KR101996723B1 - Electrode, biofuel cell and its preparing method - Google Patents

Abstract

The present invention relates to an electrode, a biofuel cell using the same, and a method of manufacturing the same. The electrode according to the present invention includes a core body 10 made of carbon nanotube fibers (CNT fiber), a base surrounding the outer periphery of the core body 10 A nanoparticle layer 31 including metal nanoparticles and surrounding the outer circumferential surface of the base layer 20 and a monomolecular material having an amine group, the monomolecular layer 31 surrounding the outer surface of the nanoparticle layer 31, (33).

Description

ELECTRODE, BIOFUEL CELL AND ITS PREPARING METHOD, AND METHOD FOR MANUFACTURING THE SAME

The present invention relates to an electrode, a biofuel cell using the biofuel cell, and a method of manufacturing the same, and more particularly, to a technique for manufacturing electrodes by coating metal nanoparticles on a tongue or a nodule fiber and applying the same to a biofuel cell .

Biofuel cells (BFCs) are a type of fuel cell that uses biomass as a fuel or uses a biocatalyst to oxidize the fuel. Such a biofuel cell is expected to be a power source for implantable biomedical devices such as a pacemaker, a neurostimulator, a drug delivery pump, and the like, as disclosed in the patent documents of the following prior art documents.

Electron transport of biofuel cells is divided into mediated electron transfer (MET) and direct electron transfer (DET) depending on the connection between enzymatic reaction and electrode reaction. MET is a method of transferring electrons through the oxidation and reduction reaction of a mediator in which electrons released from the oxidized active site of the enzyme are freely present in the solution. DET is a method in which electrons transferred from the oxidized electrode directly move to the electrode, .

MET based biofuel cells have excellent performance using osmium, ruthenium, and iron as intermediates. However, when transplanted into a living body, there is a problem of poisoning due to the electron transfer mediator outflow, instability of the mediator, and high cost arising from complicated synthesis steps.

Recently, interest in DET-based biofuel cells is increasing. However, in the case of the DET based electrode, the performance of the electrode is relatively lower than that of the MET based electrode.

KR 10-2009-0040797 A

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made in view of the above problems, and it is an object of the present invention to provide an electrode capable of controlling the degree of conductivity by coating metal nano- .

Another aspect of the present invention is to provide a biofuel cell in which a carbon nanotube fiber-based electrode is applied to a cathode and an anode to improve power generation performance.

The electrode according to the present invention comprises a core body made of carbon nanotube fibers (CNT fiber); A base layer surrounding an outer peripheral surface of the central body; A nanoparticle layer comprising metal nanoparticles and surrounding an outer circumferential surface of the base layer; And a monomolecular layer containing a monomolecular material having an amine group and surrounding the outer peripheral surface of the nanoparticle layer.

In the electrode according to the present invention, the carbon nanotube fiber is functionalized with a carboxyl group (COOH).

Further, in the electrode according to the present invention, the base layer includes a PEI polymer.

Further, in the electrode according to the present invention, the metal nanoparticles include at least one selected from the group consisting of gold, silver, aluminum, copper, and platinum.

Further, in the electrode according to the present invention, the monomolecular substance is tris (2-aminoethylamine) (TREN).

Further, in the electrode according to the present invention, a plurality of double-layered nanocomposite films in which the single-molecular layer is laminated on the nanoparticle layer are laminated.

Meanwhile, the biofuel cell according to the present invention comprises a carbon nanotube fiber electrode, an enzyme layer containing an enzyme and disposed on an outer surface of a monolayer of a carbon nanotube fiber electrode, and a monomolecular material having an amine group, An anode including a linker layer disposed on the anode; And a cathode including a carbon nanotube fiber electrode.

Also, in the biofuel cell according to the present invention, the enzyme includes at least one selected from the group consisting of glucose oxidase and D-fructose dehydrogenase.

Further, in the biofuel cell according to the present invention, the monomolecular substance of the linker layer is tris (2-aminoethylamine) (TREN).

In the biofuel cell according to the present invention, a plurality of double-layer oxide layers in which the linker layer is laminated on the enzyme layer are laminated.

Meanwhile, a method for manufacturing an electrode according to the present invention comprises the steps of: (a) coating a base layer by immersing carbon nanotube fibers in a solution in which a polymer is dissolved; (b) immersing the carbon nanotube fibers coated with the base layer in a solution in which the metal nanoparticles are dissolved, thereby coating the nanoparticle layer; And (c) immersing the carbon nanotube fibers coated with the nanoparticle layer in a solution in which a monomolecular material having an amine group is dissolved, thereby coating a monolayer; And a nanocomposite thin film of the double layer in which the monomolecular layer is laminated is formed on the nanoparticle layer.

Also, in the method of manufacturing an electrode according to the present invention, the step (b) and the step (c) are sequentially repeated so that a plurality of the nanocomposite thin films are formed.

Meanwhile, a method for fabricating a biofuel cell according to the present invention comprises the steps of: (a) immersing two carbon nanotube fibers in a solution in which a polymer is dissolved, and coating the base layer with each of the two carbon nanotube fibers; (b) immersing each of the carbon nanotube fibers coated with the base layer in a solution in which the metal nanoparticles are dissolved, thereby coating the nanoparticle layer; (c) immersing each of the carbon nanotube fibers coated with the nanoparticle layer in a solution in which a monomolecular substance having an amine group is dissolved, thereby coating a monolayer; (d) immersing any one of the carbon nanotube fibers coated with the monolayer in a solution in which an enzyme is dissolved to coat an enzyme layer; And (e) immersing the carbon nanotube fibers coated with the enzyme layer in a solution in which a monomolecular substance having an amine group is dissolved, thereby coating the linker layer.

Further, in the method of manufacturing a biofuel cell according to the present invention, the step (a) and the step (b) are sequentially and repeatedly performed so that a plurality of double-layered nanocomposite thin films in which the single- And the step (c) and the step (d) are repeated in order to form a plurality of bilayer oxide layers in which the linker layer is laminated on the enzyme layer.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to that, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor may properly define the concept of the term in order to best explain its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

According to the present invention, by packing metal nanoparticles at high density on the outer circumferential surface of carbon nanotube fibers, the electrical conductivity of the electrode can be improved, sufficient electrochemical performance and excellent flexibility can be ensured and the present invention can be applied to a flexible device. By securing stability, it has applicability to various energy storage devices as well as nanobiotechnology.

In addition, the biofuel cell based on the carbon nanotube fiber electrode increases the electron transfer rate between the active site of the enzyme and the electrode surface due to the coating of the metal nanoparticles, thereby improving power generation performance.

1 is a perspective view schematically showing an electrode according to an embodiment of the present invention.
2 is a perspective view schematically showing a biofuel cell according to an embodiment of the present invention.
3 is a process diagram of an electrode manufacturing method according to an embodiment of the present invention.
4 is a process diagram of a method for manufacturing a biofuel cell according to an embodiment of the present invention.
5 is a cross-sectional view and an EDAX analysis image of an electrode according to the present invention.
6 is an SEM image of the nanocomposite thin film stacked on the electrode according to the present invention.
FIG. 7 is a graph (a) and a CV curve (b) of the electrical conductivity of the nanocomposite thin film according to the present invention.
8 is a graph showing the performance (a) of the anode of the biofuel cell according to the present invention, the change (b) of the internal resistance (ESR) of the anode according to the glucose concentration, the cathode performance (c), and the power density to be.

BRIEF DESCRIPTION OF THE DRAWINGS The objectives, specific advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings. Also, the terms "first "," second ", and the like are used to distinguish one element from another element, and the element is not limited thereto. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the present invention, detailed description of related arts which may unnecessarily obscure the gist of the present invention will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view schematically showing an electrode according to an embodiment of the present invention.

1, the electrode according to the present invention includes a core body 10 made of carbon nanotube fibers (CNT fiber), a base layer 20 surrounding the outer peripheral surface of the core body 10, and metal nanoparticles A nanoparticle layer 31 surrounding the outer circumferential surface of the base layer 20 and a monomolecular layer 33 surrounding the outer circumferential surface of the nanoparticle layer 31 including a monomolecular material having an amine group.

The present invention relates to an electrode having improved conductivity by coating metal nanoparticles on a carbon nanotube fiber (CNT fiber), and can be applied to various devices requiring electron transfer such as a bio fuel cell and a nano bio electronic device . Particularly, when the present invention is applied to a biofuel cell that converts biological energy into electric energy, it can greatly contribute to improvement of power generation performance.

Specifically, an electrode according to the present invention includes a core body 10, a base layer 20, a nanoparticle layer 31, and a monolayer 33.

The central body 10 is disposed at the center of the electrode according to the present invention and supports the nanoparticle layer 31 and the monomolecular layer 33 to be described later. Here, the core body 10 is made of carbon nanotube fibers. The fibrous carbon nanotubes are formed of hexagons composed of six carbons connected to each other and formed in the shape of a tube having a diameter of several to several tens of nanometers, and are excellent in electric conductivity. In addition, since it has excellent mechanical strength and is stable to strain, it can be utilized as a flexible electrode material.

On the other hand, carbon nanotube fibers can be functionalized with a carboxyl group (COOH). Carbon nanotube fibers functionalized with a carboxyl group have a hydrophilic surface, so that coating of metal nanoparticles to be described later can be effectively carried out, and the metal nanoparticles can be packed with high density. Further, since the carbon nano tube is formed in the form of a porous hollow tube, the metal nanoparticles can be infiltrated not only on the surface but also inside thereof.

The base layer 20 is a layer coated on the central body 10 in the form of surrounding the outer peripheral surface of the central body 10. [ The foundation layer 20 is provided for effectively coating the nanoparticle layer 31, that is, metal nanoparticles, which will be described later, on the core body 10. As the material of the base layer 20, a polymer can be used. Typically, polyethyleneimine (PEI) can be used. However, the material of the base layer 20 is not limited to the above-described polymer, and may be any material as long as it enables the coating of the metal nanoparticles.

The nanoparticle layer 31 is a layer that is introduced into the outer peripheral surface of the core body 10 via the base layer 20. The nanoparticle layer 31 is formed such that the metal nanoparticles are in the form of a thin film and surround the outer circumferential surface of the base layer 20. The metal nanoparticles may be one kind selected from the group consisting of gold, silver, aluminum, Or more. However, the metal is not necessarily limited thereto.

The monolayer 33 is a layer laminated on the nanoparticle layer 31 and comprises a monomolecular material having an amine group. Here, the monomolecular material is coated in the form of a layer-by-layer assembly (LbL assembly) based on a solution process so as to surround the outer circumferential surface of the nanoparticle layer 31 to form the monomolecular layer 33. In the case of a film composed of metal particles, although the metal has a low resistance, since the metal particles are surrounded by the long ligand, the metal film exhibits the insulating property. Thus, in the present invention, a monomolecular material having an amine group is coated on the nanoparticle layer 31 to replace the insulating ligand, thereby improving the binding force of the metal nanoparticles and imparting electrical conductivity to the nanoparticle layer 31. Examples of the amine-containing monomolecular substance capable of performing such a role include tris (2-aminoethyl) amine (TREN), diethylenetriamine (DETA) Can be used. However, the monomolecular substance is not limited thereto.

As a result, the electrode according to the present invention has a structure in which the nanocomposite thin film 30 formed of the double layer of the nanoparticle layer 31 / the single molecular layer 33 is arranged on the outer circumferential surface of the carbon nanotube fiber by a layered self-assembly method. That is, the carbon nanotube fibers, the base layer 20, and the nanocomposite thin film 30 are sequentially stacked.

Meanwhile, the electrode according to another embodiment of the present invention may include a plurality of nanocomposite thin films 30 (not shown). A first nanocomposite film 30 in which one monolayer 33 is laminated on one of the nanoparticle layers 31 and a second monolayer 33 laminated on the other nanoparticle layer 31 A plurality of nanocomposite thin films 30 are stacked in such a manner that the nanocomposite thin films 30 are sequentially arranged. As the number of layers of the nanocomposite thin film 30 increases, the electrical conductivity increases. Therefore, the number of layers can be determined in consideration of the electrical conductivity required in the device to which the electrode according to the present invention is applied.

In summary, according to the present invention, metal nanoparticles are packed at a high density on the outer circumferential surface of carbon nanotube fibers to improve electrical conductivity of the electrode, ensure sufficient electrochemical performance and excellent flexibility, and can be applied to a flexible device, The stability of the electrode is ensured and it has applicability not only to the nano-bio field but also to various energy storage devices.

Such a carbon nanotube fiber-based electrode can be used for a biofuel cell. Hereinafter, a biofuel cell to which the electrode is applied will be described in detail.

2 is a perspective view schematically showing a biofuel cell according to an embodiment of the present invention.

2, the biofuel cell according to the present invention includes a carbon nanotube fiber electrode 110, an enzyme layer 130 including an enzyme and disposed on the outer surface of the monolayer of the carbon nanotube fiber electrode 110, And an anode 100 including a linker layer 150 disposed on the outer surface of the enzyme layer 130 and containing a monomolecular material having an amine group and a cathode 200 including a carbon nanotube fiber electrode 110, .

Biofuel cells generate electricity by inducing the movement of electrons by using hydrogen that is produced by oxidizing glucose and fuel by oxidizing hydrogen at the anode and reducing oxygen at the cathode. Electron transport of a biofuel cell is controlled by the oxidation reaction of a mediator in which electrons released from oxidation of the active site of the enzyme are freely present in the solution according to the linkage between the enzymatic reaction and the electrode reaction (MET), which transports electrons, and a direct electron transfer (DET), which transfers electrons from the oxidized electrode to the electrodes to transfer electrons. MET-based biofuel cells suffer from toxicity due to outflow of osmium, ruthenium, iron and the like, instability of the medium, and high manufacturing costs of the biofuel cell, Delivery is by DET.

Conventional DET-based biofuel cells have low power generation performance and thus have limited application. This is because the redox center of glucose oxidase is located deep within the apoenzyme and the electron transfer between the enzyme active site and the electrode surface is slow.

 Accordingly, in the present invention, the power generation performance can be improved by applying the carbon nanotube fiber electrode.

The anode 100 of the biofuel cell according to the present invention includes a carbon nanotube fiber electrode 110, an enzyme layer 130, and a linker layer 150.

The carbon nanotube fiber electrode 110 may be an electrode in which a plurality of nanocomposite thin films (nanoparticle layer / monomolecular layer) are laminated, in which carbon nanotube fibers / base layer / nanoparticle layer / monolayer layer are stacked. Other matters have been described above, but redundant descriptions are omitted or simply described.

The enzyme layer 130 includes an enzyme and is formed on the outer surface of the outermost monolayer of the electrode 110. Here, the enzyme layer 130 may be formed by coating an enzyme with a monolayer covering the enzyme layer. At this time, the enzyme may be laminated to the monolayer by a solution process and include one or more selected from the group consisting of glucose oxidase (GOx), and fructose dehydrogenase (D-fructose dehydrogenase), for example. can do. If the enzyme is an enzyme capable of oxidizing hydrogen in response to glucose serving as a fuel of the anode 100, the type thereof is not necessarily limited to the enzyme described above.

The linker layer 150 comprises a monomolecular material having an amine group and is disposed on the outer surface of the enzyme layer 130. At this time, it may be arranged in a specific part of the outer surface of the enzyme layer 130 or in a form to surround the outer surface. Here, the monomolecular material forming the linker layer 150 can be, for example, tris (2-aminoethyl) amine, TREN, diethylenetriamine (DETA) have. The linker layer 150 may be coated on the enzyme layer 130 in such a manner that the enzyme layer 130 is immersed in a solution in which the monomolecular material is dissolved.

On the other hand, a plurality of oxidation layers formed in a bilayer form by stacking the linker layer 150 on the enzyme layer 130 may be stacked. In other words, the second oxide layer 130 in which the other linker layer 150 is laminated on the first oxide layer in which one linker layer 150 is laminated on one enzyme layer 130, and the other linker layer 150 is laminated on the other enzyme layer 130 A plurality of oxide layers can be stacked.

Under the above-described structure of the anode 100, carbon nanotubes in which nanoparticle layers and monomolecular layers are disposed on the outer surface promote electron transfer between the active site of the enzyme and the electrode surface. Thus, the power generation performance of the biofuel cell according to the present invention is improved.

In the cathode 200 of the biofuel cell according to the present invention, a carbon nanotube fiber electrode 110 in which a carbon nanotube fiber / base layer / nanoparticle layer / monolayer layer is laminated can be used without introducing an enzyme. At this time, the electrode 110 may be an electrode in which a plurality of nanocomposite thin films are stacked.

A method of operating the biofuel cell based on the carbon nanotube fiber electrode 110 will be described. Here, it is assumed that the fuel of the anode 100 is glucose and the enzyme layer 130 uses GOx. At this time, glucose is oxidized to gluconolactone in the anode 100, and electrons are transferred from the GOx to the carbon nanotube fiber electrode 110. In the cathode 200, electrons are transferred through the electrolyte by a reduction reaction at the carbon nanotube fiber electrode 110.

Hereinafter, an electrode according to the present invention and a method for manufacturing a biofuel cell will be described.

3 is a process diagram of an electrode manufacturing method according to an embodiment of the present invention.

3, the method for manufacturing an electrode according to the present invention comprises the steps of: (a) immersing carbon nanotube fibers in a solution in which a polymer is dissolved to coat a base layer; (b) A step of immersing a carbon nanotube fiber coated with a base layer in a solution to coat a nanoparticle layer; and (C) immersing a nanotubular layer-coated carbon nanotube fiber in a solution in which a monomolecular substance having an amine group is dissolved Layered nanocomposite film on the outer surface of the carbon nanotube fiber, wherein the nanocomposite layer is laminated with the monomolecular layer.

The present invention relates to a method for fabricating a carbon nanotube fiber electrode according to the present invention, wherein redundant descriptions are omitted or simply described.

The electrode according to the present invention is manufactured by the following method, using a layered self-assembly method based on a solution process.

First, in order to coat the base layer with the carbon nanotube fibers, a solution in which the polymer constituting the base layer is dissolved is prepared, and carbon nanotube fibers are immersed in the solution (step (a)). Here, the polymer may be polyethyleneimine (PEI), wherein the solution is prepared by dissolving PEI in a solvent such as ethanol. However, the kind of the polymer and the solvent is not particularly limited.

Next, the carbon nanotube fiber coated with the base layer is immersed in the solution in which the metal nanoparticles are dissolved (step (b)). At this time, the metal nanoparticles are self-assembled in layers to form a film-like nanoparticle layer on the outer surface of the base layer. Here, although the gold nanoparticles protected with Tetraoctylammonium bromide (TOABr) are used as the metal nanoparticles, the metal nanoparticles are not necessarily limited to the metal nanoparticles, but may be metal nanoparticles composed of one or more kinds selected from silver, aluminum, copper, Particles may also be used. In addition, uncoated metal nanoparticles may be washed away using pure toluene or the like.

When the nanoparticle layer is formed, the carbon nanotube fibers are immersed in a solution in which the monomolecular substance having an amine group is dissolved (step (c)). At this time, the monomolecular material is laminated on the nanoparticle layer by a layered self-assembly method to form a monolayer, thereby forming a bilayer nanocomposite thin film. At this time, the weakly adsorbed monomolecular material can be removed by washing with ethanol or the like, and dried to produce an electrode having a single nanocomposite thin film. Here, the monomolecular substance induces a ligand exchange reaction between TREN and TOABr using tris (2-aminoethyl) amine (TREN). However, the monomolecular substance is not necessarily limited to TREN, and a monomolecular substance having an amine group such as diethylenetriamine (DETA) can be used without limitation.

In this case, the nanoparticle layer forming step (step (b)) and the monolayer forming step (step (c)) are sequentially repeated. At this time, washing and drying steps may be additionally performed before each immersion step.

Hereinafter, a method of manufacturing a biofuel cell based on a carbon nanotube fiber electrode according to the present invention will be described.

4 is a process diagram of a method for manufacturing a biofuel cell according to an embodiment of the present invention.

4, the method for fabricating a biofuel cell according to the present invention comprises the steps of (a) immersing two carbon nanotube fibers in a solution in which a polymer is dissolved, respectively, and coating the base layer, (b) A step of immersing each of the carbon nanotube fibers coated with the base layer in a solution in which the nanoparticles are dissolved to coat the nanoparticle layer; (c) a step of immersing the nanoparticle layer coated with the nanoparticle layer (D) immersing the carbon nanotube fibers coated with the monolayer in a solution in which the enzyme is dissolved, and coating the enzyme layer; and e) immersing the carbon nanotube fibers coated with the enzyme layer in a solution in which the monomolecular substance having an amine group is dissolved, and coating the linker layer.

A biofuel cell according to the present invention comprises an anode and a cathode. Therefore, in the method of manufacturing a biofuel cell according to the present invention, two carbon nanotube fibers are used to manufacture an anode and a cathode, respectively. Here, the cathode uses the carbon nanotube fiber electrode according to the present invention in which the enzyme layer is not formed, and therefore, it is manufactured in the same manner as the above-described electrode manufacturing method (steps (a) to (c)).

Meanwhile, in order to manufacture the anode, carbon nanotube fibers having the nanocomposite thin film formed by steps (a) to (c) are immersed in a solution in which the enzyme is dissolved (step (d)). At this time, an enzyme layer is formed on the outermost monolayer of the nanocomposite thin film. Here, the solvent used in the solution may be a phosphate buffer (PB buffer), but is not limited thereto. On the other hand, the enzyme may include at least one enzyme selected from the group consisting of glucose oxidase and D-fructose dehydrogenase.

Next, the carbon nanotube fiber having the enzyme layer formed therein is immersed in the solution in which the monomolecular substance having an amine group is dissolved (step (e)). As a result, a bilayer oxide layer is formed in which a linker layer is formed, and as a result, a linker layer is laminated on the enzyme layer. Here, the monomolecular substance may be, for example, tris (2-aminoethyl) amine, TREN, diethylenetriamine (DETA) May be phosphate buffer (PB buffer).

Meanwhile, the anode of the biofuel cell according to the present invention may be formed in a structure in which a plurality of oxidation layers are laminated. To this end, the enzyme layer forming step (d) and the linker layer forming step (e) ) Can be sequentially repeated.

Hereinafter, the present invention will be described in more detail with reference to specific examples.

Example 1: Fabrication of carbon nanotube fibers functionalized with COOH

In this example, carbon nanotube fibers functionalized with a carboxyl group (COOH) were prepared. The ends of pristine multi-walled carbon nanotube fibers were fixed to a teflon mold and nitric acid (HNO ₃ , 25 wt%) was added for 90 minutes at 70 ° C without stirring. And oxidized with a mixture of sulfuric acid (H ₂ SO ₄ , 75 wt%). At this time, in order to obtain stably functionalized carbon nanotube fibers, the above process is performed within 2 hours. Carbon nanotube fibers were prepared, washed three times with distilled water, and then dried at room temperature for 3 hours or more.

Example 2: Synthesis of TOA-gold nanoparticles

In this example, gold nanoparticles protected with tetraoctylammonium bromide (TOABr) were synthesized. 30 mM of the HAuCl _{4 ·} 3H ₂ O are dissolved in deionized water (30 ml) and mixed with each other, stirring the toluene (80 ml) dispersal TOABr of 20 mM, and 0.4 M of NaBH ₄ solution (25 ml) to Was added to the mixture and reduced. The toluene was then separated from the aqueous solution and washed several times with H ₂ SO ₄ (0.1 M, 95% purity), NaOH (0.1 M, 97%) and deionized water and finally TOA- Nanoparticles were synthesized.

Example 3: Production of carbon nanotube fiber electrode

In this embodiment, a carbon nanotube fiber electrode was prepared. PEI polymer is dissolved in the ^ethanol by immersing the prepared in Example 1 (1 mg ml ¹⁾ carbon nanotube fibers, and coating the PEI on a carbon nanotube fiber. Next, the PEI-coated fibers in Example 2. The TOA- gold nanoparticle solution synthesized in ^- and then immersed for 40 minutes in (10 mg ml ^1), was washed with pure toluene. Finally, the fibers were immersed in TREN-dispersed ethanol (1 mg ml ^{- 1} ) for 40 minutes, washed with pure ethanol to remove weakly adsorbed TREN molecules, and a single double layer nanocomposite film- (TOA-Au / TREN) ₁ fiber electrode). Here, a ligand exchange reaction takes place between TOABr and TREN.

By repeating the above procedure, a carbon nanotube fiber electrode having a structure in which a plurality of nanocomposite thin films were stacked was manufactured.

Example 4: Anode and cathode fabrication of a biofuel cell

In this embodiment, an anode and a cathode of a biofuel cell were manufactured. In order to manufacture the anode, first, glucose oxidase (glucose oxidase, GOx) the enzyme solution in phosphate buffer (PB buffer) ^- the carbon nanotubes produced in the ^{(GOx, 5 mg ml 1)} , Example 3 tube fiber electrode . Next, (TOA-Au / TREN) ₂₀ carbon nanotube fiber electrode was immersed in PB buffer in which TREN was dissolved. Here, (TOA-Au / TREN) ₂₀ is a carbon nanotube fiber electrode of Example 3 in which 20 nanocomposite thin films are laminated. Thus, a (TOA-Au / TREN) ₂₀ (GOx / TREN) ₁ fiber anode in which one enzyme double layer is formed is produced. By repeating the above procedure, a fibrous anode electrode having a structure in which a plurality of enzyme double layers were laminated was prepared.

Here, the cathode used was a (TOA-Au / TREN) ₂₀ carbon nanotube fiber electrode.

Evaluation Example 1: SEM image and EDAX analysis of carbon nanotube fiber electrode

FIG. 5 is a cross-sectional and elemental analyzer (EDAX) analysis image of a fiber / TOA-Au / TREN ₂₀ carbon nanotube fiber electrode according to the present invention, (B) to (c) show EDAX analysis results (Yellow: gold nanoparticles, Red: carbon). As a result, gold nanoparticles and TREN were successfully deposited on carbon nanotube fibers.

6 is a SEM image of the nanocomposite thin film (TOA-Au / TREN) _n of the electrode according to the present invention, according to the number of layers (n). 6 (a) is a SEM image of a surface morphology of carbon nanotube fibers (diameter 32 탆) before coating of gold nanoparticles, and FIG. 6 (b) is an enlarged image of carbon nanotube fibers before coating gold nanoparticles , And (c) to (e) of FIG. 6 are images in which n is 5, 10 and 20, respectively. 6 (f), when n is 20, CNT / (TOA-Au / TREN) ₂₀ carbon nanotube fibers (TOA-Au / TREN) ₂₀ carbon nanotube fiber (CNT) This is an enlarged image of the electrode.

From this image, it can be seen that as the number of gold nanoparticles protected with TOABr and TREN are sequentially stacked on the pure carbon nanotube fibers and the number of stacked layers (n) increases, a larger amount of gold nanoparticles are uniformly packed Can be confirmed.

6 (h) shows a CNT / (TOA-Au / TREN) ₂₀ carbon nanotube fiber Sectional image of the electrode, and Fig. 6 (i) is an enlarged cross-sectional image including gold nanoparticles in the carbon nanotube fiber electrode.

Here, hollows are formed inside the carbon nanotube fiber electrode, and it is confirmed that the gold nanoparticles penetrate not only the surface of the carbon nanotube fiber electrode but also the inside thereof.

Evaluation Example 2: Electrical characteristics of carbon nanotube fiber electrode

7A is a graph showing resistivity and electrical conductivity of a carbon nanotube fiber electrode (CNT / (TOA-Au / TREN) _n ), and FIG. 7B is a graph showing resistivity and electric conductivity of a carbon nanotube fiber electrode Is a cyclic voltammagram (CV).

As shown in FIG. 7 (a), as the number of stacks (n) of the TOA-Au and TREN double layers, that is, the nanocomposite thin films, was increased, the electrical conductivity of the electrodes was increased and the resistivity was decreased.

It can also be seen from Fig. 7 (b) that the nanocomposite film has dependency on the current density with respect to the voltage applied thereto.

Evaluation Example 3: Performance of a biofuel cell

8 is a graph showing the performance (a) of the anode of the biofuel cell according to the present invention, the change (b) of the internal resistance (ESR) of the anode according to the glucose concentration, the cathode performance (c), and the power density to be. Here, the performances of the anode and the cathode ((a) and (c)) were shown using cyclic voltammetry, and the current density was calculated from the diameter of the carbon nanotube fiber electrode measured by the SEM image The side surface area of the fiber was standardized. On the other hand, the anode was formed in the structure of CNT / (TOA-Au / TREN) ₂₀ (GOx / TREN) ₅ according to Example 4 (see the inset of FIG.

As a result, the current density of the anode increased with the concentration in the glucose concentration range of 0 to 300 mmol·l ^-1 . In particular, 300 mmol·l ^- the ^first concentration, at 0.6 V, shows a maximum current density and the minimum ESR. At this time, electrons are directly transmitted between CNT / (TOA-Au / TREN) ₂₀ and GOx.

The cathodes measure ESR in three different buffer conditions, such as nitrogen saturation, atmospheric conditions, and oxygen saturation. When provided there is sufficient fuel in the anode and cathode and the maximum current density (concentration 300 mmol·l ^-1, and the oxygen saturation of glucose) is from 0.6 V 28 ㎃㎝ ^-2, the -0.6 V 13 ㎃㎝ ^{- 2} . This is a standardized value and the electron transfer resistance is minimized from 108 [Omega] in the anode to 88 [Omega] in the cathode.

Without stirring in a wait state, a concentration of 300 mmol·l ^{- 1} of glucose The biofuel cell in the solution showed an open-circuit voltage of 1.03 V and a maximum power density of 1.31 mW cm ^-2 . In the low concentration (10 mmol·l ^-1 ) glucose solution considering the implantation, an open circuit voltage of 0.76 V and a maximum power density of 0.3 mWcm ^-2 were exhibited.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the same is by way of illustration and example only and is not to be construed as limiting the present invention. It is obvious that the modification or improvement is possible.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

10: center body 20: foundation layer
30: Nano composite thin film 31: Nano particle layer
33: monolayer 100: anode
110: Carbon nanotube fiber electrode 130: Enzyme layer
150: Linker layer 200: Cathode

Claims (14)

delete delete delete delete delete delete An anode comprising a carbon nanotube fiber electrode, an enzyme layer including an enzyme and disposed on an outer surface of the carbon nanotube fiber electrode, and a linker layer including a monomolecular material having an amine group and disposed on an outer surface of the enzyme layer; And
And a cathode including the carbon nanotube fiber electrode,
The carbon nanotube fiber electrode includes a core body made of carbon nanotube fibers (CNT fiber), a base layer surrounding the outer peripheral surface of the core body, a nanoparticle layer containing metal nanoparticles and surrounding the outer peripheral surface of the base layer, And a monomolecular layer surrounding the outer surface of the nanoparticle layer,
Wherein the monomolecular substance having an amine group is tris (2-aminoethylamine) (TREN).
The method of claim 7,
Wherein the enzyme comprises at least one member selected from the group consisting of glucose oxidase and D-fructose dehydrogenase.
delete The method of claim 7,
Wherein a plurality of oxidized layers of the double layer in which the linker layer is laminated on the enzyme layer are stacked.
delete delete (a) immersing two carbon nanotube fibers into a solution in which a polymer is dissolved, and coating each of the base layers with the carbon nanotube fibers;
(b) immersing each of the carbon nanotube fibers coated with the base layer in a solution in which the metal nanoparticles are dissolved, thereby coating the nanoparticle layer;
(c) immersing each of the carbon nanotube fibers coated with the nanoparticle layer in a solution in which a monomolecular substance having an amine group is dissolved, thereby coating a monolayer;
(d) immersing any one of the carbon nanotube fibers coated with the monolayer in a solution in which an enzyme is dissolved to coat an enzyme layer; And
(e) immersing the carbon nanotube fibers coated with the enzyme layer in a solution in which a monomolecular substance having an amine group is dissolved, thereby coating the linker layer;
Wherein the method comprises the steps of:
14. The method of claim 13,
The step (a) and the step (b) are sequentially repeated so that a plurality of double-layered nanocomposite thin films in which the monolayer layer is laminated on the base layer are repeatedly formed,
Wherein the step (c) and the step (d) are repeated in order so that a plurality of bilayer oxide layers in which the linker layer is laminated on the enzyme layer is formed.

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