 40 will be described with reference to FIGS. 5 and 6. In addition, the type of application in which the functional graphene fiber 40 is utilized is not limited.

According to an embodiment, the gas sensor may include a substrate 100, a catalyst layer 200 disposed on the substrate, a first electrode 310 disposed on the catalyst layer 200, and the catalyst layer 200. , It may include a second electrode 320 disposed to be spaced apart from the first electrode 310. The structure of the gas sensor described above has been described for illustrative purposes, and the structure of the gas sensor is not limited.

The catalyst layer 200 may include the functional graphene fiber 40 described with reference to FIGS. 1 to 4. Functional particles (FP) included in the functional graphene fiber 40 may include both metal oxides and metal particles. That is, the functional graphene fiber 40 may be formed by heat-treating the graphene oxide fiber 30 at a temperature of more than 500° C. and less than 800° C. in the manufacturing process of the functional graphene fiber 40. For example, the catalyst layer 400 may include graphene fibers (GF) having a surface provided with both Cu ₂ O particles and Cu particles.

In this case, a difference in energy level may appear between the metal oxide (eg, Cu ₂ O), the metal (eg, Cu), and the graphene fiber. As described above, as the graphene fiber contains a plurality of reduced graphene oxide (rGO), the metal oxide (eg, Cu2O), the metal (eg, Cu), and the reduction Differences in energy levels may appear between the graphene oxide (rGO).

For example, as illustrated in FIG. 5, a first energy level difference L ₁ may appear between the metal (eg, Cu) and the reduced graphene oxide (rGO). On the other hand, between the metal oxide (eg, Cu ₂ O) and the reduced graphene oxide (rGO), a second energy level difference (L ₂ ) may appear. The second energy level difference L ₂ may be greater than the first energy level difference L ₁ .

That is, the functional graphene fibers included in the catalyst layer 200 are graphene fibers extending in one direction by aggregation of a plurality of reduced graphene oxide sheets, and are disposed on the graphene fibers, and metal and metal Including functional particles containing an oxide, wherein the metal and the reduced graphene oxide have the first energy level difference (L ₁ ), the metal oxide and the reduced graphene oxide have the first energy level difference (L The second energy level difference L ₂ may be greater than ₁ ).

Accordingly, gas sensing efficiency of the gas sensor according to the embodiment may be improved. More specifically, in the case of the gas sensor, the target gas may be absorbed and dropped from the catalyst layer, and thus electrons may move and electrical resistance may change. At this time, the target gas may be sensed by measuring the changed electrical resistance.

In this case, a high energy difference may be required in order to easily absorb the target gas. On the other hand, in order for the target gas to be easily removed, a low energy difference may be required. As described above, when the catalyst layer includes the graphene fiber and the functional particles, a metal oxide (eg, Cu ₂ O) having a relatively large energy level difference can improve gas adsorption efficiency. have. On the other hand, a metal (eg, Cu) having a relatively small difference in energy level can improve gas desorption efficiency. Accordingly, in the case of the gas sensor including the functional graphene fiber according to the above embodiment, gas sensing efficiency may be improved.

The method of manufacturing a functional graphene fiber according to an embodiment of the present invention includes preparing the source solution 10 in which the graphene oxide sheet is dispersed, the coagulation including the functional material including the metal and a coagulant Spinning the source solution 10 in a bath to prepare the graphene oxide fiber 30 having a surface provided with the functional material, and the graphene oxide fiber 30 having a surface provided with the functional material By heat treatment to prepare the graphene fiber (GF) having a surface provided with the functional particle (FP) having the reduced functional material, according to the heat treatment temperature of the graphene oxide fiber, the functional particle May include those having metal particles or metal oxide particles. Accordingly, as a simple method of controlling the heat treatment temperature, various functional graphene fibers that can be applied depending on the application can be easily manufactured.

In the above, functional graphene fibers and a method of manufacturing the same according to an embodiment of the present invention have been described. Hereinafter, a functional graphene fiber according to a modified example of the present invention in which the graphene oxide fiber is produced through a source solution in which a graphene oxide sheet including a plurality of pores is dispersed, and a method of manufacturing the same will be described.

A method of manufacturing a functional graphene fiber according to a modified example of the present invention may be the same as the manufacturing method of a functional graphene fiber according to the embodiment described with reference to FIG. 1. However, in the step of preparing the source solution, the graphene oxide sheet dispersed in a solvent may include a plurality of holes. That is, a graphene oxide sheet including a plurality of pores is dispersed in a solvent, so that the source solution may be prepared.

According to an embodiment, the graphene oxide sheet including a plurality of pores may be prepared by preparing a mixed solution in which graphene oxide and hydrogen peroxide are dispersed in a solvent, and then heat-treating and filtering the mixed solution.

After the source solution is prepared, the source solution is spun into a coagulation bath to prepare graphene oxide fibers, and graphene fibers may be prepared by reducing the graphene oxide fibers. The graphene oxide fiber manufacturing step, and the graphene fiber manufacturing step, the graphene oxide fiber manufacturing step (S200) described in the manufacturing method of the functional graphene fiber according to the embodiment described with reference to FIG. 1, and It may be the same as the graphene fiber manufacturing step (S300). Accordingly, detailed descriptions are omitted.

However, in the method of manufacturing a functional graphene fiber according to the modified example, in the graphene fiber manufacturing step, when the graphene oxide fiber is heat-treated, oxygen removed from the graphene oxide fiber fills the pores. Through the graphene oxide fiber may be discharged to the outside. Accordingly, the mechanical properties of the functional graphene fiber according to the modified example may be improved.

Specifically, when preparing the functional graphene fiber through a source solution in which a general graphene oxide sheet is dispersed, in the graphene fiber manufacturing step, as the graphene oxide fiber is heat-treated, oxygen from the graphene oxide fiber (oxygen) may be released. In this case, there may be a problem in that the structures of the graphene oxide fibers are collapsed while oxygen is discharged. However, when the graphene oxide fiber includes a plurality of pores, oxygen is easily discharged along the pores, so that collapse of the structure may be prevented. Accordingly, mechanical properties of the functional graphene fiber may be improved.

In the above, functional graphene fibers and a method of manufacturing the same according to embodiments and modifications of the present invention have been described. Hereinafter, specific experimental examples and characteristic evaluation results of functional graphene fibers according to embodiments and modifications of the present invention will be described.

Functionality according to Example 1 Graphene Textile manufacturing

A source solution was prepared by dispersing the graphene oxide sheet in deionized water. The prepared source solution was spun in an aqueous solution containing CuCl ₂ , washed, wound, and dried to prepare graphene oxide fibers.

Thereafter, the dried graphene oxide fiber was heat-treated in an argon atmosphere to prepare a functional graphene fiber according to Example 1.

Functionality according to Example 2 Graphene Textile manufacturing

A source solution was prepared by dispersing the graphene oxide sheet in deionized water. The prepared source solution was spun in a coagulation bath containing NiCl ₂ , then wound and dried to prepare graphene oxide fibers.

Thereafter, the dried graphene oxide fiber was heat-treated in an argon atmosphere to prepare a functional graphene fiber according to Example 1.

Functionality according to Example 3 Graphene Textile manufacturing

A source solution was prepared by dispersing the graphene oxide sheet in deionized water. The prepared source solution was spun in a coagulation bath containing CuSO ₄ , then wound and dried to prepare graphene oxide fibers.

Thereafter, the dried graphene oxide fiber was heat-treated in an argon atmosphere to prepare a functional graphene fiber according to Example 1.

Functionality according to Example 4 Graphene Textile manufacturing

A source solution was prepared by dispersing the graphene oxide sheet in deionized water. The prepared source solution was spun in a coagulation bath containing CuSO ₄ NH ₄ , and then wound and dried to prepare graphene oxide fibers.

Thereafter, the dried graphene oxide fiber was heat-treated in an argon atmosphere to prepare a functional graphene fiber according to Example 1.

According to Example 5 Graphene Oxide fiber manufacturing

After preparing a mixed solution by dispersing graphene oxide and hydrogen peroxide in water (H ₂ O), the mixed solution was heat treated and filtered to prepare a graphene oxide sheet including a plurality of pores.

Thereafter, the prepared graphene oxide sheet was dispersed in deionized water to prepare a source solution, and then the prepared source solution was spun in a coagulation bath containing methanol, and then wound and dried to form the graphene oxide according to Example 5. The fibers were prepared.

According to Example 6 Graphene Textile manufacturing

The graphene oxide fibers according to Example 5 were heat-treated in an argon atmosphere to prepare graphene fibers according to Example 6.

Functionality according to Example 7 Graphene Textile manufacturing

A source solution was prepared by dispersing the graphene oxide sheet in deionized water. The prepared source solution was spun in a coagulation bath containing MnCl ₂ , then wound and dried to prepare graphene oxide fibers.

Thereafter, the dried graphene oxide fiber was heat-treated in an argon atmosphere to prepare a functional graphene fiber according to Example 1.

Oxidation according to Comparative Example 1 Graphene Fiber preparation

Graphene oxide fiber is prepared

According to Comparative Example 2 Graphene Fiber preparation

Graphene fibers obtained by reducing graphene oxide fibers are prepared.

Graphene fibers according to the Examples and Comparative Examples are summarized in Table 1 below.

division rescue Functional substance Example 1 Functional graphene fiber CuCl ₂ Example 2 Functional graphene fiber NiCl ₂ Example 3 Functional graphene fiber CuSO ₄ Example 4 Functional graphene fiber CuSO ₄ NH ₄ Example 5 Graphene oxide fiber (including multiple pores) - Example 6 Graphene fiber (including multiple pores) - Example 7 Functional graphene fiber MnCl ₂ Comparative Example 1 Graphene oxide fiber - Comparative Example 2 Graphene fiber -

7 and 8 are photographs of functional graphene fibers according to Example 1 of the present invention.

Referring to Figures 7 (a) and (b), SEM (Scanning Electron Microscope) photographs of the functional graphene fiber according to Example 1, shown in Figures 7 (a) and (b) at different magnifications. I did. As can be seen in Figure 7 (a) and (b), it was confirmed that a plurality of particles are provided on the graphene fiber.

8A to 8D, the functional graphene fibers according to Example 1 were shown by mapping EDS (Energy Dispersive X-ray Spectroscopy). Figure 8 (a) is a SEM photograph of the functional graphene fiber according to Example 1, Figures 8 (b) to (d) are carbon (C) and oxygen (O) for Figure 8 (a), respectively. ), and a photograph showing the distribution of copper (Cu). As can be seen from (a) to (d) of Figure 8, it can be seen that the functional graphene fiber according to Example 1 contains carbon (C), oxygen (O), and copper (Cu).

9 and 10 are photographs of functional graphene fibers according to Example 2 of the present invention.

9A and 9B, SEM photographs of the functional graphene fibers according to Example 2 were shown in FIGS. 9A and 9B at different magnifications. As can be seen in (a) and (b) of Figure 9, it was confirmed that a plurality of particles are provided on the graphene fiber.

Referring to FIGS. 10A to 10D, functional graphene fibers according to Example 2 are shown by mapping EDS (Energy Dispersive X-ray Spectroscopy). Figure 10 (a) is a SEM photograph of the functional graphene fiber according to Example 2, Figures 10 (b) to (d) are carbon (C) and oxygen (O) for Figure 10 (a), respectively. ), and a photograph showing the distribution of nickel (Ni). As can be seen from (a) to (d) of FIG. 10, it can be seen that the functional graphene fiber according to Example 2 contains carbon (C), oxygen (O), and nickel (Ni).

11 to 13 are photographs of graphene oxide fibers formed in the manufacturing process of functional graphene fibers according to Example 1 of the present invention.

11 and 12, after SEM photographing of the graphene oxide fibers formed in the manufacturing process of the functional graphene fibers according to Example 1 at different positions and magnifications, FIGS. 11A to 11C And it is shown in Figure 12 (a), (b). As can be seen in FIGS. 11 and 12, it was confirmed that the graphene oxide fiber formed in the manufacturing process of the functional graphene fiber according to Example 1 has a structure in which a plurality of graphene oxide sheets are aggregated to extend in one direction. Could

13, after EDS (Energy Dispersive X-ray Spectroscopy) mapping of graphene oxide fibers formed in the manufacturing process of functional graphene fibers according to Example 1, distribution of carbon (C) and oxygen (O) The distribution of and the distribution of copper (Cu) are shown in FIGS. 13A to 13C, respectively. As can be seen in (a) to (c) of Figure 13, the graphene oxide fiber formed in the manufacturing process of the functional graphene fiber according to Example 1 is carbon (C), oxygen (O), and copper (Cu) It was confirmed that it includes.

14 to 16 are photographs of functional graphene fibers according to Example 1 prepared by heat treatment at a temperature of 750°C.

14 and 15, a functional graphene fiber according to Example 1 was prepared, but the graphene oxide fiber was heat-treated at a temperature of 750°C to prepare a functional graphene fiber. Thereafter, the prepared functional graphene fibers were photographed by SEM at different positions and magnifications, and then shown in FIGS. 14 (a) to (c) and FIGS. 15 (a) and (b). As can be seen in FIGS. 14 and 15, the functional graphene fiber formed by heat treatment at a temperature of 750° C. was confirmed that a plurality of particles were disposed on the graphene fiber. In addition, it was confirmed that the graphene fiber has a structure in which a plurality of reduced graphene oxide sheets are aggregated to extend in one direction.

Referring to FIG. 16, after EDS (Energy Dispersive X-ray Spectroscopy) mapping of the functional graphene fiber according to Example 1 formed by heat treatment at a temperature of 750°C, the distribution of carbon (C) and oxygen (O) The distribution and the distribution of copper (Cu) are shown in FIGS. 16A to 16C, respectively. As can be seen in (a) to (c) of FIG. 16, the functional graphene fiber according to Example 1 formed by heat treatment at a temperature of 750° C. also contains carbon (C), oxygen (O), and copper (Cu). It was confirmed to include.

17 to 19 are graphs showing changes in the composition of functional particles included in the functional graphene fiber according to Example 1 of the present invention according to the heat treatment temperature.

Referring to FIG. 17, a functional graphene fiber according to Example 1 is prepared, but in the process of heat-treating the graphene oxide fiber, the heat treatment temperature is controlled to 0°C to 800°C, and functional graphene fibers formed at each temperature. It shows the components of the functional particles containing. In addition, the weight change (weight, %) of functional graphene fibers according to the heat treatment temperature was also shown.

As can be seen in FIG. 17, when the graphene oxide fiber is heat-treated at a temperature of 0° C. to 250° C. to prepare a functional graphene fiber, it was confirmed that the functional particle contains CuO. On the other hand, when a functional graphene fiber was prepared by heat treatment at a temperature of 250°C to 500°C, it was confirmed that the functional particles contained Cu ₂ O. On the other hand, when a functional graphene fiber was manufactured by heat treatment at a temperature of 500°C to 800°C, it was confirmed that the functional particles contained both Cu ₂ O and Cu. In addition, it was confirmed that as the heat treatment temperature increased, the weight of the functional graphene fibers decreased.

18 and 19, when the graphene oxide fiber is not heat treated (before thermal treatment), heat treated at a temperature of 250°C, heat treated at a temperature of 500°C, and heat treated at a temperature of 750°C. XPS (X-ray photoelectron spectroscopy) results of the functional graphene fiber according to Example 1 formed according to each case were shown.

As can be seen in FIGS. 18 and 19, it was confirmed that as the heat treatment temperature of the graphene oxide fiber increased, the peak of CC bonding and the peak of Cu 2p increased. That is, it was confirmed that the functional material CuCl ₂ was reduced to Cu ₂ O and Cu by carbothermal reaction. In addition, it was confirmed that as the heat treatment temperature of the graphene oxide fiber increased, CuO was reduced to form Cu ₂ O and Cu.

20 to 22 are graphs showing changes in the composition of functional particles included in the functional graphene fiber according to Example 2 of the present invention according to the heat treatment temperature.

Referring to FIG. 20, a functional graphene fiber according to Example 2 is prepared, but in the process of heat treating the graphene oxide fiber, the heat treatment temperature is controlled to 0°C to 800°C, and functional graphene fibers formed at each temperature It shows the components of the functional particles containing. In addition, the weight change (weight, %) of functional graphene fibers according to the heat treatment temperature was also shown.

As can be seen in FIG. 20, when the graphene oxide fiber is heat-treated at a temperature of 0° C. to 250° C. to prepare a functional graphene fiber, it was confirmed that the functional particle contains NiCl ₂ . On the other hand, when the functional graphene fiber was prepared by heat treatment at a temperature of 250°C to 500°C, it was confirmed that the functional particles contained NiO. On the other hand, when the functional graphene fiber was manufactured by heat treatment at a temperature of 500°C to 800°C, it was confirmed that the functional particles contained both NiO and Ni. In addition, it was confirmed that as the heat treatment temperature increased, the weight of the functional graphene fibers decreased.

21 and 22, when the graphene oxide fiber is not heat treated (before thermal treatment), heat treated at a temperature of 250°C, heat treated at a temperature of 500°C, and heat treated at a temperature of 750°C. XPS (X-ray photoelectron spectroscopy) results of the functional graphene fiber according to Example 1 formed according to each case were shown.

As can be seen in FIGS. 21 and 22, it was confirmed that as the heat treatment temperature of the graphene oxide fiber increased, the peak of the CC bonding increased. That is, it was confirmed that the functional material NiCl ₂ was reduced to NiO and Ni by a carbothermal reaction.

As a result, as can be seen through FIGS. 17 to 22, it can be seen that the functional particles may have metal particles or metal oxide particles depending on the heat treatment temperature of the graphene oxide fibers.

23 to 25 are photographs comparing changes in functional particles included in the functional graphene fiber according to Example 1 of the present invention according to the heat treatment heating rate.

Referring to FIG. 23, the graphene oxide fiber was heat-treated, but after heat-treating to 1000° C. at a heating rate of 10° C./min, the prepared functional graphene oxide fiber was taken by SEM. FIG. 23(a) shows a state before heat treatment, and FIG. 23(b) shows a state after heat treatment.

Referring to FIG. 24, the graphene oxide fiber was heat-treated, but after heat-treating to 1000°C at a heating rate of 15°C/min, the prepared functional graphene oxide fiber was taken by SEM. Fig. 24(a) shows a state before heat treatment, and Fig. 24(b) shows a state after heat treatment.

Referring to FIG. 25, the graphene oxide fiber was heat-treated, but after heat-treating to 1000° C. at a heating rate of 20° C./min, the prepared functional graphene oxide fiber was photographed by SEM. Fig. 25(a) shows a state before heat treatment, and Fig. 25(b) shows a state after heat treatment.

As can be seen in FIGS. 23 to 25, the size of the functional particles included in the functional graphene fiber is, when heat-treated at a temperature increase rate of 20°C/min, heat treatment at a temperature increase rate of 10°C/min, and 15°C. It was confirmed that it decreased in the order of heat treatment at a heating rate of /min. In addition, the number of functional particles increases in the order of heat treatment at a temperature increase rate of 10°C/min, heat treatment at a temperature increase rate of 20°C/min, and heat treatment at a temperature increase rate of 15°C/min. I could confirm.

26 is a graph comparing changes in functional particles included in the functional graphene fiber according to Example 1 of the present invention according to the heat treatment heating rate.

Referring to FIG. 26, the graphene oxide fiber is heat-treated but the temperature increase rate is controlled, and the number of functional particles included in the functional graphene oxide fiber manufactured according to the temperature increase rate (number of aprticles), and size (size of particles, μm) was measured and expressed.

As can be seen in FIG. 26, it was confirmed that the number of functional particles gradually increased as the heating rate increased, and then decreased from 15°C/min. In addition, it was confirmed that the size of the functional particles gradually decreased as the heating rate increased, and then increased from 15°C/min.

That is, as can be seen in FIGS. 23 to 26, when the graphene oxide fiber is heat-treated, but heat-treated at a temperature increase rate of more than 14°C/min and less than 16°C/min, the prepared functional graphene fiber contains functional particles. It was confirmed that the size was relatively small and the number was relatively large.

27 is a graph comparing the change in properties of functional graphene fibers according to embodiments of the present invention.

Referring to FIG. 27, after preparing functional graphene fibers according to Examples 1, 3, and 4, the weight of the graphene oxide fibers (weight, %) by heat treatment of each graphene oxide fiber Change was measured. As can be seen in FIG. 27, it was confirmed that the weight change of the graphene oxide fiber according to Example 1 was the largest, followed by the weight change of the graphene oxide fiber according to Examples 4 and 3 was large. . Through this, it was confirmed that CuCl ₂ as a functional material, as well as CuSO ₄ , and CuSO ₄ NH ₄ can also be used.

28 is a photograph of a graphene oxide fiber according to Comparative Example 1 and a graphene fiber according to Comparative Example 2 of the present invention, and FIG. 29 is a graphene oxide fiber according to Example 5 and Example 6 of the present invention. This is a picture of the graphene fiber.

Referring to FIGS. 28A and 28B, the graphene oxide fibers according to Comparative Example 1 and the graphene fibers according to Comparative Example 2 were photographed by SEM. Referring to FIGS. 29A and 29B, the graphene oxide fibers according to Example 5 and the graphene fibers according to Example 6 were photographed by SEM.

As can be seen through FIGS. 28 and 29, it was confirmed that the graphene oxide fiber according to Example 5 and the graphene fiber according to Example 6 had a plurality of pores formed. In addition, in the case of the graphene oxide fiber and the graphene fiber having a plurality of pores, compared to the graphene oxide fiber according to Comparative Example 1 and the graphene fiber according to Comparative Example 2, the structure does not collapse and the cross section is uniform. I could confirm.

30 is a graph comparing the mechanical properties of graphene oxide fibers and graphene fibers according to Examples and Comparative Examples of the present invention.

Referring to FIG. 30, for each of the graphene oxide fibers according to Comparative Example 1, the graphene fibers according to Comparative Example 2, the graphene oxide fibers according to Example 5, and the graphene fibers according to Example 6, Strain Stress (MPa) according to (%) was measured and shown.

As can be seen in FIG. 30, the graphene fiber according to Example 6 was mechanically compared with the graphene oxide fiber according to Comparative Example 1, the graphene fiber according to Comparative Example 2, and the graphene oxide fiber according to Example 5. It was confirmed that the characteristics were remarkably high.

31 and 32 are graphs comparing mechanical properties of graphene oxide fibers according to Comparative Examples 1 and 5 of the present invention.

Referring to FIG. 31, for each of the graphene oxide fibers according to Comparative Examples 1 and 5, tensile strength (MPa) according to a heat treatment temperature (℃) was measured and shown. Referring to FIG. 32, for each of the graphene oxide fibers according to Comparative Examples 1 and 5, the tensile modulus (GPa) according to the heat treatment temperature (℃) was measured and shown.

As can be seen in FIGS. 31 and 32, it was confirmed that the graphene oxide fiber according to Example 5 exhibited significantly higher tensile strength and tensile elasticity compared to the graphene oxide fiber according to Comparative Example 1.

33 is a graph comparing mechanical properties with graphene oxide fibers and conventional high strength fibers according to Example 6 of the present invention.

Referring to FIG. 33, as a result of measuring the Tensile Strength (GPa) according to Young's Modulus (GPa) of the graphene oxide fiber according to Example 6 and showing mechanical properties, the conventional high strength fibers vectran and p-aramid fibers It was confirmed that it exhibited similar mechanical properties.

That is, as can be seen through FIGS. 28 to 33, when the graphene oxide fiber and the graphene fiber are manufactured by using a graphene oxide sheet including a plurality of pores, it was found that mechanical strength is significantly improved. .

34 and 35 are photographs of functional graphene fibers according to Example 7 of the present invention.

34 and 35, the functional graphene fiber according to Example 7 was shown by SEM photographing at different magnifications. As can be seen in FIGS. 34 and 35, it was confirmed that a plurality of particles were provided on the graphene fiber. That is, even through manganese (Mn), it was found that the functional graphene fiber according to the embodiment can be easily manufactured.

In the above, the present invention has been described in detail using preferred embodiments, but the scope of the present invention is not limited to specific embodiments, and should be interpreted by the appended claims. In addition, those who have acquired ordinary knowledge in this technical field should understand that many modifications and variations can be made without departing from the scope of the present invention.

10: source solution
20: Preliminary graphene oxide fiber
30: graphene oxide fiber
40: functional graphene oxide fiber
100: substrate
200: catalyst layer
310: first electrode
320: second electrode

Claims (14)

Preparing a source solution in which a graphene oxide sheet is dispersed;
Spinning the source solution into a coagulation bath containing a functional material containing a metal and a coagulant to prepare graphene oxide fibers having a surface provided with the functional material; And
Heat-treating the graphene oxide fiber having a surface provided with the functional material, and preparing a graphene fiber having a surface provided with the functional particle-reduced functional material,
Depending on the heat treatment temperature of the graphene oxide fiber, the functional particle is a method of producing a functional graphene fiber comprising a metal particle or a metal oxide particle.
The method of claim 1,
The heat treatment temperature of the graphene oxide fiber, a method for producing a functional graphene fiber comprising that of less than 800 ℃ 500 ℃.
The method of claim 1,
In the graphene fiber manufacturing step,
By controlling the heat treatment heating rate of the graphene oxide fiber,
Method for producing a functional graphene fiber comprising controlling the size and number of the functional particles.
The method of claim 3,
The method of producing a functional graphene fiber comprising that the heat treatment heating rate of the graphene oxide fiber is less than 16 ℃ / min more than 14 ℃ / min.
The method of claim 1,
The graphene oxide sheet is a method of manufacturing a functional graphene fiber including a plurality of pores.
The method of claim 5,
In the graphene fiber manufacturing step,
When the graphene oxide fiber is heat-treated, oxygen removed from the graphene oxide fiber is discharged to the outside of the graphene oxide fiber through the pores.
The method of claim 1,
The metal includes any one of copper (Cu), nickel (Ni), cobalt (Co), manganese (Mn), zinc (Zn), iron (Fe), aluminum (Al), or palladium (Pd). Method for producing functional graphene fibers.
The method of claim 1,
The functional material is CuCl ₂ , CuSO ₄ , CuSO ₄ NH ₄ , NiCl ₂ , NiSO ₄ , Cobalt nitrate, Cobalt acetate, MnCl ₂ , MnNO ₃ , ZnCl ₂ , FeCl ₃ , AlCl ₃ , or any one of PdCl ₂ Method for producing a functional graphene fiber containing.
The method of claim 1,
The graphene fiber manufacturing step,
Heat-treating the graphene oxide fibers; And
A method for producing functional graphene fibers comprising the step of quenching the heat-treated graphene oxide fibers.
Graphene fibers in which a plurality of reduced graphene oxide sheets are aggregated to extend in one direction; And
It is disposed on the graphene fiber, and comprises functional particles comprising a metal having a first energy level difference from the reduced graphene oxide, and a metal oxide having a second energy level difference greater than the first energy level difference Functional graphene fiber.
The method of claim 10,
The metal includes copper (Cu), and the metal oxide is a functional graphene fiber including copper oxide (Cu ₂ O).
The method of claim 10,
The metal includes nickel (Ni), and the metal oxide is a functional graphene fiber including nickel oxide (NiO).
The method of claim 11,
The graphene fiber is a functional graphene fiber including a plurality of pores.
Board;
A catalyst layer disposed on the substrate and comprising a functional graphene fiber according to claim 10; And
Gas sensor comprising an electrode disposed on the catalyst layer.

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