JP2017224564A - Bio-fuel power generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bio-fuel power generation device high in output and excellent in temporal stability as compared with conventional power generation devices using a metal catalyst, by using, as a fuel liquid, reducing sugar, substances with an aldehyde group, or alcohols.SOLUTION: A bio-fuel power generation device 1 includes a pair of catalyst electrodes 3 provided with an ion exchange membrane 5 interposed therebetween, and generates power by oxidizing substances in a fuel liquid by a catalyst at the catalyst electrode 3 on an anode 3a side. In the bio-fuel power generation device 1, the catalyst comprises a compound of at least two metal elements, and the catalyst electrode 3 on the anode 3a side has a catalyst carrier in which the catalyst is supported on carbon particles as a carrier.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a biofuel power generation apparatus that generates power by oxidizing glucose or the like in a fuel liquid with a metal catalyst.

  In recent years, the amount of power generated by nuclear power generation has dramatically decreased in Japan due to the effects of the Great East Japan Earthquake, and the dependence on thermal power generation has increased to compensate for this, leading to the depletion of fossil fuels and excessive emissions of carbon dioxide. It is regarded as a problem.

  Along with this, there is an urgent need to shift to a power generation system that does not use fossil fuels, emits less carbon dioxide, and can stably supply power.

  As one of the methods for solving this problem, bioelectric power generation, in which fuel is almost inexhaustible and carbon dioxide emission is zero, has attracted attention.

  Bioelectric power generation is a power generation method that uses glucose or alcohols obtained from plants or the like as fuel. In biopower generation using glucose, alcohols, or the like as fuel, this is a method of taking out electrons generated when the fuel is oxidized by a catalyst. Examples of the catalyst include a protein catalyst such as an enzyme and a metal catalyst.

As described in Non-Patent Document 1, the bioelectric power generation system using a protein catalyst such as an enzyme has a very low environmental load because the reaction occurs very gently. However, the maximum output density that can be obtained is as low as about 0.02 to 0.2 mW / cm ² .

On the other hand, the biopower generation system using a metal catalyst has a maximum output density of 0.7 to 2.4 mW / cm, as described in Non-Patent Documents 2 to 5, as compared with a protein catalyst. An output of about ² and 10 times can be obtained.

A. Habrioux and 4 others, “Electrochemical charactarization of adsorbed birubin oxidase on Vulcan XC72R for the biocath preparation in a glucose / O2el / e2 7701-7705 A. Habrioux et al., “Activity of Platinum-Gold Alloys for Glucose Electrooxidation in Biofuel Cells”, J. Am. Phys. Chem. B, 2007, 111, p. 10329-10333 Debika Basu et al., "Synthesis and charactoerization of Pt-Au / C catalyst for glucose electro-oxidation for the application in direct ilGel ER 14923-14929 Debika Basu et al., “Synthesis, charactarization and application of platinum based bi-metallic catalytics for direct glucose alkalline fuel cell”, Elect. 6106-6113 Debika Basu et al., “Performance comparison of Pt-Au / C and Pt-Bi / Canode catalysts in batch and continuous direct glucose alkaline fuel cell, 13”. 867-870

  However, bioelectric power generation using conventional metal catalysts is still far from practical use, and further increase in output is desired.

  Further, in a power generation apparatus using a metal catalyst, it is important to use a metal catalyst having excellent temporal stability because the lifetime of the oxidation / reduction ability of the metal catalyst determines the life of the power generation apparatus itself.

  Furthermore, the present inventors have studied diligently using herbivorous animal excrement and mushroom waste medium as a raw material instead of a plant raw material that has been used as a raw material for glucose for use as a fuel for bioelectric power generation. We have succeeded in obtaining glucose efficiently through repeated research.

  Therefore, in the present invention, a biofuel power generation device that uses a reducing sugar, a substance having an aldehyde group, or alcohols as a fuel liquid and has high output and excellent temporal stability compared to a power generation device using a conventional metal catalyst. The purpose is to provide.

  In order to achieve the above object, the biofuel power generation device according to the first aspect of the present invention includes a pair of catalyst electrodes provided via an ion exchange membrane, and in the catalyst electrode on the anode side, In a biofuel power generation apparatus that generates power by oxidizing a substance with a catalyst, the catalyst is composed of a compound of at least two metal elements, and the catalyst electrode on the anode side is supported by carbon particles as a support. It is characterized by having a catalyst carrier.

  The biofuel power generator according to the second aspect of the present invention is characterized in that the substance in the fuel liquid is composed of a reducing sugar, a substance having an aldehyde group, or an alcohol.

  The biofuel power generation device according to the third aspect of the present invention is characterized in that the catalyst carrier includes a catalyst stabilizer made of a hydrophilic polymer compound.

  The biofuel power generator according to the fourth aspect of the present invention is characterized in that the catalyst is made of Pt and Au.

  In the biofuel power generation device according to the fifth aspect of the present invention, the catalyst electrode on the cathode side has Pt as a catalyst, and the catalyst electrode on the anode side has Pt: Au = 1: 3 to 4 (moles) as a catalyst. In the catalyst electrode on the anode side, the catalyst stabilizer in the catalyst carrier has a number of monomers that is not more than 1 times the total number of moles of Pt and Au as the catalyst. It is characterized by being included.

  The biofuel power generator according to the sixth aspect of the present invention is characterized in that the ion exchange membrane is a cation exchange membrane.

The biofuel power generation device according to the seventh aspect of the present invention includes a pair of separators made of a carbon material or a metal material outside the pair of catalyst electrodes,
A channel groove for flowing the fuel liquid is formed in a portion of the separator that is provided outside the catalyst electrode on the anode side and in contact with the catalyst electrode.

  The biofuel power generation apparatus according to the eighth aspect of the present invention is characterized in that the substance in the fuel liquid is glucose derived from excrement of herbivorous animals.

  The biofuel power generation device according to the ninth aspect of the present invention is characterized in that the substance in the fuel liquid is glucose derived from a mushroom waste medium.

  According to the biofuel power generation device of the present invention, it is possible to provide an environmentally friendly power generation device with high output and excellent stability over time as compared with a power generation device using a conventional metal catalyst.

  In addition, by using the biofuel power generation apparatus of the present invention, it is possible to provide a biofuel power generation system that integrates everything from securing a fuel liquid that can be maintained semipermanently to power generation, with a low environmental load.

Schematic diagram showing the principle of power generation 1 is an exploded perspective view of a biofuel power generation device according to the first embodiment of the present invention. The disassembled perspective view of the biofuel power generation device of this invention of 2nd Embodiment Schematic diagram showing the manufacturing method of the catalyst electrode It is a TEM image of a PtAu catalyst, (a) is a PVP concentration of 0.1 times, (b) is a PVP concentration of 1 time, (c) is a PVP concentration of 10 times, and (d) is a sample of a PVP concentration of 100 times. Graph showing the relationship between PVP concentration and maximum supported amount of catalyst Graph showing the relationship between PVP concentration and maximum power density obtained The graph which shows the examination result of the optimal ratio of the PtAu catalyst in Example 1 The graph which shows the current-voltage characteristic of the biofuel power generator of this invention in Example 2 The graph which shows the examination result of the optimal fuel liquid density | concentration in Example 3

  Hereinafter, specific embodiments of the biofuel power generation device of the present invention will be described with reference to FIGS.

First, the principle of power generation employed in the biofuel power generation apparatus 1 of the present invention will be briefly described with reference to FIG. The substance used as fuel will be described using glucose. In the power generation system, as shown in FIG. 1, an anode 3 a and a cathode 3 b having a metal catalyst are arranged in a state separated by an ion exchange membrane 5. The anode 3a is immersed in a fuel solution in which glucose and KOH are dissolved, and the cathode 3b is disposed in an oxygen gas atmosphere. In such a power generation system, the oxidation reaction of glucose is promoted by the metal catalyst provided on the anode 3a, and gluconic acid, divalent H ⁺ and divalent electrons can be generated at a predetermined speed. Then, oxygen gas is brought into contact with the divalent H ⁺ moved from the anode 3a side to the cathode 3b side through the ion exchange membrane 5, and the reaction of consuming the divalent electrons results in the reaction from the anode 3a to the cathode 3b. The electricity is generated by moving electrons to the side and generating an electric current. In addition, it is good also as adding NaOH in a fuel liquid other than KOH.

  In the biofuel power generation apparatus of the present invention, a reducing saccharide such as glucose, a substance having an aldehyde group, or alcohol is used as the substance for the fuel liquid.

  Reducing sugars include aldose (glucose, allose, altrose, mannose, gulose, idose, galactose, talose, ribose, arabinose, xylose, lyxose, erythrose, threose, glyceraldehyde, inositol), ketose (heptulose, psicose, fructose) Sorbose, tagatose, ribulose, xylulose, erythrulose, dihydroxyacetone), disaccharide (sucrose, lactose, lactulose, trehalose, cellobiose, gentiobiose) and the like.

Examples of substances having an aldehyde group include acrylic aldehyde, acetaldehyde, acetaldehyde = ethylene acetal, acetaldehyde = oxime, acetaldehyde = dimethyl acetal, acetaldehyde = semicarbazone, acetaldehyde = p-nitrophenylhydrazone, acetaldehyde = phenylhydrazone, o-anisaldehyde, p -Anisaldehyde, 1-aminoethanol, m-aminobenzaldehyde, o-aminobenzaldehyde, p-aminobenzaldehyde, isovanillin, isovaleraldehyde, isophthalaldehyde, isophthalaldehyde acid, isobutyraldehyde, isobutyraldehyde = oxime, p-isopropylbenzaldehyde, Octanal, opian acid, glycol aldehyde, group Seraldehyde, glutaraldehyde, crotonaldehyde, chloral, chloroacetaldehyde, m-chlorobenzaldehyde, o-chlorobenzaldehyde, p-chlorobenzaldehyde, salicylaldehyde, salicylaldehyde = oxime, 1,1-diethoxyethane, 3,3-di Ethoxypropene, dichloroacetaldehyde, 1,1-dichloro-2,2-diethoxyethane, 2,4-dinitrobenzaldehyde, 2,3-dihydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde, 2,5-dihydroxybenzaldehyde, 3, 4-dihydroxybenzaldehyde, p- (dimethylamino) benzaldehyde, 2,3-dimethoxybenzaldehyde, 2,4-dimethoxybenzaldehyde, 2,5-dimethoxy Benzaldehyde, 3,4-dimethoxybenzaldehyde syringaldehyde, cinnamaldehyde, succinaldehyde, α-thioacetaldehyde (trimer), β-thioacetaldehyde (trimer), α-thiobenzaldehyde (trimer), β -Thiobenzaldehyde (trimer), decanal, terephthalaldehyde, terephthalaldehyde acid, 2,2,3-trichlorobutyraldehyde, 1,3,5-trithiane, tribromoacetaldehyde, m-tolualdehyde, o-tolualdehyde, p-tolualdehyde, 1-naphthaldehyde, 2-naphthaldehyde, m-nitrobenzaldehyde, o-nitrobenzaldehyde, p-nitrobenzaldehyde, nitroformaldehyde = oxime, nonanal, vanillin paraaldehyde, para Lumaldehyde, valeraldehyde, bis (hydroxyimino) acetone, bis (methylthio) methane, hydroxyiminoacetone, 1-hydroxy-2-naphthaldehyde, 2-hydroxy-1-naphthaldehyde, 4-hydroxy-1-naphthaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, 5-hydroxymethyl-2-furaldehyde, pivalaldehyde, piperonal, 2-pyridinecarbaldehyde, pyruvaldehyde, phenylacetaldehyde, phthalaldehyde, phthalaldehyde acid, 2-butynal, butyl Aldehyde, butyraldehyde = oxime, 2-furaldehyde, propioaldehyde, propionaldehyde, 2-bromoacrylaldehyde, hexanal, heptaner Perylaldehyde, benzaldehyde, (Z, Z) -benzaldehyde azine, (E) -benzaldehyde = oxime, (Z) -benzaldehyde = oxime, benzaldehyde = hydrazone, benzaldehyde = phenylhydrazone, benzoylacetaldehyde, o-formylbenzenesulfonic acid, Formaldehyde, formaldehyde = oxime, formaldehyde = diethyl acetal, formaldehyde = dimethyl acetal, malealdehyde, malonaldehyde, mandelonitrile, methacrylaldehyde, (E) -2-methyl-2-butenal, 5-methyl-2-furaldehyde, Examples include lactaldehyde, lactaldehyde dimer, and levulin aldehyde.

Examples of alcohols include p-anisyl alcohol, 1-aminoethanol, o-aminobenzyl alcohol, p-aminobenzyl alcohol, allyl alcohol, isobutyl alcohol, p-isopropylbenzyl alcohol, isopentyl alcohol, 1-undecanol, ethanol, 1-octadecanol, 1-octanol, 2-octanol, p-chlorobenzyl alcohol, coniferyl alcohol, salicyl alcohol,
3,3-dimethyl-2-butanol, 2,2-dimethyl-1-propanol, cinnamyl alcohol, 1-decanol, 1-tetradecanol, tetrahydrofurfuryl alcohol, 1-dodecanol, 1-tridecanol, m-tolyl Methanol, o-tolylmethanol, p-tolylmethanol, m-nitrobenzyl alcohol, o-nitrobenzyl alcohol, p-nitrobenzyl alcohol, 1-nonanol, vanillyl alcohol, m-hydroxybenzyl alcohol, p-hydroxybenzyl alcohol, 4-hydroxy-4-methyl-2-pentanone, piperonyl alcohol, phenacyl alcohol, 1-phenylethanol, 2-phenylethanol, (−)-α-fenkyl alcohol, 1-butanol, 2-butanol, t -Bu Chill alcohol, trans-2-buten-1-ol, furfuryl alcohol, 1-propanol, 2-propanol, 2-propyn-1-ol, 1-hexacosanol, 1-hexadecanol, 1-hexanol, 1 -Heptadecanol, 1-heptanol, benzyl alcohol, 1-pentadecanol, 1-pentanol, 2-pentanol, t-pentyl alcohol, methanol, 2-methyl-1-butanol and the like.

  In the biofuel power generator of the present invention, Pt, Au, Pd, Mo, Fe, Co, Ru, Ni, Rh, Cu, Ir, Ag, W, Mn, etc. are used as metal catalysts for the anode 3a and the cathode 3b. At least one of these transition metals or oxides thereof is used.

  In particular, an excellent output can be obtained by using a metal catalyst made of PtAu as the anode 3a. At this time, it is preferable that Pt: Au = 1: 3 to 4 (molar ratio). By using a metal catalyst made of PtAu having a molar ratio in the above range, a biofuel power generation apparatus with excellent temporal stability can be provided. This is because when the Au ratio is less than the above range, the poisoning rate of PtAu increases, and when the metal catalyst is poisoned, the catalytic action is lowered and the oxidation of the substance as a fuel is not promoted. The function as a fuel generator is lost. Moreover, it is preferable to use Pt as the cathode 3b.

  In addition, it is important that the metal catalyst of the present invention is fixed to an electrode substrate as a catalyst carrier in which the metal catalyst is supported on carbon particles as a carrier.

  In the biofuel power generation device of the present invention, the catalyst carrier contains a catalyst stabilizer made of a hydrophilic polymer compound. As the hydrophilic polymer compound, polyvinyl pyrrolidone (PVP), polyvinyl alcohol, polyethyleneimine, polydiallyldimethylammonium chloride, polyacrylic acid, polysulfonic acid and the like can be used.

  In particular, it is preferable to use polyvinyl pyrrolidone (PVP) as a catalyst stabilizer, and an excellent output can be obtained because the content of the monomer is not more than 1 times the total number of moles of the metal catalyst in the catalyst support. Can be obtained. This is because when the concentration of the catalyst stabilizer increases, the catalyst stabilizer densely covers the surface of the metal catalyst particles, and the hydrophobicity of the metal catalyst particles decreases. This is thought to be because the driving force for the adsorption of metal catalyst particles is lost.

  First and second embodiments of the biofuel power generation apparatus 1 of the present invention using the above-described power generation principle will be described with reference to FIGS. 2 and 3.

As shown in FIG. 2, the biofuel power generation device 1 of the first embodiment of the present invention includes a pair of catalyst electrodes 3 provided via an ion exchange membrane 5, and a pair of catalyst electrodes 3 outside the catalyst electrodes 3. Current collector plates 6a and 6b are provided, and outer frames 2a and 2b are provided outside the current collector plates 6a and 6b. Then, the fuel storage portion T is provided in the outer frame 2a provided on the anode 3a side of the catalyst electrode 3, and the fuel liquid is brought into contact with the anode 3a to promote the oxidation of the substance in the fuel liquid to generate electrons, This is an apparatus that generates electricity by causing H ⁺ that has passed through the ion exchange membrane 5 to come into contact with O ₂ on the cathode 3b side to generate a reaction that consumes electrons.

  More specifically, it is important that the outer frames 2a and 2b are formed of an insulating material, and it is possible to prevent the occurrence of electric leakage through the fuel liquid. As the insulating material, a material excellent in ease of injection molding (dimensional stability), heat resistance and alkali resistance is preferable. For example, glass fiber reinforced polyacetal, modified polyphenylene ether, glass fiber reinforced polypropylene, polystyrene, acrylonitrile butadiene -Styrene (ABS), glass fiber reinforced ABS, acrylonitrile styrene, acrylic and the like. In particular, glass fiber reinforced polyacetal, modified polyphenylene ether, acrylonitrile / styrene, acrylic, etc. are excellent in compressive strength, and when the outer frames 2a and 2b are fixed with fixing members such as bolts, the compression deformation due to bolt fixing is small. Is suitable.

  The pair of catalyst electrodes 3 is made of a conductive material such as carbon cloth, and a metal catalyst composed of at least one metal element is fixed on a base material having a mesh structure that can transmit fuel liquid and the like to the front and back sides. The metal catalyst is fixed on the base material in a state of a catalyst carrier supported on carbon particles as a carrier.

  It is important to use a cation exchange membrane as the ion exchange membrane 5. This is because, in the case of an anion exchange membrane, a negatively charged substance generated by the oxidation reaction on the anode 3a side adheres to the anion exchange membrane and hinders its action as an ion exchange membrane. For example, when the fuel material is glucose, negatively charged gluconic acid is produced on the anode 3a side. Therefore, when an anion exchange membrane is employed, the gluconic acid is adhered to the anion exchange membrane. Problem arises.

  The pair of current collector plates 6a and 6b are formed with lead portions for leading or introducing electrons, respectively, and electrons are led from the lead portion of the current collector plate 6a provided on the anode 3a side, and the cathode Electrons are introduced from the lead-out portion of the current collector plate 6b provided on the 3b side.

  Further, a packing is provided between the outer frame 2a and the current collector plate 6a to prevent the fuel liquid from leaking out.

The outer frame 2b disposed on the cathode 3b side is formed with an opening for allowing the cathode 3b to come into contact with the outside air. O ₂ is taken from this opening to cause a reaction of H ⁺ and O _{2 at} the cathode 3b.

  The outer frames 2a and 2b are provided with a fixing member for fixing the ion exchange membrane 5, the pair of catalyst electrodes 3, and the pair of current collector plates 6a and 6b with the sandwiched therebetween.

In the biofuel power generation device 1 of the first embodiment of the present invention having the above-described configuration, the fuel liquid stored in the fuel storage portion T of the outer frame 2a is converted into the substance in the fuel liquid by the metal catalyst provided in the anode 3a. together to promote the oxidation to generate electrons to derive the electrons from the lead portion of the current collector plate 6a, the introduced the electrons from the lead portion of the current collector plate 6b, O ₂ in the air in contact with the cathode 3b And H ⁺ that permeates through the ion exchange membrane 5 to react with each other and consume the electrons, thereby generating an electron flow between the anode 3a and the cathode 3b to generate electric power.

  As shown in FIG. 3, the biofuel power generation device 1 of the second embodiment of the present invention includes a pair of catalyst electrodes 3 provided via an ion exchange membrane 5, and fuel on the anode 3 a side of the catalyst electrode 3. This is an apparatus for generating electricity by oxidizing a substance in the liquid with a catalyst provided on the anode 3a to generate electrons.

  More specifically, it is important that the outer frames 2a and 2b are made of an insulating material in order to prevent leakage through the fuel liquid. As the insulating material, a material excellent in ease of injection molding (dimensional stability), heat resistance and alkali resistance is preferable. For example, glass fiber reinforced polyacetal, modified polyphenylene ether, glass fiber reinforced polypropylene, polystyrene, acrylonitrile butadiene -Styrene (ABS), glass fiber reinforced ABS, acrylonitrile styrene, acrylic and the like. In particular, glass fiber reinforced polyacetal, modified polyphenylene ether, acrylonitrile / styrene, acrylic, etc. are excellent in compressive strength, so that the fixing member is configured to fix the object sandwiched between them like a bolt and nut while compressing them. Even in the case of using, it can be used for a long time without causing any compression deformation.

  As described in the first embodiment, the pair of catalyst electrodes 3 has a form in which a metal catalyst made of at least one metal element is fixed on a substrate made of carbon cloth or the like. Is fixed on the base material in the state of a catalyst carrier supported on carbon particles as a carrier.

  As shown in FIG. 3, a separator 7a made of a carbon material or a metal material is sandwiched between the anode 3a and the cathode 3b disposed with the ion exchange membrane 5 interposed therebetween, as shown in FIG. , 7b are provided. The surface of the separator 7a facing the anode 3a is formed with a rectangular wave-shaped channel groove 4 for flowing a fuel liquid, and the surface of the separator 7b facing the cathode 3b is a rectangular for flowing oxygen gas. A wave-like gas passage groove 8 is formed. In addition, the separators 7a and 7b are respectively provided with an inlet for injecting fuel liquid and oxygen gas from a fuel reservoir T and a gas tank G provided outside the flow channel groove 4 and the gas flow channel groove 8, respectively. A discharge port for discharging the fuel liquid and oxygen gas that has passed through the flow channel groove 4 and the gas flow channel groove 8 is formed. In the present embodiment, the shape of the flow channel groove 4 is described using an aspect formed in a rectangular wave shape. However, the present invention is not limited to this, and for example, a spiral shape or a plurality of vertical stripe shapes are used. Or you may employ | adopt shapes, such as a horizontal stripe shape. Moreover, it is good also as an aspect which provides multiple each about the introduction part 4a and the derivation | leading-out part 4b.

  Between the ion exchange membrane 5 and the separator 7a, a silicon gasket 9a having a shape surrounding the outer peripheral portion of the flow channel groove 4 formed in the separator 7a is provided. Further, the silicon gasket 9a and the separator 7a are provided. 7 is provided with a Teflon gasket 10a formed in the same shape as the silicon gasket 9a. By using a gasket made of two kinds of materials in combination, a high liquid tightness is realized, and the flow channel 4 This prevents the fuel liquid flowing inside from leaking out of the channel groove 4. The silicon gasket 9a and the Teflon gasket 10a have an opening for positioning the anode 3a with respect to the channel groove 4, and the opening is provided between the ion exchange membrane 5 and the separator 7a. It arrange | positions in the state which inserted the anode 3a in the part.

  Similarly, a silicon gasket 9b is provided between the ion exchange membrane 5 and the separator 7b so as to surround the outer periphery of the gas flow channel groove 8 formed in the separator 7b. A Teflon gasket 10b formed in the same shape as the silicon gasket 9b is provided between the gasket 9b and the separator 7b. By using a combination of two types of gaskets, high airtightness is realized, Oxygen gas flowing in the flow channel groove 8 is prevented from leaking out of the gas flow channel groove 8. Further, the silicon gasket 9b and the Teflon gasket 10b have an opening for positioning the position of the cathode 3b with respect to the gas flow channel groove 8, and the gap is between the ion exchange membrane 5 and the separator 7b. It arrange | positions in the state which inserted the cathode 3b in the opening part.

  As shown in FIG. 3, a current collecting plate 6a for collecting electrons generated in the anode 3a is provided outside the separator 7a, and electrons collected by the current collecting plate 6a are provided outside the separator 7b. A current collecting plate 6b is disposed for supplying the cathode 3b to the cathode 3b. The current collector plates 6a and 6b are not particularly limited as long as they are materials excellent in electrical conductivity, but in this embodiment, copper plates subjected to gold plating are used.

  As shown in FIG. 3, a pair of outer frames 2 a and 2 b in which a plurality of through holes for inserting the fixing members are formed in the thickness direction are provided outside the current collecting plates 6 a and 6 b. Between the pair of outer frames 2a and 2b, from the outer frame 2a side, the current collector plate 6a, the separator 7a, the Teflon gasket 10a, the anode 3a fitted in the opening of the silicon gasket 9a, the ion exchange membrane 5, A plurality of through-holes formed in the pair of outer frames 2a and 2b are arranged in the order of the cathode 3b fitted in the opening of the silicon gasket 9b, the silicon gasket 9b, the Teflon gasket 10b, the separator 7b, and the current collector plate 6b. Each member is sandwiched and held by inserting and fixing a fixing member such as a bolt.

  As shown in FIG. 3, the outer frame 2a, current collector plates 6a and 6b, separators 7a and 7b, silicon gaskets 9a and 9b, and Teflon gaskets 10a and 10b are connected to the flow channel groove 4 of the separator 7a from the fuel reservoir T. A fuel introduction part 11 for introducing the fuel liquid is formed with respect to the introduction part 4a into which the fuel liquid flows. The fuel introduction portion 11 includes a through hole 11a formed in the outer frame 2a and the current collector plate 6a, and a fixing portion by inserting a fuel liquid transport tube drawn from the fuel storage portion T into the through hole. It is set as the structure fixed by 11b. The tube is preferably made of an insulating material.

  In addition, oxygen gas flows from the gas tank G into the gas flow channel groove 8 of the separator 7b into the outer frame 2a, current collector plates 6a and 6b, separators 7a and 7b, silicon gaskets 9a and 9b, and Teflon gaskets 10a and 10b. A gas introduction part 12 for introducing the oxygen gas is formed in the part 8a. The gas introduction part 12 includes a through hole 12a formed in the outer frame 2a, the current collector plate 6a, the separators 7a and 7b, the silicon gaskets 9a and 9b, and the Teflon gaskets 10a and 10b. A gas transportation tube or the like drawn out from is inserted and fixed by the fixing portion 12b. The tube is preferably made of an insulating material.

  As shown in FIG. 3, the silicon gaskets 9a and 9b, the Teflon gaskets 10a and 10b, the separators 7a and 7b, the current collector plates 6a and 6b, and the outer frame 2b flow out from the discharge part 4b of the flow channel 4 of the separator 7a. A fuel lead-out part 13 and a gas lead-out part 14 are respectively formed to lead out the used fuel liquid and the used oxygen gas flowing out from the outlet of the gas flow channel groove 8 of the separator 7b. The fuel lead-out part 13 and the gas lead-out part 14 include silicon gaskets 9a and 9b, Teflon gaskets 10a and 10b, a separator 7b, a current collector plate 6b, and through holes 13a and 14a formed in the outer frame 2b, respectively. The used fuel liquid and oxygen gas flowing into the through holes 13a and 14a are led out from the outer frame 2b to the outside.

  In addition, the biofuel power generation device 1 of the present invention of the second embodiment shown in FIG. 3 has been described using the most basic configuration, and practically, between the current collector plates 6a and 6b, A plurality of sets each including a separator 7a, 7b, silicon gaskets 9a, 9b, Teflon gaskets 10a, 10b, an anode 3a, a cathode 3b, and an ion exchange membrane 5 are stacked. The number of stacks can be appropriately adjusted according to the required power generation amount.

  Moreover, in the biofuel power generation device 1 of the present invention of the second embodiment, as shown in FIG. 3, liquid tightness is provided between the outer frame 2a and the current collector plate 6a and between the current collector plate 6b and the outer frame 2b. It is good also as a structure which each provides the silicon gasket for improving.

  In the biofuel power generation device 1 of the second embodiment of the present invention having the above-described configuration, as shown in FIG. 3, the fuel is transported from the fuel reservoir T in which the fuel liquid containing glucose and KOH as fuel is stored. The fuel liquid is introduced into the flow channel 4 formed in the separator 7a adjacent to the anode 3a from the fuel introduction portion 11 through the tube, and the tube for gas transportation from the gas tank G filled with oxygen gas. Then, oxygen gas is introduced from the gas introduction part 12 into the gas flow path groove 8 formed in the separator 7b adjacent to the cathode 3b. Electrons generated as a result of oxidation of glucose in the fuel liquid in contact with the anode 3a are led to a device (not shown) connected to the biofuel power generator 1 through the current collector plate 6a. Furthermore, power is generated by electrons introduced to the current collector plate 6b through the device connected to the biofuel power generator 1 flowing toward the cathode 3b.

  According to the biofuel power generation device 1 of the first and second embodiments of the present invention as described above, the glucose oxidation promotion action is superior to that of the conventional biofuel power generation device, and a high output is realized. Is possible.

  In particular, in the biofuel power generation device 1 of the present invention, the anode 3a has a catalyst carrier on which a PtAu catalyst is supported, and the PtAu catalyst has Pt: Au = 1: 3 to 4 (molar ratio). The content of the catalyst stabilizer in the catalyst carrier is set to the number of monomers less than 1 times the total number of moles of the metal catalyst. Therefore, higher output can be obtained.

Below, the detailed manufacturing method of the anode 3a is demonstrated using FIG. The manufacturing method of the anode 3a of the catalyst electrode 3 in the biofuel power generation apparatus 1 of the present application proceeds in order from the left side to the right side on the paper as shown in FIG. Specifically, first, HAuCl ₄ is added to an aqueous PVP solution as a catalyst stabilizer, and Au chloride ions are bonded to the PVP structure to form a complex. Next, H ₂ PtCl ₆ is added to the aqueous solution to bind Pt chloride ions in the PVP structure to form a complex. PtAu alloy nanoparticles are formed by adding a large amount of NaBH ₄ as a reducing agent in a short time to the aqueous solution. Then, carbon particles as a support are put into the aqueous solution, and PtAu alloy nanoparticles are adsorbed by a hydrophobic force to form a catalyst support, followed by filtration and drying to obtain a catalyst support. . The anode 3a of the catalyst electrode 3 can be obtained by dispersing the obtained catalyst carrier in an aqueous ethanol solution to which an ionomer as a binder has been added and applying it to a carbon cloth.

As the reducing agent, hydrazine, citric acid, ascorbic acid, ethanol and the like can be used in addition to NaBH ₄ .

In the following examples, the catalyst carrier used for the anode 3a was prepared by the following method. In the description, it is assumed that Pt: Au = 1: 4 (molar ratio) and the PVP concentration is one time the molar concentration of Pt and Au. Specifically, first, the following solutions A to C were prepared. Next, 6.0 mL of the above solution A, 1.5 mL of solution B, 3.0 mL of solution C, and 136.5 mL of water were mixed, and magnetic stirring was performed for 30 minutes at room temperature. Here, Solution D was prepared. While vigorously stirring the solution (A + B + C + water), 3.0 mL of the solution D immediately after preparation was added, and stirring was further continued for 30 minutes. After stopping the stirring, a suspension obtained by adding 29.0 mg of carbon powder to the solution (A + B + C + water + D) was further magnetically stirred at room temperature for 12 hours. Finally, the suspension was filtered under reduced pressure, washed with a large amount of water, and dried at 120 ° C. for 2 hours to obtain a catalyst carrier.
<Solution A>
16.5 mg of 4 mM tetrachloroauric (III) acid aqueous solution tetrachloroauric (III) acid tetrahydrate (HAuCl ₄ .4H ₂ O) was dissolved in 10 mL of water.
<Solution B>
The 4mM hexachloroplatinic (IV) acid aqueous solution of hexachloroplatinic (IV) acid hexahydrate _{(H 2 PtCl 6 · 6H 2} O) 20.7mg dissolved in water 10 mL.
<Solution C>
10.1 mg of 10 mM poly (N-vinyl-2-pyrrolidone) (PVP) aqueous solution poly (N-vinyl-2-pyrrolidone) was dissolved in 10 mL of water.
<Solution D>
37.8 mg of 100 mM sodium borohydride aqueous solution sodium borohydride (NaBH ₄ ) was dissolved in 10 mL of water.

<Examination of catalyst carrier>
Here, regarding the catalyst carrier used for the anode 3a, the relationship between the PVP concentration and the amount of the catalyst supported was examined. In this study, Pt: Au = 1: 4 (molar ratio), and the PVP concentration at the time of preparation of the catalyst support was examined as 0.1, 1, 10, 100 times the molar concentration of Pt and Au. Went. The catalyst support was prepared by the above method. In addition, the result of having performed TEM observation about the obtained catalyst support body in the preparation stage of each catalyst support body sample is shown to Fig.5 (a)-(d). In FIGS. 5A to 5D, the black portions indicate PtAu catalyst particles. Table 1 shows the analysis results of the particle diameters obtained by performing image analysis from the respective TEM images shown in FIGS.

  The particle size was analyzed by the following method. First, 5 μL of each colloid solution prepared by the method shown in FIG. 4 was placed on a transmission electron microscope (TEM) observation grid, vacuum-dried, and then a transmission electron microscope (H-7650; manufactured by Hitachi High Technologies). Was used to observe PtAu nanoparticles. The obtained image was subjected to particle size analysis by a particle analysis function after image gradation software, image J, and threshold / brightness / contrast were prepared using image analysis software ImageJ developed by NIH. The obtained particle diameter data was subjected to statistical analysis to obtain an average value, a standard deviation (σ), and 3σ, and analyzed by a histogram. The maximum particle diameter is a value obtained by adding the average particle diameter to 3σ which is a number obtained by multiplying the particle diameter standard deviation σ by three.

  In addition, for each of the obtained catalyst support samples, thermogravimetric measurement was performed under the condition that the temperature was raised to 600 ° C. at a rate of 10 ° C./min and held for 30 to 60 minutes. Measurements were made. The obtained result is shown in FIG.

  As shown in FIGS. 4A to 4D, it can be seen that the prepared PtAu catalyst has the largest particle size of a 0.1-fold sample. Moreover, it turns out that the particle diameter of the PtAu catalyst particle of a 0.1 time sample has a large variation. As shown in FIGS. 4B to 4D, it can be seen that the particle diameters of the samples of 1 to 100 times have almost the same size.

  As shown in Table 1, the analysis result of the particle diameter of the PtAu catalyst at each PVP concentration shows that the 0.1-fold sample has a large average particle diameter of 4.05 nm, and the standard deviation value. As can be seen from FIG. And in the sample of 1 time-100 times, the average particle diameter also showed the substantially equivalent value.

  As shown in FIG. 6, the amount of the PtAu catalyst supported in the obtained catalyst support sample of each PVP concentration was supported more as the sample with a lower PVP concentration. This is because, as the concentration of PVP increases, the surface of the PtAu catalyst particles is densely covered with the catalyst stabilizer, and the hydrophobicity of the PtAu catalyst particles decreases, so that the PtAu to the carbon particles having the same hydrophobic surface is also obtained. This is thought to be because the driving force for adsorption of the catalyst particles was lost.

  Moreover, the output of the catalyst carrier sample of each PVP concentration obtained in the above examination was examined. Each of the above catalyst support samples was dispersed in an aqueous ethanol solution having a concentration of 50 vol% to a concentration of 10 mg / mL, and 2 wt% Nafion (registered trademark) was added as an ionomer to form a catalyst ink, and then a 3 × 3 cm carbon cloth. To obtain an anode 3a. Each obtained anode 3a is set in the biofuel power generation device of the present invention described in the second embodiment, and current-voltage characteristics are measured using a fuel solution in which 0.2 M glucose and 1 M KOH are dissolved. The output of each catalyst carrier sample was examined. The obtained results are shown in FIG.

Maximum power density in the case of using each catalyst carrier samples, as shown in FIG. 7, PVP concentration 6.53mW / ^cm 2 at 0.1 times the sample 1 fold in sample 6.47mW / cm ² was at 10 times the sample at 2.91mW ^/ cm 2, 100 times the sample at 0.02 mW / cm ^2. It is considered that this is because the catalyst carrier sample with a higher PVP concentration has a smaller amount of PtAu catalyst supported, and the maximum output density is also reduced accordingly. However, this relationship did not hold in the 0.1-fold sample, and the sample with 1-fold PVP concentration and the sample with 0.1-fold showed almost the same maximum power density. This is because the 0.1-fold sample has a large amount of PtAu catalyst, but the particle size of the PtAu catalyst is large, resulting in a 1-fold increase in the area of the PtAu catalyst exposed on the surface of the catalyst support. This is considered to be the same level as the sample.

  From the above examination results, it is clear that an excellent output can be obtained by including PVP of the number of monomers less than 1 times the total number of moles of Pt and Au as the catalyst support used for the anode 3a. became.

  According to the biofuel power generation apparatus 1 of the above embodiment, the anode 3a has a catalyst carrier including a catalyst made of a PtAu alloy (here, Pt: Au = 1: 4 (molar ratio)), By providing the cathode 3b with a catalyst made of Pt, it was possible to efficiently promote the oxidation reaction of glucose as a fuel liquid and obtain an excellent output.

  At this time, a high output could be obtained because the PVP concentration in the catalyst support of the anode 3a was set to the number of monomers less than 1 times the total number of moles of Pt and Au of the PtAu catalyst.

  Below, Examples 1-4 of the biofuel power generator 1 of the present invention will be described.

<Example 1>
In Example 1, the optimum ratio of Pt and Au in the PtAu catalyst was examined from the viewpoint of power density and catalyst stability. Specifically, a PtAu catalyst with a Au ratio of 0, 20, 50, 80 or 100% is applied to carbon cloth so that the molar ratio is Pt + Au = 100%, and the biofuel of the second embodiment Current-voltage characteristics were measured using the power generator 1. At this time, a mixed liquid of 0.2 M glucose and 1 M KOH was used as a fuel liquid. In addition, each PtAu catalyst was applied to a glassy carbon electrode (φ4 mm), held at -1 V (VvsAg / AgCl) for 30 sec, stepped up to 0.2 V (VvsAg / AgCl), and maintained at 3600 sec. A chronoamperometry measurement method using a fuel solution composed of a mixture with 100 mM KOH was performed, and the change with time of the current value was measured. The obtained measurement results were linearly approximated, and the poisoning rate of each PtAu catalyst having a different ratio was calculated using the obtained intercept and slope values. The obtained power density results are shown in FIG. 8, and the results showing the catalyst stability are shown in Table 2.

  First, as for the power density, as shown in FIG. 8, the Pt catalyst with the Au ratio of 0% showed the highest power density. Next, the PtAu catalyst made of a PtAu alloy showed a large value regardless of the ratio, and the Au catalyst with the Au ratio of 100% showed the lowest output density.

  Regarding the catalyst stability, as shown in Table 2, the PtAu catalyst containing a large amount of Au tended to be more stable.

  From these results, the catalyst composed of only Pt has the best output, but the catalyst made of PtAu alloy having a higher Au content has lower poisoning rate and better stability over time. It was revealed that a catalyst made of a PtAu alloy with 80% being the most excellent from the viewpoint of power density and stability over time.

<Example 2>
In Example 2, a biofuel cell having the configuration of the biofuel power generation device 1 of the present invention of the second embodiment was produced, and the cell characteristics of the biofuel cell were examined. Specifically, the anode 3a has a PtAu catalyst having a weight ratio of Pt: Au = 1: 4, and a catalyst support prepared at a PVP concentration of the number of monomers that is one time the total number of moles of Pt and Au. Prepare the body. In the catalyst carrier, 20 wt% Ketjen Black (registered trademark) (EC600JD; manufactured by Lion Corporation) was used as carbon particles. The cathode 3b includes a catalyst carrier (manufactured by ElectroChem) in which a Pt catalyst is supported on carbon particles. As the fuel liquid, an aqueous solution in which 1 M KOH was added to 0.2 M glucose was used. The biofuel cell was operated at room temperature. FIG. 9 shows a test result of current-voltage characteristics obtained from a biofuel cell having the above configuration. In FIG. 9, the horizontal axis represents current density, the vertical axis represents voltage and output density, plot X1 represents voltage, and plot X2 represents output density.

In the biofuel cell having the configuration of the biofuel power generator 1 of the present invention, as shown in FIG. 9, the voltage at the time of open circuit was 0.99 V, and the maximum current density was 85.5 mA / cm ² . Further, when the current density was 39 mA / cm ² , the output density was maximized, and a maximum output density of 13 mW / cm ² was obtained. At this time, the voltage was 0.33V. In the conventional glucose fuel cell using the metal catalyst, the maximum output density is 0.7 to 2.4 mW / cm ² , compared with the biofuel provided with the mechanism of the biofuel power generation device 1 of the present invention. The battery has a maximum power density and a maximum power density of 13 mW / cm ² , and has been found to have high power generation performance.

<Example 3>
In Example 3, the optimum concentration of the fuel liquid for the biofuel power generation apparatus 1 of the present invention was examined. Specifically, for the 0.1, 0.2 and 0.4 M glucose solutions, the output density was measured when KOH was added from 0 to 1.6 M, respectively. In the examination, the biofuel power generation apparatus 1 of the first embodiment was used. FIG. 9 shows the relationship between the obtained density conditions and the output density.

  In the biofuel cell having the configuration of the biofuel power generation device 1 of the first embodiment, as shown in FIG. 10, higher output is obtained when 0.1M and 0.2M concentration glucose solutions are used as the fuel solution. Density was obtained. As for KOH, when glucose solutions of all concentrations are used, the output density increases as the concentration increases from 0 to 0.4 M, and the concentration dependency is 0.6 M or more. I was not able to admit. From this result, it was revealed that excellent power generation performance can be obtained by using a fuel liquid having a glucose concentration of 0.2 M or less and a KOH concentration of 0.6 M or more.

  From the above examination results of Examples 1 to 3, the biofuel power generation apparatus 1 of the present invention uses a PtAu catalyst with Pt: Au = 1: 3 to 4 (molar ratio), and the total of Pt and Au. By providing the anode 3a having a catalyst carrier containing PVP as a catalyst stabilizer with the number of monomers less than 1 times the number of moles, superior power generation performance can be obtained as compared with conventional biofuel power generation devices. It became clear that

  Furthermore, when performing power generation using the biofuel power generation apparatus 1 of the present invention, a high output density is obtained by using a fuel liquid having a glucose concentration of 0.2 M or less and a KOH concentration of 0.6 M or more. It became clear that it was possible.

<Biofuel power generation system>
Hereinafter, as an applied aspect of the biofuel power generation apparatus 1 of the present invention, a low environmental load and stable biofuel power generation system using the biofuel power generation apparatus 1 of the present invention will be described.

  As disclosed in JP-A-2015-116183, the present inventors have succeeded in producing glucose from herbivorous animal excrement. Briefly, herbivorous animal excrement contains cellulose that is finely decomposed to some extent by the digestive action of the animal, and after further pulverizing the cellulose in the excrement, Glucose is obtained by decomposing glucose. The herbivorous animal excrement is always present in large quantities on the earth, and since it is waste in the first place, it can be obtained at a very low cost. In addition, compared to biofuels that use thinned wood as a starting material, the starting material can be obtained very stably without being affected by climate change.

  In addition to this, it is conceivable to produce glucose from a used waste medium generated during fungus bed cultivation of mushrooms such as beech shimeji, eringi and enoki mushroom. Briefly, glucose is obtained by pulverizing the waste microbial bed generated after cultivating mushrooms and then decomposing cellulose contained in the waste microbial bed with a cellulose-degrading enzyme. Here, the mushroom waste medium is a fungus bed discarded after a mycelium is planted on a fungus bed composed of a base material and a nutrient material, and mushrooms are harvested in 30 to 120 days. Sawdust (conifers, hardwoods, etc.), corn cob or bean hulls with crushed corn cores are used as the base material of the fungus bed, and rice bran, wheat bran (corn bran) or corn is used as nutrients Yes. The dried waste medium contains cellulose, hemicellulose, lignin and ash resulting from the base material, proteins, lipids, and carbohydrates resulting from the fungus, and most of the components are composed of sugars such as cellulose. For this reason, the mushroom waste medium which can be obtained stably is optimal as a starting material for continuously producing glucose.

  In the biofuel power generation system to which the biofuel power generation apparatus 1 of the present invention is applied, glucose produced from the above-mentioned herbivorous animal excrement or glucose produced from a mushroom waste medium is used as the fuel liquid. And In this biofuel power generation system, it is possible to stably supply an inexpensive fuel liquid, and to provide a power generation system that can be sustained semipermanently with a low environmental load.

  The biofuel power generation apparatus 1 of the present invention is not limited to the first and second embodiments and Examples 1 to 4, and various changes can be made without departing from the characteristics of the invention.

DESCRIPTION OF SYMBOLS 1 Biofuel power generator 2a, 2b Outer frame 3 Catalytic electrode 3a Anode 3b Cathode 4 Channel groove 4a Introduction part 4b Discharge part 5 Ion exchange membrane 6a, 6b Current collecting plate 7a, 7b Separator 8 Gas channel groove 8a Introduction part 9a , 9b Silicon gasket 10a, 10b Teflon gasket 11 Fuel introduction part 11a Through hole 11b Fixing part 12 Gas introduction part 12a Through hole 12b Fixing part 13 Fuel outlet 13a Through hole 14 Gas outlet 14a Through hole T Fuel storage part G Gas tank

Claims (9)

A pair of catalyst electrodes provided via an ion exchange membrane,
In the catalyst electrode on the anode side, in the biofuel power generation apparatus that generates power by oxidizing the substance in the fuel liquid with the catalyst,
The catalyst comprises a compound of at least two metal elements,
The biofuel power generator according to claim 1, wherein the catalyst electrode on the anode side has a catalyst carrier in which the catalyst is supported on carbon particles as a carrier.   The biofuel power generation apparatus according to claim 1, wherein the substance in the fuel liquid is composed of a reducing sugar, a substance having an aldehyde group, or an alcohol.   The biofuel power generator according to claim 1 or 2, wherein the catalyst carrier includes a catalyst stabilizer made of a hydrophilic polymer compound.   The biofuel power generator according to any one of claims 1 to 3, wherein the catalyst is made of Pt and Au. The catalyst electrode on the cathode side has Pt as a catalyst,
The catalyst electrode on the anode side has a PtAu alloy having Pt: Au = 1: 3 to 4 (molar ratio) as a catalyst,
In the catalyst electrode on the anode side, the catalyst stabilizer in the catalyst carrier is contained in a monomer number that is not more than 1 times the total number of moles of Pt and Au as the catalyst. Item 5. The biofuel power generation device according to item 3 or 4.   The biofuel power generator according to any one of claims 1 to 5, wherein the ion exchange membrane is a cation exchange membrane. Outside the pair of catalyst electrodes, a pair of separators made of carbon material or metal material is provided,
The flow path groove for flowing the said fuel liquid is formed in the part which the said catalyst electrode of the said separator provided in the outer side of the said catalyst electrode of the anode side contacts. Item 7. The biofuel power generation device according to any one of items 6.   The biofuel power generator according to any one of claims 1 to 7, wherein the substance in the fuel liquid is glucose derived from herbivorous animal excrement.   The biofuel power generation apparatus according to any one of claims 1 to 7, wherein the substance in the fuel liquid is glucose derived from a mushroom waste medium.