Gas storage and release material

Abstract

To provide a novel gas storage and release material, having superior storage and release characteristics for a variety of gases, particularly hydrogen, allowing gas storage and release without the need for operation of pressurization or depressurization, enabling easy synthesis from low-cost raw materials by a convenient method, providing superior reproducibility in gas storage and release, offering superior safety in hydrogen storage, and exhibiting high stability and durability.SOLUTION: A gas storage and release material comprises a metal-organic framework including a polynuclear aromatic compound with an aromatic hydrocarbon ring and an aromatic heterocyclic ring, and a polyvalent metal ion as constituent components.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gas storage and release material capable of storing and releasing various gases. [Background technology]

[0002] In order to solve environmental problems such as global warming, efforts are underway to develop clean energy sources to replace fossil fuels. Among these, hydrogen is considered one of the most promising energy sources because it is a diverse and abundant resource, has good combustion performance characteristics and calorific value, and has a low environmental impact as it does not emit carbon dioxide when generating electricity using fuel cells or internal combustion engines.

[0003] To use hydrogen as an energy source, it is necessary to build a hydrogen storage and release system that can flexibly respond to fluctuating demand. For example, it is necessary to build a hydrogen supply chain that transports hydrogen obtained by electrolyzing water using surplus electricity to utilization facilities. However, because hydrogen is a gas at room temperature and pressure, it is currently stored as high-pressure hydrogen gas in containers such as tanks and cylinders. Therefore, to use hydrogen until now, high-pressure hydrogen or liquefied hydrogen had to be transported by tank truck. Furthermore, hydrogen storage facilities required the development of large-scale infrastructure such as high-pressure hydrogen gas tanks.

[0004] When using hydrogen on-site instead of a high-pressure hydrogen gas storage and release system using a container, hydrogen storage and release systems using hydrogen storage and release materials are being considered, which can safely store and release large amounts of hydrogen at low pressure through the interaction between the hydrogen and the material.For example, the use of hydrogen storage and release materials is being considered in demonstration experiments related to the construction of a hydrogen supply chain, in which hydrogen obtained by electrolyzing water using surplus electricity from renewable energy sources such as solar power and wind power is stored in gas storage and release materials contained in tanks, and the tanks are then loaded onto trucks and transported to hydrogen utilization facilities.

[0005] Hydrogen storage materials are materials that can selectively and reversibly store and release hydrogen, and hydrogen storage alloys and functional carbon materials (graphene oxide) are considered promising. However, these hydrogen storage and release materials have problems with their hydrogen storage capacity. Furthermore, there is room for improvement in terms of performance degradation due to impurity gases and increased costs associated with using rare metals and high-purity metals as raw materials. Furthermore, hydrogen storage alloys and functional carbon materials (graphene oxide) are difficult to process, and require cooling for hydrogen storage and heating for hydrogen release. Furthermore, titanium and manganese, which make up hydrogen storage alloys, have densities of 4 to 8 g / cm. 3 Since the hydrogen storage material has a high mass, it is difficult to handle.

[0006] Patents have been filed for organic structures that exhibit gas storage and release properties. Patent Document 1 (Japanese Patent No. 5074035) discloses that gases such as methane, carbon dioxide, and propene are adsorbed into a porous polymer structure. However, the porous polymer MOF-5 disclosed in Patent Document 1 has a property that its structure is destroyed by moisture, which causes a problem of reduced gas adsorption effect. Patent Document 2 (JP 2022-022982 A) discloses an organic structure composed of a mixed organic ligand of 1,3,5-benzenetricarboxylic acid and 2-methylimidazole and Zn(II) ions. This organic structure is said to have a high specific surface area and a high hydrogen adsorption capacity at 0 to 25°C and a pressure of 100 atmospheres. However, the adsorption state is unstable due to the molecular motion of hydrogen, and the adsorption rate decreases shortly after adsorption. Patent Document 3 (JP 2012-514530 A) discloses that a metal-organic structure using fullerene, a carbon material, has a high hydrogen storage rate. However, fullerene has problems such as being easily oxidized and decomposed, causing rapid deterioration, and is too costly. Patent Document 4 (JP 2008-535657 A) discloses that a metal-organic framework formed from several types of organic ligands and metal ions exhibits a high hydrogen storage rate. However, it is difficult to purify the organic ligands, and the impurities contained therein cause side reactions during the synthesis of the metal-organic framework, resulting in problems such as poor reproducibility of hydrogen storage. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 5074035 [Patent Document 2] Japanese Patent Publication No. 2022-022982 [Patent Document 3] Special Publication No. 2012-514530 [Patent Document 4] Special Publication No. 2008-535657 Summary of the Invention [Problem to be solved by the invention]

[0008] The problem to be solved by the present invention is to provide a novel gas storage / release material that has excellent storage / release properties for various gases, particularly hydrogen, does not require pressurization or decompression operations when storing or releasing gas, can be easily synthesized from inexpensive raw materials by a simple method, has excellent reproducibility in gas storage / release, is safe when storing hydrogen, and is highly stable and durable. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result have found that a gas storage / release material containing a specific organometallic framework has excellent storage / release properties for various gases, particularly hydrogen, and that the above-mentioned problems can be solved by using this material.

[0010] That is, the present invention that solves the above problems mainly includes the following configurations. [Section 1] A gas storage and release material comprising a metal-organic framework containing, as components, a polynuclear aromatic compound having an aromatic hydrocarbon ring and an aromatic heterocycle, and a polyvalent metal ion. [Section 2] Item 2. The gas storage and release material according to item 1, wherein the polynuclear aromatic compound is a polynuclear aromatic compound having a benzene ring and an aromatic heterocycle. [Section 3] Item 3. The gas storage and release material according to item 1 or 2, wherein the polyvalent metal ions are divalent or higher valent metal ions of metals belonging to periods 3 to 6 of the periodic table. [Section 4] Item 4. The gas storage and release material according to any one of items 1 to 3, wherein the heteroatom constituting the aromatic heterocycle is one or more of nitrogen, oxygen, and sulfur. [Section 5] The metal-organic framework has structural formula (I); [ka] (In structural formula (I), Ar represents an aromatic hydrocarbon ring, R represents a linking group, Ht represents an aromatic heterocycle, and M represents a polyvalent metal ion, and multiple Ar, R, and Ht may be the same or different.) Item 5. The gas storage and release material according to any one of items 1 to 4, having a structure represented by the following formula: [Section 6] Item 6. The gas storage and release material according to Item 5, wherein Ht in the structural formula (I) is at least one selected from the group consisting of an imidazole ring, a furan ring, a pyrrole ring, a thiophene ring, an oxazole ring, a thiazole ring, a pyrazole ring, a γ-pyran ring, a pyridine ring, a piperidine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a quinoline ring, an isoquinoline ring, a purine ring, and a pteridine ring. [Section 7] The polyvalent metal ion is Fe 3+ , Al 3+ , Co 3+ , Co 2+ and Zn 2+ Item 7. The gas storage and release material according to any one of items 1 to 6, which is one or more selected from the group consisting of: [Section 8] The polynuclear aromatic compound is 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene, and the polyvalent metal ion is Fe 3+ Item 8. The gas storage and release material according to any one of items 1 to 7, wherein [Section 9] Item 9. The gas storage and release material according to any one of items 1 to 8, wherein the gas stored in the gas storage and release material is one or more selected from the group consisting of hydrogen, carbon dioxide, nitrogen, rare gases, and hydrocarbon gases. [Section 10] Item 10. The gas storage and / or release material according to any one of items 1 to 9, wherein the gas is stored and / or released by one or more means selected from the group consisting of pressurization, decompression, temperature increase, temperature decrease, application of electric potential, and irradiation with energy waves. [Section 11] Item 11. The gas storage and release material according to any one of items 1 to 10, wherein the gas storage and release material is in the form of particles, fibers, a film, a nonwoven fabric, a woven fabric, a porous body, or a molded body. [Effects of the Invention]

[0011] The present invention provides a novel gas storage / release material that has excellent storage / release properties for various gases, particularly hydrogen, does not require pressurization / depressurization operations for gas storage / release, can be easily synthesized from inexpensive raw materials by a simple method, has excellent reproducibility in gas storage / release, is safe when storing hydrogen, and is highly stable and durable.

[0012] The gas storage and release material of the present invention eliminates the need for pressurization and depressurization operations when storing and releasing gas, making it possible to omit or reduce the size of peripheral equipment that performs pressurization and depressurization, etc., and also facilitating control of gas storage and release, and further enabling hydrogen to be stored safely inside buildings.

[0013] The gas storage / release material containing the metal-organic framework of the present invention is lighter than a hydrogen storage alloy and therefore has excellent handleability, and various transportation equipment can be used, enabling increased transportation efficiency and reduced fuel costs during transportation. Furthermore, the gas storage / release material containing the metal-organic framework of the present invention does not require cooling or heating during hydrogen storage and hydrogen release. Furthermore, the gas storage / release material containing the metal-organic framework of the present invention can be easily synthesized by a simple method using commercially available, inexpensive raw material compounds, making it inexpensive and highly versatile. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 2 is a diagram showing the hydrogen storage properties of the gas storage / release material of the present invention according to Example 1 and the functional carbon material (graphene oxide) according to Comparative Example 1. [Figure 2] 1 is a TEM (transmission electron microscope) photograph of the surface of the gas storage and release material of the present invention according to Example 1. [Figure 3] 1 is a structural diagram of the gas storage and release material of the present invention according to Example 1, obtained by analysis using a simulation using a computational chemical technique. DETAILED DESCRIPTION OF THE INVENTION

[0015] The gas storage and release material of the present invention contains an organometallic structure containing a polynuclear aromatic compound having an aromatic hydrocarbon ring and an aromatic heterocycle, and a polyvalent metal ion as constituent elements. The gas storage and release material of the present invention will be described below.

[0016] [Organometallic structure] The organometallic framework contained in the gas storage / release material of the present invention comprises, as constituent elements, a polynuclear aromatic compound having an aromatic hydrocarbon ring and an aromatic heterocycle, and a polyvalent metal ion.

[0017] <Polynuclear aromatic compounds> The polynuclear aromatic compound, which is a component of the organometallic framework, has at least an aromatic hydrocarbon ring and an aromatic heterocycle, and may have a linking group connecting the aromatic hydrocarbon ring and the aromatic heterocycle.

[0018] The aromatic hydrocarbon ring contained in the polynuclear aromatic compound may be one or more selected from the group consisting of aromatic monocyclic hydrocarbon rings such as a benzene ring; and aromatic fused polycyclic hydrocarbon rings such as a naphthalene ring, an anthracene ring, a fluorene ring, and a pyrene ring. The number of aromatic hydrocarbon rings in the polynuclear aromatic compound is not particularly limited, and may be, for example, 1 or more and 4 or less. In the present invention, the polynuclear aromatic compound preferably has four or one benzene rings, more preferably one benzene ring, from the viewpoint of efficiently forming hydrogen-containing spaces.

[0019] The aromatic heterocycle contained in the polynuclear aromatic compound is not particularly limited as long as it contains one or more heteroatoms other than carbon within the ring. The ring is preferably a 3- to 9-membered ring, and these rings may be fused together. Examples of heteroatoms in the aromatic heterocycle include one or more selected from the group consisting of nitrogen, oxygen, sulfur, phosphorus, boron, silicon, antimony, arsenic, bismuth, selenium, tellurium, tin, germanium, and the like. Preferably, the heteroatom is one or more selected from the group consisting of nitrogen, oxygen, sulfur, phosphorus, boron, and silicon, and more preferably, one or more selected from the group consisting of nitrogen, oxygen, and sulfur.

[0020] Examples of the aromatic heterocycle contained in the polynuclear aromatic compound include one or more selected from the group consisting of a pyrrole ring, a furan ring, a thiophene ring, a phosphole ring, a borole ring, a silole ring, a stibole ring, an arsole ring, a bismol ring, a selenophene ring, a tellurophene ring, a stanol ring, an imidazole ring, a pyrazole ring, an oxazole ring, an isoxazole ring, a thiazole ring, a triazole ring, an oxadiazole ring, a thiadiazole ring, a dioxazole ring, a dithiazole ring, a tetrazole ring, a pentazole ring, a pyridine ring, a pyran ring, a thiopyran ring, a phospholine ring, a borabenzene ring, a silyne ring, a piperidine ring, a diazine ring, an oxazine ring, a thiazine ring, a triazine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a quinoline ring, an isoquinoline ring, a purine ring, and a pteridine ring. Preferably, it is at least one selected from the group consisting of an imidazole ring, a furan ring, a pyrrole ring, a thiophene ring, an oxazole ring, a thiazole ring, a pyrazole ring, a γ-pyran ring, a pyridine ring, a piperidine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a quinoline ring, an isoquinoline ring, a purine ring, and a pteridine ring.

[0021] The linking group that may be contained in the polynuclear aromatic compound and that links the aromatic hydrocarbon ring and the aromatic heterocycle includes one or more selected from the group consisting of an alkylene group, an ether group, a ketone group, a sulfide group (-S-), a sulfonyl group (-SO2-), an imino group (-NH- group), an azo group (-N=N-), an amide group, a group formed by combining two or more of these, etc. Preferably, it is one or more selected from the group consisting of an alkylene group, an ether group, an alkylene ether group, a sulfide group, an imino group, an alkyleneimino group, etc. having 1 to 6 carbon atoms, and more preferably an alkylene group having 1 to 3 carbon atoms.

[0022] In the present invention, the polynuclear aromatic compound may be a commercially available product or may be synthesized. Examples of the polynuclear aromatic compound include the following compounds (A-1) to (A-17). [ka]

[0023] [ka]

[0024] [ka]

[0025] <Polyvalent metal ions> The polyvalent metal ions that are components of the metal-organic framework are not particularly limited as long as they are divalent or higher ions of metals belonging to periods 3 to 6 of the periodic table. Examples include one or more polyvalent ions of metals selected from the group consisting of Mg, Al, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Ba, La, Ce, Nd, and Eu. Preferably, the polyvalent metal ions are one or more polyvalent ions of metals selected from the group consisting of Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Pd, Ag, Cd, In, and Sn, and more preferably Fe 3+ , Al 3+ , Co 3+ , Co 2+ and Zn 2+ It is one or more selected from the group consisting of:

[0026] The content of polyvalent metal ions, which are components of the metal-organic framework, is, for example, 1 mol% or more, preferably 5 mol% or more, more preferably 10 mol% or more, and can be, for example, 70 mol% or less, preferably 60 mol% or less, relative to the total amount of the metal-organic framework. If the content is less than 1 mol% or more than 70 mol%, the gas-encapsulating space in the metal-organic framework may not be formed or may shrink, which may result in a deterioration in the gas storage / release properties.

[0027] <Other components of metal-organic frameworks> The metal-organic framework may contain other components in addition to the polynuclear aromatic compound having an aromatic hydrocarbon ring and an aromatic heterocycle, and the polyvalent metal ion, such as a polynuclear aromatic compound not having an aromatic hydrocarbon ring, a polyvalent nonmetal ion, etc. The amount of other components present in the metal-organic framework can be, for example, less than 50 mol %, preferably less than 30 mol %, and more preferably less than 20 mol % of the metal-organic framework.

[0028] <Structure of metal-organic frameworks> The organometallic framework contained in the gas storage / release material of the present invention is constituted by forming a bond between a polynuclear aromatic compound having an aromatic hydrocarbon ring and an aromatic heterocycle and a polyvalent metal ion. Preferably, the framework is constituted by an ionic bond between an aromatic heterocycle in the polynuclear aromatic compound and a polyvalent metal ion, and more preferably, by an ionic bond between a heteroatom in an aromatic heterocycle in the polynuclear aromatic compound and a polyvalent metal ion.

[0029] Examples of the metal-organic framework include those represented by the structural formula (I): [ka] (In structural formula (I), Ar represents an aromatic hydrocarbon ring, R represents a linking group, Ht represents an aromatic heterocycle, and M represents a polyvalent metal ion, and multiple Ar, R, and Ht may be the same or different.) Examples include those having a structure represented by the following formula: Preferably, Ar is a trivalent or tetravalent aromatic hydrocarbon ring, R is a divalent linking group, M is a trivalent or higher metal ion, and the three-dimensional network structure is preferred.

[0030] In structural formula (I), the aromatic hydrocarbon ring Ar is preferably one or more rings selected from the group consisting of a benzene ring, a naphthalene ring, an anthracene ring, a fluorene ring, a pyrene ring, etc. A benzene ring is more preferred.

[0031] In structural formula (I), the linking group R is preferably one or more selected from the group consisting of alkylene groups having 1 to 6 carbon atoms, ether groups, alkylene ether groups having 1 to 6 carbon atoms, etc. More preferably, it is an alkylene group having 1 to 3 carbon atoms.

[0032] In structural formula (I), the aromatic heterocycle Ht is preferably an aromatic heterocycle containing one or more heteroatoms selected from nitrogen, oxygen, and sulfur, more preferably one or more selected from the group consisting of an imidazole ring, a furan ring, a pyrrole ring, a thiophene ring, an oxazole ring, a thiazole ring, a pyrazole ring, a γ-pyran ring, a pyridine ring, a piperidine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a quinoline ring, an isoquinoline ring, a purine ring, and a pteridine ring, and even more preferably an imidazole group.

[0033] [Other components contained in gas storage and release materials] The gas storage / release material of the present invention may contain other components in addition to the organometallic framework, such as one or more selected from the group consisting of resins, fillers, various additives, etc.

[0034] The resin is not particularly limited, but examples thereof include one or more selected from the group consisting of polyolefin resins, polyester resins, polyether resins, acrylic resins, polyamide resins, polyimide resins, urethane resins, and the like. The filler is not particularly limited, but examples thereof include one or more selected from the group consisting of silica, talc, clay, calcium carbonate, barium sulfate, titanium oxide, glass flakes, carbon fiber, glass fiber, metal fiber, organic fiber, organic nanofiber, inorganic nanofiber, metal nanofiber, and the like. The various additives are not particularly limited, but examples thereof include one or more selected from the group consisting of colorants such as organic pigments, inorganic pigments, and dyes, adsorbents such as zeolites and activated carbon, plasticizers, antibacterial agents, conductive materials, antioxidants, and gas storage and release materials other than the above-mentioned gas storage and release materials.

[0035] The content of the other components in the gas storage and release material can be, for example, 99% by mass or less, preferably 90% by mass or less, and more preferably 50% by mass or less. If the content of the other components exceeds 99% by mass, the gas storage properties may not be fully exhibited.

[0036] <Shape of gas storage and release material> The gas storage and release material may have any shape, such as particles, fibers, films, nonwoven fabrics, woven fabrics, porous bodies, molded bodies, and the like. In the case of particles, the average particle diameter can be arbitrarily adjusted within the range of 0.1 μm to 20 mm. The average particle diameter of the gas storage / release material in the present invention is determined by the volume-based cumulative particle diameter D at 50% cumulative volume by a laser diffraction / scattering particle size distribution measurement method. 50 is the value. In the case of fibers, the length can be adjusted arbitrarily within the range of 1 mm to 3 m, the diameter of 0.1 mm to 5 mm, and the denier number of 0.5 d to 20 d. In the case of a film, the thickness can be adjusted arbitrarily within the range of, for example, 2 μm to 5 mm, and the width and length of the film can be set to any size. In the case of nonwoven or woven fabric, for example, the basis weight is 5 g / m 2 ~200g / m 2 The ventilation rate is in the range of 5cm 3 / cm 3 s~100cm 3 / cm 3 The range of s can be adjusted arbitrarily. In the case of a porous body, for example, an apparent density of 0.1 g / cm 3 ~1.8g / cm 3 The porosity can be adjusted arbitrarily within the range of 5 to 80 vol %. In the case of a molded article, any molding means such as extrusion molding or injection molding may be used to prepare a molded article of any shape. The gas storage / release material of the present invention is preferably in the form of particles, porous material, nonwoven fabric, film or fiber from the viewpoints of ease of production, ease of adjusting the contact area with various gases, ease of handling, etc.

[0037] <Gas stored and released by gas storage and release materials> The gas stored and released by the gas storage and release material of the present invention is not particularly limited. Examples include one or more gases selected from the group consisting of hydrogen, carbon dioxide, carbon monoxide, hydrogen sulfide, ammonia, nitrogen, nitrogen dioxide, rare gases (helium, neon, argon, krypton, radon), hydrocarbon gases (methane, ethane, propane, butane, acetylene, etc.), oxygen, and halogen gases (fluorine, chlorine). Preferably, the gas is one or more gases selected from the group consisting of hydrogen, nitrogen, carbon dioxide, argon, methane, ethane, propane, and acetylene, with hydrogen being particularly preferred.

[0038] <Method of storing and releasing gas> The method for storing (associating) and releasing (desorbing) gas in the gas storage / release material of the present invention is not particularly limited. Any known method for storing and releasing hydrogen in a gas storage / release material, particularly a hydrogen storage material, can be used. Examples of such methods include one or more means selected from the group consisting of pressurization, decompression, temperature increase (heating), temperature decrease (cooling), application of electric potential, and irradiation with energy waves (ultraviolet rays, infrared rays, electromagnetic waves, etc.).

[0039] The storage means is preferably a method including one or more means selected from the group consisting of pressurization, depressurization, temperature increase (heating), temperature decrease (cooling), application of electric potential, and ultraviolet irradiation, and more preferably a method including one or more means selected from the group consisting of pressurization, depressurization, temperature increase (heating), and temperature decrease (cooling). In the present invention, a method including pressurization means is particularly preferred. The pressure to be applied when using a pressurizing means for storage is not particularly limited, but it is preferable to apply a pressure of, for example, 0.01 MPa or more, preferably 0.05 MPa or more, and more preferably 0.1 MPa or more.

[0040] The releasing means is preferably a method including one or more means selected from the group consisting of decompression, pressurization, temperature increase (heating), temperature decrease (cooling), application of electric potential, and ultraviolet irradiation, and more preferably a method including one or more means selected from the group consisting of decompression, pressurization, temperature increase (heating), and temperature decrease (cooling). In the present invention, a method including a decompression means is particularly preferred. The gas storage (association) and release (desorption) means in the gas storage and release material of the present invention is very useful because it can store (associate) and release (desorption) gas even under mild conditions when using the above means (for example, milder conditions than those for hydrogen storage alloys). The pressure to be reduced when using a pressure reducing means as the discharging means is not particularly limited, but it is preferable to reduce the pressure to, for example, 0.01 MPa or more, preferably 0.05 MPa or more, and more preferably 0.1 MPa or more.

[0041] <Method for manufacturing gas storage and release material> The method for producing the gas storage / release material of the present invention is not particularly limited. For example, a method can be mentioned in which a polynuclear aromatic compound having an aromatic hydrocarbon ring and an aromatic heterocycle, a polyvalent metal ion, and other components used as necessary are mixed and reacted as components of the metal-organic framework to form the metal-organic framework, and other components are added as necessary. The other components may be present during the reaction to form the metal-organic framework. In producing the gas storage and release material, means such as heating, pressurization, cooling, decompression, and stirring may be used as necessary.

[0042] <Applications of gas storage and release materials> The gas storage and release material of the present invention can safely store gases at room temperature (25°C ± 20°C) and atmospheric pressure for long periods of time and release the stored gases by a simple means. The gas storage and release material of the present invention is particularly useful as a hydrogen storage material because it can safely store hydrogen at room temperature (25°C ± 20°C) and atmospheric pressure for long periods of time and release the stored hydrogen by a simple means. Furthermore, since it has excellent hydrogen storage and release properties even at low pressures below atmospheric pressure, where hydrogen storage alloys and functional carbon materials (such as graphene oxide) do not exhibit hydrogen storage and release properties, it is also useful as a hydrogen storage material from this point of view. Furthermore, due to its excellent moldability, it can be easily processed into any shape, and due to its light weight, it can be easily transported and stored.

[0043] For example, hydrogen is produced in a water electrolysis hydrogen production device using electricity generated using renewable energy such as wind power, wave power, geothermal power, and solar power, and the hydrogen is stored in the gas storage and release material of the present invention housed in an on-board container, etc. The container, etc. containing the gas storage and release material with stored hydrogen is loaded onto a vehicle and transported to a hot spring facility equipped with a hydrogen storage material tank and a pure hydrogen fuel cell, and the hydrogen is transferred from the gas storage and release material to these facilities. The electricity and hot water generated by the fuel cell will be used in the hot spring facility, and "heat cascade utilization" will be implemented during hydrogen transport, with the heat generated on the hydrogen storage side being used to heat the hydrogen release side. Furthermore, the heat required to release hydrogen from the hydrogen storage material tank can be provided by utilizing low-temperature waste heat from the building, improving energy efficiency. [Example]

[0044] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0045] [Example 1] <Synthesis of Metal-Organic Frameworks> To a 500 mL separable flask, 5.0 g of 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene was added, followed by 80 mL of N,N-dimethylformamide and 20 mL of ethanol, and the mixture was irradiated with ultrasound for 20 minutes to prepare solution A. To a 200 mL beaker, 2.1 g of iron (III) chloride hexahydrate was added, followed by 20 mL of water and 30 mL of N,N-dimethylformamide, and the mixture was irradiated with ultrasound for 20 minutes to prepare solution B. Solution A and solution B were added to a 500 mL beaker, and solution C was prepared by irradiating them with ultrasound for 20 minutes. A 500 mL round-bottom flask equipped with a condenser was used as a reaction vessel, and Solution C was added to the reaction vessel. After stirring at 110°C for 12 hours, the mixture was cooled to room temperature and filtered to separate the precipitate (crystals) from the supernatant. The obtained precipitate (crystals) was mixed with 30 mL of ethanol and washed three times to obtain crystals A. Crystal A was added to a 200 mL Erlenmeyer flask, and 50 mL of ethyl acetate was added and allowed to stand for 5 hours. After that, filtration was carried out to separate into Crystal B and the supernatant. The obtained Crystal B was dried in vacuum at 120°C for 12 hours to obtain a metal-organic framework powder.

[0046] <Evaluation of hydrogen storage capacity> The hydrogen storage and release capacity was evaluated by the following method. The metal-organic structure powder obtained in Example 1 was filled into a stainless steel sample tube, and a PCT (Hydrogen Pressure-Composition-Isomers) measurement device (Microtrac, Belsop MaxG) was used to measure the reduced pressure P caused by the metal-organic structure powder adsorbing hydrogen when a constant pressure was applied to the cavity of the sample tube. The mass % of hydrogen adsorbed to the metal-organic structure powder was calculated using the gas equation of state (PV=nRT (P: pressure, V: volume, n: number of moles, R: gas constant, T: temperature)). This operation was repeated while gradually increasing the pressure applied to the cavity of the sample tube from 0 MPa to 0.9 MPa, and the amount of adsorption was plotted against the pressure. The hydrogen absorption rate curve showing the relationship between the amount of stored hydrogen (mass %) and the applied pressure for the metal-organic structure powder of Example 1 was as shown in FIG. It can be seen from FIG. 1 that the gas storage and release material synthesized in Example 1 has a high hydrogen storage capacity.

[0047] <Transmission electron microscope observation> The surface of the metal-organic structure powder obtained in Example 1 was observed using a transmission electron microscope, and the results are shown in FIG. From FIG. 2, it is confirmed that the organometallic framework obtained in Example 1 has a large number of pores of about 1 to 2 nm on its surface, and it can be inferred that gas molecules are adsorbed into the hydrogen-occupying spaces inside the molecules of the organometallic framework through these pores. The conditions for the transmission electron microscope observation are as follows: ·Equipment: Atomic resolution analytical electron microscope (manufactured by JEOL, JEM-ARM200F Dual-X) Measurement conditions: Acceleration voltage 300kV, measurement temperature -100℃

[0048] <Structural analysis of metal-organic frameworks> (FT-IR measurement) The FT-IR of the metal-organic framework powder obtained in Example 1 was measured by a single-reflection ATR method using a Fourier transform infrared spectrophotometer (manufactured by JASCO Corporation, FT / IR-6800) to analyze the molecular structure. The results are as follows. CH2: 2923cm -1 , 2943cm -1 , 2986cm -1 Phenyl ring: 3032 cm -1 , 3064cm -1 , 3089cm -1 Imidazole ring: 1123 cm -1 , 1264cm -1 , 1356cm -1 , 1402cm -1 , 1586cm -1 , 3050cm -1 , 3136cm -1 Fe 3+ :472cm -1

[0049] (Gel permeation chromatography (GPC) measurement) For the organometallic structure powder obtained in Example 1, a HPLC column (Shimadzu GLC "Shim-pack GPC-805") was attached to a gel permeation chromatography (GPC) apparatus (Shimadzu Corporation), and the gas storage / release material dissolved in N,N'-dimethylformamide solvent was injected, and the column retention time was measured. The polystyrene-equivalent molecular weight was calculated from the obtained column retention time by comparison with a calibration curve prepared in advance by measuring polystyrene whose molecular weight was known. The gel permeation chromatography device (manufactured by Shimadzu Corporation) had the following configuration: System: Nexera GPC System System controller: CBM-40 Liquid delivery unit: LC40D Online degassing unit: DGU-403 Autosampler: SIL-40C Column oven: CTO-40C Detector: RID-20ABLK, LabSolutions GPC software, LC workstation PC, LabSolutions LC Single LC Column: Shim-pack GPC-805 Solvent: N,N'-dimethylformamide

[0050] (Structural analysis) The results of FT-IR measurement and gel permeation chromatography (GPC) measurement showed that the organometallic framework obtained in Example 1 had a weight-average molecular weight of 32,000, and the N atom of the imidazole ring in 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene and Fe 3+ It was found that bonds were formed between the iron (III) ions and the cations to form complexes, forming a polymer network structure.

[0051] (Raman spectroscopy) In order to observe the molecular structure of the metal-organic framework obtained in Example 1 from various angles, Raman spectroscopy was performed to observe the Raman spectrum. The results are as follows. From the results of Raman spectroscopy, it was found that the metal-organic framework obtained in Example 1 has a structure in which the N atom of the imidazole ring in 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene and the Fe atom 3+ It was found that bonds were formed between the iron (III) ions and the cations to form complexes, forming a polymer network structure. Equipment: Laser Raman spectrometer (JASCO Corporation, NRS-3300) Excitation laser wavelength: 532nm Observed peaks (cm -1 ):106cm -1 , 135cm -1 , 453cm -1 , 532cm -1 , 804cm -1 , 1103cm -1 , 1491cm -1 , 1704cm -1 , 3384cm -1

[0052] (specific surface area measurement) The specific surface area of ​​the metal-organic framework powder obtained in Example 1 was measured using an N2 gas adsorption method under the following conditions. As a result, the specific surface area of ​​the metal-organic framework powder obtained in Example 1 was 10,250 m 2 / g, and it was found that many gas species can be adsorbed. Equipment: Specific surface area analyzer (Quantachrome, QUADRASORB evo) Measurement principle: Constant volume method Adsorption gas: Nitrogen gas Analysis items: Specific surface area by BET method

[0053] (TG-DTA analysis) The TG-DTA analysis of the metal-organic framework powder obtained in Example 1 was carried out under the following conditions. As a result, it was found that the metal-organic framework powder obtained in Example 1 did not show any change in mass until it exceeded 400°C, and was thermally stable up to 400°C. Apparatus: Differential thermal and thermogravimetric simultaneous measurement device (Rigaku Thermo plus EVO TG-DTA8122) Measurement method: Horizontal differential triple coil method Temperature range: Room temperature (25°C ± 5°C) to 500°C Heating rate: 8℃ / min Sample size: 1g TG range: 500mg Measurement atmosphere: Air

[0054] (Structural analysis by computational chemistry) The molecular structure of the metal-organic framework powder (gas storage and release material) obtained in Example 1 was analyzed by simulation using a computational chemistry technique. As a result, it was analyzed that the gas storage and release material of the present invention according to Example 1 has the molecular structure shown in Figure 3. It was inferred that the metal-organic framework powder obtained in Example 1 having the molecular structure shown in Figure 3 has hydrogen-containing spaces with diameters of about 0.4 nm (4 angstroms) to 0.7 nm (7 angstroms) within its molecules. From a comparison of the volume of the hydrogen-containing spaces with the volume of hydrogen molecules, it was inferred that several hydrogen molecules are linked together and exist in the hydrogen-containing spaces in the form of clusters.

[0055] [Comparative Example 1] 50 ml of a palladium chloride aqueous solution (5% by mass in 10% by mass HCl) was diluted 10-fold in a volumetric flask, and 30 ml of the solution was poured into a 200 ml round-bottom flask. 3.0 g of graphene oxide was added, and the round-bottom flask was immersed in an ultrasonicator (AS ONE Corporation, dual-frequency, resin housing type MCD-2P) and ultrasonicated for 2 hours. Then, 1% ammonia aqueous solution was added dropwise to the round-bottom flask until the pH indicator paper indicated a pH of 7. The resulting solution was filtered through a glass filter G3, and the powdery residue on the glass filter was washed with 10 ml of water. The resulting powder was placed in a pot mill (Kenis Corporation, MT-90 mm), placed on a benchtop pot mill stand (AS ONE Corporation, PM-001 2-7816-01), and processed at 300 rpm for 2 hours. Graphene oxide was separated from the obtained powder using a test sieve (Tokyo Screen Co., Ltd., JTS-200-45-48, mesh: plain weave, mesh size: 0.053 mm) to prepare a sample for evaluating hydrogen storage / release capacity. The graphene oxide of Comparative Example 1 is a carbon compound formed by stacking layers of two-dimensionally extending six-membered rings made of carbon-carbon bonds, with the distance between layers ranging from 0.5 nm to 2 nm and palladium dispersed between the layers.

[0056] The hydrogen storage and release capacity of the obtained sample for evaluating hydrogen storage and release capacity was evaluated in the same manner as in Example 1. The results are also shown in Figure 1. Figure 1 shows that the gas storage and release material (metal-organic framework) according to Example 1 exhibits higher hydrogen storage and release capacity than the graphene oxide according to Comparative Example 1. This confirms that the gas storage / release material of the present invention is useful as a material capable of storing and releasing gas, particularly hydrogen.

Claims

1. A gas storage and release material comprising a metal-organic framework containing, as components, a polynuclear aromatic compound having an aromatic hydrocarbon ring and an aromatic heterocycle, and a polyvalent metal ion.

2. 2. The gas storage and release material according to claim 1, wherein the polynuclear aromatic compound is a polynuclear aromatic compound having a benzene ring and an aromatic heterocycle.

3. 3. The gas storage and release material according to claim 1, wherein the polyvalent metal ions are divalent or higher valent metal ions of metals belonging to periods 3 to 6 of the periodic table.

4. 3. The gas storage and release material according to claim 1, wherein the heteroatom constituting the aromatic heterocycle is one or more of nitrogen, oxygen, and sulfur.

5. The metal-organic framework has the structural formula (I); 【Chemical 1】 (In structural formula (I), Ar represents an aromatic hydrocarbon ring, R represents a linking group, Ht represents an aromatic heterocycle, and M represents a polyvalent metal ion, and multiple Ar, R, and Ht may be the same or different.) The gas storage and release material according to claim 1 or 2, having a structure represented by:

6. 6. The gas storage and release material according to claim 5, wherein in structural formula (I), Ht is one or more selected from the group consisting of an imidazole ring, a furan ring, a pyrrole ring, a thiophene ring, an oxazole ring, a thiazole ring, a pyrazole ring, a γ-pyran ring, a pyridine ring, a piperidine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a quinoline ring, an isoquinoline ring, a purine ring, and a pteridine ring.

7. The polyvalent metal ion is Fe ３＋ , Al ３＋ , Co ３＋ , Co ２＋ and Zn ２＋ The gas storage and release material according to claim 1 or 2, which is one or more selected from the group consisting of:

8. The polynuclear aromatic compound is 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene, and the polyvalent metal ion is Fe ３＋ 3. The gas storage and release material according to claim 1 or 2, wherein:

9. 3. The gas storage and release material according to claim 1, wherein the gas stored in the gas storage and release material is one or more gases selected from the group consisting of hydrogen, carbon dioxide, nitrogen, rare gases, and hydrocarbon gases.

10. 3. The gas storage and / or release material according to claim 1, wherein the gas is stored and / or released by a method comprising one or more means selected from the group consisting of pressurization, depressurization, temperature increase, temperature decrease, application of an electric potential, and irradiation with an energy wave.

11. 3. The gas storage and release material according to claim 1, wherein the gas storage and release material is in the form of particles, fibers, a film, a nonwoven fabric, a woven fabric, a porous body, or a molded body.

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