KR102045106B1 - Graphene-carbone nano tube complex, catalyst comprising the same, membrane electrode assembly comprising the catalyst, fuel cell including the membrane electrode assembly and method for manufacturing the graphene-carbone nano tube complex - Google Patents

Abstract

The present specification relates to a graphene-carbon nanotube composite, a catalyst comprising the same, a membrane electrode assembly including the catalyst, a fuel cell including the membrane electrode assembly, and a method for preparing the graphene-carbon nanotube composite.

Description

Graphene-carbon nanotube composite, a catalyst comprising the same, a membrane electrode assembly comprising the catalyst, a fuel cell comprising the membrane electrode assembly and a method for producing a graphene-carbon nanotube composite {GRAPHENE-CARBONE NANO TUBE COMPLEX, CATALYST COMPRISING THE SAME, MEMBRANE ELECTRODE ASSEMBLY COMPRISING THE CATALYST, FUEL CELL INCLUDING THE MEMBRANE ELECTRODE ASSEMBLY AND METHOD FOR MANUFACTURING THE GRAPHENE-CARBONE NANO TUBE COMPLEX}

The present specification relates to a graphene-carbon nanotube composite, a catalyst comprising the same, a membrane electrode assembly including the catalyst, a fuel cell including the membrane electrode assembly, and a method for preparing the graphene-carbon nanotube composite.

Carbon black is generally used as a support for a fuel cell catalyst. However, when carbon black is used as a support, problems of durability due to corrosion of carbon occur.

In order to improve these problems, research on carbon nanotubes (Carbonnanotube, CNT), carbon nanofibers (CNF), carbon nanocages (CNC), which are highly resistant to corrosion, is being actively conducted. However, such crystalline carbon has a problem in that it is difficult to disperse in a polar solvent due to the strong surface water repellency. For this reason, there is a problem in that platinum is agglomerated without being evenly dispersed in the process of loading platinum on the carbon carrier.

Republic of Korea Patent Publication No. 10-2005-0098818

The present specification relates to a graphene-carbon nanotube composite, a catalyst comprising the same, a membrane electrode assembly including the catalyst, a fuel cell including the membrane electrode assembly, and a method for preparing the graphene-carbon nanotube composite.

Herein is a carbon nanotube; A polymer layer having an amine group provided on the carbon nanotubes; And it provides a graphene-carbon nanotube composite comprising a graphene provided on the polymer layer.

In addition, the present specification provides a catalyst comprising the graphene-carbon nanotube composite.

In addition, the present disclosure provides an electrochemical cell including the catalyst.

In addition, the present specification includes an anode, a cathode and a polymer electrolyte membrane provided between the anode and the cathode, and at least one of the anode and the cathode provides the membrane electrode assembly.

In addition, the present disclosure provides a fuel cell including the membrane electrode assembly.

In addition, the present specification is to form a polymer layer having an amine group provided on the carbon nanotubes; And it provides a method for producing a graphene-carbon nanotube composite comprising the step of providing a graphene on the polymer layer by reacting the graphene with carbon nanotubes on which the polymer layer is formed.

Graphene-carbon nanotube composite according to one embodiment of the present specification has the advantage of excellent dispersibility of nanoparticles.

Graphene-carbon nanotube composite according to an exemplary embodiment of the present specification is suppressed aggregation of graphene and carbon nanotubes in the composite is high utilization of graphene and carbon nanotubes.

1 is a schematic diagram illustrating a principle of electricity generation of a fuel cell.
2 is a view schematically showing the structure of a membrane electrode assembly for a fuel cell.
3 is a view schematically showing an embodiment of a fuel cell.
4 is a scanning electron microscope image of the graphene oxide-carbon nanotube composite of Example 1. FIG.
5 is a transmission electron microscope image of the catalyst of Example 1.
6 is a scanning electron microscope image of the graphene oxide-carbon nanotube composite of Comparative Example 1.
7 is a transmission electron microscope image of the catalyst of Comparative Example 1.

Hereinafter, the present specification will be described in detail.

Herein is a carbon nanotube; A polymer layer having an amine group provided on the carbon nanotubes; And it provides a graphene-carbon nanotube composite comprising a graphene provided on the polymer layer.

The average size of the graphene-carbon nanotube composite may be 100 nm or more and 10 μm or less.

In the present specification, the average size of the graphene-carbon nanotube composite refers to an average of the length of the longest line among the lines connecting two points of the surface of the carrier-nanoparticle composite.

Carbon nanotubes or (oxidized) graphene are difficult to use because of the phenomenon of coagulation with each other, but by forming a composite as described herein, the aggregation of each structure is suppressed and the characteristics of the new structure can be used without restriction. Application is possible.

Such a structure can be efficiently used as a support for the catalyst.

The carbon nanotubes are six hexagonal carbons connected to each other to form a tubular shape, and the type of the carbon nanotubes is not particularly limited, but the carbon layer consists of one layer single-walled carbon nanotubes (SW-CNT, It may include at least one of a single-walled carbon nanotube) and a multi-walled carbon nanotube (MW-CNT) formed by stacking a plurality of carbon layers.

Some or all of the surface of the carbon nanotubes may be provided with a polymer layer. 50% or more and 100% or less of the surface of the carbon nanotube surface may be provided with a polymer layer, and specifically, 75% or more and 100% or less may be provided with a polymer layer.

The polymer layer is not particularly limited as long as it includes a polymer having an amine group. Herein, the amine group is a substituent in which a hydrogen atom of ammonia is substituted with a hydrocarbon group, and is classified into a primary amine group, a secondary amine group, a tertiary amine group and a quaternary amine group according to the number of hydrogen atoms substituted.

The polymer layer may include a polymer including at least one of a primary amine group, a secondary amine group, a tertiary amine group, and a quaternary amine group.

The polymer layer may include polyalkyleneimine. Specifically, the polymer layer may include at least one of linear polyalkyleneimine, branched polyalkyleneimine, and dendrimer type polyalkyleneimine.

The polyalkyleneimine may be a polymer having an aliphatic hydrocarbon main chain and including at least 10 or more amine groups in the main chain and the side chain. In this case, the amine group includes a primary amine group, a secondary amine group, a tertiary amine group, and a quaternary amine group, and the amine groups included in the main chain and the side chain of the polyalkyleneimine are a primary amine group, a secondary amine group, At least one of the tertiary amine group and the quaternary amine group may be ten or more.

The polyalkyleneimine may include at least one of a repeating unit represented by the following Formula 1 and a repeating unit represented by the following Formula 2.

[Formula 1]

[Formula 2]

In Formulas 1 and 2, E1 and E2 are each independently an alkylene group having 2 to 10 carbon atoms, R is a substituent represented by any one of the following Formulas 3 to 5, o and p are each an integer of 1 to 1000,

[Formula 3]

[Formula 4]

[Formula 5]

In Formulas 3 to 5, A1 to A3 are each independently an alkylene group having 2 to 10 carbon atoms, and R1 to R3 are each independently a substituent represented by any one of Formulas 6 to 8,

[Formula 6]

[Formula 7]

[Formula 8]

In Formulas 6 to 8, A4 to A6 are each independently an alkylene group having 2 to 10 carbon atoms, R4 to R6 are each independently a substituent represented by Formula 9,

[Formula 9]

In Formula 9, A7 is an alkylene group having 2 to 10 carbon atoms.

The polyalkyleneimine may include at least one of a compound represented by Formula 10 and a compound represented by Formula 11 below.

[Formula 10]

[Formula 11]

In Formulas 10 and 11, X1, X2, Y1, Y2 and Y3 are each independently an alkylene group having 2 to 10 carbon atoms, R is a substituent represented by any one of the following Formulas 3 to 5, q is 1 to 1000 Is an integer, n and m are each an integer of 1 to 5, l is an integer of 1 to 200,

[Formula 3]

[Formula 4]

[Formula 5]

In Formulas 3 to 5, A1 to A3 are each independently an alkylene group having 2 to 10 carbon atoms, and R1 to R3 are each independently a substituent represented by any one of Formulas 6 to 8,

[Formula 6]

[Formula 7]

[Formula 8]

In Formulas 6 to 8, A4 to A6 are each independently an alkylene group having 2 to 10 carbon atoms, R4 to R6 are each independently a substituent represented by Formula 9,

[Formula 9]

In Formula 9, A7 is an alkylene group having 2 to 10 carbon atoms.

는 치환기의 치환위치를 의미한다.In this specification,

Means a substitution position of a substituent.

In the present specification, the alkylene group may be linear or branched chain, carbon number is not particularly limited, but is preferably 2 to 10. Specific examples include, but are not limited to, ethylene group, propylene group, isopropylene group, butylene group, t-butylene group, pentylene group, hexylene group, heptylene group and the like.

The weight average molecular weight of the polymer having an amine group may be 500 or more and 1,000,000 or less.

The thickness of the polymer layer is not particularly limited, but may be, for example, 1 nm or more and 1 μm or less.

Graphite has a structure in which planes are arranged in layers in which carbons are arranged like honeycomb hexagonal nets, and one layer of graphite is called graphene.

The graphene may include at least one of graphene oxide and reduced graphene. Since the oxidized graphene has good dispersibility in the aqueous system due to the presence of functional groups, it is possible to distribute it evenly on the polymer layer, and use graphene oxide attached to the polymer layer as graphene or reduce the graphene oxide. Can be used.

The graphene may be a single layer or multiple layers of graphene.

The average diameter of the graphene is not particularly limited, but may be 300 nm or more and 700 nm or less, and specifically, about 500 nm.

The graphene may be bonded to the amine group of the polymer layer. Specifically, when the graphene is graphene oxide, the graphene oxide includes at least one of a carboxyl group and a hydroxyl group, the amine group of the polymer layer is to be coupled with at least one of the carboxyl group and the hydroxyl group of the graphene oxide by electrostatic attraction. Can be.

With respect to the sum of the weights of the graphene, the carbon nanotubes, and the polymer layer, the graphene content may be 20 wt% or more and 80 wt% or less.

It may further include a metal nanoparticle provided on the graphene.

The metal nanoparticles are platinum (Pt), ruthenium (Ru), rhodium (Rh), molybdenum (Mo), osmium (Os), iridium (Ir), rhenium (Re), palladium (Pd), vanadium (V), Tungsten (W), Cobalt (Co), Iron (Fe), Selenium (Se), Nickel (Ni), Bismuth (Bi), Tin (Sn), Chromium (Cr), Titanium (Ti), Gold (Au), It may include one or two or more metals selected from the group consisting of cerium (Ce), silver (Ag), and copper (Cu). Specifically, the metal nanoparticles may include platinum (Pt), and a platinum alloy in which iron (Fe), cobalt (Co) or nickel (Ni) and platinum (Pt) are alloyed.

The average particle diameter of the metal nanoparticles may be 2 nm or more and 10 nm or less, and specifically 2 nm or more and 7 nm or less. In this case, the metal nanoparticles do not aggregate with each other on the composite and are well dispersed, which has the advantage of high catalytic efficiency.

According to an exemplary embodiment of the present application, the average particle diameter of the metal nanoparticles is measured for 200 or more metal nanoparticles using graphic software (MAC-View), and the average particle diameter is measured through the obtained statistical distribution. it means.

The average particle diameter of the metal nanoparticles may indirectly measure the average particle diameter of the metal nanoparticles observed by an optical microscope.

The metal nanoparticles may have a spherical shape. In the present specification, the spherical shape does not mean only a perfect spherical shape, but may include an approximately spherical shape. For example, the metal nanoparticle may not have a spherical outer surface, and a radius of curvature may not be constant in one metal nanoparticle.

The content of the metal nanoparticles may be 1 wt% or more and 50 wt% or less with respect to the sum of the weights of the carbon nanotubes, the polymer layer, the graphene, and the metal nanoparticles. Specifically, the content of the metal nanoparticles may be 10 wt% or more and 40 wt% or less with respect to the total weight of the carrier-nanoparticle composite.

The present specification provides a catalyst including the graphene-carbon nanotube composite.

The present specification provides an electrochemical cell including the catalyst.

The electrochemical cell means a battery using a chemical reaction, and if the polymer electrolyte membrane is provided, the type thereof is not particularly limited. For example, the electrochemical cell may be a fuel cell, a metal secondary battery, or a flow battery.

The present specification provides an electrochemical cell module that includes an electrochemical cell as a unit cell.

The electrochemical cell module may be formed by inserting and stacking bipolar plates between flow cells according to one embodiment of the present application.

Specifically, the battery module may be used as a power source for an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a power storage device.

The present specification includes an anode, a cathode, and a polymer electrolyte membrane provided between the anode and the cathode, and at least one of the anode and the cathode provides the membrane electrode assembly.

The present specification provides a fuel cell including the membrane electrode assembly.

FIG. 1 schematically illustrates the principle of electricity generation of a fuel cell. In the fuel cell, the most basic unit for generating electricity is a membrane electrode assembly (MEA), which is an electrolyte membrane (M) and the electrolyte membrane (M). It consists of an anode (A) and a cathode (C) formed on both sides of the. Referring to FIG. 1, which illustrates the electricity generation principle of a fuel cell, in the anode A, an oxidation reaction of a fuel F such as hydrogen or a hydrocarbon such as methanol and butane occurs to generate hydrogen ions (H ⁺ ) and electrons (e ⁻ ). And hydrogen ions move to the cathode C through the electrolyte membrane M. The cathode C reacts with hydrogen ions transferred through the electrolyte membrane M, an oxidizing agent O such as oxygen, and electrons to generate water W. This reaction causes the movement of electrons in the external circuit.

2 schematically shows the structure of a fuel cell membrane electrode assembly, wherein the fuel cell membrane electrode assembly includes an electrolyte membrane 10 and a cathode 50 positioned to face each other with the electrolyte membrane 10 therebetween; An anode 51 may be provided. The cathode is provided with a cathode catalyst layer 20 and a cathode gas diffusion layer 40 sequentially from the electrolyte membrane 10, and the anode is provided with an anode catalyst layer 21 and an anode gas diffusion layer 41 sequentially from the electrolyte membrane 10. It may be provided.

The catalyst according to the present specification may be included in at least one of a cathode catalyst layer and an anode catalyst layer in a membrane electrode assembly.

3 schematically illustrates the structure of a fuel cell, in which the fuel cell includes a stack 60, an oxidant supply unit 70, and a fuel supply unit 80.

The stack 60 includes one or two or more membrane electrode assemblies as described above, and includes two or more separators interposed therebetween when two or more membrane electrode assemblies are included. The separator serves to prevent the membrane electrode assemblies from being electrically connected and to transfer fuel and oxidant supplied from the outside to the membrane electrode assembly.

The oxidant supply unit 70 serves to supply the oxidant to the stack 60. Oxygen is typically used as the oxidant, and may be used by injecting oxygen or air into the oxidant supply unit 70.

The fuel supply unit 80 serves to supply fuel to the stack 60, and to the fuel tank 81 storing fuel and the pump 82 supplying fuel stored in the fuel tank 81 to the stack 60. Can be configured. As fuel, hydrogen or hydrocarbon fuel in gas or liquid state may be used. Examples of hydrocarbon fuels include methanol, ethanol, propanol, butanol or natural gas.

Herein is to form a polymer layer having an amine group provided on the carbon nanotubes; And it provides a method for producing a graphene-carbon nanotube composite comprising the step of providing a graphene on the polymer layer by reacting the graphene with carbon nanotubes on which the polymer layer is formed.

The method for producing the graphene-carbon nanotube composite may be cited as described above for the graphene-carbon nanotube composite.

The forming of the polymer layer may include adding a polymer having an amine group to a solvent to prepare a first solution; Adding carbon nanotubes to the first solution; And it may include the step of stirring the first solution.

The first solution may further include a salt. The salt is _{^{NO 3 -, ClO 4 -,}} SCN -, I -, Br -, Cl -, CH 3 COO -, HCOO -, F -, OH -, HPO 4 - or SO ₄ ^2- in combination with the ions It may be a salt capable of dissociating anions.

The salt may be nitrate, for example KNO ₃ .

The solvent of the first solution is not particularly limited, but may be water.

Based on the total weight of the first solution, the content of the carbon nanotubes may be 0.01 wt% or more and 1 wt% or less.

Based on the total weight of the first solution, the content of the polymer having an amine group may be 0.01 wt% or more and 1 wt% or less.

Based on the total weight of the first solution, the salt content may be 0.01 wt% or more and 1 wt% or less.

Based on the total weight of the first solution, the content of the solvent may be 97% by weight or more and 99.97% by weight or less.

The stirring time of the first solution may be 1 hour or more and 3 days or less.

Graphene is provided on the polymer layer comprises the steps of preparing the graphene; And reacting the graphene with the carbon nanotubes on which the polymer layer is formed.

The step of providing graphene on the polymer layer may include preparing a second solution by adding the graphene to a solvent; And adding the second solution to the first solution to react the graphene with the carbon nanotubes on which the polymer layer is formed. Specifically, the step of providing graphene on the polymer layer is prepared by adding a graphene oxide to the solvent to prepare a second solution; And adding the second solution to the first solution to react the carbon nanotubes with graphene oxide on which the polymer layer is formed.

The pH of the second solvent may be 7 or more. Specifically, the pH of the second solvent may be 7 or more and 11 or less. In this case, carbon nanotubes and graphene having a polymer layer formed thereon have an advantage of forming a structure by spontaneous electrostatic attraction.

The adding of the second solution to the first solution to react the carbon nanotubes with graphene oxide on which the polymer layer is formed may be a step of stirring the solution to which the second solution is added to the first solution. In this case, the stirring time may be 1 minute or more and 1 day or less.

Based on the total weight of the second solution, the graphene content may be 0.01 wt% or more and 1 wt% or less.

Based on the total weight of the second solution, the content of the solvent may be 99% by weight or more and 99.99% by weight or less.

The second solution may further include a pH adjusting agent for adjusting the pH of the second solvent to 7 or more. The pH adjusting agent is not particularly limited, but for example, NaOH may be used. At this time, NaOH aqueous solution in which NaOH is dissolved in water may be used.

In the step of providing graphene on the polymer layer, in the case of using graphene oxide, after reacting the graphene with carbon nanotubes and the graphene polymer layer is formed, it may further comprise a step of reducing the graphene oxide.

Reducing the graphene oxide may be reduced to thermal reduction, chemical reduction, electrochemical reduction or photocatalyst reduction.

In the graphene-carbon nanotube composite manufacturing method, after the graphene is provided on the polymer layer, the graphene-coated carbon nanotubes and a metal precursor are added to a solvent to provide carbon with the graphene. The method may further include forming metal nanoparticles on the nanotubes.

Forming the metal nanoparticles on the graphene-coated carbon nanotubes may include adding a graphene-coated carbon nanotube and a metal precursor to a solvent to prepare a third solution; And it may include the step of stirring the third solution.

Forming the metal nanoparticles on the graphene-coated carbon nanotubes may further include adjusting the pH of the third solution.

Forming the metal nanoparticles on the graphene-coated carbon nanotubes may further include reducing the metal precursor after stirring.

The metal precursor is a material before reduction to the metal nanoparticles, and the metal precursor may be selected according to the type of the metal nanoparticles.

Based on the total weight of the third solution, the content of the carbon nanotubes with graphene may be 0.01 wt% or more and 1 wt% or less.

Based on the total weight of the third solution, the content of the metal precursor may be 0.005% by weight or more and 0.5% by weight or less.

Based on the total weight of the third solution, the content of the solvent may be 98.5% by weight or more and 99.985% by weight or less.

In the step of adjusting the pH of the third solution, the pH of the third solution may be adjusted to 10-11, and if the pH of the third solution can be adjusted, the pH adjusting method is not particularly limited, but by adding a pH adjusting agent 3 pH of the solution can be adjusted.

The pH adjusting agent is not particularly limited, but for example, NaOH may be used, and in this case, NaOH aqueous solution in which NaOH is dissolved in water may be used.

Hereinafter, the present specification will be described in more detail with reference to Examples. However, the following examples are merely to illustrate the present specification, but not to limit the present specification.

EXAMPLE

Example 1

0.157 g of Polyethyleneimine (PEI, Mw. 1800) and 0.314 g of KNO ₃ were dissolved in 100 g of water, and 0.12 g of CNT was added thereto to prepare a dispersion. The dispersion was passed through a high pressure homogenizer to evenly disperse PEI on the surface of CNT. 10 g of graphene oxide dispersion (2% graphene oxide content) was added to 200 g of water, and the solution was adjusted to 9 with aqueous NaOH solution. Put and stirred for 24 hours. After stirring and washing and drying to obtain a graphene oxide-carbon nanotube composite.

0.05 mmol of Pt precursor K ₂ PtCl ₄ , 0.5 mmol of sodium citrate and 40 mg of graphene oxide-carbon nanotube composite were sonicated in 40 g of water, and then adjusted to pH 10 using aqueous NaOH solution and then 70 It heated up at ° C. A solution of 20 mg NaBH ₄ dissolved in 15 mL of water was added dropwise to the reaction solution to reduce the Pt precursor provided on the surface of the graphene oxide-carbon nanotube composite to Pt nanoparticles. Thereafter, distilled water was washed and dried to obtain a graphene oxide-carbon nanotube composite having Pt nanoparticles thereon.

Comparative Example 1

Instead of coating PEI on the CNT surface, Octyl amine was reacted with nanotubes. Thereafter, a composite was formed with graphene oxide as described in Example 1, and Pt nanoparticles were supported on the composite.

Experimental Example 1

Scanning electron microscope (SEM) and transmission electron microscope (TEM) measurements

Scanning electron microscope for the graphene oxide-carbon nanotube composites of Example 1 and Comparative Example 1 was measured, and the transmission electron microscope for the catalyst on which the Pt nanoparticles are loaded in the composite was measured, and the results are shown in FIGS. An image of Example 1 is shown in FIG. 5, and an image of Comparative Example 1 is shown in FIGS. 6 and 7, respectively.

6 and 7, it was confirmed that the uniform composite than the graphene oxide-carbon nanotube composite of Example 1 was not formed and the Pt nanoparticles were not uniformly formed.

10: electrolyte membrane
20, 21: catalyst layer
40, 41: gas diffusion layer
50: cathode
51: anode
60: stack
70: oxidant supply
80: fuel supply
81: fuel tank
82: pump

Claims (19)

Carbon nanotubes;
A polymer layer having an amine group provided on the carbon nanotubes; And
It includes a graphene provided on the polymer layer,
The graphene is graphene-carbon nanotube composite that is coupled to the amine group of the polymer layer. The graphene-carbon nanotube composite of claim 1, wherein the polymer layer comprises polyalkyleneimine. The graphene-carbon nanotube composite of claim 2, wherein the polyalkyleneimine comprises at least one of a repeating unit represented by Formula 1 and a repeating unit represented by Formula 2 below:
[Formula 1]

[Formula 2]

In Chemical Formulas 1 and 2,
E1 and E2 are each independently an alkylene group having 2 to 10 carbon atoms,
R is a substituent represented by any one of the following formulas 3 to 5,
o and p are each an integer from 1 to 1000,
[Formula 3]

[Formula 4]

[Formula 5]

In Chemical Formulas 3 to 5,
A1 to A3 are each independently an alkylene group having 2 to 10 carbon atoms,
R1 to R3 are each independently a substituent represented by any one of formulas 6 to 8,
[Formula 6]

[Formula 7]

[Formula 8]

In Chemical Formulas 6 to 8,
A4 to A6 are each independently an alkylene group having 2 to 10 carbon atoms,
R4 to R6 are each independently a substituent represented by the following formula (9),
[Formula 9]

In Chemical Formula 9,
A7 is an alkylene group having 2 to 10 carbon atoms. The graphene-carbon nanotube composite of claim 2, wherein the polyalkyleneimine comprises at least one of a compound represented by Formula 10 and a compound represented by Formula 11 below:
[Formula 10]

[Formula 11]

In Chemical Formulas 10 and 11,
X1, X2, Y1, Y2 and Y3 are each independently an alkylene group having 2 to 10 carbon atoms,
R is a substituent represented by any one of the following formulas 3 to 5,
q is an integer from 1 to 1000,
n and m are each an integer of 1 to 5,
l is an integer from 1 to 200,
[Formula 3]

[Formula 4]

[Formula 5]

In Chemical Formulas 3 to 5,
A1 to A3 are each independently an alkylene group having 2 to 10 carbon atoms,
R1 to R3 are each independently a substituent represented by any one of formulas 6 to 8,
[Formula 6]

[Formula 7]

[Formula 8]

In Chemical Formulas 6 to 8,
A4 to A6 are each independently an alkylene group having 2 to 10 carbon atoms,
R4 to R6 are each independently a substituent represented by the following formula (9),
[Formula 9]

In Chemical Formula 9,
A7 is an alkylene group having 2 to 10 carbon atoms. delete The graphene-carbon nanotube composite according to claim 1, wherein the graphene content is 20 wt% to 80 wt% with respect to the total weight of the graphene-carbon nanotube composite. The graphene-carbon nanotube composite of claim 1, wherein the graphene is graphene oxide. The graphene-carbon nanotube composite of claim 1, further comprising metal nanoparticles provided on the graphene. The method of claim 8, wherein the metal nanoparticles are platinum (Pt), ruthenium (Ru), rhodium (Rh), molybdenum (Mo), osmium (Os), iridium (Ir), rhenium (Re), palladium (Pd), Vanadium (V), tungsten (W), cobalt (Co), iron (Fe), selenium (Se), nickel (Ni), bismuth (Bi), tin (Sn), chromium (Cr), titanium (Ti), Graphene-carbon nanotube composites comprising one or two or more metals selected from the group consisting of gold (Au), cerium (Ce), silver (Ag) and copper (Cu). Catalyst comprising a graphene-carbon nanotube composite according to any one of claims 1 to 4 and 6 to 9. An electrochemical cell comprising the catalyst of claim 10. A membrane electrode assembly comprising an anode, a cathode and a polymer electrolyte membrane provided between the anode and the cathode, wherein at least one of the anode and the cathode comprises the catalyst of claim 10. A fuel cell comprising the membrane electrode assembly of claim 12. Adding a polymer having an amine group and a salt to a solvent to prepare a first solution;
Adding carbon nanotubes to the first solution;
Stirring the first solution to form a polymer layer having an amine group provided on a carbon nanotube; And
The method of producing a graphene-carbon nanotube composite comprising the step of providing graphene on the polymer layer by reacting the carbon nanotubes and graphene on which the polymer layer is formed. delete The method of claim 14, wherein the step of providing graphene on the polymer layer comprises the steps of preparing the graphene; And reacting the graphene with the carbon nanotubes having the polymer layer formed thereon. The method of claim 14, wherein the preparing of graphene on the polymer layer comprises: preparing a second solution by adding graphene oxide to a solvent; And adding a second solution to the first solution to react the carbon nanotubes on which the polymer layer is formed with graphene oxide. The method of claim 17, wherein the providing of graphene on the polymer layer further comprises reducing the graphene oxide. The method according to claim 14, After the graphene is provided on the polymer layer, by adding a carbon nanotube and a metal precursor with the graphene to the solvent to the metal nano on the carbon nanotube with the graphene Graphene-carbon nanotube composite manufacturing method comprising the step of forming a particle.

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