Formic acid decomposition device and hydrogen supply system

Abstract

To provide a catalyst carrier, a formic acid decomposer capable of efficiently decomposing formic acid by using the catalyst carrier, and a hydrogen supply system capable of safely and efficiently supplying hydrogen from the formic acid as an energy source.SOLUTION: A catalyst carrier is obtained by supporting a mixture of platinum fine particles coordinated and dispersed in polyvinylpyrrolidone and a cationic polymer on a support material such as PVA. The formic acid decomposer includes a catalyst tower in which the catalyst carrier is arranged, a circulation pump that circulates and supplies formic acid to the catalyst tower, and a recovery pathway for collecting the generated hydrogen-containing gas. Additionally, the hydrogen supply system comprises a formic acid production device with an electrochemical cell that produces formic acid from water and carbon dioxide, the aforementioned formic acid decomposer that decomposes formic acid into hydrogen and carbon dioxide, and a generator that includes a hydrogen engine driven by the obtained hydrogen and a power generation unit driven by the hydrogen engine, as well as a pathway for circulating the carbon dioxide generated from formic acid to the formic acid production device.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention ,ant The present invention relates to an acid decomposition apparatus and a hydrogen supply system. [Background technology]

[0002] Fossil fuels such as coal and oil have been widely used in our daily lives, but in recent years, issues such as resource depletion and global warming caused by carbon dioxide have come into question, and hydrogen energy has been attracting attention as an alternative energy source. Solar energy is also a representative example of clean energy.

[0003] For example, fuel cells and hydrogen engines have been developed that use electricity generated by solar power generation and other sources to electrolyze water to extract hydrogen, and the hydrogen is then used as a fuel source. These fuel cells and hydrogen engines are expected to be used in a variety of applications, including automobiles and home power generation facilities.

[0004] However, because hydrogen is difficult to store and transport, research is being conducted into technologies for generating and storing formic acid (HCOOH) as an intermediate hydrogen source. Formic acid is an excellent storage material because it is liquid at room temperature and has a high energy density.

[0005] The applicants have previously proposed a hydrogen supply system and method as described in Patent Document 1. The invention described in Patent Document 1 is a hydrogen supply system comprising a formic acid generator that generates formic acid by artificial photosynthesis from water and carbon dioxide in the atmosphere or exhaust gas, a formic acid storage tank that stores the formic acid generated by the formic acid generator, a formic acid decomposition device that decomposes the formic acid supplied from the formic acid storage tank into hydrogen and carbon dioxide by a catalytic reaction in a deoxygenated environment at room temperature and atmospheric pressure, a hydrogen engine that runs on hydrogen supplied from the formic acid decomposition device as fuel, and a generator that has a power generation unit that uses the hydrogen engine as a drive source.

[0006] Patent Document 1 describes, as an example of a formic acid generation device, a substrate surface coated with a mixture of titanium oxide microparticles, a dye, and a viologen compound, and as an example of a formic acid decomposition device, describes a device that decomposes formic acid into hydrogen and carbon dioxide in a deoxidized environment at room temperature and atmospheric pressure using a catalyst made of platinum microparticles dispersed in a water-soluble polymer, polyvinylpyrrolidone (hereinafter simply referred to as water-soluble polymer polyvinylpyrrolidone).

[0007] The applicants have been conducting intensive research to further improve the amount of formic acid produced even after proposing the invention described in Patent Document 1. For example, the catalyst described in Patent Document 1, which is obtained by dispersing platinum fine particles in a water-soluble polymer, polyvinylpyrrolidone, has a problem in that it is difficult to use it repeatedly. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 7133819 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in view of the above circumstances, and provides a catalyst carrier that can be used multiple times and is highly convenient. Materials The present invention aims to provide a formic acid decomposition device capable of efficiently decomposing formic acid using a formic acid decomposition apparatus, and a hydrogen supply system capable of safely and efficiently supplying hydrogen from formic acid as an energy source. [Means for solving the problem]

[0010] One aspect of the present invention is A formic acid decomposition device for decomposing formic acid into hydrogen and carbon dioxide includes at least a catalyst tower that decomposes formic acid by catalytic reaction, a circulation pump that circulates and supplies formic acid to the catalyst tower, and a recovery path that recovers the generated mixed gas of hydrogen and carbon dioxide. The catalyst tower is provided with a catalyst support material, which is formed by supporting a mixture of a cationic polymer and a dispersion liquid in which platinum fine particles are dispersed in polyvinylpyrrolidone, a water-soluble polymer, on a support member. Formic acid passes through the catalyst tower while coming into contact with the catalyst support material. Characterized by

[0011] In this case, in one aspect of the present invention, the support member may be a sheet-like member formed from a polymer compound.

[0012] Alternatively, in one aspect of the present invention, the support member may be a bead-like member formed from a polymer compound.

[0014] In this case, in another aspect of the present invention, a means for supplying a carrier gas to the catalyst tower may be provided, and the mixed gas of hydrogen and carbon dioxide may be recovered from the recovery path by the carrier gas.

[0015] Another aspect of the present invention is a hydrogen supply system comprising: a formic acid generator that generates formic acid from water and carbon dioxide in the atmosphere or exhaust gas using an electrochemical cell; a formic acid storage tank that stores the formic acid generated by the formic acid generator; the formic acid decomposition device described above that decomposes the formic acid supplied from the formic acid storage tank into hydrogen and carbon dioxide through a catalytic reaction on a catalyst support material in a deoxygenated environment at room temperature and atmospheric pressure; a hydrogen engine that uses the hydrogen from the hydrogen and carbon dioxide supplied from the formic acid decomposition device as fuel; and a generator having a power generation unit powered by the hydrogen engine, and further comprising a path for circulating the unreacted carbon dioxide discharged from the generator from the hydrogen and carbon dioxide supplied from the formic acid decomposition device to the formic acid generator.

[0016] In this case, in another aspect of the present invention, the electrochemical cell may be of an all-solid-state type.

[0017] In another aspect of the present invention, the reaction for producing formic acid in the electrochemical cell may be powered by solar energy. [Effects of the Invention]

[0018] As described above, according to the present invention, a catalyst carrier that can be used multiple times and is highly convenient is provided. Materials It is possible to provide a formic acid decomposition apparatus that can efficiently decompose formic acid using the formic acid decomposition apparatus, and a hydrogen supply system that can safely and efficiently supply hydrogen from formic acid as an energy source. [Brief explanation of the drawings]

[0019] [Figure 1]1 is a schematic diagram illustrating an example of a formic acid decomposition apparatus according to an embodiment of the present invention. [Figure 2] 1 is a schematic diagram illustrating an example of a formic acid generating apparatus according to the present invention. [Figure 3] 1 is a schematic diagram illustrating an example of a hydrogen supply system according to an embodiment of the present invention. [Figure 4] 1 is a schematic diagram showing an example of a residential energy supply system to which the present invention is applied. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Note that the embodiments described below do not unduly limit the content of the present invention as defined in the claims, and not all of the configurations described in the embodiments are necessarily essential as means for solving the problems of the present invention.

[0021] (1. Catalyst Support Material) First, the catalyst support material according to the present invention will be described. One aspect of the present invention is a catalyst support material for decomposing formic acid into hydrogen and carbon dioxide, characterized in that the support material carries a mixture of a cationic polymer and a dispersion liquid in which platinum fine particles are dispersed in a water-soluble polymer, polyvinylpyrrolidone.

[0022] Platinum acts as a catalyst for decomposing formic acid into hydrogen and carbon dioxide. Platinum is used in the form of fine particles to increase the reaction area, and it is preferable to use platinum fine particles with a particle diameter of 1 nm or more and 50 nm or less.

[0023] Water-soluble polymer polyvinylpyrrolidone (PVP) is represented by the following general formula (I) and is used to disperse platinum microparticles. Platinum microparticles tend to aggregate and precipitate when used alone, so the use of water-soluble polymer polyvinylpyrrolidone allows the platinum microparticles to maintain their catalytic function while being dispersed. The amount of water-soluble polymer polyvinylpyrrolidone (PVP) added is preferably 1% by mass or more and 20% by mass or less relative to the platinum microparticles. If the amount of water-soluble polymer polyvinylpyrrolidone (PVP) added is less than 1% by mass, a sufficient effect of improving the dispersibility of the platinum microparticles cannot be obtained. Furthermore, if the amount of water-soluble polymer polyvinylpyrrolidone (PVP) added is more than 20% by mass, the catalytic function of the platinum microparticles cannot be obtained sufficiently.

[0024] [ka]

[0025] The decomposition reaction of formic acid includes a reaction in which hydrogen and carbon dioxide are produced from formic acid, as shown in the following reaction formula (1), and a reaction in which water and carbon dioxide are produced from formic acid, as shown in the following reaction formula (2). In the present invention, by using a combination of platinum fine particles and the water-soluble polymer polyvinylpyrrolidone, hydrogen can be efficiently generated by the reaction of reaction formula (1) with almost no side reaction of reaction formula (2). HCOOH → H2+CO2 (1) 2HCOOH+O2→ 2H2O+2CO2···(2)

[0026] Thus, in the decomposition reaction of formic acid, by combining a platinum catalyst with a water-soluble polymer polyvinylpyrrolidone, the carbonyl groups of polyvinylpyrrolidone change the electronic state of the platinum microparticles, which is thought to result in an efficient hydrogen production reaction. Furthermore, in the catalyst support material according to one embodiment of the present invention, since the catalytic reaction is carried out using platinum microparticles, no particular heating or pressurization is required, and the decomposition reaction of formic acid can be carried out under deoxygenated conditions at room temperature and atmospheric pressure.

[0027] Furthermore, in a catalyst support material according to one embodiment of the present invention, the hydrogen generation efficiency is further improved by mixing a cationic polymer with the combination of a platinum catalyst and a water-soluble polymer, polyvinylpyrrolidone. Specifically, by first dispersing platinum microparticles in the water-soluble polymer, polyvinylpyrrolidone, the platinum's electronic state is optimized for formic acid decomposition. Furthermore, the cationic polymer captures formic acid (formate ions), bringing them closer to the platinum microparticles and making them more susceptible to catalytic action. This further improves the hydrogen generation efficiency. Since formate ions are anions (negative), they capture the cationic polymer (positive), making them more likely to approach the platinum microparticles.

[0028] An example of a cationic polymer that can be used is poly(diallyldimethylammonium chloride) (PDADMA), which is represented by the following general formula (II): PDADMA has a similar chemical structure to PVP, and can achieve hydrogen generation efficiency five times higher than when no cationic polymer is mixed in.

[0029] [ka]

[0030] In one embodiment of the present invention, the weight ratio of the cationic polymer to the water-soluble polymer polyvinylpyrrolidone is preferably 0.50 or more. For example, by setting the weight ratio of poly(diallyldimethylammonium chloride) (PDADMA) to the water-soluble polymer polyvinylpyrrolidone (PVP) to 0.50 or more, the efficiency of hydrogen generation can be further improved.

[0031] In the present invention, a mixture of a dispersion of the above-mentioned platinum fine particles dispersed in the water-soluble polymer polyvinylpyrrolidone and a cationic polymer is supported on a support member. In the catalyst embodiment in which platinum fine particles are dispersed in the water-soluble polymer polyvinylpyrrolidone described in Patent Document 1, after mixing with formic acid to perform a formic acid decomposition reaction, it was difficult to separate the catalyst and perform the formic acid decomposition reaction again. Therefore, in the present invention, by supporting a mixture containing the above-mentioned catalyst on a support member, it is possible to perform the formic acid decomposition reaction on the support member multiple times.

[0032] The support member is not particularly limited as long as it can support a mixture of a dispersion liquid in which platinum fine particles are dispersed in the water-soluble polymer polyvinylpyrrolidone and a cationic polymer, but it can be a film or bead-shaped material. For example, when a polymer compound that becomes a resin composition is formed into a film or bead-shaped shape, a mixture containing the catalyst can be mixed to form a catalyst support material that supports a catalyst having formic acid decomposition ability.

[0033] As an example of how to create a catalyst support material, PVA (polyvinyl alcohol) is used as the raw material, and phosphoric acid or a non-phosphoric acid-based inorganic acid is added to it. Then, a dispersion liquid (Pt-PVP) in which platinum particles are dispersed in the water-soluble polymer polyvinylpyrrolidone and a cationic polymer are added, and the material is transferred to a mold and heated and dried in air to form a film. A more specific example of how to create a support material is described in the Examples.

[0034] In this way, in the present invention, by supporting the catalyst used in the formic acid decomposition reaction on a support member, it is possible to obtain a catalyst support material that can be used repeatedly in the formic acid decomposition reaction.Furthermore, by forming the catalyst into a film or bead shape, it is possible to incorporate it into a formic acid decomposition device, making it possible to obtain a catalyst support material that is easier to handle.

[0035] (2. Formic Acid Decomposition Apparatus) Next, a formic acid decomposition apparatus according to the present invention will be described. Fig. 1 is a schematic diagram showing an example of a formic acid decomposition apparatus according to one embodiment of the present invention. Another aspect of the present invention is a formic acid decomposition apparatus 60 for decomposing formic acid into hydrogen and carbon dioxide, which comprises at least a catalyst tower 61 that decomposes formic acid by catalytic reaction, a circulation pump 62 that circulates formic acid to the catalyst tower, and a recovery path 63 that recovers the generated mixed gas of hydrogen and carbon dioxide. The catalyst tower 61 is characterized in that the above-mentioned catalyst support material 65 is disposed therein, and formic acid passes through the catalyst tower 61 while coming into contact with the catalyst support material 65. Each component of the formic acid decomposition apparatus 60 will be described below.

[0036] The catalytic tower 61 is a facility in which a catalyst support material 65 according to the present invention is disposed and which decomposes formic acid through a catalytic reaction. For example, formic acid is supplied from the top of the catalytic tower 61 and, as it flows downward, comes into contact with the catalyst support material 65 disposed in the catalytic tower 61, whereby the formic acid is decomposed according to the above-described reaction formula (1), producing hydrogen. For example, the catalytic tower 61 may be configured so that the formic acid flows along alternating slopes, with film-like catalyst support materials 65 disposed on the slopes. Alternatively, the catalytic tower 61 may be configured so that bead-like catalyst support materials 65 are laid out and the formic acid flows through the spaces between the bead-like catalyst support materials 65. In either case, it is desirable that the configuration ensures sufficient contact time between the formic acid and the catalyst support material 65. While the catalytic tower 61 is assumed to be a tower-shaped facility, it may also be configured in a shape other than a tower (e.g., a panel-like shape).

[0037] The circulation pump 62 is a device that circulates and supplies formic acid to the catalyst tower 61. As an example, the circulation pump 62 sends formic acid that has accumulated at the bottom of the catalyst tower 61 after the contact reaction between formic acid and the catalyst support material 65 back to the top of the catalyst tower 61 and supplies it back into the catalyst tower 61. When supplying the formic acid, for example, a nozzle or the like may be provided on the piping so that the formic acid is sprayed from above the catalyst tower 61. In this way, formic acid that has not been sufficiently decomposed by contact with the catalyst support material 65 can be circulated and supplied multiple times, allowing formic acid to undergo a sufficient formic acid decomposition reaction. Furthermore, although not shown in FIG. 1 , a branch valve may be provided on the path of the circulation pump 62 as needed to allow new formic acid to be supplied into the formic acid decomposition apparatus 60.

[0038] The recovery path 63 is a facility for recovering the generated mixed gas of hydrogen and carbon dioxide. As an example, as shown in Fig. 1, a branch for extracting the generated hydrogen-containing gas is provided above the catalyst tower 61, and the hydrogen is extracted. Alternatively, the recovery path 63 may be under negative pressure, or an inert carrier gas such as nitrogen may be sent from below the catalyst tower 61, to more efficiently recover the hydrogen-containing mixed gas.

[0039] As described above, in the formic acid decomposition apparatus according to one embodiment of the present invention, the formic acid decomposition reaction can be sufficiently carried out and more hydrogen can be recovered by repeatedly circulating formic acid within the catalyst tower 61. Furthermore, in the present invention, the catalyst used in the formic acid decomposition reaction is supported on a support member, which enables the catalyst support material 65 to be used repeatedly and reduces the frequency of maintenance.

[0040] (3.Formic acid generator) Next, a formic acid generator according to one embodiment of the present invention will be described. The formic acid generator is a device that generates formic acid from water and carbon dioxide during the day when excess energy can be generated by solar power generation or the like, and stores the generated formic acid as an energy source for, for example, nighttime use.

[0041] Fig. 2 is a schematic diagram showing an example of a formic acid generator according to the present invention. As an example, a formic acid generator 50 according to the present invention is an all-solid-state electrochemical cell, and as shown in Fig. 2, has a laminated structure comprising an anode 51 (such as titanium mesh) carrying a catalyst (such as IrO) capable of oxidizing water, a cation exchange membrane 52, cation exchange resin beads 53, an anion exchange membrane 54, a cathode 55 (carbonaceous gas diffusion electrode) carrying a catalyst (such as tin or bismuth oxide) capable of reducing CO and an anion exchange resin polymer, and a current collector plate 56. These components are compressed by an external jig so as to be in close contact with each other.

[0042] During operation of the formic acid generator 50 of the present invention, pure water (H2O) is supplied to the anode 51 and the cation exchange resin beads 53, and carbon dioxide (CO2) containing moisture is supplied to the cathode 55, and an external voltage generated by solar power generation or the like is applied. As a result, protons (H + ) are generated and reach the cation exchange resin beads 53 by electrophoresis. At the cathode 55, formate anions (HCO2 - ) also migrates to the anion exchange membrane 54. + ) and formate anion (HCO2 - ) reacts to liberate formic acid (HCOOH), which is expelled from the cell.

[0043] Such a formic acid generating apparatus has the following advantages: 1. By carrying out the formic acid production reaction in the presence of an anion exchange membrane and polymer, it is possible to carry out the reaction under strongly basic conditions, and the pH environment can be separated from the acidic atmosphere in the cation exchange resin beads. 2. The liberated formic acid can be rapidly discharged from the cell by modifying the shape of the cation exchange resin beads. 3. By using cation exchange resin beads, ionic conductivity can be maintained without using a supporting electrolyte.

[0044] (4. Hydrogen Supply System) Next, a hydrogen supply system according to one embodiment of the present invention will be described. Fig. 3 is a schematic diagram illustrating an example of a hydrogen supply system according to one embodiment of the present invention. One aspect of the present invention is a hydrogen supply system 100 comprising: a formic acid generator 50 that generates formic acid from water and carbon dioxide in the atmosphere or exhaust gas using an electrochemical cell; a formic acid storage tank 40 that stores the formic acid generated by the formic acid generator 50; a formic acid decomposition device 60 that decomposes the formic acid supplied from the formic acid storage tank 40 into hydrogen and carbon dioxide through a catalytic reaction on a catalyst support material 65 in a deoxidized environment at room temperature and atmospheric pressure; a hydrogen engine 70 that uses hydrogen from the hydrogen and carbon dioxide supplied from the formic acid decomposition device 60 as fuel; and a generator 80 having a power generation unit powered by the hydrogen engine 70. The hydrogen supply system 100 further comprises a path 90 that circulates the unreacted carbon dioxide discharged from the generator 80 out of the hydrogen and carbon dioxide supplied from the formic acid decomposition device 60 to the formic acid generator 50.

[0045] In a hydrogen supply system 100 according to one embodiment of the present invention, as shown in Fig. 3, during the daytime when sunlight is available, the formic acid generator 50 generates formic acid from water and carbon dioxide in the atmosphere or exhaust gases using an electrochemical cell. At this time, electricity generated by solar power generation using sunlight is used for the formic acid generation reaction using the electrochemical cell, but the source of electricity is not necessarily limited to solar power generation, and other power sources may also be used.

[0046] The formic acid produced by the formic acid production device 50 is temporarily stored in the formic acid storage tank 40. Then, at night when sunlight cannot be utilized, the formic acid stored in the formic acid storage tank 40 is decomposed by the formic acid decomposition device 60 to produce hydrogen, and the obtained hydrogen is supplied to the hydrogen engine 70 to drive the generator 80, which is driven by the hydrogen engine 70.

[0047] The hydrogen engine 70 is driven by hydrogen supplied from the formic acid decomposition device 60 as fuel, and as the hydrogen engine 70 operates, the hydrogen reacts with oxygen in the air and burns. As a result, water is produced as shown in the following equation (3). The hydrogen engine 70 drives the generator 80, which generates electricity as the generator 80 operates. 2H2+O2→2H2O (3)

[0048] Although carbon dioxide is also supplied to the hydrogen engine 70 from the formic acid decomposition device 60, this carbon dioxide does not have any effect on the combustion reaction within the hydrogen engine 70. Therefore, it is possible to omit the process of providing a separator to separate hydrogen and carbon dioxide in advance.

[0049] The present invention further includes a pathway 90 for circulating the unreacted carbon dioxide discharged from the generator 80 out of the hydrogen and carbon dioxide supplied from the formic acid decomposition device 60 to the formic acid generator 50. Specifically, when formic acid decomposes, equal volumes of hydrogen (H) and carbon dioxide (CO) are generated. When these are supplied to the generator 80, such as a hydrogen engine, only the hydrogen reacts with air and is burned to generate electricity. On the other hand, carbon dioxide does not react and is discharged directly from the generator 80, eliminating the need for a separate process for separating hydrogen and carbon dioxide. Furthermore, providing a pathway 90 for circulating the discharged carbon dioxide to the formic acid generator 50 allows carbon dioxide, a greenhouse gas, to be circulated without being discharged outside the system, enabling more efficient use of carbon dioxide. Carbon dioxide can be reused by converting it back into formic acid, as shown in the following reaction equation (4): 2H2O+2CO2→ 2HCOOH+O2···(4)

[0050] 4 is a schematic diagram showing an example of a residential energy supply system to which the present invention is applied. The residential energy supply system 1000 of the present invention is an energy supply system 1000 that uses hydrogen as an energy source in a general home 110, and is equipped with a generator (residential hydrogen power generation equipment) 80 such as a fuel cell that generates electricity using hydrogen as fuel or a hydrogen generator driven by a hydrogen engine 70 that uses hydrogen as fuel, and supplies power from the generator 80, and hot water is supplied from a hot water storage tank 130 using residual heat from the generator 80.

[0051] The residential energy supply system 1000 of the present invention can convert solar energy into electrical energy using a solar cell panel 140 installed on the roof of the house 110, for example, and use the converted energy as a power source for a formic acid generator 50 that generates formic acid using an electrochemical cell. In addition, the daytime energy supply system may be equipped with a daytime hydrogen supply system 150 that generates hydrogen by electrolyzing water, as a daytime energy supply system that uses solar energy.

[0052] Furthermore, the residential energy supply system 1000 of the present invention is a nighttime energy supply system that supplies hydrogen as an energy source to a general residence 110 at night, and is equipped with the hydrogen supply system 100 of the present invention, which has a formic acid generator 50 that generates formic acid using an electrochemical cell installed in the residence 110, a formic acid storage tank 40 that stores the formic acid generated by the formic acid generator 50, a formic acid decomposition device 60 that decomposes the formic acid supplied from the formic acid storage tank 40 into hydrogen and carbon dioxide, and a generator 80 that supplies carbon dioxide supplied from the formic acid decomposition device 60 without being separated from the hydrogen to the formic acid generator 50.

[0053] As described above, the hydrogen supply system 100 in the residential energy supply system 1000 includes the formic acid generator 50 and the formic acid decomposer 60. Therefore, during the daytime when sunlight is available, the formic acid generator 50 generates formic acid using an electrochemical cell and stores the generated formic acid in the formic acid storage tank 40. At night when sunlight is not available, the formic acid decomposer 60 decomposes the formic acid stored in the formic acid storage tank 40 into hydrogen and carbon dioxide in a deoxidized environment at room temperature and atmospheric pressure, and the resulting hydrogen can be safely and efficiently supplied to the generator 80 as an energy source.

[0054] Furthermore, a heat recovery device, such as a heat exchanger, may be provided around the generator 80 to recover the heat generated by the hydrogen engine 70. Specifically, the heat recovery device is connected to the hydrogen engine 70 so that the heat (exhaust heat) generated when the hydrogen engine 70 generates electricity can be utilized. The heat recovery device functions as a hot water generator, and is connected to the hot water storage tank 130 shown in FIG. 4, for example. The water (hot water) stored in the hot water storage tank 130 is heated by the heat recovered by the heat recovery device and can be used to supply hot water within the house.

[0055] The generator 80 may also be provided with an inverter as appropriate. The inverter converts DC power supplied from the generator 80 into AC power. The AC power output from the inverter can be supplied to electrical appliances in the home.

[0056] As described above, the hydrogen supply system 100 according to the present invention and the residential energy supply system 1000 using the same effectively utilize solar energy to generate and store formic acid, and at night when sunlight cannot be used, the hydrogen obtained by decomposing the formic acid can be safely and efficiently supplied to the generator 80 as an energy source, thereby providing energy for the home. [Example]

[0057] The present invention will be explained in more detail below using examples, but the present invention is not limited to the following examples in any way.

[0058] (Preparation of catalyst support material) 0.8 g of polyvinyl alcohol (PVA, average molecular weight 3500) and disodium hydrogen phosphate dodecahydrate (Na2HPO4·(H2O) 12 173 mg of CI 173 mg was mixed with 40 mL of pure water, heated to dissolve the entire mixture, and then cooled to room temperature. Approximately 1000 μL of 8 wt% hydrochloric acid was added to adjust the pH to 1.0, and 400 μL of a platinum nanoparticle solution dispersed in polyvinylpyrrolidone (Pt-PVP solution) and 40 μL of a cationic polymer (poly(diallyldimethylammonium chloride) (PDADMA)) were added.

[0059] The mixture was transferred to a Teflon-coated tray (9 x 12 cm) and dried under air at 40°C for 12 hours. After that, the film was peeled off from the tray and cut into 1 cm squares. 2 This film was vacuum dried at 100°C for 6 hours, and the dried film was placed in degassed pure water and stored in a refrigerator.

[0060] (Performance comparison of catalyst support materials) The performance of the catalyst support material according to one embodiment of the present invention prepared in the above example was compared with that of the composition for decomposing formic acid used in the above Patent Document 1 (a mixed solution of a dispersion of platinum microparticles dispersed in the water-soluble polymer polyvinylpyrrolidone and a cationic polymer).

[0061] In the examples of the present invention, the catalyst support material (film 10 cm) prepared by the above-mentioned method was 2 As a comparative example, 30 μL of a mixed solution of a dispersion of platinum fine particles dispersed in the water-soluble polymer polyvinylpyrrolidone and a cationic polymer was used. These were added to a 0.3 M aqueous formic acid solution, and the volume of hydrogen generated was measured. This operation was repeated 10 times, and the average value was calculated. Note that the same film was used for all 10 tests for the catalyst support material according to the examples of the present invention, while a new solution was used each time for the comparative example.

[0062] As a result, the average volume of hydrogen generated in the examples was 4.2±0.5 mL, and the average volume of hydrogen generated in the comparative example was 3.6±0.1 mL. This shows that the catalyst support material according to one embodiment of the present invention can exhibit formic acid decomposition performance equal to or better than that of the comparative example in which a new product was used each time, even when used multiple times.

[0063] Although the embodiments and examples of the present invention have been described in detail above, it will be readily apparent to those skilled in the art that many modifications are possible without substantially departing from the novel features and effects of the present invention. Therefore, all such modifications are intended to be included within the scope of the present invention.

[0064] For example, a term that is described at least once in the specification or drawings together with a different term having a broader or equivalent meaning can be replaced with that different term anywhere in the specification or drawings. Furthermore, the configurations of the catalyst support material, the formic acid decomposition device, and the hydrogen supply system are not limited to those described in the embodiments and examples of the present invention, and various modifications are possible. [Explanation of symbols]

[0065] 40 formic acid storage tank, 50 formic acid generator, 51 anode, 52 cation exchange membrane, 53 cation exchange resin beads, 54 anion exchange membrane, 55 cathode, 56 current collector, 60 formic acid decomposition device, 61 catalyst tower, 62 circulation pump, 63 recovery path, 65 catalyst support material, 70 hydrogen engine, 80 generator, 90 path for circulating carbon dioxide to the formic acid generator, 100 hydrogen supply system, 110 house, 130 hot water storage tank, 140 solar panel, 150 daytime hydrogen supply system, 1000 residential energy supply system

Claims

1. 1. A formic acid decomposition apparatus for decomposing formic acid into hydrogen and carbon dioxide, comprising: at least, a catalyst tower that decomposes formic acid through a catalytic reaction; a circulation pump that circulates and supplies formic acid to the catalyst tower; a recovery path for recovering the generated mixed gas of hydrogen and carbon dioxide; Equipped with A formic acid decomposition apparatus characterized in that a catalyst support material is placed in the catalyst tower, and the catalyst support material is made by supporting a mixture of a dispersion liquid in which platinum fine particles are dispersed in polyvinylpyrrolidone, a water-soluble polymer, and a cationic polymer, on a support member, and the formic acid passes through the catalyst tower while coming into contact with the catalyst support material.

2. 2. The formic acid decomposition apparatus according to claim 1, wherein the support member is a sheet-like member made of a polymer compound.

3. 2. The formic acid decomposition apparatus according to claim 1, wherein the support member is a bead-shaped member made of a polymer compound.

4. 2. The formic acid decomposition apparatus according to claim 1, further comprising a means for supplying a carrier gas to said catalyst tower, and recovering the mixed gas of hydrogen and carbon dioxide from said recovery line by means of said carrier gas.

5. a formic acid generator for generating formic acid from water and carbon dioxide in the atmosphere or exhaust gas using an electrochemical cell; a formic acid storage tank for storing the formic acid generated by the formic acid generator; a formic acid decomposition apparatus according to claim 1, which decomposes the formic acid supplied from the formic acid storage tank into hydrogen and carbon dioxide by a catalytic reaction on a catalyst support material in a deoxidized environment at room temperature and atmospheric pressure; a generator including a hydrogen engine that is driven by the hydrogen from the hydrogen and carbon dioxide supplied from the formic acid decomposition device, and a power generation unit that uses the hydrogen engine as a drive source; Equipped with A hydrogen supply system further comprising a path for circulating the hydrogen supplied from the formic acid decomposition device and the carbon dioxide discharged from the generator without reacting, to the formic acid production device.

6. 6. The hydrogen supply system according to claim 5, wherein the electrochemical cell is an all-solid-state type.

7. 6. The hydrogen supply system according to claim 5, wherein solar power is utilized for the reaction of formic acid production in the electrochemical cell.

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