Carbon dioxide absorption and release device

Abstract

To provide an electrically-responsive carbon dioxide absorption / discharge device capable of efficiently absorbing / discharging carbon dioxide by low energy.SOLUTION: According to an embodiment, a carbon dioxide absorption / discharge device including an electrode having a porous composite is provided. The porous composite includes a conductive member and a porous material on the conductive member. The porous material has an angstrom or nanometer-sized pore, and the pore internally includes a molecular part exhibiting oxidoreduction activity by electrical response.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION Embodiments of the present invention relate to a carbon dioxide absorption and release device. [Background technology]

[0002] The technology of absorbing carbon dioxide into absorbents such as amines is used in CCS (Carbon dioxide Capture and Storage) plants at thermal power plants and other facilities, and is considered a leading candidate for a technology to prevent global warming. The absorbent that absorbed carbon dioxide is typically heated in a regeneration tower and regenerated by releasing the carbon dioxide, allowing it to be reused. The typical temperature during this process is around 140°C, which consumes a large amount of energy. The heat and energy required for regeneration are also known as the heat duty or energy penalty. Lowering this heating temperature and streamlining the release of carbon dioxide would reduce energy consumption and promote its widespread use as a technology to prevent global warming.

[0003] In addition, porous materials are also known to be used as carbon dioxide adsorbents. Because porous materials have a relatively large specific surface area, their ability to adsorb large amounts of gas or organic molecules by selecting pore sizes and functional groups on the pore surfaces with high carbon dioxide affinity has led to the development of applications such as gas storage, gas separation, catalysts, and reaction sites. Known porous materials include zeolites, porous silica, porous alumina, porous carbon materials, metal-organic frameworks (MOFs), covalent-organic frameworks (COFs), and materials in which the pores of these porous materials have been modified with amine molecules. Even when using such porous materials, regeneration of the carbon dioxide adsorbent is primarily performed by heating, which necessitates energy conservation, as with amines and other absorbents.

[0004] One energy-saving regeneration method is to replace the adsorbed carbon dioxide with water vapor. The carbon dioxide is released from the adsorbent through a replacement reaction between the adsorbed carbon dioxide and water vapor. This method allows the heating temperature to be lowered to below 100°C, but the released gas contains water vapor in addition to carbon dioxide. Therefore, a subsequent process is required to cool the released gas and condense the water vapor to separate it from the carbon dioxide. Therefore, although this method can be more energy-efficient than thermal desorption, it is not the optimal method for regenerating the absorbent.

[0005] On the other hand, a technology is being investigated that uses polymers containing electroresponsive active groups to separate carbon dioxide by switching the potential instead of heating. This method is expected to have an energy-saving effect because it allows carbon dioxide to be released without heating. However, because polymers do not have the pores of zeolites and have a small surface area, the utilization rate of the electroresponsive active groups is low. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-90328 [Patent Document 2] International Publication No. WO2012 / 144189 [Patent Document 3] International Publication No. WO2016 / 035321 [Patent Document 4] Japanese Patent Application Laid-Open No. 2017-125234 [Patent Document 5] Special Publication No. 2018-533470 [Non-patent literature]

[0007] [Non-Patent Document 1] Chem. Mater. 2017, 29, 5, 2074-2080 [Non-patent document 2] Carbon 171 (2021) 248-256 [Non-patent document 3] CCS Chem. 2020, 2, 696-706 [Non-patent document 4] Mater. Chem. Front., 2017, 1, 1310-1316 [Non-Patent Document 5] J. Am. Chem. Soc. 2020, 142, 1, 16-20 [Non-patent document 6] ACS Energy Lett. 2020, 5, 2256-2264 [Non-Patent Document 7] Nat. Commun. 5:4503 (2014) [Non-patent document 8] Inorg. Chem. 2017, 56, 13741-13747 [Non-Patent Document 9] J. Am. Chem. Soc. 2014, 136, 16112-16115 [Non-Patent Document 10] Chem. Mater. 2016, 28, 5, 1298-1303 [Non-Patent Document 11] Energy Environ. Sci., 2019, 12, 3530 [Non-Patent Document 12] Molecules 2017, 22, 1149 [Non-Patent Document 13] Electrochemistry Communications 122 (2021) 106881 [Non-Patent Document 14] Saga Prefectural Industrial Promotion Organization, Kyushu Synchrotron Light Research Center, Prefectural Beamline Usage Report, Project Number: 1707066F, "Study on the Electronic States of Metal-Organic Frameworks by Photoelectron Spectroscopy," by Keitaro Eguchi and Shohei Yamamoto, Graduate School of Science, Nagoya University (http: / / www.saga-ls.jp / site_files / file / Publication / Experiment Report / H29 / F / 1707066F(Nagoya University_Eguchi).pdf) Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the embodiment is to provide an electrically responsive carbon dioxide absorption / release device that can absorb and release carbon dioxide efficiently with low energy. [Means for solving the problem]

[0009] According to an embodiment, the porous composite and a second conductive member A carbon dioxide absorption / release device is provided, which includes an electrode comprising: 1st A conductive member and 1st and a porous body on the conductive member. The first conductive member has one or more of the following shapes: a rod shape, a tube shape, a fiber shape, a sheet shape, and a flake shape. The porous material has pores of angstrom size or nanometer size, and contains molecular moieties in the pores that exhibit redox activity in response to electricity. The electrode may be a composite electrode that further comprises, in addition to the porous composite and the second conductive member, one or more structural reinforcing members selected from the group consisting of a fibrous carbon material, a conductive inorganic-organic hybrid material, a conductive polymer, a non-conductive polymer, and an ion-conductive polymer. Alternatively, the electrode may further comprise a current collector having a flat plate shape and a porous composite provided on its main surface, or a mesh shape with the porous composite embedded therein. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view illustrating an example of a carbon dioxide absorption and release device according to an embodiment. [Figure 2] FIG. 2 is an enlarged cross-sectional view of part A shown in FIG. [Figure 3] FIG. 2 is a schematic cross-sectional view showing an example of a porous body included in the carbon dioxide absorption and release device according to the embodiment. [Figure 4] Graph showing the X-ray diffraction spectrum of the porous composite prepared in Example 2. [Figure 5] Graph showing X-ray diffraction spectra of the porous composite and its raw material produced in Example 12. [Figure 6] Graph showing thermogravimetric analysis of the porous composite produced in Example 2. [Figure 7] Graph showing thermogravimetric analysis of the porous composite prepared in Example 12. [Figure 8] 10 is a scanning transmission electron microscope photograph of the porous composite prepared in Example 12. [Figure 9]1 is a scanning transmission electron microscope photograph of the porous composite prepared in Example 2. [Figure 10] FIG. 2 is a cross-sectional view schematically illustrating an electrochemical cell used to evaluate the electrochemical performance of the carbon dioxide absorption / release device prepared in the examples. [Figure 11] Graph showing the cyclic voltammetry curve of the porous composite prepared in Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0011] The following describes the embodiments with reference to the drawings as appropriate. Note that common components throughout the embodiments are designated by the same reference numerals, and redundant explanations will be omitted. The drawings are schematic diagrams for explaining and facilitating understanding of the embodiments, and the shapes, dimensions, ratios, etc. may differ from those of actual devices. However, these can be appropriately modified in design, taking into consideration the following explanation and known techniques.

[0012] The following embodiments relate to a device and method for separating carbon dioxide from a carbon dioxide-containing gas by an electrochemical process, which has been found to be an electrically responsive device that efficiently releases carbon dioxide.

[0013] [Carbon dioxide absorption and release device] The carbon dioxide absorption / release device according to the embodiment is a porous composite and a second conductive member The porous composite includes an electrode comprising: 1st A conductive member and 1st and a porous body on the conductive member. The porous body has a thickness of 10 Angstroms (10 -10 m) size or nanometers (10 -9 The nanopores have pores of a size (m) and contain a molecular moiety that exhibits redox activity by electrical response.

[0014] This carbon dioxide absorption / desorption device adsorbs and desorbs carbon dioxide to the molecular moiety by changing the electric potential applied to the device. A device using a composite material that absorbs and desorbs carbon dioxide using such electrically responsive redox-active molecular moieties can absorb and desorb carbon dioxide at room temperature. Furthermore, the use of a porous material increases the surface area, making it possible to increase the density of electrically responsive active sites compared to electrically responsive polymers. Therefore, this device can absorb and desorb carbon dioxide with low energy.

[0015] Such a device can suitably absorb carbon dioxide as described above, and can be suitably applied to a device for recovering carbon dioxide contained in factory exhaust gases or the atmosphere.

[0016] According to embodiments, a device for electro-swing gas adsorption is provided. The electrochemical swing process involves maintaining a specific potential in the forward direction and then repeatedly maintaining a different potential in the reverse direction. In this manner, the affinity for a target adsorbate can be tuned by using redox-active groups that can be oxidized at one potential and reduced at a different potential. According to such embodiments, energy is efficiently delivered to drive the electrochemical reaction that results in the capture of the target substance (e.g., CO).

[0017] The electrode may further include a current collector on which the porous composite is provided. The porous composite may be supported on the current collector. For example, the porous composite may be formed on the surface of the current collector. Alternatively, the porous composite may be supported on a current collector in the form of a mesh, for example.

[0018] The current collector can act as a conductor to transfer charge to the porous composite, causing the redox-active moieties to respond electrically. By changing the potential of the current collector, the redox-active moieties in the porous composite can be oxidized and reduced, causing them to adsorb and release carbon dioxide.

[0019] The porous composite is 1st The porous composite includes a conductive member and a porous body having pores of angstrom size or nanometer size. 1st The porous body is located on the surface of a conductive member. The porous body contains a molecular moiety that exhibits redox activity in response to electricity. This molecular moiety can be, for example, an organic functional group whose redox state changes in response to the application of an electric charge, i.e., a redox-active group that exhibits electrical response. The molecular moiety can also be contained on the surface of the porous body. The surface of the porous body here includes not only the outer surface located on the periphery but also the inner surfaces of the pores (pore wall surfaces).

[0020] The porous composite is 1st It can be obtained by combining a conductive material with a porous body. 1st This is done by modifying (coating) the surface of the conductive member with a porous material.

[0021] In the porous composite, the molecular part that shows redox activity by electrical response in the porous body is 1st It is preferable that the porous body is in close proximity to or in contact with the conductive member. 1st At least a part of the surface of the conductive member is coated or porous. 1st For example, the porous body may contain an electrically responsive covalent-organic framework (COF) or an electrically responsive metal-organic framework (MOF), which will be described later. 1st It may be included in the porous composite so as to coat the conductive member.

[0022] The presence of COFs or MOFs in the composite is confirmed in two steps. First, thermogravimetric analysis (TG) is performed in an inert atmosphere. If weight loss of the binder component is observed between 200°C and 300°C and between 300°C and 500°C, it is assumed that COFs or MOFs are present in the composite. Note that conductive materials do not decompose up to nearly 1000°C in an inert atmosphere. If weight loss is observed between 300°C and 500°C, further X-ray diffraction (XRD) analysis is performed. If it is confirmed that one to two diffraction lines originating from COFs or MOFs appear in the range of 3°C to 10°C in addition to the diffraction lines originating from the conductive material (20°C to 30°C), it is determined that COFs or MOFs are present in the composite.

[0023] Also 1st The presence of COF or MOF on the surface of the conductive material is confirmed by scanning transmission electron microscope (STEM). 1st If it is confirmed that a layer different in appearance from the conductive member is stacked, this provides direct evidence that the surface is coated.

[0024] Both COFs and MOFs may be contained in the porous composite. That is, the porous composite may contain at least one of COFs and MOFs. When a porous composite contains both COFs and MOFs, the results are considered to be similar to the above analysis results.

[0025] Porous materials 1st It is preferable to coat the surface of the conductive member thinly with a thickness of 1 nm or more and 5 nm or less. 1stThe thinner the conductive material is coated, the higher the conductivity of the porous composite, and the more active sites there are for adsorbing and desorbing CO2. MOFs and COFs have a very large specific surface area and can contain many active sites, but because they are not as conductive as metals, the electrical path only passes near the surface of MOFs and COFs alone. Therefore, the internal active sites cannot contribute to CO2 adsorption and desorption, so there is a high possibility that the high specific surface area will not be utilized. In order to utilize the high specific surface area of ​​MOFs and COFs, that is, the high active site density, it is desirable, for example, to directly contact the MOFs or COFs with the surface of a conductive support to effectively pass an electrical path. 1st It is preferable to coat the surface of the conductive member thinly. 1st By coating the conductive material as a porous body, a further increase in specific surface area can be expected. 1st The conductive material may be, for example, a material having a linear or planar shape, and specifically, carbon nanotubes (CNTs) may be mentioned as an example. Therefore, from the specific surface area of ​​the porous composite, 1st The degree of coverage or adhesion of the porous body to the conductive member can be roughly estimated.

[0026] The specific surface area of ​​a porous composite can be evaluated by adsorbing molecules with known adsorption areas onto the powder particle surfaces and determining the specific surface area of ​​the sample from the amount of adsorption. For example, if the porous composite is mounted on a current collector, scrape off as much of the composite as possible from the current collector, and then subject the recovered powder to vacuum degassing at 120°C for 8 hours using a Microtrac-Bell Corporation BELPREP-VAC II pretreatment device. The specific surface area is then measured at an adsorption temperature of 77K using a Microtrac-Bell Corporation BELSORP-MINI II specific surface area and pore distribution analyzer. The adsorbed gas used is, for example, nitrogen.

[0027] It is preferable that the specific surface area of ​​the porous body itself is large. The redox-active molecular parts contained in the porous body become negatively charged at the reduction potential, making it possible to chemically adsorb carbon dioxide. The more opportunities there are for the molecular parts to come into contact with carbon dioxide, the greater the amount of adsorption. Therefore, it is preferable that the specific surface area of ​​the porous body is approximately 10 m. 2 / g to several thousand m 2 It is preferable to use a porous material with a pore size of about 1 / g, which makes it possible to obtain a compact device that can absorb and release a large amount of carbon dioxide.

[0028] The carbon dioxide absorption / release device includes an electrode having the porous composite, 1st In addition to the conductive member, a second conductive member can also be included. By separately adding a second conductive member to the first conductive member contained in the porous composite, the electrical connection between the porous composite can be reinforced. When the electrode includes a current collector, the electrical connection between the porous composite and the current collector can also be reinforced. Examples of the second conductive member include carbon materials such as carbon nanotubes, graphite, graphene, carbon fiber, and ketjen black. The second conductive member preferably has a shape that allows it to easily penetrate small gaps. Therefore, tubular or particulate carbon materials with a major axis of approximately several micrometers are more preferable as the second conductive member than fibrous carbon materials. The same conductive member as the first conductive member may be used as the second conductive member.

[0029] The electrode may further include a structural reinforcement member that physically entangles and reinforces the porous composite. Examples of such structural reinforcement members include fibrous carbon materials, conductive inorganic-organic hybrid materials, conductive polymers, non-conductive polymers, and ion-conductive polymers. The structural reinforcement member preferably has a fine fiber shape, which is advantageous for entanglement of the porous composite, and is even more preferably conductive. To achieve physical reinforcement, the structural reinforcement member preferably has a length of 1 μm or more. Examples of structural reinforcement members that can be used include carbon nanofibers, polyaniline, polythiophene, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), polyvinylidene fluoride (PVdF), polymethyl methacrylate (PMMA), polyimide (PI), polyethylene oxide, polypropyl oxide, polyacrylonitrile, and polyvinyl chloride. The inclusion of a structural reinforcement member allows the porous composite to function as a self-supporting sheet-shaped composite electrode without a current collector. One or more components included in the electrode may function as a structural reinforcement member.

[0030] The electrode may further include a binder. The binder may or may not be included. The binder can, for example, bind the current collector, the porous composite, and optionally the second conductive member. Examples of binders that can be used include polyvinylidene fluoride (PVdF), polymethyl methacrylate (PMMA), and polyimide (PI).

[0031] Furthermore, when a non-conductive polymer as a binder is dispersed in the form of fine fibers among the porous composite, the binder can also function as the structural reinforcing member.

[0032] Such a carbon dioxide absorption / release device can further include an electrolyte held in the porous composite. The electrolyte can be contained, for example, in the pores of the porous composite. By including the electrolyte, the conductivity of the porous composite is improved, thereby increasing the ability to absorb and release CO2.

[0033] The device includes an electrode having the porous composite as a working electrode, and a potential is applied to the working electrode to apply a charge to the redox-active molecular moiety contained in the porous composite. In other words, by controlling the potential of the electrode, the redox state of the porous body contained in the porous composite is switched between an oxidized state and a reduced state. The porous body can adsorb carbon dioxide in the reduced state and can release carbon dioxide in the oxidized state.

[0034] For example, a potential can be applied to the working electrode (electrode having a porous composite) by using a counter electrode and applying a voltage between the two electrodes. For example, the carbon dioxide absorption / release device may include a counter electrode for the electrode included in the device. In other words, the carbon dioxide absorption / release device may be configured as an electrochemical cell using the working electrode and counter electrode. The device is not limited to an electrochemical cell. A specific example of an electrochemical cell is a three-electrode cell that further includes a reference electrode in addition to the working electrode and counter electrode.

[0035] A specific example of a carbon dioxide absorption / release device according to an embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a schematic cross-sectional view showing an example of a carbon dioxide absorption / release device according to an embodiment. Fig. 2 is an enlarged cross-sectional view of part A shown in Fig. 1.

[0036] The carbon dioxide absorption / release device 1 includes an electrode 4 that includes a current collector 2 and a porous composite 3. The current collector 2 has a flat plate shape, and the porous composite 3 is provided on one of its main surfaces. In the example shown, the porous composite 3 is provided on only one surface of the current collector 2, but the porous composite 3 may be provided on multiple surfaces of the current collector 2. Alternatively, the porous composite 3 may be embedded inside the current collector 2 that is not flat but has a mesh shape, for example. The current collector 2 may also be omitted.

[0037] The porous composite 3 is 1st The conductive member 3a and the porous body 3b are included. The porous body 3b is 1st It is located on the conductive member 3a.

[0038] The current collector, the conductive member, the porous body, and the electrolyte will be described in detail below.

[0039] (current collector) A member made of carbon or metal can be used as the current collector. The better the conductivity and the larger the surface area of ​​the current collector, the more redox-active molecular moieties the charge can be transferred to. Examples of carbon members include glassy carbon, graphite sheet, carbon felt, carbon cloth, carbon mesh, carbon paper, and carbon sheet with a gas diffusion layer. Examples of metal members include copper plate, copper sheet, copper mesh, aluminum plate, aluminum sheet, aluminum mesh, nickel plate, nickel sheet, and nickel mesh. The carbon members and metal members are not limited to those mentioned above.

[0040] (Conductive material) The conductive member (first conductive member) of the porous composite can be, for example, a carbon material with good conductivity. The first conductive member includes, for example, one or more selected from the group consisting of carbon nanotubes, graphite, graphene, carbon nanofibers, and Ketjen black. The shape of the first conductive member is preferably linear or planar to increase contact probability, and is preferably rod-shaped, tubular, fibrous, sheet-shaped, or flake-shaped. The second conductive member outside the porous composite can be, for example, a carbon material with good conductivity such as carbon nanotubes, graphite, graphene, carbon nanofibers, carbon fiber, or Ketjen black, or a polymer material with good conductivity such as polyaniline, polythiophene, or poly(3,4-ethylenedioxythiophene)polystyrenesulfonate (PEDOT:PSS). The shape of the second conductive member is preferably a shape that can easily penetrate small gaps, and is preferably tubular or granular. The first and second conductive members may each be one type, or multiple types may be mixed.

[0041] The conductive member includes a member that can function as a structural reinforcing member that physically reinforces the porous composite. The conductive member that also serves as a structural reinforcing member preferably has a fine fiber shape with a diameter of several nanometers to several hundred nanometers and a length of several micrometers to several tens of micrometers so as to be efficiently entangled with the porous composite. For example, Second Conductive materials with a length of 1 μm or more as conductive members can entangle the porous composite and provide physical reinforcement. Such long conductive materials can have a length of, for example, 20 μm or less. It is more preferable that the diameter of such conductive materials be 200 nm or more and 800 nm or less. Examples of conductive members that can physically reinforce the porous composite include one or more selected from the group consisting of carbon nanofibers, polyaniline, polythiophene, and PEDOT:PSS. The conductive member can include, in addition to the long conductive materials described above, conductive materials with a length of less than 1 μm that do not exhibit a physically reinforcing effect. Such short conductive materials can have a length (or the longest dimension, such as the major axis) of, for example, 500 nm or more.

[0042] (porous body) The porous body used in the carbon dioxide absorption / release device includes a porous material having a large number of pores. The pores preferably have a diameter of 5 nm or less. Specifically, the porous body is preferably a sub-nanoporous or nanoporous material having pores of angstrom size (1 nm or less) to nanometer size, more specifically, 0.5 nm to 5 nm.

[0043] Such a porous body contains a molecular moiety that is reduced in response to an electric current to bond with carbon dioxide and oxidized in response to an electric current to release the bond with carbon dioxide. Such a molecular moiety can be an organic molecule contained as a functional group in the molecular structure that constitutes the porous body. Such an organic molecule can be arbitrarily selected from among known organic molecules that exhibit redox reactions. Furthermore, derivatives of these organic molecules can also be used. Specific examples will be given later.

[0044] The porous body contains the above-mentioned electrically responsive redox-active molecular moiety on its surface. The surface of the porous body here includes the outer surface and pore surfaces of the porous body. The molecular moiety can be located on the outer surface of the porous body. Alternatively, the molecular moiety can be contained within the pores while embedded in the pore surface of the porous body. Alternatively, the molecular moiety can be contained within the pores while hanging from the pore surface of the porous body. "Hanging from the pore surface" refers, for example, to a state in which the molecular moiety protrudes from the pore surface of the porous body and hangs like a pendant. Here, "embedded in the pore surface" refers, for example, to a state in which the molecular structure constituting the porous body, which corresponds to the wall surface of the pore, contains a cross-linked (bridge-type) functional group (the above-mentioned molecular moiety) whose redox state changes in response to electricity. Furthermore, "hanging from the pore surface" refers, for example, to a state in which the molecular structure constituting the porous body, which corresponds to the wall surface of the pore, is bonded to a pendant functional group whose redox state changes in response to electricity.

[0045] The arrangement of molecular moieties in a porous body will be described with reference to the drawings. Fig. 3 is a schematic cross-sectional view showing an example of a porous body included in a carbon dioxide absorption and release device according to an embodiment. The illustrated porous body 3b includes a plurality of pores 5. The porous body 3b includes first molecular moieties 6a arranged on a porous body surface 3c outside the pores 5 and second molecular moieties 6b arranged on pore surfaces 5a, which are the wall surfaces within the pores 5. The first molecular moieties 6a and the second molecular moieties 6b include those embedded in the surface of the porous body 3b (porous body surface 3c or pore surfaces 5a) and those hanging from the surface.

[0046] The content of molecular moieties that exhibit redox activity through electrical response in the porous body is preferably 10% by mass or more and 80% by mass or less, and more preferably 20% by mass or more and 75% by mass or less, based on the total mass of the porous body.

[0047] Generally, the greater the amount of active groups contained in the adsorbent, the greater the amount of carbon dioxide absorbed and desorbed per unit volume of the adsorbent. Therefore, from the viewpoints of energy consumption, plant equipment size, and treatment efficiency, a larger amount of active groups is desirable.

[0048] However, if the amount of redox-active molecular moieties per unit volume of the porous body is too large, the redox-active groups may come close to each other, causing pore blockage or making it difficult for carbon dioxide to access the active groups, which may result in insufficient utilization of the active groups. Therefore, the content of molecular moieties that exhibit redox activity upon electrical response in the porous body is preferably 90 mass% or less, more preferably 75 mass% or less, based on the total mass of the porous body.

[0049] By setting the content of the molecular moiety to 10% by mass or more, it is possible to obtain a sufficient amount and rate of carbon dioxide adsorption, and to achieve excellent treatment efficiency. Therefore, a porous body having a content of the redox-active molecular moiety within the above range is advantageous in that it not only has a high carbon dioxide absorption amount and rate in carbon dioxide recovery applications, but also a large amount of carbon dioxide desorption from the porous body and a high carbon dioxide desorption rate (reaction rate), allowing for efficient carbon dioxide recovery.

[0050] Specific examples of organic molecules that can function as electrically responsive redox-active molecular moieties in porous materials include one or more selected from the group consisting of quinones, imines, and imides. Specific examples include benzoquinone, anthraquinone, phenanthrenequinone, phenanthroline, pyridine, phenazine, pyrimidine, methyl viologen, benzodipyrrole, phthalimide, phthaldiimide, naphthaleneimide, naphthalenediimide, and derivatives of these organic molecules. The chemical formulas of the above organic molecules are shown below. Derivatives of methyl viologen (also known as 1,1'-dimethyl-4,4'-bipyridinium dichloride) include, for example, viologens such as 1,1'-dibenzyl-4,4'-bipyridinium dichloride (also known as benzyl viologen), 1,1'-diphenyl-4,4'-bipyridinium dichloride, 1,1'-bis(2,4-dinitrophenyl)-4,4'-bipyridinium dichloride, 1,1'-di-n-octyl-4,4'-bipyridinium dibromide, and 1,1'-diheptyl-4,4'-bipyridinium dibromide.

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[0061] The chemical reaction responsible for the absorption and release of carbon dioxide (CO2) due to the oxidation and reduction of the molecular parts contained in the porous material in response to electricity will be explained using the electric response reaction of anthraquinone as an example of a redox-active organic molecule. Anthraquinone absorbs two electrons at a reduction potential, and if CO2 is present in the environment, it forms a chemical bond with CO2 according to the following reaction formula, thereby absorbing the CO2.

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[0063] The above chemical reaction proceeds reversibly, and when exposed to an oxidizing potential, CO2 is released according to the following reaction formula, returning to the original anthraquinone structure.

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[0065] As in the above example, the organic molecules used as the molecular portions that serve as active sites in the porous body are preferably highly chemically stable, since they are regenerated by absorbing and releasing CO2 and can be reused repeatedly.

[0066] The organic molecule preferably contains at its terminal one or more groups selected from the group consisting of an amino group, a carboxyl group, an aldehyde group, a carbonyl group, and a nitrile group.

[0067] The porous body preferably contains one or more selected from the group consisting of a covalent-organic framework (COF), a metal-organic framework (MOF), a porous carbon material, a zeolite, a porous silica, a porous alumina, and a porous material in which the pores of the porous body are modified with amine molecules. For example, the porous body may contain an electrically responsive COF. Alternatively, the porous body may contain an electrically responsive MOF.

[0068] The COF contained in the porous body preferably contains one or more bonds selected from the group consisting of imine bonds, hydrazine bonds, azine bonds, imide bonds, phenazine bonds, triazine bonds, and enamine bonds obtained by a condensation reaction between an organic molecule having an amino group and an organic molecule having an aldehyde group or a carbonyl group, or a cyclization reaction of an organic molecule having a nitrile group.

[0069] In the COF, it is desirable for charge to be transferred smoothly to the redox-active molecular moiety. Therefore, it is preferable for the two-dimensional structural units of the COF to form a three-dimensional structure by Π-Π stacking. Inclusion of such a layered structure by Π-Π stacking in a porous material improves the efficiency of electrical response and promotes low energy. Examples of COFs that form a three-dimensional structure by Π-Π stacking include TpPa COF, PA-COF, 4KT-Tp COF, 2KT-Tp COF, 1KT-Tp COF, DAAQ-TFP-COF, PI-COF-1, PI-COF-2, PI-COF-3, CS-COF, CTF-1, CTF-2, TAPB-PDA-COF, N3-COF, COF-42, and derivatives thereof. It is preferable to include one or more of these COFs that can form a layered structure by Π-Π stacking. The chemical structures of the above-mentioned COFs are shown below. TpPa COFs include COF-TpPa-1 and TpPa-(OH)2. In the TpPa COF structure below, R1 = H and R2 = H in COF-TpPa-1, and R1 = OH and R2 = OH in TpPa-(OH)2. The specific surface area of ​​the COFs in the above examples varies depending on the pore structure, and the amount of CO2 that can theoretically be adsorbed per unit weight of COF varies depending on the number of redox active sites in the organic molecules.

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[0086] Using some of the COFs listed above as examples, the imine bonds, azine bonds, enamine bonds, hydrazone bonds, or imide bonds contained in these COFs are shown below.

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[0092] On the other hand, since the above MOF has a three-dimensional structure established by ionic bonds, it is preferable that it has both high water resistance and heat resistance. In particular, it is preferable to use an MOF having a structure in which 12 dicarboxylic acids are coordinated to a hexanuclear Zr6O4(OH)4 cluster. The structure is shown below. In the structure below, ○ (open circle) represents the Zr6O4(OH)4 cluster, and the solid line represents the dicarboxylic acid ligand.

[0093] [ka]

[0094] A preferred example of an MOF having a structure in which 12 dicarboxylic acids are coordinated to a hexanuclear ZrO(OH) cluster is an MOF having a UiO (Universitet i Oslo) structure. For example, it is preferable to use one or more selected from the group consisting of UiO-66, UiO-67, UiO-68, and derivatives thereof. UiO-66, UiO-67, and UiO-68 have structures in which the dicarboxylic acid ligands are 1,4-benzenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, and 4,4″-terphenyldicarboxylic acid, respectively. The above-mentioned derivatives refer to compounds in which a new functional group has been introduced into the benzene ring of the ligands contained therein. Functional groups include, for example, amino groups, hydroxyl groups, alkoxy groups, amide groups, aldehyde groups, acyl groups, ester groups, and carbonyl groups such as carboxyl groups. Other examples of the above-mentioned derivatives include compounds in which the benzene ring of the ligand is substituted with a heteroaromatic ring such as a pyridine ring or an imidazole ring. In addition, with regard to UiO-67, derivatives also include compounds in which 4,4′-biphenyldicarboxylic acid is substituted with a heterocyclic compound such as 9-fluorenone-2,7-dicarboxylic acid, fluorene-2,7-dicarboxylic acid, or carbazole-2,7-dicarboxylic acid.

[0095] A specific example of a MOF with a UiO structure is 2,6-Zr-AQ-MOF (ZrO(OH)(C 16 O6H6)6(C3H7NO3) 17 (H2O) 22 ) and 1,4-Zr-AQ-MOF (Zr6O4(OH)4(C 16 O6H6)4(C2O2H3) 2.76 (CO2H) 1.24 (C3H7NO) 11 (H2O) 40) are examples of MOFs. In these MOFs, 2,6-dicarboxy-9,10-anthraquinone and 1,4-dicarboxy-9,10-anthraquinone are coordinated as dicarboxylic acid ligands to the hexanuclear Zr6O4(OH)4 cluster, and are present on the surface of the pores of the MOF. In other words, anthraquinone is included as a bridging functional group. The structures of these MOFs are shown below. In the following, a simplified structure is shown, with only one anthraquinone site clearly indicated and the remaining 11 sites (solid lines) omitted.

[0096] [ka]

[0097] [ka]

[0098] Other examples of MOFs include MOFs with Cu(2,7-anthraquinonedicarboxylic acid) structure (Cu(2,7-AQDC) structure), Mn(2,7-anthraquinonedicarboxylic acid) structure (Mn(2,7-AQDC) structure), or IRMOF structure. Furthermore, examples include analogue structures of IRMOF-9 in which biphenylenedicarboxylic acid is replaced with anthraquinonedicarboxylic acid.

[0099] Cu(2,7-AQDC) has a network structure in which bridge-type 2,7-AQDC ligands are coordinated to paddlewheel-type dinuclear complex Cu2(Ac)4 clusters as nodes. Note that π-π interactions can occur between some of the 2,7-AQDC ligands, but the structure is reinforced by these π-π interactions. Mn(2,7-AQDC) has a lattice structure in which bridge-type 2,7-AQDC ligands are coordinated to Mn complex clusters. The specific surface area of ​​the MOFs in the above examples varies depending on the pore structure, and the amount of CO2 that can theoretically be adsorbed per unit weight of the MOF varies depending on the number of redox-active sites in the organic molecules.

[0100] The porous material used as the porous body is not limited to the above materials. For example, activated carbon or mesoporous silica can also be used as the porous body. Activated carbon or mesoporous silica may be used alone, or may be modified with an electrically responsive active group.

[0101] MOFs can contain one or more central metals selected from the group consisting of zirconium, copper, and manganese. The central metal can be, for example, the central metal of a metal complex, and the metal complex can be contained within the MOF as a cluster. For example, the MOF having the UiO structure described above contains a cluster of Zr6O4(OH)4, a complex containing zirconium as the central metal. Cu(2,7-AQDC) contains a cluster of a complex containing copper as the central metal, and Mn(2,7-AQDC) contains a cluster of a complex containing manganese as the central metal.

[0102] (electrolyte) The porous composite may contain an electrolyte. For example, an electrolyte containing one or more selected from the group consisting of an ion-bonding salt and an ion-conducting polymer can be used as the electrolyte component. The electrolyte may also be present inside the pores of the porous body.

[0103] Specifically, the ionically bondable salt is preferably one or more selected from the group consisting of alkali metal salts, alkaline earth metal salts, transition metal salts, amphoteric metal salts, ammonium salts, imidazolium salts, pyridinium salts, and phosphonium salts. The ionically bondable salt may be in the form of a solid or liquid, and examples of liquids include ionic liquids.

[0104] The cations of the ionically bonded salts include alkali metals such as Li, Na, K, Rb, and Cs; alkaline earth metals such as Mg, Ca, Sr, and Ba; transition metals such as Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Pd, and Ag; amphoteric metals such as Al, Ga, and Sn; ammonium ions and ammonium ions substituted with lower hydrocarbons of C1 to C5 (N(C n H 2n+1 )4 +, n=1 to 5); imidazolium ion or imidazolium ion having one to three substituents; pyridinium ion or pyridinium ion having one to three substituents; and phosphonium ion PR4 having four substituents. + (R: hydrocarbon group), one or more selected from the group consisting of these may be used, and one of the above may be used alone or a combination of two or more may be used.

[0105] The anion of the ionic salt is Cl - , Br - , and I - Halogens such as nitrate ions (NO3 - ), PF6 - , BF4 - , CH3COO - , CF3COO - , ClO4 - , and N(SO2CF3)2 - One or more selected from the group consisting of may be used, and one of the above may be used alone or a combination of two or more may be used.

[0106] As the ion-conducting polymer, it is preferable to use, for example, one or more selected from the group consisting of polyethylene oxide (PEO), polypropyl oxide (PPO), polyacrylonitrile (PAN), polyvinyl chloride (PVC), and ionic liquid polymer.

[0107] Among the above ion-conductive polymers, PEO, PPO, PAN, and PVC can also function as structural reinforcing members that physically reinforce the porous composite.

[0108] <Manufacturing method> Such a carbon dioxide absorption / release device can be manufactured, for example, as follows.

[0109] First, a porous composite is prepared. The porous composite, the second conductive member, and a binder are added to a solvent. The resulting mixture is kneaded to prepare a paste. This paste is applied, for example, to a current collector. For example, when a flat current collector is used, the paste is applied to one or both sides of the current collector. Next, the applied paste is heated and dried to obtain an electrode including the current collector and the porous composite.

[0110] The above is merely an example, and the paste does not necessarily need to contain a binder. Depending on the properties of the conductive material, it may be possible to form a self-standing electrode by heating and drying the paste. In other words, an electrode containing, for example, the porous composite alone can be obtained without using a current collector.

[0111] The porous composite is synthesized, for example, by adding the first conductive member to a raw material solution containing raw materials used to synthesize a single porous body, including organic molecules that exhibit redox activity due to electrical response.

[0112] The porous material used for the porous body is preferably one whose structure does not change even when it is combined with the conductive member, because if the structure of the porous material changes, the specific surface area decreases, or the number of pores decreases, resulting in a decrease in effective active groups, thereby reducing the carbon dioxide adsorption / desorption capacity.

[0113] When an electrolyte is to be contained in a device, for example, an electrolyte solution is prepared, the prepared solution is cast on the surface of an electrode, and then vacuum impregnation is carried out, thereby allowing the electrolyte to be contained in the electrode.

[0114] The carbon dioxide absorption / release device described above includes an electrode having a porous composite. 1st The device includes a conductive member and a porous body thereon. The porous body contains molecular moieties in angstrom- or nanometer-sized pores that exhibit redox activity in response to electricity. This device is an electrically responsive carbon dioxide absorption / desorption device that can efficiently absorb and desorb carbon dioxide using low energy.

[0115] [Carbon dioxide separation method] The carbon dioxide absorption / release device according to the above embodiment has a porous composite having a porous body containing redox-active molecular moieties on a conductive member, and is therefore able to adsorb carbon dioxide at a reduction potential and release carbon dioxide at an oxidation potential, thereby enabling efficient recovery and concentration of carbon dioxide.

[0116] A carbon dioxide separation method according to an embodiment includes using the carbon dioxide absorption / release device to remove carbon dioxide from a gas containing carbon dioxide by adsorbing carbon dioxide onto a porous body, and desorbing the carbon dioxide from the porous body to regenerate the porous body. Adsorbing carbon dioxide into the porous body includes passing an electric current through the porous body at the reduction potential of the porous body, and contacting the gas containing carbon dioxide with the porous body while maintaining the electric potential flowing through the porous body at the reduction potential. Regenerating the porous body by desorbing carbon dioxide from the porous body includes switching the electric potential flowing through the porous body that has adsorbed carbon dioxide to the oxidation potential of the porous body. The regenerated porous body can be reused.

[0117] After carbon dioxide has been separated from the porous material, the device can be set to a reducing potential again to perform the carbon dioxide adsorption process again. In this way, the potential of the current passed through the porous material can be switched between the reducing potential and the oxidizing potential, allowing the device to be used repeatedly.

[0118] The method for contacting a gas containing carbon dioxide with the carbon dioxide absorption / release device is not particularly limited. For example, a method can be mentioned in which the carbon dioxide absorption / release device is immersed in an electrolyte solution, and the gas containing carbon dioxide is bubbled into the electrolyte solution to adsorb the carbon dioxide in the electrolyte solution. Another example can be a method in which the carbon dioxide absorption / release device is placed in a gas stream containing carbon dioxide.

[0119] The concentration of carbon dioxide brought into contact with the device is not particularly limited, but can accommodate a wide range of CO2 concentrations, from atmospheric levels to levels emitted by thermal power plants, etc. Specifically, the carbon dioxide concentration is preferably 0.01 vol% or more and 50 vol% or less, and more preferably 0.04 vol% or more and 50 vol% or less.

[0120] The ambient temperature during carbon dioxide absorption / desorption treatment is usually preferably 10°C or higher and 60°C or lower. A more preferable temperature is 50°C or lower, and an especially preferable temperature is 20°C or higher and 45°C or lower. The lower the temperature at which absorption is performed, the greater the amount of carbon dioxide adsorbed. The lower limit of the treatment temperature can be determined based on the gas temperature in the process, the heat recovery target, etc. The carbon dioxide adsorption pressure is usually approximately equal to atmospheric pressure. To improve absorption performance, it is possible to increase the pressure to a higher level. However, from the perspective of reducing the energy consumption required for compression, it is preferable to perform the treatment at atmospheric pressure.

[0121] A method for absorbing and releasing carbon dioxide using such a carbon dioxide absorption and release device may include, for example, the following steps: passing an electric current through the porous composite at a reducing potential; carbon dioxide contacting and adsorbing the redox-active molecular moiety; changing the potential to an oxidation potential and passing a current; The process by which carbon dioxide desorbs from redox-active molecular moieties.

[0122] The carbon dioxide separation method described above includes adsorbing carbon dioxide into a porous body contained in a carbon dioxide absorption / release device, desorbing and separating the carbon dioxide from the porous body to which the carbon dioxide has been adsorbed, and regenerating the porous body. Carbon dioxide is adsorbed into the porous body while the current flowing through the porous body is maintained at a reduction potential. The current flowing through the porous body is switched to an oxidation potential, and carbon dioxide is desorbed while the oxidation potential is maintained. This separation method allows carbon dioxide to be absorbed and released efficiently with low energy.

[0123] [Example] Hereinafter, examples of the carbon dioxide absorption and release device will be described.

[0124] (Example 1) <Synthesis of TpPA-(OH)2-CNT composite> 1st A porous composite modified with TpPa-(OH)2 as a porous body was prepared on carbon nanotubes (CNT) as a conductive member. TpPa-(OH)2 is a COF containing benzoquinone (BQ) as a redox-active molecular moiety. As a reactant for obtaining the COF, 2,5-diaminohydroquinone dihydrochloride (Pa(OH)2·2HCl) was prepared referring to Non-Patent Document 1 (Chem. Mater. 2017, 29, 5, 2074-2080; Suman Chandra, et al.). CNT was added to the raw material solution containing Pa(OH)2·2HCl so that BQ:CNT = 5:6 (weight ratio) to synthesize the TpPA-(OH)2-CNT composite. The product was washed by extracting with methanol at 105 °C for 12 hours using a Soxhlet extractor, and then dried under reduced pressure at 120 °C for 2 hours.

[0125] <Film formation on the current collector> The TpPA-(OH)2-CNT composite obtained above, ketjen black (Second conductive member) and PVdF (binder) were added to N-methylpyrrolidone (NMP) so that the weight ratio of TpPA-(OH)2-CNT composite: ketjen black: PVdF = 8:1:1. The obtained mixture was kneaded until it became a suitable paste. The produced paste was coated on the current collector. A graphite sheet was used as the current collector. After air-drying the paste overnight, the device of Example 1 was obtained by drying under reduced pressure at 110 °C for 2 hours.

[0126] (Example 2) <Synthesis of DAAQ-TFP-COF-CNT composite> 1stA porous composite was fabricated by modifying CNTs as a conductive component with DAAQ-TFP-COF as a porous material. DAAQ-TFP-COF is a COF containing anthraquinone (AQ) as the redox-active molecular moiety. 2,6-anthraquinonediamine (DAAQ) was prepared as the reactant for obtaining this COF, following Non-Patent Document 2 (Carbon 171 (2021) 248-256; Xueying Kong, et al.). CNTs were added to a DAAQ-containing raw material solution at a weight ratio of DAAQ:CNT = 5:6 to synthesize the DAAQ-TFP-COF-CNT composite. The product was washed by extraction with methanol using a Soxhlet filter at 105°C for 12 hours and then dried under reduced pressure at 120°C for 2 hours.

[0127] <Film formation on current collector> The DAAQ-TFP-COF-CNT composite (hereinafter referred to as AQ-COF_CNT) obtained above and the carbon material (Second conductive member) and PVdF (binder) The mixture was added to NMP so that the weight ratio of AQ-COF_CNT:carbon material:PVdF was 8:1:1. The resulting mixture was kneaded until it became a paste. The resulting paste was applied to a current collector. A graphite sheet was used as the current collector. The paste was air-dried overnight and then dried under reduced pressure at 110°C for 2 hours to obtain the device of Example 2.

[0128] Example 3 <Synthesis of 1KT-Tp COF-CNT composite> 1stA porous composite was fabricated by modifying CNTs as a conductive component with 1KT-Tp COF as a porous material. 1KT-Tp COF is a COF containing fluorene as the redox-active molecular moiety. 2,7-diamino-9H-fluoren-9-one (1KT-BD) was prepared as the reactant for obtaining this COF, following Non-Patent Document 3 (CCS Chem. 2020, 2, 696-706; Miao Li, et al.). CNTs were added to a raw material solution containing 1KT-BD at a weight ratio of 1KT-BD:CNT = 5:6 to synthesize the 1KT-Tp COF-CNT composite. The product was washed by extraction with methanol using a Soxhlet filter at 105°C for 12 hours and then dried under reduced pressure at 120°C for 2 hours.

[0129] <Film formation on current collector> The 1KT-Tp COF-CNT composite obtained above and Ketjenblack (Second conductive member) and PVdF (binder) The above was added to NMP so that the weight ratio of 1KT-Tp COF-CNT composite: Ketjen black: PVdF was 8:1:1. The resulting mixture was kneaded until it became a paste. The resulting paste was applied to a current collector. A graphite sheet was used as the current collector. The paste was air-dried overnight and then dried under reduced pressure at 110°C for 2 hours to obtain the device of Example 3.

[0130] Example 4 <Synthesis of 2KT-Tp COF-CNT composite> 1stWe fabricated a porous composite by modifying CNTs as a conductive component with 2KT-Tp COF. 2KT-Tp COF is a COF containing phenanthrene as the redox-active molecular moiety. Based on Non-Patent Document 3 (CCS Chem. 2020, 2, 696-706; Miao Li, et al.), we synthesized a 2KT-Tp COF-CNT composite by adding CNTs to a raw material solution containing 2,7-diaminophenanthrene-9,10-dione (2KT-BD) in a weight ratio of 2KT-BD:CNT = 5:6. The product was washed by extraction with methanol using a Soxhlet filter at 105°C for 12 hours and then dried under reduced pressure at 120°C for 2 hours.

[0131] <Film formation on current collector> The 2KT-Tp COF-CNT composite obtained above and Ketjenblack (Second conductive member) and PVdF (binder) The above was added to NMP so that the weight ratio of 2KT-Tp COF-CNT:Ketjen black:PVdF was 8:1:1. The resulting mixture was kneaded until it became a paste. The resulting paste was applied to a current collector. A graphite sheet was used as the current collector. The paste was air-dried overnight and then dried under reduced pressure at 110°C for 2 hours to obtain the device of Example 4.

[0132] Example 5 (Synthesis of 4KT-Tp COF-CNT composite) 1stA porous composite modified with 4KT-Tp COF was prepared on CNT as a conductive member. 4KT-Tp COF is a COF containing phenanthrene as a redox-active molecular moiety. Referring to Non-Patent Document 3 (CCS Chem. 2020, 2, 696-706; Miao Li, et al.), CNT was added to a raw material solution containing 2, 7-diaminopyrene-4,5,9,10-tetraone (4KT-BD) so that 4KT-BD:CNT = 5:6 (weight ratio) to synthesize a 4KT-Tp COF-CNT composite. The product was washed by extraction with methanol at 105 °C for 12 hours using Soxhlet, and then dried under reduced pressure at 120 °C for 2 hours.

[0133] <Film formation on the current collector> The 4KT-Tp COF-CNT composite obtained above, ketjen black (Second conductive member) and PVdF (binder) were added to NMP so that 4KT-Tp COF-CNT composite:ketjen black:PVdF = 8:1:1 (weight ratio). The resulting mixture was kneaded until it became a suitable paste. The produced paste was applied onto the current collector. A graphite sheet was used as the current collector. After air-drying the paste overnight, the device of Example 5 was obtained by drying under reduced pressure at 110 °C for 2 hours.

[0134] (Example 6) <Synthesis of TpPa-Py COF-CNT composite> 1stA porous composite modified with TpPa-Py COF was prepared on CNT as a conductive member. TpPa-Py COF is a COF containing pyridine as a redox-active molecular moiety. Referring to Non-Patent Document 4 (Mater. Chem. Front., 2017, 1, 1310-1316; Qui Sun, et al.), CNT was added to a raw material solution containing 2, 6-diaminopyridine (TpPa-Py) so that the weight ratio of TpPa-Py:CNT was 5:6 to synthesize a TpPa-Py COF-CNT composite. The product was washed by extraction with methanol at 105 °C for 12 hours using Soxhlet, and then dried under reduced pressure at 120 °C for 2 hours.

[0135] <Film formation on the current collector> The TpPa-Py COF-CNT composite obtained above, Ketjen black (Second conductive member) and PVdF (binder) were added to NMP so that the weight ratio of TpPa-Py COF-CNT composite: Ketjen black: PVdF was 8:1:1. The resulting mixture was kneaded until it became a suitable paste. The produced paste was applied onto a current collector. A graphite sheet was used as the current collector. After the paste was air-dried overnight, it was dried under reduced pressure at 110 °C for 2 hours to obtain the device of Example 6.

[0136] (Example 7) <Synthesis of DAPH-TFP COF-CNT composite> 1stA porous composite modified with DAPH-TFP COF was prepared on CNT as a conductive member. DAPH-TFP COF is a COF containing pyridine as a redox-active molecular moiety. Referring to Non-Patent Document 5 (J. Am. Chem. Soc. 2020, 142, 1, 16-20; Edon Vitaku, et al.), CNT was added to a raw material solution containing 2, 7-diamino-phenazine (DAPH·Bnzph) so that DAPH·Bnzph:CNT = 5:6 (weight ratio) to synthesize a DAPH-TFP COF-CNT composite. The product was washed by extraction with methanol at 105 °C for 12 hours using Soxhlet, and then dried under reduced pressure at 120 °C for 2 hours.

[0137] <Film formation on the current collector> The DAPH-TFP COF-CNT composite obtained above, ketjen black (Second conductive member) and PVdF (binder) were added to NMP so that DAPH-TFP COF-CNT composite: ketjen black: PVdF = 8:1:1 (weight ratio). The resulting mixture was kneaded until it became a suitable paste. The produced paste was applied onto a current collector. A graphite sheet was used as the current collector. After the paste was air-dried overnight, it was dried under reduced pressure at 110 °C for 2 hours to obtain the device of Example 7.

[0138] (Example 8) <Synthesis of PI-COF-1-CNT composite> 1stA porous composite modified with PI-COF-1 was prepared on CNT as a conductive member. PI-COF-1 is a COF containing pyridine as a redox-active molecular moiety. Referring to Non-Patent Document 7 (Nat Commun 5:4503 (2014); Qianrong Fang, et al.), CNT was added to a raw material solution containing pyromellitic dianhydride (PMDA) and tris(4-aminophenyl)amine (TAPA) so that PMDA:CNT = 5:6 (weight ratio) to synthesize a PI-COF-1-CNT composite. The product was washed by extraction with methanol at 105 °C for 12 hours using Soxhlet, and then dried under reduced pressure at 120 °C for 2 hours.

[0139] <Film formation on the current collector> The PI-COF-1-CNT composite obtained above, ketjen black (Second conductive member) and PVdF (binder) were added to NMP so that the PI-COF-1-CNT composite: ketjen black: PVdF = 8:1:1 (weight ratio). The resulting mixture was kneaded until it became a suitable paste. The produced paste was applied onto a current collector. A graphite sheet was used as the current collector. After the paste was air-dried overnight, it was dried under reduced pressure at 110 °C for 2 hours to obtain the device of Example 8.

[0140] (Example 9) <Synthesis of PI-COF-2-CNT composite> 1stA porous composite modified with PI-COF-2 was prepared on CNT as a conductive member. PI-COF-2 is a COF containing pyridine as a redox-active molecular moiety. Referring to Non-Patent Document 7 (Nat Commun 5:4503 (2014); Qianrong Fang, et al.), CNT was added to a raw material solution containing PMDA and 1,3,5-tris(4-aminophenyl)benzene (TAPB) so that PMDA:CNT = 5:6 (weight ratio) to synthesize a PI-COF-2-CNT composite. The product was washed by extraction with methanol at 105 °C for 12 hours using Soxhlet, and then dried under reduced pressure at 120 °C for 2 hours.

[0141] <Film formation on the current collector> The PI-COF-2-CNT composite obtained above, ketjen black (Second conductive member) and PVdF (binder) were added to NMP so that PI-COF-2-CNT composite: ketjen black: PVdF = 8:1:1 (weight ratio). The resulting mixture was kneaded until it became a suitable paste. The produced paste was coated on the current collector. A graphite sheet was used as the current collector. After air-drying the paste overnight, the device of Example 9 was obtained by drying under reduced pressure at 110 °C for 2 hours.

[0142] (Example 10) <Synthesis of PI-COF-3-CNT composite> 1stA porous composite modified with PI-COF-3 was prepared on CNT as a conductive member. PI-COF-3 is a COF containing pyridine as a redox-active molecular moiety. Referring to Non-Patent Document 7 (Nat Commun 5:4503 (2014); Qianrong Fang, et al.), CNT was added to a raw material solution containing PMDA and 1,3,5-tris[4-amino(1,1-biphenyl-4-yl)]benzene (TABPB) so that PMDA:CNT = 5:6 (weight ratio) to synthesize a PI-COF-3-CNT composite. The product was washed by extraction with methanol at 105 °C for 12 hours using Soxhlet, and then dried under reduced pressure at 120 °C for 2 hours.

[0143] <Film formation on the current collector> The PI-COF-3-CNT composite obtained above, Ketjen black (Second conductive member) and PVdF (binder) were added to NMP so that the weight ratio of PI-COF-3-CNT composite: Ketjen black: PVdF = 8:1:1. The resulting mixture was kneaded until it became a suitable paste. The produced paste was coated on the current collector. A graphite sheet was used as the current collector. After the paste was air-dried overnight, the device of Example 10 was obtained by drying under reduced pressure at 110 °C for 2 hours.

[0144] (Example 11) <Addition of ionic bond salt> A 60 wt% acetonitrile solution of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIM-Tf2N) was prepared. After casting 20 μL of the prepared solution onto a device prepared in the same manner as the device of Example 2, vacuum impregnation was carried out to obtain the device of Example 11.

[0145] (Example 12) <Synthesis of AQ-UiO-CNT composite> 1stA porous composite modified with AQ-UiO on CNT as a conductive member was prepared. AQ-UiO is a MOF containing anthraquinone (AQ) as a redox-active molecular moiety. Referring to Non-Patent Document 8 (Inorg. Chem. 2017, 56, 13741-13747; Paul J. Celis-Salazar, et al.), CNT was added to a raw material solution containing 2,6-anthraquinone dicarboxylic acid so that the weight ratio to AQ-UiO was 8:1 to synthesize an AQ-UiO-CNT composite (hereinafter AQ-MOF_CNT). The product was suction filtered with dimethylformamide (DMF), washed with DMF, and dried under reduced pressure at 120 °C for 2 hours.

[0146] <Film formation on the current collector> The AQ-MOF_CNT obtained above, Ketjen black (Second conductive member) and PVdF (binder) were added to NMP so that the weight ratio of AQ-MOF_CNT: Ketjen black: PVdF was 7:2:1. The obtained mixture was kneaded until it became a suitable paste. The produced paste was applied onto a current collector. A graphite sheet was used as the current collector. After the paste was air-dried overnight, it was dried under reduced pressure at 110 °C for 2 hours to obtain the device of Example 12.

[0147] (Example 13) <Addition of ionic bond salt> A 60 wt% acetonitrile solution of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIM-Tf2N) was prepared. After casting 20 μL of the prepared solution onto a device prepared in the same manner as the device of Example 12, vacuum impregnation was carried out to obtain the device of Example 13.

[0148] (Example 14) <Synthesis of Cu(2,7-AQDC)-CNT composite> 1stA porous composite modified with Cu(2,7-AQDC) was prepared on CNT as a conductive member. Cu(2,7-AQDC) is a MOF containing anthraquinone (AQ) as a redox-active organic molecule. Referring to Non-Patent Document 9 (J. Am. Chem. Soc. 2014, 136, 16112-16115; Zhongyue Zhang, et al.), CNT was added to a raw material solution containing 2,7-anthraquinone dicarboxylic acid so that the weight ratio to Cu(2,7-AQDC) was 8:1 to synthesize a Cu(2,7-AQDC)-CNT composite. The product was suction-filtered with DMF, then washed with DMF and dried under reduced pressure at 120 °C for 2 hours.

[0149] <Film formation on the current collector> The Cu(2,7-AQDC)-CNT composite obtained above, ketjen black (Second conductive member) and PVdF (binder) were added to NMP so that the weight ratio of Cu(2,7-AQDC)-CNT composite: ketjen black: PVdF was 7:2:1. The resulting mixture was kneaded until it became a suitable paste. The produced paste was coated on the current collector. A graphite sheet was used as the current collector. After air-drying the paste overnight, the device of Example 14 was obtained by drying under reduced pressure at 110 °C for 2 hours.

[0150] (Example 15) <Synthesis of Mn(2,7-AQDC)-CNT composite> 1stA porous composite modified with Mn(2,7-AQDC) was prepared on CNT as a conductive member. Mn(2,7-AQDC) is a MOF containing anthraquinone (AQ) as a redox-active organic molecule. Referring to Non-Patent Document 10 (Chem. Mater. 2016, 28, 5, 1298-1303; Zhongyue Zhang, et al.), CNT was added to a raw material solution containing 2,7-anthraquinone dicarboxylic acid so that the weight ratio to Mn(2,7-AQDC) was 8:1 to synthesize a Mn(2,7-AQDC)-CNT composite. The product was suction-filtered with DMF, then washed with DMF and dried under reduced pressure at 120 °C for 2 hours.

[0151] <Film formation on the current collector> The Mn(2,7-AQDC)-CNT composite obtained above, Ketjen black (Second conductive member) and PVdF (binder) were added to NMP so that the weight ratio of Mn(2,7-AQDC)-CNT composite: Ketjen black: PVdF was 7:2:1. The obtained mixture was kneaded until it became a suitable paste. The produced paste was coated on a current collector. A graphite sheet was used as the current collector. After the paste was air-dried overnight, it was dried under reduced pressure at 110 °C for 2 hours to obtain the device of Example 15.

[0152] (Example 16) <Fabrication of DAAQ-TFP-COF-CNT-CNF composite electrode> As follows, in the device of Example 2, part of CNT (First conductive member) was replaced with carbon nanofibers (CNF) (Second conductive member) and the current collector was omitted hand to fabricate a self-supporting electrode. CNT was added to a raw material solution containing DAAQ so that the weight ratio of DAAQ: CNT was 8:1 to synthesize a DAAQ-TFP-COF-CNT composite (AQ-COF_CNT). The product was washed by extraction with methanol at 105 °C for 12 hours using a Soxhlet extractor and then dried under reduced pressure at 120 °C for 2 hours.

[0153] The AQ-COF_CNT and CNF obtained above (Second conductive member) were added to a solvent such that AQ-COF:CNT:CNF = 8:1:1 (weight ratio). The resulting dispersion was applied onto a slide glass by the doctor blade method and heat-treated at 120 °C for 20 hours. The film obtained by peeling from the slide glass by washing was subjected to vacuum drying for 1 hour to obtain the device of Example 16.

[0154] (Comparative Example 1) (Preparation of DAAQ-TFP-COF (COF) + non-fibrous carbon material device) CNT (First conductive member) was synthesized under the same composition and synthesis conditions as in Example 2 except that CNT was omitted, porous material to obtain DAAQ-TFP-COF. The obtained DAAQ-TFP-COF (porous material) and Ketjen black (Second conductive member) and PVdF (binder) were added to NMP such that COF:Ketjen black:PVdF = 8:1:1 (weight ratio). The resulting mixture was kneaded until it became a suitable paste-like state. The produced paste was applied onto a current collector. A graphite sheet was used as the current collector. After air-drying the paste overnight, the device of Comparative Example 1 was obtained by vacuum drying at 110 °C for 2 hours.

[0155] (Comparative Example 2) (Preparation of AQ-UiO + non-fibrous carbon material device) CNT (First conductive member) was synthesized under the same composition and synthesis conditions as in Example 12 except that CNT was omitted, porous material to obtain AQ-UiO. The obtained AQ-UiO (porous material) and Ketjen black (Second conductive member) and PVdF (binder) were added to NMP such that AQ-UiO:Ketjen black:PVdF = 7:2:1 (weight ratio). The resulting mixture was kneaded until it became a suitable paste-like state. The produced paste was applied onto a current collector. A graphite sheet was used as the current collector. After air-drying the paste overnight, the device of Comparative Example 2 was obtained by vacuum drying at 110 °C for 2 hours.

[0156] (Evaluation) <XRD measurement> X-ray diffraction (XRD) measurements were performed on the COF-CNT and MOF-CNT prepared in Example 2 and Example 12. The measurement results are shown in FIGS. 4 and 5, respectively.

[0157] The XRD measurement was carried out as follows. Using an XRD measurement apparatus (Ultima IV manufactured by Rigaku), the measurement was performed within a measurement range of 3° to 40°, a step width of 0.02°, and a scan speed of 4° / min.

[0158] FIG. 4 is a graph showing the XRD spectrum of the porous composite AQ-COF_CNT prepared in Example 2. Peaks 100 and 110 on the left side of the graph are respectively attributed to the (100) plane and (110) plane of DAAQ-TFP-COF. The broad peak 310 on the right side is attributed to CNT. The peaks 100 and 110 of COF are at approximately the same positions as the peaks in the spectrum of the pure DAAQ-TFP-COF not complexed with CNT, indicating that the structure of the COF does not change even when complexed with CNT.

[0159] FIG. 5 is a graph showing the XRD spectra of the porous composite AQ-MOF_CNT prepared in Example 12, its raw material AQ-MOF, and CNT. The curve 300 (solid line) shown at the top represents the XRD spectrum of the porous composite AQ-MOF_CNT. The curve 302 (dashed line) shown in the middle represents the XRD spectrum of AQ-MOF as a single MOF. The curve 301 (dotted line) shown at the bottom represents the XRD spectrum of single CNT. Since the peak positions in the curve 300 representing the porous composite AQ-MOF_CNT coincide with the sum of the peak positions in the curve 302 representing the single AQ-MOF and the curve 301 representing the single CNT, it can be seen that the structure of the MOF does not change even when complexed with CNT.

[0160] <Thermogravimetric analysis> Thermogravimetric analysis was performed on AQ-COF_CNT and AQ-MOF_CNT. A TG measuring device (TG / DTA6300, EXSTAR6000 manufactured by Seiko Instruments) was used. For the TG measurement conditions, a sample of about 3 mg to 5 mg was filled into a high-temperature alumina open pan, and while flowing G2 grade argon gas at 100 ccm, the temperature was measured from 30 °C to 700 °C at a heating rate of 10 °C / min.

[0161] Figures 6 and 7 respectively show graphs representing the thermogravimetric analysis results for AQ-COF_CNT (the porous composite of Example 2) and AQ-MOF_CNT (the porous composite of Example 12). Since a weight loss can be confirmed at 300 °C or higher in each figure, it can be seen that COF and MOF are present.

[0162] <STEM analysis> For the AQ-COF_CNT and AQ-MOF_CNT prepared in Example 2 and Example 12, observations were made using a scanning transmission electron microscope (STEM). An atomic resolution analytical electron microscope (ARM200F manufactured by JEOL Ltd.) was used for the STEM. The sample was prepared by scooping the sample onto a microgrid by a wet dispersion method using ethanol. The acceleration voltage was set to 200 kV.

[0163] The obtained STEM images are shown in Figures 8 and 9. From each figure, since there are deposits on the CNT surface that are clearly different from CNTs, it can be seen that COF or MOF is present on the CNT surface. Specifically, in the AQ-MOF_CNT (the porous composite of Example 12) 30 whose STEM image is shown in Figure 8, it is clearly seen that MOF 30b is present on the surface of CNT 30a. Similarly, in the AQ-COF_CNT (the porous composite of Example 2) 31 whose STEM image is shown in Figure 9, it is clearly seen that COF 31b is present on the surface of CNT 31a.

[0164] <Specific surface area measurement> The specific surface area was measured according to the procedure described above for each of the COF-CNT composites and MOF-CNT composites produced in Examples 1 to 16 and Comparative Examples 1 and 2. The measurement results are shown in Table 1 below.

[0165] <Electrochemical measurements> The electrochemical performance was evaluated for each of the devices fabricated in Examples 1 to 16 and Comparative Examples 1 and 2. Specifically, a test device was constructed using each of the fabricated devices, and cyclic voltammetry (CV) measurements were performed.

[0166] The test device was constructed as a three-electrode electrochemical cell. Fig. 10 shows a cross-sectional view of the test device. The test device 10 had a working electrode 14 made of each of the devices prepared in Examples 1 to 16 and Comparative Examples 1 and 2, a carbon electrode as the counter electrode 15, and an Ag / Ag reference electrode 16. + An electrode (acetonitrile / 0.1M (M: mol / l) TBAP solution / 0.01M AgNO3) was used (TBAP: tetrabutylammonium perchlorate). As the electrolyte 12, a 0.1M TBAP solution in acetonitrile was used.

[0167] Before the measurement, argon (Ar) gas was passed through the nozzle 13 into the electrolyte 12 in the glass cell 11 for about 30 minutes, and CV measurement was performed using the potentiostat 19. Next, 100% carbon dioxide gas was passed through the nozzle 13 for about 30 minutes, and CV measurement was performed again. The measured values ​​were measured based on the immersion area of ​​the device (approximately 2 cm2). 2 ) was measured and calculated per amount (g) of composite (COF-CNT or MOF-CNT) present in the immersed area.

[0168] As a specific example, the CV measurement results of the COF-CNT (DAAQ-TFP-COF-CNT) of Example 2 are shown in Figure 11. Figure 11 is a graph showing the cyclic voltammetry curve of the porous composite prepared in Example 2. In this graph, the curve from the first CV measurement under an Ar atmosphere is shown by a dashed line 21, and the curve from the second CV measurement under a CO2 atmosphere is shown by a solid line 20. As the graph shows, the CV measurement of -1.6 V (vs. Ag / Ag+ ) and -0.7V (vs. Ag / Ag + ) an increase in the current value was confirmed in the CO2 atmosphere compared to the inert gas (Ar) atmosphere. + ) is the reduction potential where the CO2 adsorption reaction occurs, -0.7V (vs. Ag / Ag + ) is the oxidation potential at which the CO2 desorption reaction occurs, so the amount of CO2 that contributed to the electrochemical reaction (EC reaction) was calculated from the area obtained by drawing a tangent line connecting the positions of the minimum and maximum values ​​before and after these potentials.

[0169] Table 1 below summarizes the porous composite or porous material in each device, the ionic liquid added as an electrolyte to be impregnated into the device, the specific surface area of ​​each porous composite measured as described above, and the amount of CO2 calculated from the CV measurement results for the devices fabricated in Examples 1 to 16 and Comparative Examples 1 and 2. Note that for Examples 1 to 16, COFs and MOFs were used as porous bodies. First conductive member In contrast, in Comparative Examples 1 and 2, COF and MOF were synthesized without CNT. The second conductive material is Ketjenblack without being composited with other first conductive materials. Just mixed with a first conductive member; Because it is not a composite, it can be said to be a synthesis of a "porous material" rather than a porous composite.

[0170] [Table 1]

[0171] Comparisons between Example 2 and Comparative Example 1, and between Example 12 and Comparative Example 2, show that the conductivity of COFs and MOFs can be increased by combining them with CNTs, thereby increasing the amount of CO2 adsorption.

[0172] A comparison of Examples 1 to 11 with Examples 12 to 16 reveals that COFs, which have higher conductivity than MOFs, adsorb a larger amount of CO. Furthermore, a comparison of Example 2 with Example 11, and a comparison of Example 12 with Example 13 reveals that for both COFs and MOFs, the conductivity is further improved and the amount of CO increases when the COF / MOF retains an electrolyte such as an ionic liquid.

[0173] As mentioned above, the theoretical maximum CO2 adsorption capacity varies depending on the three-dimensional structure of the MOF or COF and the number of redox active sites.

[0174] According to one or more of the above-described embodiments and examples, a carbon dioxide absorption and release device is provided. 1st The device includes an electrode having a porous composite including a conductive member and a porous body thereon. The porous composite has pores of angstrom size or nanometer size, and the pores contain molecular moieties that exhibit redox activity in response to electricity. Such a device can efficiently absorb and release carbon dioxide with low energy consumption, and can perform efficient carbon dioxide gas separation.

[0175] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. The inventions described in the original claims of this application are set forth below. [1] A conductive member; a porous body on the conductive member, the porous body having pores of angstrom size or nanometer size and including a molecular moiety that exhibits redox activity in response to electricity; A carbon dioxide absorption / release device comprising an electrode having a porous composite comprising: [2] The carbon dioxide absorption / release device according to [1], wherein the porous body is capable of adsorbing carbon dioxide in a reduced state and releasing carbon dioxide in an oxidized state. [3] The carbon dioxide absorption / release device according to [1] or [2], wherein the molecular moiety includes one or more selected from the group consisting of quinones, imines, and imides. [4] The carbon dioxide absorption and release device according to [1] or [2], wherein the molecular moiety includes one or more selected from the group consisting of benzoquinone, anthraquinone, phenanthrenequinone, phenanthroline, pyridine, phenazine, pyrimidine, methyl viologen, benzodipyrrole, phthalimide, phthaldiimide, naphthaleneimide, naphthalenediimide, and derivatives thereof. [5] The carbon dioxide absorption / release device according to any one of [1] to [4], wherein the porous body contains an electrically responsive covalent organic framework. [6] The carbon dioxide absorption / release device according to [5], wherein the covalent organic framework contains one or more bonds selected from the group consisting of imine bonds, hydrazine bonds, azine bonds, imide bonds, phenazine bonds, triazine bonds, and enamine bonds. [7] The carbon dioxide absorption / release device according to [6], wherein the porous body includes a layered structure formed by π-π stacking of the covalent organic framework. [8] The carbon dioxide absorption / release device according to any one of [1] to [4], wherein the porous body includes a metal organic framework having electrical responsiveness. [9] The carbon dioxide absorption / release device according to [8], wherein the metal organic framework contains one or more central metals selected from the group consisting of zirconium, copper, and manganese.

[10] The carbon dioxide absorption / release device according to [9], wherein the metal organic framework has a UiO structure, a Cu(2,7-anthraquinonedicarboxylic acid) structure, or a Mn(2,7-anthraquinonedicarboxylic acid) structure.

[11] The carbon dioxide absorption / release device according to any one of [1] to

[10] , wherein the conductive member has one or more shapes selected from the group consisting of a rod, a tube, a fiber, a sheet, and a flake.

[12] The carbon dioxide absorption / release device according to any one of [1] to

[11] , wherein the conductive member includes one or more selected from the group consisting of carbon nanotubes, graphite, graphene, carbon nanofibers, ketjen black, polyaniline, polythiophene, and poly(3,4-ethylenedioxythiophene) polystyrene sulfonic acid.

[13] The carbon dioxide absorption / release device according to any one of [1] to

[12] , wherein the porous body modifies at least a part of the surface of the conductive member.

[14] The carbon dioxide absorption / release device according to any one of [1] to

[13] , wherein the conductive member includes a conductive material having a length of less than 1 μm and a conductive material having a length of 1 μm or more.

[15] The carbon dioxide absorption / release device according to any one of [1] to

[14] , further comprising a non-conductive polymer.

[16] The carbon dioxide absorption / release device according to any one of [1] to

[15] , further comprising an electrolyte held in the porous composite.

[17] The carbon dioxide absorption / release device according to

[16] , wherein the electrolyte comprises one or more selected from the group consisting of ion-bonding salts and ion-conducting polymers.

[18] The carbon dioxide absorption / release device according to

[17] , wherein the electrolyte contains the ionically binding salt, and the ionically binding salt contains one or more selected from the group consisting of alkali metal salts, alkaline earth metal salts, transition metal salts, amphoteric metal salts, ammonium salts, imidazolium salts, pyridinium salts, and phosphonium salts.

[19] The carbon dioxide absorption / release device according to

[17] or

[18] , wherein the electrolyte contains the ion-conductive polymer, and the ion-conductive polymer contains one or more selected from the group consisting of polyethylene oxide, polypropyl oxide, polyacrylonitrile, polyvinyl chloride, and ionic liquid polymers.

[20] The carbon dioxide absorption / release device according to any one of [1] to

[19] , wherein the electrode is provided with the porous composite and further comprises a current collector containing one or more selected from the group consisting of glassy carbon, graphite sheet, carbon felt, carbon cloth, carbon mesh, carbon paper, a carbon sheet with a gas diffusion layer, a copper plate, a copper sheet, a copper mesh, an aluminum plate, an aluminum sheet, an aluminum mesh, a nickel plate, a nickel sheet, and a nickel mesh. [Explanation of symbols]

[0176] 1... carbon dioxide absorption / release device, 2... current collector, 3... porous composite, 3a... 1st Conductive member, 3b...porous body, 3c...porous body surface, 4...electrode, 5...pore, 5a...pore surface, 6a...first molecular portion, 6b...second molecular portion, 10...test device, 11...glass cell, 12...electrolyte, 13...nozzle, 14...working electrode, 15...counter electrode, 16...reference electrode, 19...potentiostat.

Claims

1. A first conductive member having one or more shapes selected from the group consisting of a rod shape, a tube shape, a fiber shape, a sheet shape, and a flake shape; a porous body disposed on the first conductive member, having pores of angstrom size or nanometer size, and including a molecular moiety that exhibits redox activity in response to electricity; a porous composite comprising: a second conductive member external to the porous composite; A structural reinforcing member comprising one or more of a fibrous carbon material, a conductive inorganic-organic hybrid material, a conductive polymer, a non-conductive polymer, and an ion-conductive polymer; A carbon dioxide absorption / release device comprising a composite electrode comprising:

2. A first conductive member having one or more shapes selected from the group consisting of a rod shape, a tube shape, a fiber shape, a sheet shape, and a flake shape; a porous body disposed on the first conductive member, having pores of angstrom size or nanometer size, and including a molecular moiety that exhibits redox activity in response to electricity; a porous composite comprising: a second conductive member outside the porous composite; a current collector having a flat plate shape and the porous composite provided on its main surface, or a current collector having a mesh shape and the porous composite embedded therein; A carbon dioxide absorption and release device comprising an electrode comprising:

3. 3. The carbon dioxide absorption and release device according to claim 1, wherein the porous body is capable of adsorbing carbon dioxide in a reduced state and releasing carbon dioxide in an oxidized state.

4. The carbon dioxide absorption and release device according to claim 1 , wherein the molecular moiety includes one or more selected from the group consisting of quinones, imines, and imides.

5. 4. The carbon dioxide absorption and release device according to claim 1, wherein the molecular moiety comprises one or more selected from the group consisting of benzoquinone, anthraquinone, phenanthrenequinone, phenanthroline, pyridine, phenazine, pyrimidine, methyl viologen, benzodipyrrole, phthalimide, phthaldiimide, naphthaleneimide, naphthalenediimide, and derivatives thereof.

6. The carbon dioxide absorption and release device according to claim 1 , wherein the porous body contains an electrically responsive covalent organic framework.

7. 7. The carbon dioxide absorption and release device according to claim 6, wherein the covalent organic framework comprises one or more selected from the group consisting of an imine bond, a hydrazine bond, an azine bond, an imide bond, a phenazine bond, a triazine bond, and an enamine bond.

8. The carbon dioxide absorption and release device according to claim 7 , wherein the porous body includes a layered structure formed by π-π stacking of the covalent organic framework.

9. The carbon dioxide absorption and release device according to claim 1 , wherein the porous body contains an electrically responsive metal organic framework.

10. 10. The carbon dioxide absorption and release device of claim 9, wherein the metal organic framework comprises one or more central metals selected from the group consisting of zirconium, copper, and manganese.

11. 11. The carbon dioxide absorption and release device according to claim 10, wherein the metal organic framework has a UiO structure, a Cu(2,7-anthraquinonedicarboxylic acid) structure, or a Mn(2,7-anthraquinonedicarboxylic acid) structure.

12. 12. The carbon dioxide absorption and release device according to claim 1, wherein the second conductive member comprises one or more selected from the group consisting of carbon nanotubes, graphite, graphene, carbon nanofibers, Ketjen black, polyaniline, polythiophene, and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate.

13. The carbon dioxide absorption / release device according to claim 1 , wherein the porous body modifies at least a part of the surface of the first conductive member.

14. The carbon dioxide absorption and release device according to claim 1 , wherein the second conductive member includes a conductive material having a length of less than 1 μm and a conductive material having a length of 1 μm or more.

15. The carbon dioxide absorption and release device according to claim 1 , further comprising a non-conductive polymer.

16. 16. The carbon dioxide absorption and release device according to claim 1, further comprising an electrolyte held in the porous composite.

17. 17. The carbon dioxide absorption and release device according to claim 16, wherein the electrolyte comprises one or more selected from the group consisting of an ion-bonding salt and an ion-conducting polymer.

18. 18. The carbon dioxide absorption and release device according to claim 17, wherein the electrolyte comprises the ionically binding salt, and the ionically binding salt comprises one or more selected from the group consisting of alkali metal salts, alkaline earth metal salts, transition metal salts, amphoteric metal salts, ammonium salts, imidazolium salts, pyridinium salts, and phosphonium salts.

19. 19. The carbon dioxide absorption and release device according to claim 17 or 18, wherein the electrolyte comprises the ion-conducting polymer, and the ion-conducting polymer comprises one or more selected from the group consisting of polyethylene oxide, polypropyl oxide, polyacrylonitrile, polyvinyl chloride, and an ionic liquid polymer.

20. A carbon dioxide absorption and release device as described in claim 2, wherein the current collector comprises one or more selected from the group consisting of glassy carbon, graphite sheet, carbon felt, carbon cloth, carbon mesh, carbon paper, carbon sheet with a gas diffusion layer, copper plate, copper sheet, copper mesh, aluminum plate, aluminum sheet, aluminum mesh, nickel plate, nickel sheet, and nickel mesh.

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