Electrolysis device and electrolysis method

Abstract

The disclosed electrolysis device yields a product by the electrolysis of a prescribed component in a gas. The electrolysis device comprises a cathode part where a product is generated, an anode part, and an ion-exchange membrane. The cathode part contains a cathode conductive member which exhibits conductivity in at least a part thereof, and a cathode catalyst-containing layer. The cathode catalyst-containing layer has a reaction region in which an electrolysis reaction of a prescribed component occurs. The cathode conductive member is in contact with the cathode catalyst-containing layer that is in the reaction region. A recess serving as a gas flow path is not formed in the surface of the cathode conductive member that is in contact with the reaction region.

Description

Electrolysis device and electrolysis method CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This disclosure claims the benefit of priority to Japanese Patent Application No. 2024-129990, filed on August 6, 2024, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to an electrolysis device and an electrolysis method.

[0003] Various electrolysis devices have been proposed in the past. In recent years, a device that produces formic acid from carbon dioxide by electrolysis has been proposed.

[0004] Claim 1 of Patent Document 1 (JP 2023-133966 A) describes "a carbon dioxide reduction device comprising: an anode section including an anode that oxidizes water to produce oxygen and an anode solution flow path that supplies an anode solution to the anode; a cathode section including a cathode that reduces carbon dioxide to produce formic acid and a gas flow path that supplies carbon dioxide gas to the cathode; and a cation exchange membrane sandwiched between the anode section and the cathode section, wherein the cathode comprises, in order from the cation exchange membrane side, a catalyst layer containing a metal complex as a cathode catalyst and a gas diffusion layer; and wherein an alkaline solution is supplied as the anode solution."

[0005] Japanese Patent Application Laid-Open No. 2023-133966

[0006] At the cathode of an electrolyzer, a product is produced by a reduction reaction. When utilizing this product, it is important to efficiently extract the product from the electrolyzer. One of the objectives of the present disclosure is to provide an electrolyzer (and an electrolysis method) that allows for efficient extraction of the product produced at the cathode.

[0007] One aspect of the present disclosure relates to an electrolysis device that obtains a product by electrolyzing a predetermined component in a gas, the electrolysis device comprising: a cathode section in which the product is generated; an anode section; and an ion exchange membrane disposed between the cathode section and the anode section; the cathode section comprises a cathode conductor member having at least a portion thereof being electrically conductive; and a cathode catalyst-containing layer disposed between the ion exchange membrane and the cathode conductor member; the cathode catalyst-containing layer has a reaction region in which an electrolysis reaction of the predetermined component occurs; the cathode conductor member is in contact with the cathode catalyst-containing layer in the reaction region; and no recesses that serve as a flow path for the gas are formed on the surface of the cathode conductor that is in contact with the reaction region.

[0008] Another aspect of the present disclosure relates to an electrolysis method for obtaining a product by electrolyzing a predetermined component in a gas using an electrolysis device, wherein the electrolysis device includes: a cathode section in which the product is generated; an anode section; and an ion exchange membrane disposed between the cathode section and the anode section; the cathode section includes a cathode conductive member having at least a portion thereof electrically conductive, and a cathode catalyst-containing layer disposed between the ion exchange membrane and the cathode conductive member; and the product generated in the cathode catalyst-containing layer is discharged in a gaseous state from the cathode catalyst-containing layer.

[0009] The present disclosure provides an electrolysis apparatus (and an electrolysis method) that allows for efficient extraction of products produced on the cathode side. The novel features of the invention are set forth in the appended claims, but the invention, both in terms of structure and content, together with other objects and features of the invention, will be better understood from the following detailed description taken in conjunction with the drawings.

[0010] FIG. 1 is a side view schematically illustrating an example of an electrolyzer according to the present disclosure. FIG. 2A is a cross-sectional view taken along line IIA-IIA in FIG. 1. FIG. 2B is a cross-sectional view taken along line IIB-IIB in FIG. 1. FIG. 3A is a schematic view of a portion of an example of an electrolyzer according to the present disclosure. FIG. 3B is a schematic view of another portion of an example of an electrolyzer according to the present disclosure. FIG. 4A is a schematic view of a portion of another example of an electrolyzer according to the present disclosure. FIG. 4B is a schematic view of a portion of another example of an electrolyzer according to the present disclosure. FIG. 4C is a schematic view of a portion of another example of an electrolyzer according to the present disclosure. FIG. 4D is a schematic view of a portion of another example of an electrolyzer according to the present disclosure. FIG. 5 is a schematic view of the configuration of another example of an electrolyzer according to the present disclosure. FIG. 6 is a schematic view of a portion of an example of an electrolyzer according to the present disclosure. FIG. 7 is a schematic view of a portion of another example of an electrolyzer according to the present disclosure.

[0011] The following describes embodiments of the present disclosure using examples, but the present disclosure is not limited to the examples described below. In the following description, specific numerical values ​​and materials may be exemplified, but other numerical values ​​and materials may be applied as long as the effects of the present disclosure are obtained. In this specification, the term "numerical value A to numerical value B" includes numerical value A and numerical value B and can be read as "numerical value A or greater and numerical value B or less." In the following description, when lower and upper limits for specific physical properties or conditions are exemplified, any of the exemplified lower limits and any of the exemplified upper limits can be arbitrarily combined, as long as the lower limit is not greater than the upper limit. In the following description, when examples of components or methods are listed, only one of the listed examples may be used, or multiple of the listed examples may be used in combination, unless otherwise specified.

[0012] (Electrolysis device) Hereinafter, the electrolysis device according to this embodiment may be referred to as the "electrolysis device (E)." The electrolysis device (E) is an electrolysis device that obtains products by electrolyzing predetermined components in a gas. The electrolysis device (E) includes a cathode section where products are generated, an anode section, and an ion exchange membrane disposed between the cathode section and the anode section. The cathode section includes a cathode conductive member, at least a portion of which is electrically conductive, and a cathode catalyst-containing layer disposed between the ion exchange membrane and the cathode conductive member. The cathode conductive member is in contact with the cathode catalyst-containing layer in the reaction region. The surface of the cathode conductive member that contacts the reaction region does not have a recess formed thereon to serve as a gas flow path.

[0013] In conventional electrolyzers (e.g., the electrolyzer described in Patent Document 1), grooves serving as gas flow paths are formed in the cathode current collector plate adjacent to the gas diffusion layer. After investigation, the present inventors discovered that conventional electrolyzers sometimes fail to efficiently extract products from the cathode. In conventional electrolyzers, grooves are formed in the cathode current collector plate, causing the pressure applied to the cathode components (catalyst layer, gas diffusion layer) to differ between the grooved and non-grooved areas. This results in gas flow easiness varying depending on the position within the cathode component. As a result, products accumulate in areas where gas flow is difficult. Depending on conditions such as the vapor pressure of the product, the cathode temperature, and the gas pressure, the product accumulated in areas where gas flow is difficult may liquefy. Furthermore, as the gas flow path in the cathode component becomes longer, the product concentration increases downstream of the gas flow path in the cathode component, making the product more likely to liquefy near the end of the cathode component. The liquefied product is difficult to extract from the cathode. In other words, it becomes difficult to efficiently extract the product produced on the cathode side. The flow paths formed on the cathode current collector of conventional electrolyzers are usually designed to have a tortuosity of 2.0 or more. The tortuosity T is calculated by the following formula (1): T=f / s (1)

[0014] In equation (1), f is the path passing through the gap between the gas inlet and the gas outlet. In conventional electrolyzers, f is the total length of the flow path formed in the cathode current collector plate. s is the distance between the gas inlet and the gas outlet. When there are multiple combinations of gas inlet and gas outlet parts and their corresponding flow paths, the tortuosity is calculated by arithmetically averaging the tortuosity T of the paths for each combination.

[0015] As a result of further investigation, the inventors of the present application found that the configuration of the electrolyzer (E) makes it possible to efficiently extract the product generated on the cathode side. The present disclosure is based on this new finding. Hereinafter, the product generated on the cathode side may be referred to as "product (P)."

[0016] The gas (raw material gas) introduced into the cathode section contains a predetermined component (element or compound). The gas may consist of only the predetermined component, or may be a mixture of the predetermined component and another gas. The concentration of the predetermined component in the gas may be 0.01% by volume or more, or 1.00% by volume or more, or may be 100% by volume or less, or 20.0% by volume or less. As long as the product (P) can be produced, the components other than the predetermined component are not particularly limited. The other components may be mainly air (nitrogen gas, oxygen gas, water vapor gas). The other components may include carbon monoxide gas, etc.

[0017] Examples of the gas (raw material gas) include exhaust gas, gas obtained by extracting a predetermined component from exhaust gas, and other gases. When the predetermined component is carbon dioxide, the gas may be exhaust gas. For example, the gas may be exhaust gas from an incinerator or exhaust gas emitted from a factory. When the predetermined component is carbon dioxide, the concentration of carbon dioxide in the gas may be 1.00% by volume or more.

[0018] The surface of the cathode conductive member in the region in contact with the reaction region is flat and does not have any recesses through which gas can flow. However, minute recesses that do not substantially function as gas flow paths may be formed on the surface of the cathode conductive member. The depth of such recesses is 200 μm or less (e.g., 100 μm or less, 50 μm or less, or 10 μm or less).

[0019] The cathode catalyst-containing layer has a gas inlet (gas inlet region, gas inlet surface) and a gas outlet (gas outlet region, gas outlet surface). Gas is introduced into the cathode catalyst-containing layer at the gas inlet. Gas is discharged from the cathode catalyst-containing layer at the gas outlet.

[0020] The direction connecting the gas inlet and gas outlet is defined as the first direction D1. The direction perpendicular to the first direction D1 and parallel to the reaction region is defined as the second direction D2. The maximum length of the reaction region in the second direction D2 is defined as Lr. The length Lin of the gas inlet in the second direction D2 may be 0.8Lr or more, and the length Lout of the gas outlet in the second direction D2 may be 0.8Lr or more. This configuration expands the gas passage area within the cathode catalyst-containing layer, and the product concentration in the gas outlet is kept low. As a result, the gas is less likely to liquefy, making it easier to extract the product (P).

[0021] Lin may be 0.5 Lr or more, or 0.8 Lr or more, and may be 1.0 Lr or less. Lout may be 0.5 Lr or more, or 0.8 Lr or more, and may be 1.0 Lr or less.

[0022] The maximum length Lr1 of the reaction region in the first direction may be 0.1 Lr or more, or 0.5 Lr or more, or 1.0 Lr or more. The maximum length Lr1 of the reaction region in the first direction may be 1.0 Lr or less, 0.8 Lr or less, or 0.5 Lr or less. By setting the length Lr1 to 0.8 Lr or less, it is easy to maintain the partial pressure of the product (P) at a partial pressure equal to or less than the saturated vapor pressure, and it is easy to prevent condensation of the product (P).

[0023] The tortuosity of the gas flow path in the cathode section may be 1.5 or less, or 1.1 or less. Within these ranges, the partial pressure of the product (P) contained in the gas after passing through the reaction region can be easily maintained at a partial pressure equal to or less than the saturated vapor pressure, and condensation of the product (P) can be easily prevented.

[0024] The planar shape of the reaction region is not particularly limited. The planar shape of the reaction region is the shape in the direction perpendicular to the thickness direction of the cathode catalyst-containing layer. The planar shape of the reaction region may be rectangular, trapezoidal, circular, or any other shape.

[0025] The planar shape of the reaction region may be a rectangle having a first side and a second side opposite the first side. In one example, the gas inlet may be arranged along the first side, and the gas outlet may be arranged along the second side. In another example, the gas inlet may be arranged parallel to the first side, and the gas outlet may be arranged parallel to the second side. According to these examples, the gas flows in one direction from the first side to the second side, thereby particularly suppressing the accumulation of the product (P). In these examples, the gas inlet and the gas outlet may have a strip-like shape. For example, the gas inlet may have a strip-like shape arranged along the first side (or parallel to the first side), and the gas outlet may have a strip-like shape arranged along the second side (or parallel to the second side).

[0026] The planar shape of the reaction region may be a trapezoid having a first side and a second side parallel to the first side. In this case, the gas inlet may be located along the first side, and the gas outlet may be located along the second side. The first side may be longer or shorter than the second side.

[0027] The gas inlet and gas outlet may be disposed between the ion exchange membrane and the cathode conductive member. For example, the gas inlet may be on a side surface of the cathode catalyst-containing layer. In other words, the side surface of the cathode catalyst-containing layer may function as the gas inlet. This configuration allows the flow of gas to be regulated so that most of the introduced gas passes through the reaction region. As a result, the product (P) can be effectively discharged using the introduced gas, and retention of the product (P) can be suppressed.

[0028] The cathode catalyst-containing layer may include a cathode catalyst layer and a gas diffusion layer disposed between the cathode catalyst layer and the cathode conductive member. When gas diffusibility in the cathode catalyst layer is insufficient, the gas diffusion layer can be used to promote the electrolysis reaction.

[0029] The gas diffusion layer may be a porous sheet containing carbon fibers. Carbon materials are characterized by low polarity. Therefore, porous sheets containing carbon fibers have little interaction with the product (P) and are less likely to adsorb the product (P). Therefore, by using a porous sheet containing carbon fibers, retention of the product (P) can be suppressed. Furthermore, porous sheets containing carbon fibers are hydrophobic, which is preferable in that trace amounts of water that have permeated the ion exchange membrane are less likely to remain in the gas diffusion layer. Alternatively, the gas diffusion layer may be another porous sheet. Examples of gas diffusion layers will be described later.

[0030] When the gas diffusion property in the cathode catalyst layer is high, the cathode catalyst-containing layer does not need to include a gas diffusion layer, and in that case, the cathode catalyst-containing layer may be composed of only the cathode catalyst layer.

[0031] The anode section may include an anode catalyst layer. In this case, a liquid to be electrolyzed by the anode catalyst layer may be supplied to the anode catalyst layer. In the electrolyzer (E) having this configuration, a gas is supplied to the cathode catalyst layer, and a liquid is supplied to the anode catalyst layer. The liquid may be an acidic aqueous solution. The liquid may be an aqueous solution that does not substantially contain cations other than protons. Some of the ions contained in the liquid permeate the ion exchange membrane. When the only cations contained in the liquid are protons, the only cationic species that migrate to the cathode section are protons. The protons that migrate to the cathode section are converted into anions (e.g., HCOO) generated in the cathode section. － ) to generate a product (P) (e.g., formic acid). The generated product (P) is diluted with gas and discharged from the reaction region. "Substantially free of cations other than protons" means that cations other than protons are not intentionally added. The concentration of cations other than protons in the aqueous solution may be 0.01 mol / L or less, or 0.001 mol / L or less. The cations contained in the liquid (cations other than protons) may be metal cations, organic cations, or complex cations. In the case of metal cations, they may be cations of alkali metals or alkaline earth metals. In order to suppress permeation through the proton exchange membrane, the cations contained in the liquid (cations other than protons) may be cations with a large ionic radius.

[0032] The ion exchange membrane may be a cation exchange membrane or a proton exchange membrane.

[0033] The electrolyzer (E) may further include a condenser arranged in the gas flow path downstream of the gas outlet. In this case, at least a portion of the product (P) may be recovered by the condenser. The condenser is not particularly limited, and a known condenser may be used. For example, a condenser including a trap portion and a cooler that cools the trap portion with a refrigerant may be used. The product (P) in the gas is liquefied by cooling and recovered.

[0034] The saturated vapor pressure of the product (P) at 20°C may be 3 kPa or more. Such a product (P) can be easily extracted from the cathode catalyst-containing layer using a gas flow. The saturated vapor pressure of the product (P) at 20°C may be 8 kPa or less. In this case, the product (P) easily becomes liquid, so the effect of the electrolyzer (E) is particularly enhanced. The saturated vapor pressure of the product (P) at 20°C may be 3 kPa or more and 8 kPa or less.

[0035] The predetermined component may be carbon dioxide. That is, carbon dioxide may be electrolyzed (reduced) at the anode. By electrolyzing (reducing) carbon dioxide at the anode, formic acid can be produced. The saturated vapor pressure of formic acid at 20°C is 4.6 kPa.

[0036] The predetermined component may be a substance other than carbon dioxide. For example, the predetermined component may be N ２ or nitrogen oxides (NO, NO ２ In one example of the electrolysis device (E), the predetermined component may be N ２ and the product (P) is NH ３ is.

[0037] Examples of components of the electrolyzer (E) are described below. However, the components of the electrolyzer (E) are not limited to the following examples. If known components of electrolyzers can be used, they may be used. The following mainly describes the case where the predetermined component is carbon dioxide, but if the predetermined component is a substance other than carbon dioxide, a catalyst or the like will be selected accordingly.

[0038] The electrolyzer (E) includes a cathode section, an anode section, and an ion exchange membrane. The cathode section, the anode section, and the ion exchange membrane function as an electrolysis section.

[0039] By applying a DC voltage between the cathode part (e.g., a cathode catalyst-containing layer) and the anode part (e.g., an anode catalyst layer), a predetermined component can be electrolyzed (reduced) to generate a product (P). The magnitude of the DC voltage to be applied is selected depending on the type of catalyst, the type of the predetermined component, the type of product (P), the type of substance to be electrolyzed (oxidized) in the anode part, and the like.

[0040] (Cathode section) As described above, the cathode section includes a cathode conductive member and a cathode catalyst-containing layer. The cathode catalyst-containing layer includes a cathode catalyst layer. The cathode catalyst-containing layer may include a cathode catalyst layer and a gas diffusion layer. In this case, the components of the ion exchange membrane and the cathode member are arranged in the following order: ion exchange membrane / cathode catalyst layer / gas diffusion layer / cathode conductive member.

[0041] At least a portion of the cathode conductor is conductive. The cathode conductor is a member for passing current through the cathode catalyst layer. A conductive plate may be used as the cathode conductor. For example, a metal plate or a graphite plate may be used as the cathode conductor. The cathode conductor may be a laminate composed of multiple layers. The surface of the cathode conductor may be plated. By using a conductive plate, it is possible to pass current evenly over the entire reaction region. When passing current through the entire cathode catalyst-containing layer via a portion of the cathode catalyst-containing layer, only the portion of the cathode conductor that contacts the portion may be conductive.

[0042] The cathode catalyst layer contains a catalyst for electrolyzing (reducing) a predetermined component. The catalyst is selected depending on the predetermined component. When the predetermined component is carbon dioxide, a catalyst that reduces carbon dioxide to produce formic acid may be used. Known catalysts may be used as the catalyst. Examples of the catalyst include organometallic complexes, metal elements, and metal compounds.

[0043] The organometallic complex may have a central metal (Pd, Cd, In, Sn, Hg, Ti, Pb, Bi, etc.) and a ligand containing a coordinating atom (N, S, P, O, C, Si, etc.) coordinated to the central metal. The complex may be a tetracoordinated complex or a hexacoordinated complex. The complex may include a phthalocyanine structure coordinated to the central metal or a porphyrin structure coordinated to the central metal. Examples of metal elements include Pd, Cd, In, Sn, Hg, Ti, Pb, Bi, etc. Examples of metal compounds include compounds of specific elements (oxides, sulfides, nitrides, phosphides, carbonates, nitrates, sulfates, fluorides, etc.). Examples of specific elements include Pd, Cd, In, Sn, Hg, Ti, Pb, Bi, etc. The catalyst may be a calcined product of an organometallic complex, a calcined product of a metal element, or a calcined product of a metal compound. The catalyst may be a composite material of carbon and another substance (organometallic complex, elemental metal, or metal compound), in which case the metal may be in a monoatomic state.

[0044] The catalyst may be in the form of particles. The average particle size of the particulate catalyst is preferably 50 μm or less, and may be 1 μm or less. The average particle size may be 1 nm or more, or 10 nm or more. The average particle size is the volume-based median diameter (D50).

[0045] At least a part of the surface of the catalyst may be coated with an ionic resin. The ionic resin may be a cationic resin. The cationic resin is preferred in that it improves the faradaic efficiency of the product (P). － The ionic resin captures the cations, thereby maintaining the catalyst surface in an alkaline atmosphere. Examples of cationic resins include resins (e.g., polymers) that contain cationic groups and / or groups that can be ionized into cationic groups.

[0046] The cationic resin may contain at least one functional group selected from the group consisting of an aminoalkyl group, a cyclic amino group, an imidazolium group, a pyridinium group, and a phosphonium group. When the cationic resin contains these functional groups, the surface charge density of the catalyst surface can be further increased, further improving the faradaic efficiency. Furthermore, when the functional group of the cationic resin is covalently bonded to the catalyst, the functional group of the cationic resin and the catalyst are strongly bonded. As a result, the faradaic efficiency can be further improved.

[0047] Examples of cationic resins include Fumion (e.g., FAA-3-SOLUT-10) manufactured by Fumatech, Aemion+ (e.g., AP3-HNN9-00-X) manufactured by Ionomr Innovations, PiperION manufactured by Versogen, Sustainion (e.g., XA-9) manufactured by Dioxide Materials, poly(vinylimidazolium), and poly(diallyldimethylammonium). Anion exchange resins may also be used as the cationic resin.

[0048] The cathode catalyst layer may have a layer having a pH buffering effect on at least a portion of its surface. The layer having a pH buffering effect may be composed of one layer or multiple layers. The layer having a pH buffering effect may be a free-standing membrane. The layer having a pH buffering effect may be a porous body. When the layer having a pH buffering effect is a porous body, at least a portion of the layer may be an accumulation of particles having a pH buffering effect.

[0049] The layer having pH buffering properties may include an anion exchange membrane (anion exchange resin membrane). In this case, the catalyst surface can be maintained in an alkaline atmosphere, thereby improving the Faraday efficiency. The layer having pH buffering properties may be a laminate of an anion exchange resin layer and a cation exchange resin layer. In this case, the anion exchange resin layer may be a free-standing membrane. When the layer having pH buffering properties is porous, the porosity may be in the range of 10 to 90% (e.g., in the range of 30 to 70%). In this case, the product (P) can be easily discharged from the layer having pH buffering properties.

[0050] The cathode catalyst layer may include a support and a catalyst supported on the support. The support may be a support used in known cathode catalyst layers. For example, the support may be a conductive porous material such as carbon paper. The thickness of the cathode catalyst layer may be in the range of 10 μm to 150 μm (e.g., in the range of 20 μm to 100 μm).

[0051] The gas diffusion layer may be a porous layer. The gas diffusion layer is usually electrically conductive. In this case, a current can be supplied to the cathode catalyst layer via the gas diffusion layer. In the case where the gas diffusion layer is not electrically conductive, a current is supplied to the cathode catalyst layer without passing through the gas diffusion layer.

[0052] The gas diffusion layer may be a conductive porous sheet. For example, the gas diffusion layer may be made of a porous metal or carbon paper. Carbon paper is a porous sheet made of carbon fiber. Carbon paper is conductive. Carbon paper diffuses gas. The gas diffusion layer may be made of carbon paper with a water-repellent layer formed on one or both sides. The water-repellent layer may be a layer made of a fluorine-based resin (e.g., polytetrafluoroethylene). The water-repellent layer may be disposed adjacent to the cathode catalyst layer. Using a gas diffusion layer including a water-repellent layer can prevent water from penetrating from the ion exchange membrane into the gas diffusion layer. Note that using a thin water-repellent layer makes it possible to pass a current through the cathode catalyst layer via the gas diffusion layer.

[0053] The thickness of the gas diffusion layer may be in the range of 50 μm to 1500 μm (e.g., in the range of 100 μm to 150 μm). The thickness of the gas diffusion layer may be in the range of 1 to 100 times (e.g., in the range of 5 to 50 times) the thickness of the cathode catalyst layer. The thickness of the cathode catalyst-containing layer without the gas diffusion layer may be in the range of 50 μm to 2000 μm (e.g., in the range of 100 μm to 500 μm). In this case, the cathode catalyst-containing layer may contain a known carrier.

[0054] (Anode section) The anode section may include an anode catalyst layer. The anode catalyst layer includes a catalyst that electrolyzes (oxidizes) a substance supplied to the anode catalyst layer. The catalyst is selected depending on the substance to be electrolyzed (oxidized) in the anode catalyst layer. The substance to be electrolyzed in the anode catalyst layer may be a liquid or a gas. The liquid supplied to the anode catalyst layer may or may not be flowing. Examples of gases to be electrolyzed in the anode catalyst layer include hydrogen gas.

[0055] When the predetermined component is carbon dioxide, an aqueous solution may be supplied to the anode catalyst layer. In this case, the anode catalyst layer may be a layer containing a catalyst capable of electrolyzing (oxidizing) water. Examples of such catalysts include Ru, Ni, Fe, Co, Mn, and Ir, alloys containing these elements, and oxides of these elements. Ruthenium oxide may also be used as the catalyst. The anode catalyst layer may include a conductive support and a catalyst supported on the conductive support.

[0056] The aqueous solution supplied to the anode catalyst layer may be acidic or alkaline. The acidic aqueous solution may be an aqueous solution of an inorganic acid or an organic acid. Examples of inorganic acids include sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid. Examples of organic acids include acetic acid and oxalic acid. The pH of the acidic aqueous solution may be 4.0 or less, or 3.0 or less, or may be −1.0 or more, or 1.0 or more.

[0057] The anode section may include a plate-shaped member for forming a space adjacent to the anode catalyst layer. The plate-shaped member may have a recess formed therein for holding the liquid supplied to the anode catalyst layer. For example, the plate-shaped member may have a recess formed therein for allowing the liquid supplied to the anode catalyst layer to flow. Alternatively, the plate-shaped member and a spacer may form a space for allowing the liquid supplied to the anode catalyst layer to flow. The plate-shaped member may be conductive so that a current supplied to the anode catalyst layer can flow therethrough. For example, the plate-shaped member may be formed from a material described as the material for the cathode conductive member.

[0058] (Ion Exchange Membrane) The ion exchange membrane is a membrane that allows ions to pass through. Preferably, the ion exchange membrane is a membrane that is difficult for liquids to pass through. A known ion exchange membrane may be used as the ion exchange membrane. When the predetermined component is carbon dioxide, a cation exchange membrane (typically, a proton exchange membrane) may be used as the ion exchange membrane. By using a cation exchange membrane, it is possible to prevent anions generated in the cathode section from migrating to the anode section. The cation exchange membrane (proton exchange membrane) may be a fluororesin having cation exchange ability. Examples of cation exchange membranes (proton exchange membranes) include Nafion (registered trademark) and Flemion (registered trademark). The ion exchange membrane may also be a laminated membrane of multiple different layers. For example, a coating layer having a pH buffering effect may be formed on the surface of a normal ion exchange membrane.

[0059] (Others) The electrolyzer (E) may include components other than those described above, as necessary. For example, the electrolyzer (E) may include a DC power supply for applying a DC voltage to the cathode section and the anode section. The DC power supply may be an AC-DC converter that converts AC to DC. The electrolyzer (E) may include a pump or valve for controlling the movement of a gas supplied to the anode section. The electrolyzer (E) may include a pump or valve for controlling the movement of a substance supplied to the cathode section. The electrolyzer (E) may include a sensor and / or a control device for controlling electrolysis. The control device may include a storage device in which a program for controlling electrolysis is recorded, and a processing device for executing the program.

[0060] The current density, calculated by dividing the current by the area of ​​the cathode reaction region, was 50 mA / cm ２ or more (for example, 100 mA / cm ２ In this case, the faradaic efficiency of the product (P) is improved and the discharge of the product (P) from the reaction region is promoted.

[0061] By maintaining an alkaline atmosphere only in the vicinity of the catalyst layer, it is possible to improve the faradaic efficiency of the electrolysis of the raw material gas while suppressing the electrolysis of water, which is a side reaction. － ) reacts with cations (e.g., protons) to produce product (P), which can be diluted with gas and discharged from the reaction zone. Cations are supplied from the anode through an ion exchange membrane.

[0062] The electrolyzer (E) may include a plurality of electrolysis units connected in parallel. In this case, the electrolyzer (E) may include a gas pipe for distributing the raw material gas to each electrolysis unit and a gas pipe for circulating the gas discharged from each electrolysis unit. The number of electrolysis units included in the electrolyzer (E) can be selected depending on the flow rate of the raw material gas.

[0063] The electrolyzer (E) may include a separation device for separating the product (P). The separation device is disposed in the gas flow path downstream of the gas outlet. Examples of the separation device include a condenser, a distillation device, etc. The angle formed by a horizontal plane passing through the electrolysis unit and a line connecting the electrolysis unit and the separation device may be 45°C or less (e.g., 30°C or less). The angle formed by a vertical line passing through the electrolysis unit and a line connecting the electrolysis unit and the separation device may be 45°C or less (e.g., 30°C or less).

[0064] The device for separating the product (P) may be a device for separating the product (P) in a gaseous state. In one example of such a case, the product (P) in the gas discharged from the gas discharge section is extracted using an extracting material within the device. The product (P) is extracted by the extracting material and becomes a liquid. Other components in the gas are discharged in a gaseous state. The extracted product (P) is heated and isolated from the extracting material. In this method, the components including the product (P) are condensed to form a liquid, and the product (P) can be isolated by distilling the liquid. In this method, the proportion of the product (P) in the liquid is high, and the proportion of water in the liquid (water has a large specific heat and latent heat) can be very low. This reduces the heating energy required during distillation and the energy required to recover the product (P).

[0065] When the product (P) is formic acid, the extraction agent may be a known extraction agent such as N,N-dibutylformamide, N,N-dibutylacetamide, N,N-heptylformamide, N-butyl-N-ethylhexylformamide, N-butyl-N-cyclohexylformamide, N-ethylformanilide, or a mixture thereof.

[0066] The present disclosure further provides an electrolyzer (X) other than the electrolyzer (E). The electrolyzer (X) is an electrolyzer that obtains products by electrolyzing predetermined components in a gas (feed gas). The electrolyzer (X) includes a cathode section where products are generated, an anode section, and an ion exchange membrane disposed between the cathode section and the anode section. The cathode section includes a cathode conductive member, at least a portion of which is electrically conductive, and a cathode catalyst-containing layer disposed between the ion exchange membrane and the cathode conductive member. In the electrolyzer (E), the product (P) generated in the cathode section is mixed in a gaseous state with the gas (feed gas) in the cathode catalyst-containing layer and discharged. By lowering the partial pressure of the product (P) discharged from the gas discharge section below the saturated vapor pressure of the product (P) at the temperature of the gas in the gas discharge section, the product (P) can be extracted in a gaseous state from the reaction region. The partial pressure of the product (P) can be adjusted by adjusting the electrolysis current, the temperature during the electrolysis reaction, the pressure of the raw material gas, the flow rate of the raw material gas, etc. For example, the partial pressure of the product (P) can be reduced by increasing the flow rate of the raw material gas. In one example, the gas flow rate and current can be adjusted to satisfy the inequality of the following equation (2). (I Ｐ / Q)<{(2×n×F×P Ｔ ) / (P Ｏ ×V Ｔ ) (2)

[0067] I Ｐ is the generation current (A) of the product (P) and is calculated by multiplying the current by the Faraday efficiency of the product (P). Q is the flow rate (L / sec) of the gas discharged from the gas discharge part. n is the number of electrons required to obtain 1 mol of the product (P) from the raw material gas. F is the Faraday constant (A x sec / mol). P Ｔ is the saturated vapor pressure (atm) of the product (P) at the temperature during the electrolysis reaction. P Ｏ is the pressure (atm) of the gas discharged from the gas discharge port, which is usually 1.0 atm. Ｔis the volume (L / mol) per 1 mol of ideal gas at a temperature and pressure of 1 atm during the electrolysis reaction. When the concentration of a predetermined component in the raw material gas is low, the partial pressure of the product (P) can be easily reduced by components other than the predetermined component. The concentration of the predetermined component in the gas may be 0.01 vol% or more, or 1.00 vol% or more, or may be 100 vol% or less, or 20.0 vol% or less. As long as the product (P) can be produced, the components other than the predetermined component are not particularly limited. The other components may be mainly air (nitrogen gas, oxygen gas, water vapor gas). The other components may include carbon monoxide gas, etc.

[0068] The electrolyzer (E) may include a device for separating the product (P) in a gaseous state in the gas flow path downstream of the cathode catalyst-containing layer.

[0069] The present disclosure further provides an electrolyzer (Y) other than the electrolyzer (E). The electrolyzer (Y) is an electrolyzer that obtains products by electrolyzing predetermined components in a gas. The electrolyzer (Y) includes a cathode section where products are generated, an anode section, and an ion exchange membrane disposed between the cathode section and the anode section. The cathode section includes a cathode conductive member, at least a portion of which is electrically conductive, and a cathode catalyst-containing layer disposed between the ion exchange membrane and the cathode conductive member. The cathode catalyst layer has a reaction region where an electrolysis reaction occurs. The cathode section has a gas inlet section for introducing gas into the reaction region and a gas outlet section for discharging electrolyzed gas from the reaction region. The direction connecting the gas inlet section and the gas outlet section is the first direction. The direction perpendicular to the first direction and parallel to the reaction region is the second direction. The maximum length of the reaction region in the second direction is Lr. The length Lin of the gas inlet section in the second direction is 0.8Lr or greater. The length Lin of the gas discharge section in the second direction is 0.8Lr or more. Here, the direction parallel to the reaction region refers to the direction parallel to the surface of the sheet when the reaction region is considered to be a sheet. From another perspective, the direction parallel to the reaction region is the direction perpendicular to the stacking direction of the cathode catalyst-containing layer 110, the ion exchange membrane 130, and the anode section 120.

[0070] The electrolyzer (X) and the electrolyzer (Y) differ from the electrolyzer (E) in that a recess serving as a gas flow path may be formed in the cathode conductive member. Of course, the cathode conductive member of the electrolyzer (X) and the electrolyzer (Y) does not necessarily have to have a recess serving as a gas flow path. The components described for the electrolyzer (E) can be applied to the other components of the electrolyzer (X) and the electrolyzer (Y), so redundant description will be omitted.

[0071] (Electrolysis Method) The present disclosure further provides an electrolysis method (M). The electrolysis method (M) is a method for obtaining a product by electrolyzing a predetermined component in a gas using an electrolysis device. The electrolysis device includes a cathode section where the product is generated, an anode section, and an ion exchange membrane disposed between the cathode section and the anode section. The cathode section includes a cathode conductive member, at least a portion of which is electrically conductive, and a cathode catalyst-containing layer disposed between the ion exchange membrane and the cathode conductive member. The product generated in the cathode catalyst-containing layer (product (P)) is discharged in a gaseous state from the cathode catalyst-containing layer.

[0072] The electrolysis method (M) can be carried out using the electrolysis device (E), the electrolysis device (X), or the electrolysis device (Y). The matters described for these devices are applicable to the electrolysis method (M), and therefore, redundant descriptions will be omitted.

[0073] The above description discloses the following examples of the invention: (Example 1) An electrolysis device for obtaining a product by electrolyzing a predetermined component in a gas, comprising: a cathode section in which the product is produced, an anode section, and an ion exchange membrane disposed between the cathode section and the anode section, the cathode section comprising a cathode conductor member at least partially having electrical conductivity, and a cathode catalyst-containing layer disposed between the ion exchange membrane and the cathode conductor member, the cathode catalyst-containing layer having a reaction region in which an electrolysis reaction of the predetermined component occurs, the cathode conductor member being in contact with the cathode catalyst-containing layer in the reaction region, and no recesses serving as a flow path for the gas are formed on the surface of the cathode conductor member that is in contact with the reaction region. (Invention Example 2) The electrolysis device according to Invention Example 1, wherein the cathode catalyst-containing layer has a gas inlet and a gas outlet, the gas is introduced into the cathode catalyst-containing layer at the gas inlet, and the gas is discharged from the cathode catalyst-containing layer at the gas outlet. (Invention Example 3) The electrolysis device according to Invention Example 2, wherein a direction connecting the gas inlet and the gas outlet is a first direction, a direction perpendicular to the first direction and parallel to the reaction region is a second direction, a maximum length of the reaction region in the second direction is Lr, a length Lin of the gas inlet in the second direction is 0.8Lr or more, and a length Lout of the gas outlet in the second direction is 0.8Lr or more. (Invention Example 4) The electrolyzer according to Invention Example 3, wherein the planar shape of the reaction region is a rectangle having a first side and a second side opposite the first side, the gas inlet portion is disposed parallel to the first side, and the gas outlet portion is disposed parallel to the second side. (Invention Example 5) The electrolyzer according to any one of Invention Examples 2 to 4, wherein the gas inlet portion is a side surface of the cathode catalyst-containing layer. (Invention Example 6) The electrolyzer according to any one of Invention Examples 1 to 5, wherein the cathode catalyst-containing layer includes a cathode catalyst layer and a gas diffusion layer disposed between the cathode catalyst layer and the cathode conductor.(Invention Example 7) The electrolyzer according to Invention Example 6, wherein the gas diffusion layer is a porous sheet containing carbon fiber. (Invention Example 8) The electrolyzer according to any one of Invention Examples 1 to 7, wherein the anode section includes an anode catalyst layer, and a liquid to be electrolyzed by the anode catalyst layer is supplied to the anode catalyst layer. (Invention Example 9) The electrolyzer according to any one of Invention Examples 1 to 8, wherein the saturated vapor pressure of the product at 20°C is 3 kPa or more. (Invention Example 10) The electrolyzer according to any one of Invention Examples 1 to 9, wherein the predetermined component is carbon dioxide. (Example 11) An electrolysis method for obtaining a product by electrolyzing a predetermined component in a gas using an electrolysis device, wherein the electrolysis device includes: a cathode section where the product is produced; an anode section; and an ion exchange membrane arranged between the cathode section and the anode section; the cathode section includes a cathode conductive member, at least a portion of which is electrically conductive, and a cathode catalyst-containing layer arranged between the ion exchange membrane and the cathode conductive member; and the product produced in the cathode catalyst-containing layer is discharged in a gaseous state from the cathode catalyst-containing layer.

[0074] Examples of embodiments according to the present disclosure will be specifically described below with reference to the drawings. The embodiments described below can be modified based on the above description. Furthermore, the matters described below may be applied to the above embodiments. Furthermore, in the embodiments described below, matters that are not essential to the device according to the present disclosure may be omitted.

[0075] (Embodiment 1) A side view of an example of an electrolyzer (E) is shown in FIG. 1. A cross-sectional view taken along line IIA-IIA in FIG. 1 is shown in FIG. 2A. A cross-sectional view taken along line IIB-IIB in FIG. 1 is shown in FIG. 2B. In FIG. 1, the portion where the reaction region 110r is located is hatched. FIG. 1 shows a first direction D1 connecting the gas inlet 110a and the gas outlet 110b. Furthermore, FIG. 1 shows a second direction D2 that is perpendicular to the first direction D1 and parallel to the reaction region 110r (more specifically, the main surface of the reaction region 110r). The gas (raw material gas) flows along the first direction D1. In other words, the first direction D1 is the direction in which the gas flows.

[0076] The electrolyzer 10 shown in the figure includes an electrolysis unit 11. The electrolysis unit 11 includes a cathode unit 100, an anode unit 120, and an ion exchange membrane 130. The ion exchange membrane 130 is disposed between the cathode unit 100 and the anode unit 120. In the example shown in the figure, a spacer 141 is used to prevent leakage of gas and liquid.

[0077] In the cathode section 100, a product (P) is produced from a predetermined component in the gas. The cathode section 100 includes a cathode conductive member 101 and a cathode catalyst-containing layer 110. The cathode catalyst-containing layer 110 includes a gas diffusion layer 111 and a cathode catalyst layer 112. The ion exchange membrane 130 and the components of the cathode section 100 are arranged in the following order: ion exchange membrane 130 / cathode catalyst layer 112 / gas diffusion layer 111 / cathode conductive member 101.

[0078] Through holes 101a and 101b are formed in the cathode conductive member 101. Gas is introduced through the through hole 101a. After passing through the reaction region, the gas is discharged through the through hole 101b.

[0079] The anode section 120 includes an anode catalyst layer 121 and a plate-like member 122. The plate-like member 122 and a spacer 141 form a space 120s adjacent to the anode catalyst layer 121. The space 120s is a space through which a liquid supplied to the anode catalyst layer 121 flows. The plate-like member 122 has a supply port for supplying a liquid to the space 120s and a discharge port through which the liquid supplied to the space 120s is discharged. The shape of the plate-like member 122 is not limited to the shape shown in FIG. 1 , and may be any shape that allows a substance to be electrolyzed in the anode section 120 to be supplied to the anode catalyst layer 121.

[0080] The cathode conductor 101 and the plate-like member 122 may each be pressed toward the ion exchange membrane 130. The method of pressing is not limited, and known methods may be used. For example, they may be pressed together using bolts and nuts. The cathode catalyst layer 112 and the anode catalyst layer 121 are each connected to a DC power supply (not shown). The cathode catalyst layer 112 may be connected to the DC power supply via the gas diffusion layer 111 and the cathode conductor 101. The anode catalyst layer 121 may be connected to the DC power supply via the plate-like member 122.

[0081] The cathode section 100 has a gas inlet section 110a for introducing gas into the cathode catalyst-containing layer 110, and a gas outlet section 110b for discharging electrolyzed gas from the cathode catalyst-containing layer 110. That is, the gas is introduced into the cathode catalyst-containing layer 110 from the gas inlet section 110a and is discharged from the cathode catalyst-containing layer 110 at the gas outlet section 110b.

[0082] In the example shown in the figure, the gas inlet 110a is one side surface 110s1 of the cathode catalyst-containing layer 110, and the gas outlet 110b is the other side surface 110s2 of the cathode catalyst-containing layer 110. The side surface 110s2 is the side surface opposite to the side surface 110s1. The gas inlet 110a and the gas outlet 110b are disposed between the ion exchange membrane 130 and the cathode conductive member 101.

[0083] Fig. 3A shows a top view of the electrolysis unit 11 other than the cathode conductive member 101 as viewed from the cathode conductive member 101 side. Fig. 3B shows a top view of the cathode conductive member 101 as viewed from the gas diffusion layer 111 side. In Fig. 3A, the reaction region 110r is hatched.

[0084] 3A, the cathode catalyst-containing layer 110 has a reaction region 110r. The reaction region 110r is a region where the cathode catalyst layer 112 and the anode catalyst layer 121 face each other with the ion exchange membrane 130 sandwiched therebetween. In the reaction region 110r, an electrolysis reaction of a predetermined component occurs.

[0085] As shown in the figure, the cathode conductor 101 contacts the entire surface of the reaction region 110r on the cathode conductor 101 side. Of the surface of the cathode conductor 101, the entire region 101rs in contact with the reaction region 110r is flat, and no recesses through which gas can flow are formed. The surface of the reaction region 110r in contact with the cathode conductor 101 also appears flat. However, because the gas diffusion layer 111 is porous, there are microscopic irregularities on the surface of the reaction region 110r.

[0086] 3A shows the maximum length Lr of the reaction region 110r in the second direction D2. Also shown are the length Lin of the gas inlet 110a in the second direction D2 and the length Lout of the gas outlet 110b in the second direction D2. In the example shown in FIG. 3A, Lin, Lout, and Lr are equal.

[0087] In the electrolyzer 10, the cathode conductive member 101 contacts one entire side of the reaction region 110r, allowing gas to flow evenly within the reaction region 110r. This prevents the product (P) from accumulating within the reaction region 110r. Furthermore, because the surface of the cathode conductive member 101 is flat, the product (P) does not accumulate in recesses formed on the surface of the cathode conductive member 101. This allows the electrolyzer 10 to efficiently extract the generated product (P).

[0088] An example in which the predetermined component is carbon dioxide and the product (P) is formic acid will be described. Note that the configuration described below is an example, and the present disclosure is not limited to the following example.

[0089] In this example, Nafion, a proton exchange membrane, is used as the ion exchange membrane. Carbon paper with a fluororesin layer formed on one side is used as the gas diffusion layer. A polytetrafluoroethylene porous membrane and a tin complex supported on the porous membrane are used as the cathode catalyst layer. A porous sintered body layer (a sintered body layer of titanium particles) and a layer containing iridium oxide supported on the sintered body layer are used as the anode catalyst layer. A sulfuric acid aqueous solution with a pH of 2 is supplied to the anode catalyst layer.

[0090] A gas containing carbon dioxide is supplied to the cathode catalyst-containing layer 110. An acidic aqueous solution (e.g., an aqueous sulfuric acid solution) is supplied to the anode catalyst layer 121. With these supplied, a DC voltage is applied between the cathode catalyst layer 112 and the anode catalyst layer 121. As a result, carbon dioxide is reduced in the cathode catalyst layer 112 to produce formic acid (HCOOH). Furthermore, an oxidation reaction occurs in the anode catalyst layer 121. An example of these reactions is shown below. (Cathode side) CO ２ +2H ＋ +2e － →HCOOH (anode side) H ２ O → 1 / 2O ２ +2H ＋ +2e －

[0091] In this example configuration, electrolysis was performed at room temperature using gas with a carbon dioxide concentration of 10% by volume. The formic acid produced by electrolysis did not remain in the cathode catalyst-containing layer 110, and the formic acid could be extracted in a gaseous state.

[0092] 2B shows an example in which the gas inlet 110a is one side surface 110s1 of the cathode catalyst-containing layer 110, and the gas outlet 110b is the other side surface 110s2 of the cathode catalyst-containing layer 110. However, the gas inlet 110a and the gas outlet 110b may be located in other parts. FIG. 4A shows a partial cross-sectional view of an example in which the gas inlet 110a and the gas outlet 110b are located on the main surface of the cathode catalyst-containing layer 110. FIG. 4B shows a top view of the configuration of FIG. 4A, viewed from the cathode conductive member 101 side.

[0093] 4A, the portion of the surface of the cathode conductive member 101 that is exposed in the through-hole 101a is the gas inlet 110a, and the portion of the surface of the cathode conductive member 101 that is exposed in the through-hole 101b is the gas outlet 110b.

[0094] One of the gas inlet 110a and the gas outlet 110b may be located on a side surface of the cathode catalyst-containing layer 110, and the other on the main surface of the cathode catalyst-containing layer 110. Alternatively, gas may be introduced and / or discharged from a portion other than the through-holes without forming through-holes in the cathode conductive member 101. A cross-sectional view of another example of the arrangement of the cathode conductive member 101 and the cathode catalyst-containing layer 110 is shown in Figure 4C. A top view of the configuration of Figure 4C, viewed from the cathode conductive member 101 side, is shown in Figure 4D.

[0095] 4A to 4D, the planar shape of the reaction region 110r is a rectangle having a first side and a second side opposite the first side. The band-like gas inlet 110a is arranged parallel to the first side. The band-like gas outlet 110b is arranged parallel to the second side.

[0096] The electrolyzer 10 may include a device for separating the product (P). An example of the configuration of an electrolyzer 10 including such a device is shown in FIG. 5 . The electrolyzer 10 shown in FIG. 5 includes an electrolysis unit 11, flow paths 191 and 192, and a device 200. The flow path 191 is a flow path through which gas G1 electrolyzed in the cathode unit flows. The flow path 192 is a flow path through which gas electrolyzed in the cathode unit flows. In other words, the flow path 192 is a flow path downstream of the gas discharge unit 110b. The device 200 is disposed in the flow path 192. The device 200 is a device for separating the product (P). The device 200 may be any of the devices described above. At least a portion of the product (P) is separated from the gas G2a electrolyzed in the cathode unit by the device 200. The gas G2b, in which the concentration of the product (P) has been reduced, flows through the flow path 192 downstream of the device 200. The gas G2b is treated as necessary.

[0097] FIG. 6 shows an example of a case where the device 200 is a condenser. The condenser 210 in FIG. 6 includes a trap 211 that collects the liquid product (P) (e.g., formic acid) and a cooling device (not shown). The cooling device includes a pipe through which a refrigerant passes. The trap 211 is cooled by the cooling device. As a result, the product (P) in the gas is liquefied and accumulates in the trap 211. At this time, other substances (e.g., water) may also be liquefied in addition to the product (P). The liquefied product (P) can be discharged from a discharge path 212 or the like at the bottom of the trap 211.

[0098] FIG. 7 shows an example of the device 200 being a distillation column (distillation apparatus). The distillation column 220 includes a chamber containing an extractant for the product (P) and an extractant outlet. The extractant outlet is located at the top of the distillation column 220. The gas (gas containing the product (P)) discharged from the gas outlet is introduced into the distillation column 220 from the bottom. The gas introduced into the distillation column 220 comes into contact with the extractant (extractant for the product (P)) discharged from the extractant outlet. The product (P) accumulates as a liquid at the bottom of the distillation column together with the extractant. The gas from which the product (P) has been removed is discharged near the top of the distillation column 220. The product (P) can be isolated by heating the liquid accumulated at the bottom of the distillation column 220.

[0099] The present disclosure can be used for electrolysis devices and electrolysis methods. While the present invention has been described with respect to presently preferred embodiments, such disclosure should not be interpreted as limiting. Various modifications and variations will no doubt become apparent to those skilled in the art to which the present invention pertains upon reading the above disclosure. Therefore, the appended claims should be construed to cover all modifications and variations that do not depart from the true spirit and scope of the present invention.

[0100] 10: Electrolyzer 100: Cathode section 101: Cathode conductive member 110: Cathode catalyst-containing layer 110a: Gas inlet section 110b: Gas outlet section 110r: Reaction region 111: Gas diffusion layer 112: Cathode catalyst layer 120: Anode section 121: Anode catalyst layer 130: Ion exchange membrane D1: First direction D2: Second direction

Claims

1. An electrolysis device that obtains a product by electrolyzing a predetermined component in a gas, comprising: a cathode section where the product is generated; an anode section; and an ion exchange membrane arranged between the cathode section and the anode section, wherein the cathode section comprises a cathode conductor member at least a portion of which is electrically conductive, and a cathode catalyst-containing layer arranged between the ion exchange membrane and the cathode conductor member, wherein the cathode catalyst-containing layer has a reaction region where an electrolysis reaction of the predetermined component occurs, the cathode conductor member contacts the cathode catalyst-containing layer in the reaction region, and the surface of the cathode conductor that contacts the reaction region does not have a recess formed thereon to serve as a flow path for the gas.

2. The electrolysis device according to claim 1, wherein the cathode catalyst-containing layer has a gas inlet and a gas outlet, the gas being introduced into the cathode catalyst-containing layer at the gas inlet, and the gas being discharged from the cathode catalyst-containing layer at the gas outlet.

3. The electrolysis apparatus according to claim 2, wherein a direction connecting the gas inlet and gas outlet is a first direction, a direction perpendicular to the first direction and parallel to the reaction region is a second direction, a maximum length of the reaction region in the second direction is Lr, a length Lin of the gas inlet in the second direction is 0.8Lr or more, and a length Lout of the gas outlet in the second direction is 0.8Lr or more.

4. The electrolysis apparatus according to claim 3, wherein the planar shape of the reaction region is a rectangle having a first side and a second side opposite to the first side, the gas inlet section is arranged parallel to the first side, and the gas outlet section is arranged parallel to the second side.

5. The electrolyzer according to claim 2, wherein the gas inlet is a side surface of the cathode catalyst-containing layer.

6. The electrolysis device according to claim 1, wherein the cathode catalyst-containing layer includes a cathode catalyst layer and a gas diffusion layer disposed between the cathode catalyst layer and the cathode conductive member.

7. The electrolysis device according to claim 6, wherein the gas diffusion layer is a porous sheet containing carbon fibers.

8. The electrolysis device according to claim 1, wherein the anode section includes an anode catalyst layer, and a liquid to be electrolyzed by the anode catalyst layer is supplied to the anode catalyst layer.

9. The electrolysis apparatus according to claim 1, wherein the saturated vapor pressure of the product at 20°C is 3 kPa or more.

10. An electrolysis device according to any one of claims 1 to 9, wherein the predetermined component is carbon dioxide.

11. An electrolysis method for obtaining a product by electrolyzing a predetermined component in a gas using an electrolysis device, wherein the electrolysis device includes: a cathode section in which the product is produced; an anode section; and an ion exchange membrane disposed between the cathode section and the anode section; the cathode section includes a cathode conductive member, at least a portion of which is electrically conductive, and a cathode catalyst-containing layer disposed between the ion exchange membrane and the cathode conductive member; and the product produced in the cathode catalyst-containing layer is discharged in a gaseous state from the cathode catalyst-containing layer.

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