JP2006156354A - Electronic mediator, enzyme immobilization electrode, fuel cell, electronic apparatus, vehicle, power generation system, co-generation system and electrode reaction utilization apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell which widely improves an output by using an electronic mediator in which a potential can be raised while taking a large current value. <P>SOLUTION: In the fuel cell including a structure having a fuel electrode 1 and an air electrode 3 facing to each other via an electrolyte layer 5 of a proton conductor, and an enzyme immobilization electrode in which at least fuel decomposition enzyme and an electronic mediator are immobilized to the fuel electrode 1, a concrete chemical constitution of the electronic mediator is specified. The electronic mediator are 2-amino -1, 4-naphthoquinone (ANQ), 2-methoxy -1, 4-naphthoquinone (MNQ), etc. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electron mediator, an enzyme-immobilized electrode, a fuel cell, an electronic device, a moving body, a power generation system, a cogeneration system, and an electrode reaction utilization device.

A fuel cell basically includes a fuel electrode (negative electrode), an oxidizer electrode or an air electrode (positive electrode), and an electrolyte (proton conductor), and its operation principle is the reverse operation of water electrolysis. Water and oxygen generate water (H ₂ O) and generate electricity. That is, the fuel (hydrogen) supplied to the fuel electrode is oxidized and separated into electrons and protons (H ⁺ ), the electrons are transferred to the fuel electrode, and H ⁺ moves through the electrolyte to the oxidant electrode. In the oxidizer electrode, this H ⁺ reacts with oxygen supplied from the outside and electrons sent from the fuel electrode through an external circuit to generate H ₂ O.

  In this way, a fuel cell is a highly efficient power generator that directly converts the chemical energy of fuel into electrical energy, and the chemical energy of fossil energy such as natural gas, oil, and coal can be used regardless of where and when it is used. Moreover, it can be extracted as electrical energy with high conversion efficiency. For this reason, research and development of fuel cells for large-scale power generation has been actively conducted. For example, there is a track record of demonstrating that a fuel cell is mounted on a space shuttle and water for crew can be supplied simultaneously with power, and that it is a clean power generator.

In recent years, fuel cells capable of operating in a relatively low temperature range from room temperature to about 90 ° C. such as a polymer electrolyte fuel cell using an ion exchange membrane as an electrolyte have been developed and attracted attention. ing.
From the various advantages described above, the polymer electrolyte fuel cell is not only used for large-scale power generation, but also for applications to small systems such as automobile power supplies, portable power supplies such as personal computers and mobile devices.

  However, although the polymer electrolyte fuel cell has an advantage that it can be operated at a relatively low temperature as described above, it has many problems. For example, when methanol is used as the fuel and the catalyst is operated near room temperature, poisoning of the catalyst by carbon monoxide (CO), generation of energy loss due to crossover, and catalyst of expensive noble metal such as platinum (Pt) are required. It is difficult to handle when using hydrogen as a fuel.

  Accordingly, attention has been paid to the fact that biological metabolism performed in living organisms is a highly efficient energy conversion mechanism, and proposals have been made to apply this to fuel cells. The biological metabolism here includes respiration and photosynthesis performed in microorganisms and cells. Biological metabolism has the characteristics that the power generation efficiency is extremely high and the reaction proceeds under mild conditions of about room temperature.

For example, respiration takes nutrients such as sugars, fats, and proteins into microorganisms or cells, and these chemical energies are converted to carbon dioxide (glycolytic and tricarboxylic acid (TCA) cycles through a number of enzymatic reaction steps. In the process of generating CO ₂ ), nicotinamide adenine dinucleotide (NAD ⁺ ) is reduced to form reduced nicotinamide adenine dinucleotide (NADH), which is converted into redox energy, that is, electric energy, and further an electron transfer system In this mechanism, the electric energy of NADH is directly converted into electric energy of proton gradient and oxygen is reduced to generate water. The electrical energy obtained here produces ATP from adenosine diphosphate (ADP) via adenosine triphosphate (ATP) synthase, and this ATP is used for reactions necessary for the growth of microorganisms and cells. Used. Such energy conversion occurs in the cytosol and mitochondria.

In addition, photosynthesis captures light energy and reduces nicotinamide adenine dinucleotide phosphate (NADP ⁺ ) via an electron transfer system to reduce nicotinamide adenine dinucleotide phosphate (NADPH), thereby converting it into electrical energy. In the process of conversion, it is a mechanism that oxidizes water to produce oxygen. This electric energy takes in CO ₂ and is used for carbon fixation reaction, and is used for carbohydrate synthesis.

  As a technique for utilizing the above-described biological metabolism in a fuel cell, a microbial cell that obtains an electric current by taking out the electric energy generated in the microorganism through the electron mediator and passing the electrons to the electrode has been reported. (For example, refer to Patent Document 1).

  However, since microorganisms and cells have many unnecessary functions in addition to the intended reaction such as conversion from chemical energy to electrical energy, the above-described method consumes electrical energy for reactions that are not originally intended. Therefore, there is a problem that the energy conversion efficiency is low and the loss increases accordingly.

  In recent years, fuel cells have been developed that achieve high energy conversion efficiency using enzymes and electron mediators involved in the conversion reaction of chemical energy to electrical energy in biological metabolism. It can be obtained (see, for example, Patent Document 2 and Non-Patent Document 1).

JP 2000-133297 A JP 2004-71559 A Chem. Lett. 32 (10) 880-881 (2003)

  However, according to the study by the present inventors, in the conventionally known fuel cells described in Patent Document 2 and Non-Patent Document 1, the amount of electric energy that can be extracted from the fuel is reduced by the combination of the electron mediator and the enzyme. There was a problem of being restricted. This will be described below.

FIG. 1 shows a general state diagram of a potential-current curve in a fuel cell. In FIG. 1, curves 1101 to 1103 indicate a potential-current curve on the negative electrode side, and a curve 1104 indicates a potential-current curve on the positive electrode side.
In order to increase the current value, the redox potential of the electron mediator may be brought close to the redox potential of the enzyme to increase the reaction rate between the electron mediator and the enzyme. The potential becomes small (curve 1103 in the figure).
On the other hand, when the potential is increased, the oxidation-reduction potential of the enzyme and the oxidation-reduction potential of the electron mediator are separated from each other, and the current value is generally reduced from the standard state (curve 1102) (in the figure, Curve 1101).
As described above, in an enzyme-electron mediator type fuel cell, since the current value and the potential are generally in a trade-off relationship as described above, an electron mediator that increases the potential at the same time while using a large current value is used. It is very difficult to do this, and this has been a major obstacle to improving the output of the enzyme-electron mediator type fuel cell.

Therefore, the problem to be solved by the present invention is applied to a fuel cell capable of dramatically improving the output by applying an electronic mediator capable of simultaneously increasing the potential while taking a large current value, and to the fuel cell. And providing a suitable enzyme-immobilized electrode and electron mediator.
The problem to be solved by the present invention is, more generally, an electrode for a fuel cell or the like that can achieve a dramatic improvement in output by applying an electronic mediator that can simultaneously increase the potential while taking a large current value. It is to provide a reaction utilization device.
Another problem to be solved by the present invention is to provide an electronic device, a moving body, a power generation system, and a cogeneration system using the excellent fuel cell as described above.

  As a result of intensive studies to solve the above problems, the present inventors have identified a specific chemical structure of an electron mediator suitable for application to an electrode reaction utilization device such as a fuel cell, and this electron mediator. It has been proved that the output can be drastically improved by actually applying it to a fuel cell, and the present invention has been devised.

（式中、Ｘ₁ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなることを特徴とする電子メディエーターである。 That is, in order to solve the above problem, the first invention
General formula

(Wherein X ₁ represents any _one of hydrogen, an alkyl group, and an aryl group)
It is an electron mediator characterized by consisting of the compound represented by these, or its derivative (s).

（式中、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなることを特徴とする電子メディエーターである。 The second invention is
General formula

(In the formula, X ₂ and X ₃ represent hydrogen, an alkyl group, or an aryl group)
It is an electron mediator characterized by consisting of the compound represented by these, or its derivative (s).

（式中、Ｘ₁ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体、および／または、
一般式

（式中、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなることを特徴とするものである。
この酵素固定化電極においては、好適には、多孔質カーボンからなる電極材に、少なくとも、酵素および電子メディエーターが固定化される。酵素は例えば分解酵素、特に燃料分解酵素であり、必要に応じてこれに加えて他の一種または二種以上の酵素を含む。 The third invention is
In an enzyme-immobilized electrode on which an enzyme and an electron mediator are immobilized,
The above electronic mediator is
General formula

(Wherein X ₁ represents any _one of hydrogen, an alkyl group, and an aryl group)
Or a derivative thereof and / or
General formula

(In the formula, X ₂ and X ₃ represent hydrogen, an alkyl group, or an aryl group)
It consists of the compound represented by these, or its derivative (s).
In this enzyme-immobilized electrode, preferably, at least an enzyme and an electron mediator are immobilized on an electrode material made of porous carbon. The enzyme is, for example, a decomposing enzyme, particularly a fuel decomposing enzyme, and optionally contains one or more other enzymes.

（式中、Ｘ₁ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体、および／または、
一般式

（式中、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなることを特徴とするものである。
この負極においては、好適には、多孔質カーボンからなる電極材に、少なくとも、酵素および電子メディエーターが固定化される。酵素は少なくとも燃料分解酵素を含み、必要に応じてこれに加えて他の一種または二種以上の酵素を含む。
燃料としては、各種のものを用いることができ、必要に応じて選ばれるが、代表的なものを挙げると、メタノール、エタノール、単糖類、多糖類などである。
例えば、燃料としてグルコースのような単糖類を用いる場合には、好適には、酵素として、単糖類の酸化を促進し分解する酸化酵素と、酸化酵素によって還元される補酵素を酸化体に戻す補酵素酸化酵素とが固定化される。この補酵素酸化酵素の作用により、補酵素が酸化体に戻るときに電子が生成され、補酵素酸化酵素から電子メディエーターを介して電極に電子が渡される。酸化酵素としては例えばグルコースデヒドロゲナーゼ（ＧＤＨ）が、補酵素としては例えばニコチンアミドアデニンジヌクレオチド（ＮＡＤ⁺ ）あるいはニコチンアミドアデニンジヌクレオチドリン酸（ＮＡＤＰ⁺ ）が、補酵素酸化酵素としては例えばジアホラーゼ（ＤＩ）が用いられる。
負極に上記の電子メディエーター、補酵素としての還元型ニコチンアミドアデニンジヌクレオチド（ＮＡＤＨ）、酸化酵素としてのグルコースデヒドロゲナーゼおよび補酵素酸化酵素としてのジアホラーゼを固定化する場合、最も好適には、これらを１．０（ｍｏｌ）：０．３３〜１．０（ｍｏｌ）：（１．８〜３．６）×１０⁶ （Ｕ）：（０．８５〜１．７）×１０⁷ （Ｕ）の比で固定化する。ただし、Ｕ（ユニット）とは、酵素活性を示す一つの指標であり、ある温度およびｐＨにおいて１分間当たり１μｍｏｌの基質が反応する度合いを示す。 The fourth invention is:
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(Wherein X ₁ represents any _one of hydrogen, an alkyl group, and an aryl group)
Or a derivative thereof and / or
General formula

(In the formula, X ₂ and X ₃ represent hydrogen, an alkyl group, or an aryl group)
It consists of the compound represented by these, or its derivative (s).
In this negative electrode, preferably, at least an enzyme and an electron mediator are immobilized on an electrode material made of porous carbon. The enzyme contains at least a fuel decomposing enzyme and, if necessary, one or more other enzymes.
Various types of fuels can be used and are selected as necessary. Typical examples include methanol, ethanol, monosaccharides, polysaccharides, and the like.
For example, when a monosaccharide such as glucose is used as the fuel, it is preferable that the enzyme is an oxidase that promotes and decomposes monosaccharides and a coenzyme that is reduced by the oxidase is returned to the oxidized form. Enzyme oxidase is immobilized. By the action of the coenzyme oxidase, electrons are generated when the coenzyme returns to the oxidized form, and the electrons are transferred from the coenzyme oxidase to the electrode via the electron mediator. For example, glucose dehydrogenase (GDH) is used as an oxidase, nicotinamide adenine dinucleotide (NAD ⁺ ) or nicotinamide adenine dinucleotide phosphate (NADP ⁺ ) is used as a coenzyme, and diaphorase (DI) is used as a coenzyme oxidase. ) Is used.
When the above-mentioned electron mediator, reduced nicotinamide adenine dinucleotide (NADH) as a coenzyme, glucose dehydrogenase as an oxidase, and diaphorase as a coenzyme oxidase are immobilized on the negative electrode, most preferably 0.0 (mol): 0.33 to 1.0 (mol): (1.8 to 3.6) × 10 ⁶ (U): (0.85 to 1.7) × 10 ⁷ (U) ratio Immobilize with. However, U (unit) is an index indicating enzyme activity, and indicates the degree to which 1 μmol of substrate reacts per minute at a certain temperature and pH.

  When using polysaccharides (which are polysaccharides in a broad sense and refer to all carbohydrates that produce two or more monosaccharides by hydrolysis, including oligosaccharides such as disaccharides, trisaccharides, and tetrasaccharides) as fuel, Preferably, in addition to the above-mentioned oxidase, coenzyme oxidase, coenzyme and electron mediator, a degradation enzyme that promotes degradation such as hydrolysis of polysaccharides and produces monosaccharides such as glucose is also immobilized. . Specific examples of the polysaccharide include starch, amylose, amylopectin, glycogen, cellulose, maltose, sucrose, and lactose. These are a combination of two or more monosaccharides, and any polysaccharide contains glucose as a monosaccharide of the binding unit. Note that amylose and amylopectin are components contained in starch, and starch is a mixture of amylose and amylopectin. When glucoamylase is used as a polysaccharide degrading enzyme and glucose dehydrogenase is used as an oxidase degrading monosaccharides, polysaccharides that can be decomposed to glucose by glucoamylase, such as starch, amylose, amylopectin, glycogen If it contains any one of maltose, it is possible to generate electricity using this as fuel. Glucoamylase is a degrading enzyme that hydrolyzes α-glucan such as starch to produce glucose, and glucose dehydrogenase is an oxidase that oxidizes β-D-glucose to D-glucono-δ-lactone.

  In a fuel cell using cellulase as a degrading enzyme and glucose dehydrogenase as an oxidase, cellulose that can be decomposed into glucose by cellulase can be used as a fuel. More specifically, the cellulase may be any of cellulase (EC 3.2.1.4), exocellobiohydrase (EC 3.2.1.91), β-glucosidase (EC 3.2.1.21) and the like. Or at least one kind. In addition, glucoamylase and cellulase may be mixed and used as the degrading enzyme. In this case, most of the polysaccharides produced in nature can be decomposed, so those containing a large amount of these, for example, garbage Etc. can be used as fuel.

In a fuel cell using α-glucosidase as a degrading enzyme and glucose dehydrogenase as an oxidase, maltose that is decomposed into glucose by α-glucosidase can be used as a fuel.
In a fuel cell using sucrose as a decomposing enzyme and glucose dehydrogenase as an oxidase, sucrose that is decomposed into glucose and fructose by sucrose can be used as a fuel. More specifically, sucrase is α-glucosidase (EC 3.2.1.20), sucrose-α-glucosidase (EC 3.2.1.48), β-fructofuranosidase (EC 3.2.1. 26) or the like.
In a fuel cell using β-galactosidase as a degrading enzyme and glucose dehydrogenase as an oxidase, lactose that is decomposed into glucose and galactose by β-galactosidase can be used as a fuel.
If necessary, these polysaccharides serving as fuel may also be immobilized on the negative electrode.

In particular, in a fuel cell using starch as a fuel, a gelatinized solid fuel obtained by gelatinizing starch can also be used. In this case, the gelatinized starch can be brought into contact with a negative electrode on which an enzyme or the like is immobilized, or can be immobilized on the negative electrode together with the enzyme or the like. When such an electrode is used, the starch concentration on the negative electrode surface can be maintained at a higher level than when starch dissolved in the solution is used, the enzymatic degradation reaction becomes faster, and the output is improved. The fuel handling is easier than in the case of a solution, the fuel supply system can be simplified, and the fuel cell can be made useless, so that it is very advantageous when used in a mobile device.
The enzyme may or may not be immobilized on the positive electrode. Where the enzyme is immobilized, it typically comprises an oxidase enzyme. As this oxidase, for example, bilirubin oxidase, laccase, ascorbate oxidase and the like can be used. In this case, an electron mediator is preferably immobilized on the positive electrode in addition to the enzyme. As the electron mediator, for example, potassium hexacyanoferrate, potassium ferricyanide, potassium octacyanotungstate and the like are used. The electron mediator is preferably immobilized at a sufficiently high concentration, for example, 0.64 × 10 ⁻⁶ mol / mm ² or more on average.
As the positive electrode or negative electrode material, a conventionally known material such as a carbon-based material can be used, and a skeleton made of a porous material and a carbon-based material covering at least a part of the surface of the skeleton are mainly used. A porous conductive material containing a material as a component can be used. This porous conductive material can be obtained by coating at least a part of the surface of the skeleton made of the porous material with a material mainly composed of a carbon-based material. The porous material constituting the skeleton of the porous conductive material may be basically any material as long as the skeleton can be stably maintained even if the porosity is high. It does not matter whether or not there is sex. As the porous material, a material having high porosity and high conductivity is preferably used. As such a porous material having a high porosity and high conductivity, specifically, a metal material (metal or alloy) or a carbon-based material with a strong skeleton (improved brittleness) is used. Can do. When a metal material is used as the porous material, various options can be considered because the metal material has different state stability depending on the usage environment such as pH and potential of the solution. For example, nickel, copper, silver, gold A foam metal such as nickel-chromium alloy and stainless steel or a foam alloy is one of the easily available materials. As the porous material, a resin material (for example, a sponge-like material) can be used in addition to the metal material and the carbon-based material. The porosity and pore diameter (minimum pore diameter) of this porous material are in balance with the thickness of the material mainly composed of a carbon-based material that is coated on the surface of the skeleton made of this porous material. Is determined according to the required porosity and pore diameter. The pore diameter of the porous material is generally 10 nm to 1 mm, typically 10 nm to 600 μm. On the other hand, it is necessary to use a material that covers the surface of the skeleton and has conductivity and is stable at an assumed operating potential. Here, a material mainly composed of a carbon-based material is used as such a material. Carbon-based materials generally have a wide potential window, and many are chemically stable. Specifically, the carbon-based material is mainly composed of a carbon-based material, and the carbon-based material is the main component, and the secondary material is selected according to the characteristics required for the porous conductive material. Some materials contain a small amount of material. Specific examples of the latter material include a material whose electrical conductivity has been improved by adding a metal or other highly conductive material to the carbon-based material, or a polytetrafluoroethylene-based material or the like added to the carbon-based material. Thus, it is a material imparted with functions other than conductivity, such as imparting surface water repellency. There are various types of carbon-based materials, but any carbon-based material may be used. In addition to carbon alone, carbon may be added with other elements. The carbon-based material is particularly preferably a fine powder carbon material having high conductivity and a high surface area. Specific examples of the carbon-based material include materials imparted with high conductivity such as KB (Ketjen Black) and functional carbon materials such as carbon nanotubes and fullerenes. As a coating method of the material mainly composed of the carbon-based material, any coating method can be used as long as the surface of the skeleton made of the porous material can be coated by using an appropriate binder as necessary. Also good. The pore diameter of the porous conductive material is selected to a size that allows a solution containing a substrate or the like to easily enter and exit through the pores, and is generally 9 nm to 1 mm, more generally 1 μm to 1 mm, and more generally Specifically, it is 1 to 600 μm. A state in which at least a part of the surface of the skeleton made of a porous material is coated with a material mainly composed of a carbon-based material, or a surface of at least a part of the skeleton made of a porous material is mainly composed of a carbon-based material In the state coated with the material, it is desirable to prevent all the holes from communicating with each other or clogging with a material mainly composed of a carbon-based material.
When an electrolyte containing a buffer substance (buffer solution) is used as the proton conductor, sufficient buffer capacity can be obtained during high output operation, and the ability inherent to the enzyme can be fully demonstrated. Therefore, it is effective that the concentration of the buffer substance contained in the electrolyte is 0.2 M or more and 2.5 M or less, preferably 0.2 M or more and 2 M or less, more preferably 0.4 M or more and 2 M or less, More preferably, it is 0.8M or more and 1.2M or less. Buffer substances, in general, as long as _a pK _a of 6 to 9, may it be used What Specific examples and, dihydrogen phosphate ion (H ₂ PO ₄ ^- ), 2-amino-2-hydroxymethyl-1,3-propanediol (abbreviated to Tris), 2- (N-morpholino) ethanesulfonic acid (MES), cacodylic acid, carbonic acid (H ₂ CO ₃ ), hydrogen citrate Ions, N- (2-acetamido) iminodiacetic acid (ADA), piperazine-N, N′-bis (2-ethanesulfonic acid) (PIPES), N- (2-acetamido) -2-aminoethanesulfonic acid ( ACES), 3- (N-morpholino) propanesulfonic acid (MOPS), N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid (HEPES), N-2-hydroxyethylpiperazine- '-3-propanesulfonic acid (HEPPS), N- [tris (hydroxymethyl) methyl] glycine (abbreviation tricine), glycylglycine, N, N-bis (2-hydroxyethyl) glycine (abbreviation bicine), etc. . Examples of the substance that generates dihydrogen phosphate ion (H ₂ PO ₄ ⁻ ) include sodium dihydrogen phosphate (NaH ₂ PO ₄ ) and potassium dihydrogen phosphate (KH ₂ PO ₄ ). The pH of the electrolyte containing the buffer substance is preferably around 7, but may generally be any of 1-14.
This fuel cell can be used for almost anything that requires electric power, and can be of any size. For example, electronic devices, mobile objects (automobiles, motorcycles, aircraft, rockets, spacecrafts, etc.), power devices, construction machinery It can be used for machine tools, power generation systems, cogeneration systems, etc. The output, size, shape, type of fuel, etc. are determined depending on the application.

（式中、Ｘ₁ 、Ｘ₄ は水素、アルキル基、アリール基、ハロゲンのいずれかを表し、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなることを特徴とする電子メディエーターである。 The fifth invention is:
General formula

(In the formula, X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen, and X ₂ and X ₃ represent any one of hydrogen, an alkyl group, and an aryl group)
It is an electron mediator characterized by consisting of the compound represented by these, or its derivative (s).

（式中、Ｘ₁ 、Ｘ₄ は水素、アルキル基、アリール基、ハロゲンのいずれかを表し、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなることを特徴とするものである。
この酵素固定化電極には、必要に応じて、式（３）で表される化合物またはその誘導体からなる電子メディエーターに加えて、式（１）で表される化合物またはその誘導体からなる電子メディエーター、および／または、式（２）で表される化合物またはその誘導体からなる電子メディエーターを併せて固定化してもよい。
第６の発明においては、上記以外のことについては、その性質に反しない限り、第３および第４の発明に関連して説明したことが成立する。 The sixth invention is:
In an enzyme-immobilized electrode on which an enzyme and an electron mediator are immobilized,
The above electronic mediator is
General formula

(In the formula, X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen, and X ₂ and X ₃ represent any one of hydrogen, an alkyl group, and an aryl group)
It consists of the compound represented by these, or its derivative (s).
The enzyme-immobilized electrode, if necessary, in addition to an electron mediator composed of a compound represented by the formula (3) or a derivative thereof, an electron mediator composed of a compound represented by the formula (1) or a derivative thereof, And / or an electron mediator composed of a compound represented by the formula (2) or a derivative thereof may be immobilized together.
In the sixth aspect of the invention, what has been described in relation to the third and fourth aspects of the invention other than the above is valid as long as it is not contrary to the nature thereof.

（式中、Ｘ₁ 、Ｘ₄ は水素、アルキル基、アリール基、ハロゲンのいずれかを表し、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなることを特徴とするものである。
第７の発明においては、上記以外のことについては、その性質に反しない限り、第４および第６の発明に関連して説明したことが成立する。 The seventh invention
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(In the formula, X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen, and X ₂ and X ₃ represent any one of hydrogen, an alkyl group, and an aryl group)
It consists of the compound represented by these, or its derivative (s).
In the seventh invention, the matters other than the above are explained in relation to the fourth and sixth inventions unless they are contrary to the nature.

（式中、Ｘ₁ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体、および／または、
一般式

（式中、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなるものであることを特徴とするものである。 The eighth invention
In an electronic device using one or more fuel cells,
At least one of the fuel cells is
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(Wherein X ₁ represents any _one of hydrogen, an alkyl group, and an aryl group)
Or a derivative thereof and / or
General formula

(In the formula, X ₂ and X ₃ represent hydrogen, an alkyl group, or an aryl group)
It consists of the compound represented by these, or its derivative (s), It is characterized by the above-mentioned.

（式中、Ｘ₁ 、Ｘ₄ は水素、アルキル基、アリール基、ハロゲンのいずれかを表し、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなるものであることを特徴とするものである。
第８および第９の発明による電子機器は、基本的にはどのようなものであってもよく、携帯型のものと据え置き型のものとの双方を含むが、具体例を挙げると、携帯電話、モバイル機器（携帯情報端末機（ＰＤＡ）など）、ロボット、パーソナルコンピュータ（デスクトップ型、ノート型の双方を含む）、ゲーム機器、カメラ一体型ＶＴＲ（ビデオテープレコーダ）、車載機器、家庭電気製品、工業製品などである。
第８および第９の発明においては、上記以外のことについては、その性質に反しない限り、第４および第６の発明に関連して説明したことが成立する。 The ninth invention
In an electronic device using one or more fuel cells,
At least one of the fuel cells is
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(In the formula, X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen, and X ₂ and X ₃ represent any one of hydrogen, an alkyl group, and an aryl group)
It consists of the compound represented by these, or its derivative (s), It is characterized by the above-mentioned.
The electronic devices according to the eighth and ninth inventions may be basically any type, and include both portable type and stationary type. For example, a mobile phone , Mobile devices (such as personal digital assistants (PDAs)), robots, personal computers (including both desktop and notebook types), game devices, camera-integrated VTRs (video tape recorders), in-vehicle devices, home appliances, Industrial products.
In the eighth and ninth inventions, what has been described in relation to the fourth and sixth inventions holds true for matters other than those described above, unless they are contrary to the nature thereof.

（式中、Ｘ₁ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体、および／または、
一般式

（式中、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなるものであることを特徴とするものである。 The tenth invention is
In a mobile body using one or more fuel cells,
At least one of the fuel cells is
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(Wherein X ₁ represents any _one of hydrogen, an alkyl group, and an aryl group)
Or a derivative thereof and / or
General formula

(In the formula, X ₂ and X ₃ represent hydrogen, an alkyl group, or an aryl group)
It consists of the compound represented by these, or its derivative (s), It is characterized by the above-mentioned.

（式中、Ｘ₁ 、Ｘ₄ は水素、アルキル基、アリール基、ハロゲンのいずれかを表し、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなるものであることを特徴とするものである。
第１０および第１１の発明による移動体は、基本的にはどのようなものであってもよく、具体例を挙げると、自動車、二輪車、航空機、ロケット、宇宙船などである。
第１０および第１１の発明においては、上記以外のことについては、その性質に反しない限り、第４および第６の発明に関連して説明したことが成立する。 The eleventh invention is
In a mobile body using one or more fuel cells,
At least one of the fuel cells is
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(In the formula, X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen, and X ₂ and X ₃ represent any one of hydrogen, an alkyl group, and an aryl group)
It consists of the compound represented by these, or its derivative (s), It is characterized by the above-mentioned.
The mobile body according to the tenth and eleventh inventions may be basically any type, and specific examples include automobiles, motorcycles, aircraft, rockets, spacecrafts, and the like.
In the tenth and eleventh inventions, what has been described in relation to the fourth and sixth inventions holds true for matters other than those described above, unless they are contrary to the nature thereof.

（式中、Ｘ₁ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体、および／または、
一般式

（式中、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなるものであることを特徴とするものである。 The twelfth invention
In a power generation system using one or more fuel cells,
At least one of the fuel cells is
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(Wherein X ₁ represents any _one of hydrogen, an alkyl group, and an aryl group)
Or a derivative thereof and / or
General formula

(In the formula, X ₂ and X ₃ represent hydrogen, an alkyl group, or an aryl group)
It consists of the compound represented by these, or its derivative (s), It is characterized by the above-mentioned.

（式中、Ｘ₁ 、Ｘ₄ は水素、アルキル基、アリール基、ハロゲンのいずれかを表し、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなるものであることを特徴とするものである。
第１２および第１３の発明による発電システムは、基本的にはどのようなものであってもよく、その規模も問わない。
第１２および第１３の発明においては、上記以外のことについては、その性質に反しない限り、第４および第６の発明に関連して説明したことが成立する。 The thirteenth invention is
In a power generation system using one or more fuel cells,
At least one of the fuel cells is
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(In the formula, X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen, and X ₂ and X ₃ represent any one of hydrogen, an alkyl group, and an aryl group)
It consists of the compound represented by these, or its derivative (s), It is characterized by the above-mentioned.
The power generation system according to the twelfth and thirteenth inventions may be basically any type, and the scale thereof is not limited.
In the twelfth and thirteenth inventions, the matters other than those described above are explained in relation to the fourth and sixth inventions unless they are contrary to the nature thereof.

（式中、Ｘ₁ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体、および／または、
一般式

（式中、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなるものであることを特徴とするものである。 The fourteenth invention is
In a cogeneration system using one or more fuel cells,
At least one of the fuel cells is
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(Wherein X ₁ represents any _one of hydrogen, an alkyl group, and an aryl group)
Or a derivative thereof and / or
General formula

(In the formula, X ₂ and X ₃ represent hydrogen, an alkyl group, or an aryl group)
It consists of the compound represented by these, or its derivative (s), It is characterized by the above-mentioned.

（式中、Ｘ₁ 、Ｘ₄ は水素、アルキル基、アリール基、ハロゲンのいずれかを表し、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなるものであることを特徴とするものである。
第１４および第１５の発明によるコージェネレーションシステムは、基本的にはどのようなものであってもよく、その規模も問わない。
第１４および第１５の発明においては、上記以外のことについては、その性質に反しない限り、第４および第６の発明に関連して説明したことが成立する。 The fifteenth invention
In a cogeneration system using one or more fuel cells,
At least one of the fuel cells is
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(In the formula, X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen, and X ₂ and X ₃ represent any one of hydrogen, an alkyl group, and an aryl group)
It consists of the compound represented by these, or its derivative (s), It is characterized by the above-mentioned.
The cogeneration system according to the fourteenth and fifteenth inventions may be basically any type, and the scale thereof is not limited.
In the fourteenth and fifteenth inventions, the matters other than those described above are explained in relation to the fourth and sixth inventions unless they are contrary to their properties.

（式中、Ｘ₁ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体、および／または、
一般式

（式中、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなることを特徴とするものである。 The sixteenth invention is
In an electrode reaction utilization device having an electrode on which an enzyme and an electron mediator are immobilized,
The above electronic mediator is
General formula

(Wherein X ₁ represents any _one of hydrogen, an alkyl group, and an aryl group)
Or a derivative thereof and / or
General formula

(In the formula, X ₂ and X ₃ represent hydrogen, an alkyl group, or an aryl group)
It consists of the compound represented by these, or its derivative (s).

（式中、Ｘ₁ 、Ｘ₄ は水素、アルキル基、アリール基、ハロゲンのいずれかを表し、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなることを特徴とするものである。 The seventeenth invention
In an electrode reaction utilization device having an electrode on which an enzyme and an electron mediator are immobilized,
The above electronic mediator is
General formula

(In the formula, X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen, and X ₂ and X ₃ represent any one of hydrogen, an alkyl group, and an aryl group)
It consists of the compound represented by these, or its derivative (s).

In the sixteenth and seventeenth inventions, the electrode reaction utilization device includes the above-described fuel cell, that is, a biofuel cell, a biosensor (such as a glucose sensor), a bioreactor, and the like. A suitable one is used.
In the sixteenth and seventeenth inventions, what has been described in relation to the third, fourth, and sixth inventions holds true for matters other than those described above, unless they are contrary to their properties.

In the present invention configured as described above, an electron mediator comprising a compound having a chemical structure represented by the above formula (1), (2) or (3) or a derivative thereof has the lowest unoccupied orbital (LUMO). Is stable and has an effect of improving the structural affinity with the enzyme. In particular, an electron mediator having a chemical structure represented by the formula (3) has a particularly high hydrophobicity due to the presence of X ₁ , X ₃ and X ₄ , and is difficult to elute in the liquid.
In the compound having the chemical structure represented by the above formula (2) or (3), the effect of improving the structural affinity with the enzyme in the electron mediator comprising the NX ₂ X ₃ group being an amino group (NH ₂ ) The hydrophobicity will be described in more detail.
In general, when the redox potential of the electron mediator is lowered, the potential is too low to carry out the redox reaction in the enzyme reaction. However, as a result of repeated studies by the present inventors, when an amino group is present as in the chemical structure represented by the above formula (2) or (3), the enzyme reaction rate is large even when the redox potential is low. It was found that the effect was further enhanced with the enzyme / electron mediator immobilized electrode. This suggests that the amino group plays a very important role in the enzyme reaction with an enzyme (for example, diaphorase). The chemical reaction rate is governed by the product of both the energy aspect and the reaction probability (frequency factor). Since the amino group is disadvantageous in terms of energy, the enzyme reaction rate should naturally decrease, but it actually increases, so it is considered that the amino group plays some role for the frequency factor. Thus, the electron mediator having an amino group is weakly basic, and it is reasonable to consider that it reacts with an H ⁺ adduct when reacting with an enzyme. Assuming this, the neutral and negatively charged enzyme (for example, diaphorase has an isoelectric point of 4 and is neutral and negatively charged) is an H ⁺ adduct of the electron mediator described above. It is thought that they attract each other electrostatically, and this is considered to be a major factor that increases the frequency factor. Furthermore, looking at the LUMO electron density distribution of the above H ⁺ adduct of the electron mediator (contributing greatly to the charge distribution and redox reaction), the LUMO electron density is localized on the positively charged amino group side. It has become. This means that the part where the electron mediator approaches the enzyme is the reaction site as it is, and this is also one of the reasons why the enzyme reaction rate is fast when this electron mediator is used. Conceivable. Since ACNQ (2-amino-3-carboxy-1,4-naphthoquinone) conventionally used as an electron mediator also has an amino group, the enzyme reaction rate should be faster. Since the adjacent carboxylic acid interacts with the amino group, the superiority in the enzyme reaction inherent to the amino group is negated, so the actual enzyme reaction is considered to be low. Actually, for example, in the case of AMNQ (2-amino-3-methyl-1,4-naphthoquinone), since it does not interact with the adjacent methyl group, it is explained from the fact that a fast enzyme reaction rate is maintained. it can.
Next, regarding the effect of this alkyl group when X ₁ in the chemical structure represented by the above formula (2) or (3) is an alkyl group such as a methyl group, the alkyl group is an electron donating group Therefore, the hydrophobicity of the electron mediator can be dramatically improved.

  According to the present invention, the enzyme-immobilized electrode or the electrode constituting the fuel cell, specifically, the electron mediator immobilized with the enzyme on the negative electrode is represented by the above formula (1), (2) or (3). By applying a compound having a chemical structure, the energy of the lowest empty orbital (LUMO) of the electron mediator can be stabilized and an effect of improving the structural affinity with the enzyme can be obtained. Therefore, the existing electron mediator (ACNQ, Unlike the case of using VK3), the potential can be raised at the same time while taking a large current value. For this reason, the output can be dramatically improved as compared with the conventionally proposed fuel cell. In addition, when a compound having a chemical structure represented by the formula (3) is applied as an electron mediator, since the hydrophobicity of the electron mediator itself is high, a voltage is applied to the enzyme-immobilized electrode or the negative electrode of the fuel cell. Even in the applied state, the dissolution of the electron mediator from the immobilized film can be extremely effectively suppressed. As a result, the output stability and life of the fuel cell can be improved. By using such an excellent fuel cell, it is possible to realize a high-performance electronic device, a moving body, a power generation system, a cogeneration system, and the like.

  Moreover, according to the electrode reaction utilization apparatus by this invention, the compound which has a chemical structure represented by said Formula (1), (2) or (3) as an electron mediator fix | immobilized with an enzyme to an electrode was applied. Therefore, for the same reason as described above, the output can be dramatically improved. In particular, when the compound having the chemical structure represented by the formula (3) is applied as an electron mediator, the output stability and The lifetime can be improved. For example, in a biosensor such as a glucose sensor, the sensitivity can be greatly improved. Especially when a compound having a chemical structure represented by the formula (3) is applied as an electron mediator, the lifetime of the sensor itself is improved. Can also be planned.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 2 shows a schematic configuration diagram of the fuel cell according to the first embodiment of the present invention.
As shown in FIG. 2, the fuel cell 10 includes a fuel electrode (negative electrode: anode) 1, an air electrode (positive electrode: cathode) 3, and an electrolyte layer 5 that isolates the fuel electrode 1 and the air electrode 3. It is comprised by. In other words, the fuel cell 10 has a structure in which the fuel electrode 1 and the air electrode 3 face each other with the electrolyte layer 5 interposed therebetween, or a pair of electrodes in which the electrolyte layer 5 is composed of the fuel electrode 1 and the air electrode 3. It is pinched by. The electrolyte layer 5 has ion permeability, and is specifically a proton conductor.
The fuel electrode 1 has at least an enzyme and an electron mediator supported on an electrode material. The fuel electrode 1 extracts electrons from a fuel 7 such as glucose and generates protons (H ⁺ ) 9.
On the other hand, in the air electrode 3, H ⁺ moved from the fuel electrode 1 through the electrolyte layer 5 reacts with, for example, oxygen (O ₂ ) in the air to generate water (H ₂ O).

The electrode material constituting the fuel electrode 1 is preferably made of a porous material so that a large amount of enzymes and electron mediators described later can be supported.
Specifically, the fuel electrode 1 includes, for example, an enzyme involved in fuel decomposition on a porous electrode material such as carbon paper, and a coenzyme (a reductant is generated in association with the oxidation reaction of the fuel). For example, NAD ⁺ , NADP ^{+ and the} like, a coenzyme oxidase (eg, diaphorase: DI) that oxidizes a reduced form of the coenzyme (eg, NADH, NADPH, etc.), and the coenzyme oxidase to oxidize the coenzyme Electron mediators (for example, 2-amino-1,4-naphthoquinone: ANQ, 2-methoxy-1,4-naphthoquinone: MNQ, etc.) that receive the generated electrons and pass them to the electrode are used as an immobilizing material (for example, a polymer). Etc.).

Examples of the enzyme involved in the decomposition of fuel include alcohol dehydrogenase (ADH) that oxidizes methanol to formaldehyde, formaldehyde dehydrogenase (FalDH) that oxidizes formaldehyde to formic acid, and formic acid that oxidizes from formic acid to CO ₂ when the fuel is methanol. Dehydrogenase (FateDH) is mentioned. By these oxidases, methanol is finally decomposed to CO ₂ at room temperature.

  When the fuel is ethanol, examples of enzymes involved in fuel decomposition include alcohol dehydrogenase (ADH) that oxidizes ethanol to acetaldehyde and aldehyde dehydrogenase (AlDH) that oxidizes acetaldehyde to acetic acid. By these oxidases, ethanol is oxidized to acetic acid at room temperature.

In addition, when the fuel is glucose, an enzyme involved in the decomposition of the fuel includes glucose dehydrogenase (GDH).
By the action of this oxidase, β-D-glucose is oxidized to D-glucono-δ-lactone.
D-glucono-δ-lactone is converted to D-gluconate by hydrolysis.

  When the fuel is a polysaccharide starch, examples of enzymes involved in the decomposition of the fuel include glucoamylase and glucose dehydrogenase (GDH). Starch is decomposed into β-D-glucose by the action of glucoamylase, and β-D-glucose is oxidized to D-glucono-δ-lactone by the action of glucose dehydrogenase.

Enzymes involved in fuel decomposition are not limited to the above-mentioned oxidases, but these are NAD ⁺ -dependent dehydrogenases. When these oxidases are used, NAD ⁺ is used as a coenzyme. NAD ⁺ -dependent dehydrogenase reduces the coenzyme NAD ⁺ by oxidizing (dehydrogenating) the fuel to produce NADH and H ⁺ . This reaction is represented by the following formula (4).
Fuel + NAD ⁺ → Fuel oxidant + NADH + H ⁺ (4)

The generated NADH is oxidized to NAD ⁺ by DI to generate two electrons and H ⁺ as shown in the following formula (5).
NADH → NAD ⁺ + H ⁺ + 2e ⁻ (5)

Therefore, two electrons and two H ⁺ are generated by one oxidation reaction per fuel molecule.
The electrons generated in the above process are transferred from DI to the electrode via the electron mediator, and H ⁺ is transported to the air electrode 3 through the electrolyte layer 5.

Next, an electronic mediator will be described.
In the first embodiment, the electron mediator supported on the enzyme-immobilized electrode constituting the fuel electrode 1 is specified as a compound having the structure of the following formula (1) and / or the following formula (2).

（式中、Ｘ₁ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体、および／または、
一般式

（式中、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなるものである。 That is, the electron mediator supported on the enzyme-immobilized electrode is
General formula

(Wherein X ₁ represents any _one of hydrogen, an alkyl group, and an aryl group)
Or a derivative thereof and / or
General formula

(In the formula, X ₂ and X ₃ represent hydrogen, an alkyl group, or an aryl group)
Or a derivative thereof.

In the above formula (1), X ₁ is any _one of hydrogen, an alkyl group, and an aryl group. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, and a t-butyl group. , A pentyl group, a hexyl group, and the like. Among these, a methyl group is particularly preferable.

In the above formula (2), X ₂ and X ₃ are any one of hydrogen, an alkyl group, and an aryl group. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, A t-butyl group, a pentyl group, a hexyl group and the like can be mentioned, and among these, hydrogen is particularly preferable.

The electron mediator exchanges electrons with the electrode, and the voltage of the fuel cell depends on the redox potential of the electron mediator.
By using the compound represented by the above formula (1) and / or formula (2) as the electron mediator, the energy of the lowest empty orbit (LUMO) of the electron mediator is stabilized, and the structural affinity with the enzyme As a result of the improvement in performance, it was confirmed that a significantly higher output was obtained than when the existing electron mediator (ACNQ, VK3) was used.

  The above enzyme, coenzyme, and electron mediator are adjusted to a pH optimum for the enzyme, for example, around pH 7, using a buffer such as Tris buffer or phosphate buffer so that the electrode reaction can be performed efficiently and constantly. Is preferably maintained. Further, the ionic strength (IS) is too large or too small to adversely affect the enzyme activity, but considering the electrochemical response, it should be an appropriate ionic strength, for example, about 0.3. Is preferred. However, pH and ionic strength have optimum values for each enzyme used, and are not limited to the values described above.

The enzyme, coenzyme, and electron mediator may be used in a state dissolved in a buffer solution. In the first embodiment, the enzyme, coenzyme, and electron mediator are immobilized on an electrode using an immobilizing material. This makes it possible to efficiently capture the enzyme reaction phenomenon occurring in the vicinity of the electrode as an electrical signal. As such an immobilizing material, for example, a combination of glutaraldehyde (GA) and poly-L-lysine (PLL) or a combination of sodium polyacrylate (PAAcNa) and poly-L-lysine (PLL). These may be used, these may be used alone, and further other polymers may be used.
Since the fuel electrode 1 has the above-described configuration, it can directly generate H ⁺ by contacting with a fuel such as glucose near room temperature.

Next, the air electrode 3 will be described.
The air electrode 3 is mainly composed of carbon powder on which a catalyst is supported or catalyst particles not held by carbon. Examples of the catalyst include platinum (Pt) fine particles, iron (Fe), nickel (Ni), cobalt (Co), an alloy of platinum such as ruthenium (Ru) and platinum, or fine particles such as oxide. Can be applied. Specifically, the air electrode 3 has a configuration in which, for example, a catalyst layer made of the above catalyst or a carbon powder containing a catalyst, and a gas diffusion layer are sequentially laminated from the electrolyte layer 5 side. The gas diffusion layer is made of a porous carbon material.

In addition, the air electrode 3 is a fuel electrode 1 side by a separator formed of a predetermined film (for example, cellophane: methylcellulose film) made of a material that is insulating and has proton permeability and does not transmit the solution of the electrolyte layer 5. It is preferable to have a configuration separated from the above. By this separator, the air electrode 3 is in a state of being present in the gas phase by preventing the solution constituting the electrolyte layer 5 from oozing out to the air electrode 3 side. With such a configuration, the air electrode 3 can be supplied with oxygen (O ₂ ) directly from the gas phase and can efficiently reduce the oxygen in the gas phase. An extremely high current density can be obtained without providing a separate mechanism for supplying dissolved oxygen in the solution by stirring or bubbling.

Next, the electrolyte layer 5 will be described.
The electrolyte layer 5 is a proton conductive membrane that transports H ⁺ generated in the fuel electrode 1 to the air electrode 3, and is made of a material that does not have electron conductivity and can transport H ⁺ . Specific examples of the electrolyte layer 5 include perfluorocarbon sulfonic acid (PFS) resin films, copolymer films of trifluorostyrene derivatives, polybenzimidazole films impregnated with phosphoric acid, and aromatic polyethers. Examples thereof include a ketone sulfonic acid film, PSSA-PVA (polystyrene sulfonate polyvinyl alcohol copolymer), PSSA-EVOH (polystyrene sulfonate ethylene vinyl alcohol copolymer), and the like. Among these, those made of an ion exchange resin having a fluorine-containing carbon sulfonic acid group are suitable, and specifically, Nafion (trade name, manufactured by DuPont) is used.

In the fuel cell 10 having the above-described configuration, NADH is generated from the coenzyme NAD ⁺ when one or more types of NAD ⁺ -dependent dehydrogenases oxidize fuel on the fuel electrode 1 side. The NADH thus generated passes two electrons to the fuel electrode 1 via the electron mediator by DI and returns to NAD ⁺ . The electrons passed to the fuel electrode 1 reach the air electrode 3 through an external circuit, thereby generating a current.
Further, H ⁺ generated in the above-described process moves to the air electrode 3 through the electrolyte layer 5. In the air electrode 3, water is generated from the reached H ⁺ , the two electrons supplied from the external circuit, and oxygen.

When methanol is used as the fuel, alcohol dehydrogenase (ADH) that acts on methanol as a catalyst and oxidizes to formaldehyde, formaldehyde dehydrogenase (FalDH) that acts on formaldehyde and oxidizes to formic acid, and acts on formic acid and oxidizes to CO ₂ It is decomposed to CO ₂ through a three-stage oxidation process with formate dehydrogenase (FateDH). That is, three NADHs are generated per molecule of methanol, and six electrons are generated.

When ethanol is used as a fuel, alcohol dehydrogenase (ADH) that acts on ethanol as a catalyst and oxidizes to acetaldehyde and aldehyde dehydrogenase (AlDH) that acts on acetaldehyde and oxidizes to acetic acid undergo a two-stage oxidation process, Decomposes to acetic acid. That is, a total of 4 electrons are generated by two-stage oxidation reaction per molecule of ethanol.
Incidentally, ethanol may take the method of decomposing to CO ₂ as well as methanol. In this case, acetaldehyde dehydrogenase (AalDH) is allowed to act on acetaldehyde to form acetyl CoA, which is then passed to the TCA circuit. Further electrons are generated in the TCA circuit.

When glucose is used as a fuel, glucose dehydrogenase (GDH) can be used as a catalyst.
As a result, β-D-glucose is decomposed into D-glucono-δ-lactone, and two electrons are generated per glucose molecule through this oxidation reaction.

In addition, D-glucono-delta-lactone is hydrolyzed in water to D-gluconate. In addition to glucose dehydrogenase (GDH), when gluconokinase and phosphogluconate dehydrogenase (PhGDH) catalysts are used, D-gluconate converts adenosine triphosphate (ATP) to adenosine in the presence of gluconokinase. It is phosphorylated by hydrolysis into diphosphate (ADP) and phosphoric acid to become 6-phospho-D-gluconate, and further, by the action of phosphogluconate dehydrogenase (PhGDH), 2-keto-6- Oxidized to phospho-D-gluconate.
Therefore, in this case, glucose is decomposed into 2-keto-6-phospho-D-gluconate, and a total of 4 electrons are generated by a two-step oxidation reaction per molecule of glucose.

It is also possible to take a method of decomposing glucose to CO ₂ . In this case, it is necessary to utilize sugar metabolism. Complex enzyme reactions utilizing sugar metabolism are roughly divided into glucose degradation and pyruvic acid production by the glycolytic system and TCA cycle. The glycolysis system and the TCA circuit are widely known reaction systems, and the description thereof is omitted. However, when this is used, more electric energy can be extracted.

  Examples of the fuel to be applied to the fuel cell include methanol, ethanol, glucose and starch mentioned above, and other alcohols, other sugars, fats, proteins, organic acids such as intermediate products of glucose metabolism (glucose- 6-phosphate, fructose-6-phosphate, fructose-1,6-bisphosphate, triose phosphate isomerase, 1,3-bisphosphoglycerate, 3-phosphoglycerate, 2-phosphoglycerate, phosphoenolpyruvate , Pyruvic acid, acetyl-CoA, citric acid, cis-aconitic acid, isocitric acid, oxalosuccinic acid, 2-oxoglutaric acid, succinyl-CoA, succinic acid, fumaric acid, L-malic acid, oxaloacetic acid, etc.), these A mixture or the like can be used. Also for these fuels, electric energy can be taken out by decomposing them using enzymes.

  In this case, it is preferable to select an enzyme that is involved in the decomposition of the fuel according to the fuel used. For example, as an enzyme for fuel decomposition immobilized on the fuel electrode 1, glucose dehydrogenase, a series of enzymes of an electron transport system, ATP synthase, an enzyme involved in sugar metabolism (for example, hexokinase, glucose phosphate isomerase, phosphoflurane) Fructose diphosphate aldolase, triose phosphate isomerase, glyceraldehyde phosphate dehydrogenase, phosphoglyceromutase, phosphopyruvate hydratase, pyruvate kinase, L-lactate dehydrogenase, D-lactate dehydrogenase, pyruvate dehydrogenase, citrate synthase , Aconitase, isocitrate dehydrogenase, 2-oxoglutarate dehydrogenase, succinyl-CoA synthetase, succinate dehydrogenase, fumarase, malonate dehydrogenase Dehydrogenase, etc.) can be cited a well-known enzyme, such as.

  In the above description, the case where the enzyme-immobilized electrode is applied as the fuel electrode 1 (negative electrode or anode electrode) has been described as an example. However, the present invention is not limited to the above-described example. 3 (positive electrode or cathode electrode) may be an enzyme-immobilized electrode, and both electrodes of the fuel electrode 1 and the air electrode 3 may be enzyme-immobilized electrodes. Specifically, for example, an enzyme-immobilized electrode in which an oxygen reductase as a catalyst is immobilized may be applied as the air electrode 3. As this oxygen reductase, for example, bilirubin oxidase can be used. In this case, the oxygen reductase is preferably used in combination with an electron mediator that transfers electrons to and from the electrode. As this electron mediator, for example, hexacyanoferrate ion or the like can be used.

Examples will be described.
A specific sample was prepared for the fuel cell.
In the following, various samples in which the electron mediator was changed were prepared, and these characteristics were evaluated.

[Comparative Example 1]
Using vitamin K3 (VK3) described in Patent Document 2 as an electron mediator, an enzyme-immobilized electrode 20 having a structure as shown in FIG. 3 was produced. The enzyme-immobilized electrode 20 has a configuration in which an enzyme-electron mediator-PLL film 22 and a polyacrylic acid film 23 are laminated on a glassy carbon electrode 21.
A method for producing the enzyme-immobilized electrode 20 will be described below.
GDH / DI / NADH = 1.05 U / 5 U / μL in 0.1 M phosphate buffer (pH 8.0) solution 8 μL was mixed with 160 μg / μL NADH in 0.1 M phosphate buffer (pH 8.0) solution 2 μL. Thereafter, this was added to a glassy carbon electrode and dried at room temperature (in a dry storage container containing silica gel) for 60 minutes. Thereafter, 10 μL of 2% (w / w) PLL (M = 39000) solution was added and dried at 40 ° C. for 15 minutes. Next, 4 μL of a 0.29 M VK3 solution (in acetone) was added and dried at 40 ° C. for 10 minutes. Further, 4 μL of 0.066% (w / v) sodium polyacrylate (PAAcNa) (M = 8000) solution was added and dried at 40 ° C. for 15 minutes. Finally, 10 μL of 0.1 M phosphate buffer (pH 7.0) solution was added and dried at 40 ° C. for 30 minutes. This operation was repeated three times.

  Cyclic voltammetry (CV) was measured with a 0.1 M phosphate buffer solution in which glucose as a fuel was adjusted to 400 mM using the enzyme-immobilized electrode 20 to which the vitamin K3 (VK3) was applied as an electron mediator (10 mV). / Sec, reference electrode: Ag / AgCl), the steady-state current value was 43 μA, and the rising voltage was −0.10 V. CV data is indicated by a solid line in FIG.

[Comparative Example 2]
Using 2-amino-3-carboxy-1,4-naphthoquinone (ACNQ) described in Patent Document 1 as an electron mediator, an enzyme-immobilized electrode 20 having a configuration as shown in FIG. 3 was produced.
A method for producing the enzyme-immobilized electrode 20 will be described below.
10 μL of 10 mM ACNQ solution (in acetone) was added to the glassy carbon electrode and dried at 40 ° C. for 10 minutes. This operation was first repeated 12 times. Thereafter, 10 μL of 2% (w / w) PLL (M = 39000) solution was added and dried at 40 ° C. for 15 minutes.
Next, GDH / DI / NADH = 2.1 U / 5 U / μL in 0.1 M phosphate buffer (pH 8.0) solution 8 μL, 640 μg / μL NADH in 0.1 M phosphate buffer (pH 8.0) solution 2 μL After mixing, this was added to the glassy carbon electrode and dried at room temperature (in a dry storage room containing silica gel) for 60 minutes. Further, 4 μL of 0.033% (w / v) PAAcNa (M = 8000) solution was added and dried at 40 ° C. for 15 minutes. Finally, 20 μL of 0.1 M phosphate buffer (pH 7.0) solution was added and dried at 40 ° C. for 30 minutes. This operation was repeated three times.

  Cyclic voltammetry (CV) was measured with a 0.1 M phosphate buffer solution in which glucose as a fuel was adjusted to 400 mM using the enzyme-immobilized electrode 20 in which ACNQ produced as described above was applied to an electron mediator. (10 mV / sec, reference electrode: Ag / AgCl), the steady-state current value (0.6 V) was 23 μA, and the rising voltage was −0.28 V. The CV data is indicated by a broken line in FIG.

[Example 1]
2-Methoxy-1,4-naphthoquinone (MNQ) was applied as an electron mediator to prepare enzyme-immobilized electrode 20.
GDH / DI / NADH = 1.05 U / 5 U / μL in 0.1 M phosphate buffer (pH 8.0) solution 8 μL was mixed with 160 μg / μL NADH in 0.1 M phosphate buffer (pH 8.0) solution 2 μL. Thereafter, this was added to a glassy carbon electrode and dried at room temperature (in a dry storage container containing silica gel) for 60 minutes. Thereafter, 10 μL of 2% (w / w) PLL (M = 39000) solution was added and dried at 40 ° C. for 15 minutes. Next, 8 μL of 70 mM MNQ solution (in acetone) was added and dried at 40 ° C. for 10 minutes. This operation was repeated twice. Furthermore, 4 μL of 0.066% (w / v) PAAcNa (M = 8000) solution was added and dried at 40 ° C. for 15 minutes. Finally, 10 μL of 0.1 M phosphate buffer (pH 7.0) solution was added and dried at 40 ° C. for 30 minutes. This operation was repeated three times.

  Cyclic voltammetry (CV) was measured with a 0.1 M phosphate buffer solution in which glucose as a fuel was adjusted to 400 mM using the enzyme-immobilized electrode 20 in which the MNQ was applied to an electron mediator (10 mV / sec, Reference electrode: Ag / AgCl), steady-state current value (0.6V) was 32 μA, and rising voltage was −0.27V. The CV data is shown by the alternate long and short dash line in FIG.

[Example 2]
2-Amino-1,4-naphthoquinone (ANQ) was applied as an electron mediator to produce enzyme-immobilized electrode 20.
GDH / DI / NADH = 1.05 U / 5 U / μL in 0.1 M phosphate buffer (pH 8.0) solution 8 μL was mixed with 160 μg / μL NADH in 0.1 M phosphate buffer (pH 8.0) solution 2 μL. Thereafter, this was added to a glassy carbon electrode and dried at room temperature (in a dry storage container containing silica gel) for 60 minutes. Thereafter, 10 μL of a 2% (w / w) PLL (M = 135000) solution was added and dried at 40 ° C. for 25 minutes. Next, 9.35 μL of 60 mM ANQ solution (in acetone) was added and dried at 40 ° C. for 10 minutes. This operation was repeated twice. Further, 4 μL of 0.066% (w / v) PAAcNa (M = 30000) solution was added and dried at 40 ° C. for 15 minutes. Finally, 10 μL of 0.1 M phosphate buffer (pH 7.0) solution was added and dried at 40 ° C. for 30 minutes. This operation was repeated three times.

Cyclic voltammetry (CV) was measured with a 0.1 M phosphate buffer solution in which glucose as a fuel was adjusted to 400 mM using the enzyme-immobilized electrode 20 in which the above ANQ was applied to an electron mediator (10 mV / sec, Reference electrode: Ag / AgCl), steady current value (0.6 V) was 67 μA, and rising voltage was −0.34 V. The CV data is shown by the two-dot chain line in FIG.
The measurement results of the rising potential (mV) and steady-state current value (μA) in the enzyme-immobilized electrodes 20 of Examples 1 and 2 and Comparative Examples 1 and 2 described above are shown in Table 1 below.

From the results shown in FIG. 4 and Table 1, in Examples 1 and 2 to which the electron mediator having the chemical structure represented by the above formula (1) and / or formula (2) was applied, the conventional electron mediator was applied. Compared to Comparative Examples 1 and 2, it was found that the rising potential and the steady current value were well balanced, and a high current value was obtained with a relatively low rising potential.
Next, a fuel cell was assembled using the enzyme-immobilized electrode 20 produced as described above, and each characteristic was evaluated.

[Comparative Example 3]
By using the same method as in Comparative Example 1 above, 1 cm ² of carbon paper was applied as a carbon electrode, and a fuel cell having the structure shown in FIG.
As a result of introducing a 400 mM glucose aqueous solution into the fuel electrode 1 side, an output of 3 mW / cm ² was confirmed at 25 ° C.

[Comparative Example 4]
In the same manner as in Comparative Example 2 above, 1 cm ² of carbon paper was applied as a carbon electrode, and a fuel cell having an enzyme-immobilized electrode 20 as a fuel electrode 1 having a configuration as shown in FIG.
As a result of introducing a 400 mM glucose aqueous solution into the fuel electrode 1 side, an output of ² mW / cm ² was confirmed at 25 ° C.

Example 3
By using the same method as in Example 1 above, 1 cm ² of carbon paper was applied as the carbon electrode, and a fuel cell having the structure shown in FIG.
As a result of introducing a 400 mM glucose aqueous solution into the fuel electrode 1 side, an output of 7 mW / cm ² was confirmed at 25 ° C.

Example 4
By using the same method as in Example 2 above, 1 cm ² of carbon paper was applied as a carbon electrode, and a fuel cell having the structure shown in FIG.
As a result of introducing a 400 mM glucose aqueous solution into the fuel electrode 1 side, an output of 20 mW / cm ² was confirmed at 25 ° C.
The measurement results of the outputs in the fuel cells of Comparative Examples 3 and 4 and Examples 3 and 4 are shown in Table 2 below.

  From the results shown in Table 2 above, in Examples 3 and 4 in which the electron mediator having the chemical structure represented by the above formula (1) and / or formula (2) is supported on the enzyme-immobilized electrode 20, conventional electrons are used. Compared with Comparative Examples 3 and 4 to which a mediator is applied, an extremely high output is obtained. By using an electron mediator having a chemical structure represented by the above formula (1) and / or formula (2), fuel can be obtained. It was confirmed that the performance of the battery improved dramatically.

（式中、Ｘ₁ 、Ｘ₄ は水素、アルキル基、アリール基、ハロゲンのいずれかを表し、Ｘ₂ 、Ｘ₃ は水素、アルキル基、アリール基のいずれかを表す）
で表される化合物またはその誘導体からなるものである。 Next explained is a fuel cell according to the second embodiment of the invention.
In the second embodiment, the electron mediator applied to the enzyme-immobilized electrode 20 used as the fuel electrode 1 is specified as a compound having a chemical structure represented by the following formula (3).
That is, the electron mediator supported on the enzyme-immobilized electrode 20 is
General formula

(In the formula, X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen, and X ₂ and X ₃ represent any one of hydrogen, an alkyl group, and an aryl group)
Or a derivative thereof.

In the above formula (3), X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen. Examples of the alkyl group of X ₁ include a methyl group, an ethyl group, a propyl group, an isopropyl group, n- A butyl group, a t-butyl group, an s-butyl group, a pentyl group, a hexyl group, and the like can be mentioned. Among these, a methyl group is particularly preferable. Examples of the alkyl group of X ₄ include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a t-butyl group, a s-butyl group, a pentyl group, and a hexyl group. Hydrogen is preferred. X ₂ and X _{3 each} represent hydrogen, an alkyl group, or an aryl group. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a t-butyl group, and an s-butyl group. , A pentyl group, a hexyl group, and the like. Among these, a combination of hydrogen and an isopropyl group or a s-butyl group is particularly preferable.

By using the compound represented by the above formula (3) as the electron mediator, the energy of the lowest empty orbit (LUMO) of the electron mediator is stabilized, and the structural affinity with the enzyme is improved, thereby improving the above formula (1). ), An output improvement equivalent to or higher than that of the electron mediator shown in (2) was confirmed. In addition, by designing the molecule to improve the hydrophobicity of the electron mediator, the life of the enzyme-immobilized electrode 20 is dramatically increased compared to the electron mediator represented by the formula (1) or formula (2). We were able to.
Other than the above are the same as in the first embodiment.

Examples will be described.
A specific sample was prepared for the fuel cell.
In the following, various samples in which the electron mediator was changed were prepared and evaluated for these characteristics.

Example 5
2-Methoxy-1,4-naphthoquinone (MNQ) was applied as an electron mediator to prepare enzyme-immobilized electrode 20.
GDH / DI / NADH = 1.05 U / 5 U / μL in 0.1 M phosphate buffer (pH 8.0) solution 8 μL was mixed with 160 μg / μL NADH in 0.1 M phosphate buffer (pH 8.0) solution 2 μL. Thereafter, this was added to a glassy carbon electrode and dried at room temperature (in a dry storage container containing silica gel) for 60 minutes. Thereafter, 10 μL of 2% (w / w) PLL (M = 39000) solution was added and dried at 40 ° C. for 15 minutes. Next, 8 μL of 70 mM MNQ solution (in acetone) was added and dried at 40 ° C. for 10 minutes. This operation was repeated twice. Furthermore, 4 μL of 0.066% (w / v) PAAcNa (M = 8000) solution was added and dried at 40 ° C. for 15 minutes. Finally, 10 μL of 0.1 M phosphate buffer (pH 7.0) solution was added and dried at 40 ° C. for 30 minutes. This operation was repeated three times.

  Cyclic voltammetry (CV) was measured with a 0.1 M phosphate buffer solution in which glucose as a fuel was adjusted to 400 mM using the enzyme-immobilized electrode 20 in which the MNQ was applied to an electron mediator (10 mV / sec, Reference electrode: Ag / AgCl), steady-state current value (0.6V) was 32 μA, and rising voltage was −0.27V. The CV data is shown by the alternate long and short dash line in FIG.

Example 6
2-Amino-1,4-naphthoquinone (ANQ) was applied as an electron mediator to produce enzyme-immobilized electrode 20.
GDH / DI / NADH = 1.05 U / 5 U / μL in 0.1 M phosphate buffer (pH 8.0) solution 8 μL was mixed with 160 μg / μL NADH in 0.1 M phosphate buffer (pH 8.0) solution 2 μL. Thereafter, this was added to a glassy carbon electrode and dried at room temperature (in a dry storage container containing silica gel) for 60 minutes. Thereafter, 10 μL of a 2% (w / w) PLL (M = 135000) solution was added and dried at 40 ° C. for 25 minutes. Next, 9.35 μL of 60 mM ANQ solution (in acetone) was added and dried at 40 ° C. for 10 minutes. This operation was repeated twice. Further, 4 μL of 0.066% (w / v) PAAcNa (M = 30000) solution was added and dried at 40 ° C. for 15 minutes. Finally, 10 μL of 0.1 M phosphate buffer (pH 7.0) solution was added and dried at 40 ° C. for 30 minutes. This operation was repeated three times.

  When cyclic voltammetry (CV) was measured with a 0.1 M phosphate buffer solution in which glucose as a fuel was adjusted to 400 mM using the enzyme-immobilized electrode 20 in which the above ANQ was applied to an electron mediator (10 mV / sec, Reference electrode: Ag / AgCl), steady current value (0.6 V) was 67 μA, and rising voltage was −0.34 V. The CV data is shown by the two-dot chain line in FIG.

Example 7
2-Amino-3-methyl-1,4-naphthoquinone (AMNQ) was applied as an electron mediator to prepare an enzyme-immobilized electrode 20.
GDH / DI / NADH = 1.05 U / 5 U / μL in 0.1 M phosphate buffer (pH 8.0) solution 8 μL was mixed with 160 μg / μL NADH in 0.1 M phosphate buffer (pH 8.0) solution 2 μL. Thereafter, this was added to a glassy carbon electrode and dried at room temperature (in a dry storage container containing silica gel) for 60 minutes. Thereafter, 10 μL of a 2% (w / w) PLL (M = 135000) solution was added and dried at 40 ° C. for 25 minutes. Next, 9.35 μL of 60 mM AMNQ solution (in acetone) was added and dried at 40 ° C. for 10 minutes. This operation was repeated twice. Further, 4 μL of 0.066% (w / v) PAAcNa (M = 30000) solution was added and dried at 40 ° C. for 15 minutes. Finally, 10 μL of 0.1 M phosphate buffer (pH 7.0) solution was added and dried at 40 ° C. for 30 minutes. This operation was repeated three times.

  When cyclic voltammetry (CV) was measured with a 0.1 M phosphate buffer solution in which glucose as a fuel was adjusted to 400 mM using the enzyme-immobilized electrode 20 in which the above AMNQ was applied to an electron mediator (10 mV / sec, Reference electrode: Ag / AgCl), steady current value (0.6 V) was 64 μA, and rising voltage was −0.40 V. The CV data is shown by the dotted line in FIG.

Example 8
2-N-isopropylamino-3-methyl-1,4-naphthoquinone (A (iPr) MNQ) was applied as an electron mediator to prepare an enzyme-immobilized electrode 20.
GDH / DI / NADH = 1.05 U / 5 U / μL in 0.1 M phosphate buffer (pH 8.0) solution 8 μL was mixed with 160 μg / μL NADH in 0.1 M phosphate buffer (pH 8.0) solution 2 μL. Thereafter, this was added to a glassy carbon electrode and dried at room temperature (in a dry storage container containing silica gel) for 60 minutes. Thereafter, 10 μL of a 2% (w / w) PLL (M = 135000) solution was added and dried at 40 ° C. for 25 minutes. Next, 9.35 μL of 60 mM A (iPr) MNQ solution (in acetone) was added and dried at 40 ° C. for 10 minutes. This operation was repeated twice. Further, 4 μL of 0.066% (w / v) PAAcNa (M = 30000) solution was added and dried at 40 ° C. for 15 minutes. Finally, 10 μL of 0.1 M phosphate buffer (pH 7.0) solution was added and dried at 40 ° C. for 30 minutes. This operation was repeated three times.

  Cyclic voltammetry (CV) was measured with a 0.1 M phosphate buffer solution in which glucose as a fuel was adjusted to 400 mM using the enzyme-immobilized electrode 20 in which the above A (iPr) MNQ was applied to an electron mediator ( 10 mV / sec, reference electrode: Ag / AgCl), steady-state current value (0.6 V) was 138 μA, and rising voltage was −0.33 V. The CV data is shown by the solid line in FIG.

Example 9
2-N-secondary butylamino-3-methyl-1,4-naphthoquinone (A (sBu) MNQ) was applied as an electron mediator to prepare an enzyme-immobilized electrode 20.
GDH / DI / NADH = 1.05 U / 5 U / μL in 0.1 M phosphate buffer (pH 8.0) solution 8 μL was mixed with 160 μg / μL NADH in 0.1 M phosphate buffer (pH 8.0) solution 2 μL. Thereafter, this was added to a glassy carbon electrode and dried at room temperature (in a dry storage container containing silica gel) for 60 minutes. Thereafter, 10 μL of a 2% (w / w) PLL (M = 135000) solution was added and dried at 40 ° C. for 25 minutes. Next, 9.35 μL of 60 mM A (sBu) MNQ solution (in acetone) was added and dried at 40 ° C. for 10 minutes. This operation was repeated twice. Further, 4 μL of 0.066% (w / v) PAAcNa (M = 30000) solution was added and dried at 40 ° C. for 15 minutes. Finally, 10 μL of 0.1 M phosphate buffer (pH 7.0) solution was added and dried at 40 ° C. for 30 minutes. This operation was repeated three times.

Cyclic voltammetry (CV) was measured with a 0.1 M phosphate buffer solution in which glucose as a fuel was adjusted to 400 mM using the enzyme-immobilized electrode 20 in which the above A (sBu) MNQ was applied to an electron mediator ( 10 mV / sec, reference electrode: Ag / AgCl), steady-state current value (0.6 V) was 58 μA, and rising voltage was −0.36 V. CV data is indicated by a broken line in FIG.
Table 3 below shows the measurement results of the rising potential (mV) and steady-state current value (μA) of the enzyme-immobilized electrodes 20 of Examples 7, 8, and 9 and Examples 5 and 6 described above.

From the results shown in FIG. 5 and Table 3, in Examples 7, 8, and 9 to which the electron mediator having the chemical structure represented by the above formula (3) was applied, it was represented by the above formula (1) or (2). As compared with Examples 5 and 6 to which the electron mediator having the chemical structure is applied, it was found that the balance between the rising potential and the steady current value is good, and a high current value can be obtained with a relatively low rising potential.
Next, a fuel cell was assembled using the enzyme-immobilized electrode 20 produced as described above, and each characteristic was evaluated.

Example 10
By using the same method as in Example 5 above, 1 cm ² of carbon paper was applied as the carbon electrode, and a fuel cell having the structure shown in FIG.
As a result of introducing a 400 mM glucose aqueous solution into the fuel electrode 1 side, an output of 7 mW / cm ² was confirmed at 25 ° C.

Example 11
By using the same method as in Example 6 above, 1 cm ² of carbon paper was applied as a carbon electrode, and a fuel cell having the structure shown in FIG.
As a result of introducing a 400 mM glucose aqueous solution into the fuel electrode 1 side, 20 mW /
The output of cm ² was confirmed.

Example 12
By using the same method as in Example 7 above, 1 cm ² of carbon paper was applied as the carbon electrode, and a fuel cell having the structure shown in FIG.
As a result of introducing a 400 mM glucose aqueous solution to the fuel electrode 1 side, 18 mW /
The output of cm ² was confirmed.

Example 13
By using the same method as in Example 8 above, 1 cm ² of carbon paper was applied as a carbon electrode, and a fuel cell having the structure shown in FIG.
As a result of introducing a 400 mM glucose aqueous solution into this fuel electrode 1 side, 22 mW /
The output of cm ² was confirmed.

Example 14
By using the same method as in Example 9 above, 1 cm ² of carbon paper was applied as the carbon electrode, and a fuel cell having the structure shown in FIG.
As a result of introducing a 400 mM glucose aqueous solution into the fuel electrode 1 side, 14 mW /
The output of cm ² was confirmed.
The measurement results of the outputs of the fuel cells of Examples 10 and 11 and Examples 12, 13, and 14 are shown in Table 4 below.

From the results shown in Table 4, in Examples 12, 13, and 14 in which the electron mediator having the chemical structure represented by the above formula (3) is supported on the enzyme-immobilized electrode 20, the above formula (1) or ( Compared with Examples 10 and 11 to which the electron mediator having the chemical structure represented by 2) is applied, an output equal to or higher than that is obtained, and thus the electron mediator having the chemical structure represented by the above formula (3). It has become clear that the performance of the fuel cell is sufficient when using.
Example 15
Using the enzyme-immobilized electrode 20 produced on the glassy carbon electrode 21 by the same method as in Example 6, chronoamperometry measurement was performed at 0.1 V (vs Ag / AgCl) for 1 hour. The current value after 1 hour was 29 μA / cm ² . FIG. 6 shows the result of this chronoamperometry with a solid line.

Example 16
Using the enzyme-immobilized electrode 20 produced on the glassy carbon electrode 21 by the same method as in Example 7, chronoamperometry measurement was performed at 0.1 V (vs Ag / AgCl) for 1 hour. The current value after 1 hour was 31 μA / cm ² . FIG. 6 shows the result of this chronoamperometry with a dotted line.

Example 17
Using the enzyme-immobilized electrode 20 produced on the glassy carbon electrode 21 by the same method as in Example 8, chronoamperometry measurement was performed at 0.1 V (vs Ag / AgCl) for 1 hour. The current value after 1 hour was 44 μA / cm ² . FIG. 6 shows the result of this chronoamperometry with a one-dot chain line.

Example 18
Using the enzyme-immobilized electrode 20 prepared on the glassy carbon electrode 21 by the same method as in Example 9, chronoamperometry measurement was performed at 0.1 V (vs Ag / AgCl) for 1 hour. The current value after 1 hour was 44 μA / cm ² . FIG. 6 shows the result of this chronoamperometry with a broken line.

The measurement results of chronoamperometry after 0.1 V and 1 hour in Example 15 and Examples 16, 17, and 18 are shown in Table 5 below.

  From the results shown in Table 5, in Examples 16, 17, and 18 in which the electron mediator having the chemical structure represented by the above formula (3) is supported on the enzyme-immobilized electrode 20, the above formula (1) or ( As compared with Example 15 in which the electron mediator having the chemical structure represented by 2) was applied, it was clarified that the decrease in the current value was greatly suppressed and the durability of the enzyme-immobilized electrode 20 was greatly improved. It was.

Next explained is a fuel cell according to the third embodiment of the invention.
In the third embodiment, a specific structural example of the fuel cell will be described.
As shown in FIGS. 7A and 7B, this fuel cell includes, for example, a fuel electrode 1 composed of an enzyme / coenzyme / electron mediator-immobilized carbon electrode in which an enzyme, a coenzyme, and an electron mediator are immobilized on a carbon electrode with an immobilizing material. For example, the air electrode 3 made of an enzyme / electron mediator-immobilized carbon electrode in which an enzyme or an electron mediator is immobilized on a carbon electrode with an immobilizing material is opposed to the carbon electrode via the electrolyte layer 5. In this case, Ti current collectors 31 and 32 are provided on the air electrode 3 and the fuel electrode 1, respectively, so that current collection can be performed easily. Reference numerals 33 and 34 denote fixed plates. The fixing plates 33 and 34 are fastened to each other by a screw 35, and the air electrode 3, the fuel electrode 1, the electrolyte layer 5, and the Ti current collectors 31 and 32 are sandwiched between them. One surface (outer surface) of the fixing plate 33 is provided with a circular recess 33a for taking in air, and a plurality of holes 33b penetrating to the other surface are provided on the bottom surface of the recess 33a. These holes 33 b serve as air supply paths to the air electrode 3. On the other hand, a circular recess 34a for fuel loading is provided on one surface (outer surface) of the fixed plate 34, and a number of holes 34b penetrating to the other surface are provided on the bottom surface of the recess 34a. These holes 34 b serve as a fuel supply path to the fuel electrode 1. A spacer 36 is provided in the periphery of the other surface of the fixing plate 34, and when the fixing plates 33 and 34 are fastened to each other with screws 35, the interval between them becomes a predetermined interval. .
As shown in FIG. 7B, a load 37 is connected between the Ti current collectors 31 and 32, and power is generated by putting, for example, a glucose solution as a fuel in the recess 34 a of the fixed plate 34.
Other than the above are the same as those in the first or second embodiment.

Next explained is a fuel cell according to the fourth embodiment of the invention.
The fuel cell according to the fourth embodiment has the same configuration as the fuel cell according to the first embodiment, except that a porous conductive material as shown in FIG. 8 is used for the electrode material of the fuel electrode 1.
FIG. 8A schematically shows the structure of the porous conductive material, and FIG. 8B is a cross-sectional view of the skeleton of the porous conductive material. As shown in FIGS. 8A and B, this porous conductive material is composed of a skeleton 41 made of a porous material having a three-dimensional network structure and a carbon-based material 42 covering the surface of the skeleton 41. This porous conductive material has a three-dimensional network structure in which a large number of holes 43 surrounded by the carbon-based material 42 correspond to a network. In this case, these holes 43 communicate with each other. The form of the carbon-based material 42 is not limited and may be any of a fibrous shape (needle shape) and a granular shape.

As the skeleton 41 made of a porous material, a foam metal or a foam alloy such as nickel foam is used. The porosity of the skeleton 41 is generally 85% or more, more typically 90% or more, and the pore diameter is typically, for example, 10 nm to 1 mm, more typically 10 nm to 600 μm, and more generally 1 to 600 μm, typically 50 to 300 μm, more typically 100 to 250 μm. The carbon material 42 is preferably a highly conductive material such as ketjen black, but a functional carbon material such as carbon nanotube or fullerene may be used.
The porosity of the porous conductive material is generally 80% or more, more typically 90% or more, and the diameter of the hole 43 is typically, for example, 9 nm to 1 mm, more generally 9 nm to It is 600 μm, more generally 1 to 600 μm, typically 30 to 400 μm, more typically 80 to 230 μm.

Next, a method for producing this porous conductive material will be described.
As shown in FIG. 9A, first, a skeleton 41 made of a foam metal or a foam alloy (for example, foam nickel) is prepared.
Next, as shown in FIG. 9B, a carbon-based material 42 is coated on the surface of the skeleton 41 made of the foam metal or foam alloy. As this coating method, a conventionally known method can be used. For example, the carbon-based material 42 is coated by spraying an emulsion containing carbon powder, an appropriate binder, or the like onto the surface of the skeleton 41 by spraying. The coating thickness of the carbon-based material 42 is determined according to the porosity and the pore diameter required for the porous conductive material in consideration of the porosity and the pore diameter of the skeleton 41 made of the foam metal or foam alloy. In this coating, a large number of holes 23 surrounded by the carbon-based material 42 are communicated with each other.
In this way, the target porous conductive material is manufactured.
Other than the above are the same as those in the first or second embodiment.

  According to the fourth embodiment, the porous conductive material obtained by coating the surface of the skeleton 41 made of foam metal or foam alloy with the carbon-based material 42 has a sufficiently large diameter of the holes 43 and a rough three-dimensional network shape. While having a structure, it has high strength and high conductivity, and a necessary and sufficient surface area can be obtained. Therefore, the fuel electrode 1 composed of the enzyme / coenzyme / electron mediator immobilized electrode obtained by immobilizing the enzyme, coenzyme and electron mediator on the porous conductive material is used as an electrode material. It is possible to perform the enzyme metabolism reaction at high efficiency, or the enzyme reaction phenomenon occurring in the vicinity of the electrode can be efficiently captured as an electric signal, and is stable regardless of the use environment. It is possible to realize a high-performance fuel cell.

Next explained is a fuel cell according to the fifth embodiment of the invention.
In this fuel cell, the electrolyte layer 5 includes a buffer solution such as a phosphate buffer solution or a Tris buffer solution, and at least the electrolyte layer 5 around the enzyme immobilized on the fuel electrode 1 and the air electrode 3 has a buffer solution. A concentration of 0.2M to 2.5M, preferably 0.2M to 2M, more preferably 0.4M to 2M, and even more preferably 0.8M to 1.2M is included. In this way, a high buffering capacity can be obtained, and even when the fuel cell operates at a high output, it can be maintained at an optimum pH for the enzyme, for example, around pH 7, so that the original ability of the enzyme can be fully exhibited. Can do. As the phosphate buffer, for example, NaH ₂ PO ₄ or KH ₂ PO ₄ is used.
Other than the above are the same as those in the first or second embodiment.

  According to the fifth embodiment, when the concentration of the buffer substance (buffer solution) contained in the electrolyte layer 5 is not less than 0.2M and not more than 2.5M, a sufficient buffer capacity can be obtained. Even during high power operation of the fuel cell, the pH of the electrolyte layer 5 around the enzyme immobilized on the fuel electrode 1 and the air electrode 3 can be maintained near the optimum pH, and the ability of the enzyme is inherent Can be fully exhibited. As a result, a high-performance fuel cell capable of high output operation can be realized.

Next explained is a fuel cell according to the sixth embodiment of the invention.
In this fuel cell, starch which is a polysaccharide is used as a fuel. In addition, with the use of starch as fuel, glucoamylase, which is a degrading enzyme that decomposes starch into glucose, is also immobilized on the fuel electrode 1.
In this biofuel cell, when starch is supplied as fuel to the fuel electrode 1 side, this starch is hydrolyzed into glucose by glucoamylase, and this glucose is further decomposed by glucose dehydrogenase. At the same time, NAD ⁺ is reduced to produce NADH, which is oxidized by diaphorase and separated into two electrons, NAD ⁺ and H ⁺ . Therefore, two electrons and two H ⁺ are generated by one-step oxidation reaction per molecule of glucose. In the two-stage oxidation reaction, a total of 4 electrons and 4 H ⁺ are generated. The electrons thus generated are transferred to the electrode of the fuel electrode 1, and H ⁺ moves through the electrolyte layer 5 to the air electrode 3. In the air electrode 3, the H ⁺ reacts with oxygen supplied from the outside and electrons sent from the fuel electrode 1 through an external circuit to generate H ₂ O.
Except for the above, the fuel cell is the same as that of the first or second embodiment.
According to the sixth embodiment, the same advantages as those of the first or second embodiment can be obtained, and since the starch is used as the fuel, the amount of power generation is larger than when glucose is used as the fuel. The advantage that can be increased can be obtained.

Next explained is the seventh embodiment of the invention. In the seventh embodiment, a notebook personal computer will be described as an example of a fuel cell mounting device.
As shown in FIG. 10, the notebook personal computer 51 includes a personal computer main body 53 having a keyboard operation unit 52 disposed on the upper surface and a lid 55 having a liquid crystal display 54 mounted on the lower surface. The personal computer main body 53 and the lid 55 can be rotated by a hinge on the back side and fixed at an arbitrary position. By closing the lid 55 and overlaying it on the personal computer main body 53, the liquid crystal display 54 is overlaid on the keyboard operation unit 52 and covered with each other. A battery storage unit 56 is provided on a side surface of the personal computer main body 53, and a fuel cell 57, which is a portable power supply device, is detachably attached to the battery storage unit 56 for use. As the fuel cell 57, any one of the fuel cells according to the first to sixth embodiments is used.

  The fuel cell 57 includes a power generation unit 58 that generates power using fuel (for example, glucose) and air (oxygen), a fuel cartridge 59 that supplies fuel to the power generation unit 58, and air that supplies air to the power generation unit 58. A supply unit 60, a control unit 61 that controls the power generation operation of the power generation unit 58, a battery case 62 that integrally stores them, and the like are provided. The battery case 62 is provided with an air inlet 63 and an air outlet 64 and a connection portion 65 for electrically connecting the personal computer main body 53 and the fuel cell 57.

Next, an eighth embodiment of the invention will be described. In the eighth embodiment, a dog type robot will be described as an example of a fuel cell mounting device.
As shown in FIG. 11, a fuel cell system 72 is mounted on a dog-type robot 71 of an electronic pet. In the fuel cell system 72, any one of the fuel cells according to the first to sixth embodiments is used. The dog-shaped robot 71 includes a drum portion 73, a head portion 74 attached to the front upper portion of the body portion 73, and two forefoot portions 75 attached to both front portions of the body portion 73. , Two rear legs 76 attached to both sides on the rear side of the body part 73, and a tail part 77 attached to the upper rear side of the body part 73.

  The head 74 of the dog-shaped robot 71 is provided with a neck portion 78 projecting downward. The neck portion 78 is pivoted up and down and left and right within a predetermined range with respect to the body portion 73 by the neck joint. Mounted freely and up and down. Further, a jaw part 79 is attached to the lower part of the neck part 78 by a temporomandibular joint so that the jaw part 79 can be raised and lowered. A pair of ear portions 80 are attached to the rear upper portion of the neck portion 78 so as to be substantially symmetrical with respect to each other and turnable by respective ear joints.

  In addition, the pair of forefoot portions 75, the pair of rear foot portions 76, and the tail portion 77 are connected to each other by a pair of forefoot joints, a pair of rear foot joints, and a tail joint, respectively, so as to be rotatable and upright. Further, the pair of forefoot portions 75 are each composed of an upper foot portion 82 and a lower foot portion 83, and both are connected to each other by a fore knee joint 84 so as to be rotatable and upright. And the forefoot part 85 is attached to the front-end | tip part of the leg lower part 83 by an ankle joint so that raising / lowering is possible.

  Similarly, each of the pair of rear foot portions 76 includes an upper foot portion 86 and a lower foot portion 87, and both are connected to each other by a rear knee joint 88 so as to be freely rotatable and up / down. A rear foot portion 89 is attached to the distal end portion of the lower foot portion 87 by an ankle joint so as to be raised and lowered. Furthermore, the tail part 77 is rotatably attached to the body part 73 by a tail joint.

  Each of the joints described above represents a specific example of the drive unit of the dog robot 71. Each of these joints is individually attached with one or two drive motors for rotating or raising / lowering each joint. Also, in the body part 73, an electronic device control unit comprising a microcomputer and a storage device (RAM, ROM, etc.) for driving and controlling all drive motors and various detection sensors, voice recognition devices and other mechanisms. Is built-in. By driving and controlling all the drive motors with this electronic device controller, it is possible to cause the dog-shaped robot 71 to perform a walking motion or to perform various operations such as “hand” and “sitting”.

  The fuel cell system 72 includes the same number of power generation units 90 as the number of joints provided for each joint, the fuel cell control unit 91 that controls the power generation operation of all the power generation units 60, and all the power generation units 90. On the other hand, the fuel supply means 92 supplies fuel (methanol, ethanol, glucose, etc.) as fuel, and the air supply means 93 supplies air (oxygen) to each power generation unit 90. Of course, the fuel used for the power generation reaction may be not only a liquid such as an aqueous glucose solution but also a gas obtained by vaporizing a liquid such as methanol. In addition, it is good also as a structure which provides auxiliary equipments, such as a cooling fan for cooling the electric power generation part 90, a control part, and other heat generating sources. In addition, the common part shared by the fuel cell system 72 and the dog robot 71 is a component of the fuel cell system 72 and a component of the dog robot 71, and these dogs can be shared by sharing these components. It is possible to reduce the number of components of the fuel cell mounting device including the type robot 71 and the fuel cell system 72. In addition, as the shared unit, for example, a cooling fan for cooling the above-described control unit and other heat sources, an auxiliary device such as a pump or an air conditioner, a fuel supply unit that supplies fuel to the power generation unit 90, a power generation unit 90 Any heater may be used as long as it can be shared, such as heaters used for heating air supply means for supplying air, auxiliary equipment such as electric heaters, temperature sensors, humidity sensors, radiators, DC / DC converters, and the like. In addition, a structural member of a fuel cell mounting device such as a housing that houses an electronic device or a fuel cell may be used as a shared portion, and when the power generation unit 90 of the fuel cell is sandwiched using the wall surface portion of the housing. Can also use this wall surface as a common part. Furthermore, it is good also considering the fastening member of the electric power generation part which has a stack structure as a shared part.

  The same number of power generation units 90 (90a to 90j) as the number of joints provided for each joint as a power generation unit are disposed in the vicinity of the corresponding joints. That is, the head 74 is provided with a power generation unit 90 a for the ear 80 and a power generation unit 90 b for the jaw 79. Further, the body portion 73 includes a power generation portion 90c for the neck portion 78, a power generation portion 90d for the front foot portion 75, a power generation portion 90e for the rear foot portion 76, and a power generation portion 90f for the tail portion 77. Has been.

  Further, a power generation unit 90g for the front knee joint 84 is disposed on the upper foot portion 82 of the forefoot portion 75, and a power generation portion 90h for the front foot portion 85 is disposed on the lower foot portion 83. A power generation portion 90 i for the rear knee joint 88 is disposed on the upper foot portion 86 of the rear foot portion 76, and a power generation portion 90 j for the rear foot portion 89 is disposed on the lower foot portion 87. These power generation units 90a to 90j are connected to the fuel supply means 92 by a fuel pipe 94 so that fuel can be supplied.

  Corresponding to each of the power generation units 90a to 90j, air intake holes showing a specific example of the air supply means 93 are provided in the vicinity of the body 73, the head 74, and the front and rear legs 75, 76. Is provided. The air introduced from these air intake holes is used for power generation together with hydrogen in each of the power generation units 90a to 90j. As a specific example of the fuel supply unit 92, for example, a glucose aqueous solution storage tank capable of storing a 1M glucose aqueous solution can be used.

  An outline of a general configuration of the fuel cell system 72 is shown in FIG. In FIG. 12, reference numeral 100 denotes a fuel cartridge filled with fuel, and is constituted by a flat box having a quadrangular shape. A base substrate 101 is placed on the upper surface of the fuel cartridge 100, and a power generation unit 90, a cooling fan 102, two drying fans 103 that dry the water generated by the power generation unit 90, and the fuel cartridge 100. Two on-off valves 104 that open and close the fuel supply port by adjusting the flow rate of fuel from the power generation unit 90 to the power generation unit 90, a regulator 105 that compensates for fluctuations in the current value and the voltage value extracted from the power generation unit 90, and the like are mounted. .

  In addition, cooling fins 106 are disposed on the upper surface of the power generation unit 90 to release and cool the heat of the power generation unit 90 to the outside. The cooling fin 106 is mounted with a plurality of large-scale semiconductor integrated circuits (LSIs) and other control components constituting the control unit 91, a temperature sensor 107, and a humidity sensor 108.

  According to the eighth embodiment, the power generation unit 90 is provided in the vicinity of each joint that requires power, and power is generated as necessary for each joint. Therefore, compared to the conventional method in which electricity is generated by a single power generation unit and the power is supplied to all joints, the output of each power generation cell can be kept small, thus increasing the power generation efficiency. be able to.

  And since the output of one power generation cell is small, the heat management and water management of each power generation cell can be made easy, and the system configuration can be simplified. Further, by sharing a part of the components of the fuel cell system 72 and a part of the components of the dog-type robot 71, for example, a control unit, a fuel cell mounting device comprising the dog-type robot 71 and the fuel cell system 72 is provided. It is possible to simplify the configuration without wasting the entire components.

  Of the constituent elements of the fuel cell system 72, those that can be shared as the constituent elements of the dog-type robot 71 are not limited to the above-described control unit. For example, in the cooling fan 102, the drying fan 103, and other constituent elements If it is the same kind that is shared by the fuel cell system 72 and the animal robot, it can be shared.

Next, a ninth embodiment of the invention will be described. In the ninth embodiment, a dog type robot will be described as an example of a fuel cell mounting device.
As shown in FIG. 13, a fuel cell system 142 is mounted on a dog-type robot 141 of an electronic pet. In the fuel cell system 142, any one of the fuel cells according to the first to sixth embodiments is used. Since the structures of the dog-type robot 141 and the fuel cell system 142 are substantially the same as those of the dog-type robot 71 and the fuel cell system 72 described in the eighth embodiment, detailed description thereof will be omitted. The dog-type robot 141 includes a fuel cell system 142 including a plurality of power generation units 130 a to 130 j and a secondary battery 150 that supplies power to the fuel cell control unit 131 that controls the operation of the fuel cell system 142. Has been. In the ninth embodiment, the fuel cell control unit 131 of the fuel cell system 142 and the control unit of the dog robot 141 are shared by the fuel cell system 142 and the dog robot 141. In addition, the shared part of the fuel cell system 142 and the dog robot 141 is a fuel supply means for supplying fuel to the power generation unit 130 such as a cooling fan, a pump or an auxiliary device such as an air conditioner for cooling other heat sources. , Heaters used for heating air supply means for supplying air to the power generation unit 130, auxiliary equipment such as electric heaters, temperature sensors, humidity sensors, radiators, DC / DC converters, etc. But you can. In addition, a structural member of a fuel cell mounting device such as a housing for storing an electronic device or a fuel cell may be used as a shared portion, and when the power generation portion of the fuel cell is sandwiched using the wall surface portion of the housing The wall surface portion can be used as a common portion. Furthermore, it is needless to say that the fastening member of the power generation unit 130 having a stack structure may be used as a common unit.

  The dog-type robot 141 has substantially the same configuration as the dog-type robot 71 described in the eighth embodiment, and mainly includes a body part 143, a head 144, a neck part 148, a jaw part 149, an ear part 120, and two pieces. The front foot portion 145, the two rear foot portions 146, the movable portion such as the tail portion 147, and a plurality of joint portions for moving these freely.

  The plurality of joint portions are drive portions for moving the movable portion, and are driven by, for example, a drive motor. The joint portion includes a drive motor for moving the joint portion. These drive motors freely move the movable parts connected via the joints. The joint portion is rotated or lifted by the driving force generated by the drive motor, and the movable portion connected to the joint can be freely rotated or lifted. For example, a pair of forefoot portions 145 that are movable portions can be rotated and moved up and down by a pair of forefoot joints. Further, a required number of drive motors can be provided at each joint.

  The power generation units 130a to 130j are arranged in the vicinity of each joint of the dog robot 141, and each of the power generation units 130a to 130j supplies electric power to a driving motor located in the vicinity of each power generation unit. For example, the power generation unit 130 h arranged in the vicinity of the anterior knee joint 124 supplies electric power to a drive motor provided in the anterior knee joint 124. Similar to the power generation unit 130h provided in the vicinity of the anterior knee joint 124, the power generation units arranged in the vicinity of each joint supply power to the drive motors provided in the respective joints. As described above, the power generation units 130a to 130j constituting the fuel cell are dispersedly arranged in the dog-type robot 141, and each power generation is performed by supplying power from one power generation unit 130 to a driving motor included in one joint. The output burden of the units 130a to 130j can be reduced. In the dog-shaped robot 141, the power generation units 130 are individually arranged in the vicinity of each joint. However, the number of the power generation units 130 may not be the same as the number of joints. Further, it is only necessary that the power supply to the plurality of drive motors is shared by the plurality of power generation units. For example, power may be supplied from one power generation unit to the plurality of drive motors among the plurality of power generation units. . Furthermore, the structure is not limited to the structure in which the power generation unit is built in the dog-shaped robot 141, and a power generation unit may be separately attached from the outside in order to compensate for the shortage of power supplied to the drive unit.

  According to the fuel cell mounting device configured by the dog-type robot 141 and the fuel cell system 142 configured by the plurality of power generation units 130a to 130j, power is supplied from one power generation unit to all the drive motors provided in the dog-type robot. As compared with the case of supplying power, it is possible to reduce the output required per one power generation unit. By reducing the output of the power generation units 130a to 130j, it is possible to reduce the amount of heat and the amount of moisture generated by the power generation reaction of each power generation unit. Therefore, the heat and water generated by the power generation reaction can be easily managed, and the power generation unit can generate power in an optimal environment while managing the temperature of the power generation unit and the amount of moisture contained in the power generation cell of this power generation unit. The dog robot 141 can be stably operated.

  Furthermore, since the power generation units 130a to 130j are dispersedly arranged in the dog-type robot 141, it is possible to replace each power generation unit individually. Maintenance of the type robot 141 can be performed. In addition, when the power of all the drive motors is supplied from one power generation unit, there may be a problem in the drive of all the drive motors when a problem occurs in this power generation unit. According to the plurality of power generation units 103a to 130j distributed in the interior of 141, even when a problem occurs in one power generation unit, the drive motor that has been supplied with power from this one power generation unit is driven. Only the trouble occurs, and the other drive motors are driven without any trouble. Furthermore, when a problem occurs in a specific power generation unit, only this power generation unit can be replaced, and the maintenance of the dog-type robot 141 can be easily performed. Moreover, it is also possible to perform maintenance by exchanging the movable part having the built-in power generation part among the movable parts of the dog-shaped robot 141.

  Inside the body portion 143 is an electronic device control unit comprising a microcomputer and a storage device (RAM, ROM, etc.) for controlling the drive of all drive motors and various detection sensors, voice recognition devices and other mechanisms. Is built-in. This electronic device control unit is a control unit that is built in the dog-type robot 141 like the drive motor described above, and controls the operation of the dog-type robot 141 by being driven to process data and commands. is there. The dog-type robot 141 shares the electronic device control unit with the control unit 131 that controls the operation of the fuel cell system 142, and therefore the electronic device control unit is not shown. Further, when the fuel cell control unit and the electronic device control unit are not shared, the fuel cell control unit can be driven by electric power supplied from the fuel cell.

  The control unit 131 shared with the electronic device control unit is a control unit for the dog-shaped robot 141 and is a drive unit that is driven by electric power in the same manner as the drive motor included in the joint unit described above. The control unit 131 is driven by power supplied from a secondary battery 150 such as a lithium ion secondary battery provided in the vicinity of the control unit 131. The drive unit included in the dog robot 141 is classified into a drive unit such as a joint unit that is moved by a drive motor, and a drive unit such as an electronic device control unit that is shared with the control unit 131. When comparing the load fluctuations of the driving motor and the control unit 131, the load fluctuations of the control unit 131 including the microcomputer usually tend to be larger than the load fluctuations of the driving motor. Specifically, a drive unit such as a drive motor has almost no load fluctuation thereafter if power necessary to start driving is supplied. That is, when the horizontal axis represents the time during which the drive motor is driven and the vertical axis represents the magnitude of the load, the magnitude of the load changes in a substantially rectangular shape with respect to the time axis.

  On the other hand, the load of the control unit 131 tends to fluctuate in a pulse manner with respect to the drive time. Specifically, the load of the control unit 131 not only has a large fluctuation range, but also the load rises steeply and falls sharply with respect to the time axis. The electric power required for driving the control unit 131 varies greatly due to this pulse-like load variation. In many cases, it is difficult for the power generation unit 130 included in the fuel cell to supply a required electric power following a sudden load change, and the control unit 131 is not driven stably, thereby stabilizing the dog robot 141. May not be able to drive. Further, even when the electronic device control unit is provided separately from the control unit 131, it is difficult to stably drive the electronic device control unit.

  Therefore, this dog-shaped robot 141 not only shares power supply by a plurality of power generation units, but also uses a power source that supplies power according to load fluctuations of the drive unit. In particular, a secondary unit that can supply power from a power generation unit 130 to a drive unit such as a drive motor, and can supply power to a control unit 131 that tends to have a large load fluctuation following a sudden load fluctuation. Electric power is supplied from the battery 150. The secondary battery 150 is a power supply unit that can store electrical energy by repeatedly charging, stores the electrical energy supplied from the power generation units 130d and 130e, and supplies the electrical energy as power to the control unit 131. To do. Thus, the dog-type robot 141 can be driven stably by properly using the power source that supplies power according to the load fluctuation. The power supply means is not limited to the secondary battery 150, but may be a battery such as a capacitor, a micro turbine, a primary battery, or a solar battery, or a combination of these power supply means. Moreover, you may share supply of electric power with one electric power generation part and several electric power supply means.

Next explained is the tenth embodiment of the invention. In the tenth embodiment, a power supply system will be described.
As shown in FIG. 14, the power supply system 160 has a larger load fluctuation than the fuel cell 161 that supplies power to the plurality of drive units 163 and the drive units 163 a and 163 b that are supplied with power from the fuel cell 161. The secondary battery 162 is configured to supply power to the driving unit 163c. As the fuel cell 161, any one of the fuel cells according to the first to sixth embodiments is used. When supplying electric power to various electric appliances used at home, electric power is supplied from the secondary battery 162 to electric appliances whose load fluctuation is larger than that of electric appliances supplied with power from the fuel cell 161. For example, an electric appliance that requires a high voltage at the time of lighting, such as a lighting fixture, is lit by supplying power from the secondary battery 162, and electric power from the fuel cell 161 is supplied to other electric appliances with small load fluctuations. Supply. That is, the drive unit 163c corresponds to a lighting fixture, and the other electric appliances correspond to the drive units 163a and 163b. In addition, since the secondary battery 162 can be charged from the fuel cell 161 when various electric devices are not driven, the secondary battery 162 supplies electric power to a required drive unit after storing electric energy. Power supply means. According to such a power supply system 160, by properly using the fuel cell and the power supply means according to the load fluctuation of the drive unit, it is possible to stably supply power to a system composed of various drive units with different load fluctuations. Can be supplied.

  The power supply system 160 is not limited to supplying power to various electric appliances used in the home, but can be applied to supplying power to a system having a drive unit with different load fluctuations. . For example, in a transport device such as an electric vehicle equipped with a fuel cell, power is supplied from a power supply means such as a secondary battery to various devices having a large load fluctuation compared to a drive motor for moving the transport device. Thus, it is possible to stably operate the entire transportation apparatus. The power supply means is not limited to a secondary battery, and a capacitor can be used. The power supply means is not limited to a secondary battery, and may be a microturbine, a battery such as a primary battery or a solar battery, a primary battery, or a combination of these power supply means.

Although the embodiments and examples of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments and examples, and various modifications based on the technical idea of the present invention are possible. It is.
For example, the numerical values, structures, configurations, shapes, materials, and the like given in the above-described embodiments and examples are merely examples, and different numerical values, structures, configurations, shapes, materials, and the like may be used as necessary. Good.

It is a basic diagram which shows the curve regarding the general oxidation-reduction potential and electric current value in a fuel cell. 1 is a schematic diagram showing a fuel cell according to a first embodiment of the present invention. It is a basic diagram which shows the enzyme fixed electrode applied to the fuel cell by 1st Embodiment of this invention. It is a basic diagram which shows the CV curve of the enzyme fixed electrode to which various electron mediators are applied in 1st Embodiment of this invention. It is a basic diagram which shows the CV curve of the enzyme fixed electrode to which various electron mediators are applied in 2nd Embodiment of this invention. It is a basic diagram which shows the chronoamperometry measurement curve of the enzyme fixed electrode to which various electron mediators are applied in 2nd Embodiment of this invention. It is sectional drawing and a basic diagram which show the fuel cell by 3rd Embodiment of this invention. It is the basic diagram and sectional drawing for demonstrating the structure of the porous conductive material used for an electrode material in the fuel cell by 4th Embodiment of this invention. It is an approximate line figure for explaining the manufacturing method of the porous conductive material used for the electrode material in the fuel cell by a 4th embodiment of this invention. It is a basic diagram which shows the notebook type personal computer by 7th Embodiment of this invention. It is a basic diagram which shows the dog-type robot by 8th Embodiment of this invention. It is a basic diagram which shows the fuel cell system used in the dog-type robot by 8th Embodiment of this invention. It is an approximate line figure showing a dog type robot by a 9th embodiment of this invention. It is a basic diagram which shows the electric power supply system by 10th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel electrode, 3 ... Air electrode, 5 ... Electrolyte layer, 7 ... Fuel, 41 ... Skeleton, 42 ... Carbon material, 43 ... Hole, 51 ... Notebook computer, 57, 161 ... Fuel cell, 71, 141 ... Dog type robot, 72, 142 ... Fuel cell system, 160 ... Power supply system

Claims (19)

General formula

(Wherein X ₁ represents any _one of hydrogen, an alkyl group, and an aryl group)
An electron mediator comprising a compound represented by the formula: General formula

(In the formula, X ₂ and X ₃ represent hydrogen, an alkyl group, or an aryl group)
An electron mediator comprising a compound represented by the formula: In an enzyme-immobilized electrode on which an enzyme and an electron mediator are immobilized,
The above electronic mediator is
General formula

(Wherein X ₁ represents any _one of hydrogen, an alkyl group, and an aryl group)
Or a derivative thereof and / or
General formula

(In the formula, X ₂ and X ₃ represent hydrogen, an alkyl group, or an aryl group)
An enzyme-immobilized electrode comprising a compound represented by the formula:   The enzyme-immobilized electrode according to claim 3, wherein at least the enzyme and the electron mediator are immobilized on an electrode material made of porous carbon. In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(Wherein X ₁ represents any _one of hydrogen, an alkyl group, and an aryl group)
Or a derivative thereof and / or
General formula

(In the formula, X ₂ and X ₃ represent hydrogen, an alkyl group, or an aryl group)
A fuel cell comprising a compound represented by the formula:   6. The fuel cell according to claim 5, wherein at least the enzyme and the electron mediator are immobilized on an electrode material made of porous carbon. General formula

(In the formula, X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen, and X ₂ and X ₃ represent any one of hydrogen, an alkyl group, and an aryl group)
An electron mediator comprising a compound represented by the formula: In an enzyme-immobilized electrode on which an enzyme and an electron mediator are immobilized,
The above electronic mediator is
General formula

(In the formula, X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen, and X ₂ and X ₃ represent any one of hydrogen, an alkyl group, and an aryl group)
An enzyme-immobilized electrode comprising a compound represented by the formula: In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(In the formula, X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen, and X ₂ and X ₃ represent any one of hydrogen, an alkyl group, and an aryl group)
A fuel cell comprising a compound represented by the formula: In an electronic device using one or more fuel cells,
At least one of the fuel cells is
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(Wherein X ₁ represents any _one of hydrogen, an alkyl group, and an aryl group)
Or a derivative thereof and / or
General formula

(In the formula, X ₂ and X ₃ represent hydrogen, an alkyl group, or an aryl group)
An electronic device comprising a compound represented by the formula: In an electronic device using one or more fuel cells,
At least one of the fuel cells is
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(In the formula, X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen, and X ₂ and X ₃ represent any one of hydrogen, an alkyl group, and an aryl group)
An electronic device comprising a compound represented by the formula: In a mobile body using one or more fuel cells,
At least one of the fuel cells is
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(Wherein X ₁ represents any _one of hydrogen, an alkyl group, and an aryl group)
Or a derivative thereof and / or
General formula

(In the formula, X ₂ and X ₃ represent hydrogen, an alkyl group, or an aryl group)
A moving body comprising a compound represented by the formula: In a mobile body using one or more fuel cells,
At least one of the fuel cells is
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(In the formula, X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen, and X ₂ and X ₃ represent any one of hydrogen, an alkyl group, and an aryl group)
A moving body comprising a compound represented by the formula: In a power generation system using one or more fuel cells,
At least one of the fuel cells is
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(Wherein X ₁ represents any _one of hydrogen, an alkyl group, and an aryl group)
Or a derivative thereof and / or
General formula

(In the formula, X ₂ and X ₃ represent hydrogen, an alkyl group, or an aryl group)
A power generation system comprising a compound represented by the formula: In a power generation system using one or more fuel cells,
At least one of the fuel cells is
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(In the formula, X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen, and X ₂ and X ₃ represent any one of hydrogen, an alkyl group, and an aryl group)
A power generation system comprising a compound represented by the formula: In a cogeneration system using one or more fuel cells,
At least one of the fuel cells is
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(Wherein X ₁ represents any _one of hydrogen, an alkyl group, and an aryl group)
Or a derivative thereof and / or
General formula

(In the formula, X ₂ and X ₃ represent hydrogen, an alkyl group, or an aryl group)
A cogeneration system comprising a compound represented by the formula or a derivative thereof. In a cogeneration system using one or more fuel cells,
At least one of the fuel cells is
In a fuel cell having a structure in which a positive electrode and a negative electrode are opposed via a proton conductor, and an enzyme and an electron mediator are immobilized on the negative electrode,
The above electronic mediator is
General formula

(In the formula, X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen, and X ₂ and X ₃ represent any one of hydrogen, an alkyl group, and an aryl group)
A cogeneration system comprising a compound represented by the formula or a derivative thereof. In an electrode reaction utilization device having an electrode on which an enzyme and an electron mediator are immobilized,
The above electronic mediator is
General formula

(Wherein X ₁ represents any _one of hydrogen, an alkyl group, and an aryl group)
Or a derivative thereof and / or
General formula

(In the formula, X ₂ and X ₃ represent hydrogen, an alkyl group, or an aryl group)
The electrode reaction utilization apparatus characterized by consisting of the compound represented by these, or its derivative (s). In an electrode reaction utilization device having an electrode on which an enzyme and an electron mediator are immobilized,
The above electronic mediator is
General formula

(In the formula, X ₁ and X ₄ represent any one of hydrogen, an alkyl group, an aryl group, and a halogen, and X ₂ and X ₃ represent any one of hydrogen, an alkyl group, and an aryl group)
The electrode reaction utilization apparatus characterized by consisting of the compound represented by these, or its derivative (s).

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