electrolyzer

Abstract

The present invention relates to an electrolysis device comprising: an electrolysis cell including a gas diffusion layer, a cathode, a separator, an anode, and an electrolyte; and an acidic solution storage tank connected to an outlet flow path for discharging a product from the cathode outside the electrolysis cell, wherein the separator is a cation separator.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0077536, filed on June 16, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to an electrolyzer that electrochemically reduces carbon dioxide. [Background technology]

[0003] Carbon dioxide is a greenhouse gas that contributes to global warming and must be reduced. Methods for reducing carbon dioxide emissions include capture, chemical conversion, and electrochemical conversion. Electrochemical conversion, among others, allows for precise control of the components to produce other synthetic gases, which offers greater economic benefits than simply removing carbon dioxide. Carbon dioxide can also be electrolyzed with water to produce carbon monoxide, ethylene, methane, formic acid, formate salts, various hydrocarbons, and organic compounds such as aldehydes or alcohols.

[0004] The process of electrochemically decomposing carbon dioxide is similar to that of water electrolysis, but since the activity of the electrochemical reaction increases in a strongly alkaline atmosphere, a certain concentration of KOH aqueous solution is generally used as the electrolyte. When water is supplied to the anode and an electric current is applied, the water is decomposed into hydrogen ions and electrons, generating oxygen gas. The electrons move to the cathode via an external conductor, and the hydrogen ions move to the cathode via an ion-selective separator. At this time, the transferred electrons react with the carbon dioxide and water supplied to the cathode to produce carbon monoxide and hydroxide ions (OH - ) and the hydroxide ions generated are transported to the anode via hydrogen ions (H +) to produce water, resulting in an electrically neutral state. Through the above process, the electrochemical decomposition reaction of carbon dioxide is completed. At this time, the water supplied along with carbon dioxide reacts with the electrons transferred separately from the carbon monoxide production reaction, and is electrolyzed to produce hydrogen gas and hydroxide ions at the same time. This reaction between water and electrons can be said to be in a competitive relationship with the carbon monoxide production reaction. Because the reaction is an electrochemical reaction, the amount of carbon monoxide produced and the hydrogen / carbon dioxide ratio can be easily adjusted by adjusting the voltage.

[0005] On the other hand, conventional electrolyzers produce OH at the cathode as a side reaction during the electrolysis of carbon dioxide. - is generated, and the OH - reacts further with the supplied carbon dioxide to form carbonate (HCO3 - Therefore, conventional electrolyzers have a problem in that the supplied carbon dioxide is not converted into the desired product but instead produces carbonates, resulting in a loss of carbon dioxide. Furthermore, conventional electrolyzers have a problem in that the carbonates pass through the anion exchange membrane and diffuse to the anode, where they are oxidized to produce carbon dioxide, thereby reducing the efficiency of the electrolysis. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] KR10-2018-0133688A Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved by the present invention is to provide an electrolysis apparatus capable of preventing the loss of carbon dioxide converted into carbonate by further separating carbon dioxide from carbonate generated by a side reaction during the electrolysis of carbon dioxide, thereby improving the yield of the product. [Means for solving the problem]

[0008] The present invention provides an electrolysis device.

[0009] (1) The present invention provides an electrolysis device comprising: an electrolysis cell including a gas diffusion layer, a cathode, a separator, an anode, and an electrolyte; and an acidic solution storage tank connected to an outlet flow path for discharging a product from the cathode outside the electrolysis cell, wherein the separator is a cation separator.

[0010] (2) The present invention provides the electrolysis apparatus according to (1) above, wherein the acid solution storage tank contains an acid solution containing one or more selected from the group consisting of phosphoric acid, hydrochloric acid, sulfuric acid, nitric acid, acetic acid, citric acid, and oxalic acid.

[0011] (3) The present invention provides an electrolysis apparatus according to (1) or (2) above, wherein the electrolyte is an aqueous solution containing one or more selected from the group consisting of Cs2CO3, CsHCO3, Cs2SO4, CsCl, CsNO3, K2CO3, KHCO3, K2SO4, K3PO4, KCl, KNO3, Na2CO3, NaHCO3, Na2SO4, Na3PO4, NaCl, and NaNO3.

[0012] (4) The present invention provides the electrolyzer according to any one of (1) to (3), wherein the electrolytic cell is a zero-gap membrane electrode assembly cell in which the gas diffusion layer, the cathode, the separator, and an anode having an anode fluid flow path formed therein are stacked in this order.

[0013] (5) The present invention provides an electrolysis device according to any one of (1) to (4), wherein a product produced by the electrolysis reaction at the cathode is transferred to the acidic solution storage tank via the discharge flow path, and the product includes carbon monoxide, water vapor, and salt.

[0014] (6) The present invention provides the electrolysis device according to (5) above, wherein carbon dioxide produced from the salt in the acid solution storage tank is supplied to the electrolysis cell.

[0015] (7) The present invention provides the electrolyzer according to (5) or (6) above, wherein the salt is a carbonate.

[0016] (8) The present invention provides the electrolyzer according to any one of (1) to (7) above, wherein the electrolyzer electrolyzes carbon dioxide.

[0017] (9) The present invention provides the electrolyzer according to (8) above, wherein the carbon dioxide is supplied to the electrolytic cell in a state containing water vapor.

[0018] (10) The present invention provides the electrolyzer according to any one of (1) to (9), wherein the electrolyzer electrolyzes carbon dioxide to produce one or more compounds selected from the group consisting of carbon monoxide, ethylene, methane, formic acid, hydrocarbons, aldehydes, and alcohols. [Effects of the Invention]

[0019] The electrolysis device of the present invention can prevent the loss of carbon dioxide by connecting an acid solution storage tank to an electrolysis cell and separating carbon dioxide from salts produced by side reactions in the acid solution storage tank.

[0020] Furthermore, the electrolyzer of the present invention can improve the efficiency of carbon dioxide electrolysis by reducing the loss of carbon dioxide, thereby increasing the yield of the product. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic diagram of a carbon dioxide electrolysis device according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention will be described in more detail below for better understanding of the present invention. In this regard, the terms and words used in the specification and claims should not be interpreted in a limited way to their ordinary or dictionary meanings, but should be interpreted in a way that is consistent with the technical concept of the present invention, based on the principle that the inventors can appropriately define the concepts of terms in order to best describe their invention.

[0023] The terms used in this specification are merely used to describe exemplary embodiments and are not intended to limit the present invention. The singular expressions include the plural expressions unless the context clearly indicates otherwise.

[0024] As used herein, the terms "comprises," "comprises," or "having" are intended to specify the presence of embodied features, numbers, steps, components, or combinations thereof, and should be understood as not precluding the presence or possible addition of one or more other features, numbers, steps, components, or combinations thereof.

[0025] The present invention provides an electrolysis device comprising an electrolysis cell including a gas diffusion layer, a cathode 13, a separator 15, an anode 11, and an electrolyte; and an acidic solution storage tank 20 connected to an outlet flow path 30 for discharging a product from the cathode 13 outside the electrolysis cell, wherein the separator 15 is a cation separator.

[0026] According to one embodiment of the present invention, the electrolyzer can be used in any electrochemical conversion field, and the electrolyzer can be a device capable of producing useful chemicals through electrochemical conversion, such as a fuel cell or water electrolysis, or a device capable of reducing and converting carbon dioxide and NOx. Specifically, the electrolyzer can be an electrochemical conversion device that converts carbon dioxide into carbon monoxide and ethylene.

[0027] In the conventional electrolysis cell having a structure in which the electrolyte flows in front of the cathode, as explained in the background art above, OH generated by a side reaction during the reduction process of carbon dioxide is - reacts further with carbon dioxide to form carbonate (HCO3 - ), resulting in a loss of carbon dioxide. This problem could be solved by passing an acidic electrolyte in front of the cathode, but this would result in an additional problem of increased voltage due to the additional resistance generated by the acidic electrolyte. Furthermore, an anion exchange membrane is typically used as the separator in a carbon dioxide electrolysis cell. While anion exchange membranes have fast ion transport and excellent carbon dioxide conversion efficiency, they have very low mechanical strength. Furthermore, the carbonates diffuse through the anion exchange membrane to the anode, where they are oxidized to produce carbon dioxide, reducing the efficiency of the electrolysis.

[0028] Therefore, the inventors of the present invention developed an electrolyzer that can reduce the loss of supplied carbon dioxide by separating carbon dioxide from the produced carbonate without diffusing the produced carbonate to the anode 11. Specifically, the electrolyzer includes an electrolytic cell and an acid solution storage tank 20 connected to the outside of the electrolytic cell. The electrolyzer includes the cathode 13 and the anode 11, a gas diffusion layer disposed in close contact with the cathode 13, and a separator 15 and an electrolyte disposed between the cathode 13 and the anode 11. The electrolyzer of the present invention can also include an electrolytic cell having a zero-gap membrane electrode assembly structure, which will be described later. The electrolytic cell having the zero-gap membrane electrode assembly structure has a structure in which the electrolyte does not flow in front of the cathode 13, but flows only in front of the anode 11, thereby solving the additional problem of voltage rise during the electrolysis reaction. Furthermore, the electrolysis cell includes a cation exchange membrane, which can prevent the produced carbonate from being transported to the anode 11 side.

[0029] FIG. 1 is a schematic diagram of a carbon dioxide electrolysis device according to the present invention.

[0030] According to one embodiment of the present invention, the cathode 13 is connected to a supply line through which reactants are supplied and an exhaust flow path 30 through which products generated after electrolysis are discharged. The reactant may be carbon dioxide. The carbon dioxide is in a gaseous state and may contain water vapor at about 40 to 60°C. The products are generated by electrolyzing the carbon dioxide and may be one or more selected from the group consisting of carbon monoxide, ethylene, methane, formic acid, hydrocarbons, aldehydes, and alcohols. Unreacted carbon dioxide, the water vapor, and carbonates generated by side reactions may also be discharged from the exhaust flow path 30 along with the products.

[0031] Referring to FIG. 1, the acidic solution storage tank 20 is connected to the discharge flow path 30, and carbon dioxide can be further separated from the carbonate by the acidic solution filled in the acidic solution storage tank 20. Specifically, hydrogen ions (H + ) and carbonate (HCO3 - ) can react to produce water and carbon dioxide. In addition, the acid solution storage tank 20 can contain an acid solution containing at least one selected from the group consisting of phosphoric acid, hydrochloric acid, sulfuric acid, nitric acid, acetic acid, citric acid, and oxalic acid. The acid solution can react with the produced carbonate to regenerate carbon dioxide. Compared to conventional electrolyzers, the electrolyzer of the present invention further includes the acid solution storage tank 20, which can regenerate carbon dioxide from carbonate, thereby improving electrolysis efficiency and reducing the amount of carbon dioxide lost as carbonate.

[0032] According to an embodiment of the present invention, the separator 15 may be a cation separator 15, specifically, a Nafion separator 15. The cation separator 15 may serve to prevent carbonates generated in the cathode 13 from diffusing toward the anode 11. Furthermore, if the separator 15 is an anion separator 15, the diffusion of carbonates toward the anode 11 may inhibit smooth transport of the carbonates to the acid solution storage tank 20, resulting in a decrease in overall electrolysis efficiency and an increase in carbon dioxide loss.

[0033] According to one embodiment of the present invention, the electrolyte is an acidic or neutral electrolyte containing a cation (Na + , K. + , Cs + ) can be an aqueous solution containing Cs2CO3, CsHCO3, Cs2SO4, CsCl, CsNO3, K2CO3, KHCO3, K2SO4, K3PO4, KCl, KNO3, Na2CO3, NaHCO3, Na2SO4, Na3PO4, NaCl, or NaNO3.

[0034] According to one embodiment of the present invention, the electrolysis cell may be a zero-gap membrane electrode assembly cell in which the gas diffusion layer, the cathode 13, the separator 15, and the anode 11 having a liquid flow path formed therein are sequentially stacked. Specifically, the zero-gap membrane electrode assembly may be formed in the form of a very thin membrane plate in order to increase driving voltage and current efficiency.

[0035] While conventional electrolytic cells have a gap structure in which the electrodes and separator are spaced apart by several millimeters, the zero-gap electrolytic cell is a sandwich-type electrolytic cell in which the cathode and anode are in contact with each other across the separator, eliminating the gap between the electrodes and the separator. The zero-gap electrolytic cell reduces the solution ionic resistance due to the presence of electrolyte and can reduce the increase in mass transfer resistance due to generated gases when large-area electrodes are implemented.

[0036] The electrolyte flowing on the cathode 13 side is called the cathode 13 solution, and the electrolyte flowing on the anode 11 side is called the anode 11 solution. However, the zero-gap membrane electrode assembly does not contain the cathode 13 solution, but only the anode 11 solution. The zero-gap membrane electrode assembly has the advantage of accelerating ion transport, reducing overvoltage, and increasing current efficiency by minimizing the gap between the cathode 13, anode 11, and separator 15. In this case, separators may be disposed on both sides of the zero-gap membrane electrode assembly to form a single cell.

[0037] According to an embodiment of the present invention, the discharge passage 30 transports products generated by the electrolysis reaction at the cathode 13 to the acidic solution storage tank 20. The products may include carbon dioxide, carbon monoxide, water vapor, and salt. The carbon dioxide generated in the acidic solution storage tank 20 may be supplied to the electrolysis cell.

[0038] Carbon dioxide is separated from carbonate in the acid solution storage tank 20, and the generated carbon dioxide can be further supplied to the cathode 13 via a supply line. The electrolysis device of the present invention can reduce carbon dioxide loss and increase electrolysis efficiency by separating carbon dioxide from carbonate in the acid solution storage tank 20 and circulating the carbon dioxide to the electrolysis cell.

[0039] The decomposition principle of the electrolyzer and each component of the electrolyzer will be described below.

[0040] Electrolysis refers to the decomposition of a substance through an oxidation-reduction reaction by applying a direct current voltage, which is a non-spontaneous decomposition reaction. The anode is an oxidation electrode that oxidizes water to generate oxygen, generating hydrogen ions. The hydrogen ions generated at the anode are transferred to the cathode via the electrolyte. The cathode is a reduction electrode, and reactants input to the cathode can react with electrons and hydrogen ions transferred from the anode to generate products. The separator can also be disposed between the anode and cathode. The separator is made of an inert material that does not participate in the electrochemical reaction itself, but it can provide a path for ions to move between the anode and cathode and separate the anode and cathode from physical contact.

[0041] In addition, the anode and the cathode of the electrolyzer of the present invention may each include a catalyst layer. Furthermore, water vapor supplied together with carbon dioxide in the cathode region undergoes an electroreduction reaction on the surface of the cathode to generate a reduction product. Therefore, the cathode may include a gas diffusion layer to uniformly supply humidified carbon dioxide gas to the cathode region. When the cathode includes a hydrophobic gas diffusion layer, the supplied carbon dioxide can be smoothly diffused, distributed, and supplied to the catalyst layer of the cathode. Furthermore, the hydrophobic gas diffusion layer effectively prevents water condensation, thereby ensuring a continuous and uniform supply of carbon dioxide and facilitating the electrolysis reaction. Furthermore, the catalyst layer may have a porous surface to effectively exhibit gas permeability.

[0042] According to one embodiment of the present invention, the anode may include a catalyst active in water electrolysis, and the catalytic layer of the anode may include, for the oxygen evolution reaction, one or more selected from the group consisting of Pt, Au, Pd, Ir, Ag, Rh, Ru, Ni, Al, Mo, Cr, Cu, Ti, W, alloys thereof, or mixed metal oxides such as Ta2O5, IrO2, etc. Specifically, the anode in the electrolyzer of the present invention may include titanium (Ti) coated with iridium oxide (IrO2).

[0043] Furthermore, since the carbon dioxide reduction reaction occurring at the cathode competes with the hydrogen generation reaction, a high voltage is required for the hydrogen generation reaction, and a catalyst active in the carbon dioxide reduction reaction may be included. The catalytic layer of the cathode may contain one or more elements selected from the group consisting of Sn, Sn alloys, Al, Au, Ag, C, Cd, Co, Cr, Cu, Cu alloys, Ga, Hg, In, Mo, Nb, Ni, NiCo2O4, Ni alloys, Ni-Fe alloys, Pb, Rh, Ti, V, W, Zn, and mixtures thereof for the hydrogen generation reaction. Specifically, the cathode in the electrolyzer of the present invention may contain silver (Ag).

[0044] The separator may include a cation exchange membrane (CEM), as described above, and may be a Nafion exchange membrane. The CEM acts as a barrier to prevent the reduced substances generated at the cathode by catalytic action from moving to the anode and being oxidized, and it also suppresses the permeation of anions and allows hydrogen ions (H + ) can be a separate phase permeable to cations.

[0045] The electrolyte solution may be the electrolyte solution according to the present invention as described above, specifically an acidic electrolyte solution, more specifically an aqueous solution containing cesium hydrocarbonate. The electrolyte composition may contain the electrolyte solution at a concentration of 0.1 to 15.0 M, preferably 0.25 to 10.0 M. The concentration of the electrolyte solution is related to the product generation efficiency (target product generation efficiency relative to the applied current density) and voltage. The higher the concentration of the electrolyte solution, the lower the generated voltage, required voltage, or overvoltage. However, the above conditions are preferred to minimize increased production costs and the generation of adducts due to side reactions.

[0046] The gas diffusion layer may be a porous body made of a carbon material such as carbon fiber cloth, carbon fiber felt, or carbon fiber paper, or a porous metal body made of a thin metal plate with a mesh structure such as expanded metal or metal mesh. In the electrolysis device of the present invention, a carbon fiber cloth may be used as the gas diffusion layer.

[0047] According to one embodiment of the present invention, the electrolyzer can be used in all fields requiring electrochemical conversion, particularly for electrochemically decomposing carbon dioxide to obtain desired products. Specifically, the electrolyzer can electrolyze carbon dioxide to produce one or more products selected from the group consisting of carbon monoxide, ethylene, methane, formic acid, hydrocarbons, aldehydes, and alcohols.

[0048] Although the present invention may be embodied in various different forms, it is not intended to be limited to the embodiments set forth herein, and the present invention is not limited to the embodiments set forth herein.

[0049] Example 1 A carbon dioxide electrolyzer was operated under the following operating conditions: A carbon dioxide electrolyzer was operated that included a zero-gap membrane electrode assembly in which an anode, a cation separator (type: Nafion® 212), a cathode, and a gas diffusion layer were stacked in this order, and an acidic solution storage tank connected to the outside of the cathode and the membrane electrode assembly and filled with an acidic solution (85%, H3PO4). Reaction current density: 100mA / cm 2 (Constant current operation) Reaction voltage: 1 to 4 V Reaction temperature: 40℃ Reaction pressure: 1 atm (normal pressure) Anode catalyst: IrO2 on Ti mesh Cathode catalyst: Ag powder Electrode area: 100cm 2 Gas diffusion layer: Sigracet 39BB Anode electrolyte: 1.0M CsHCO3 (25ml / min) Cathode reactant: 40°C humidified CO2 gas (200 ccm) 40℃ Humidified CO2 gas supply flow rate: 200ml / min

[0050] Example 2 Reaction current density: 200mA / cm 2 The carbon dioxide electrolyzer was operated under the same conditions as in Example 1, except that the operation was carried out as follows.

[0051] Example 3 Reaction current density: 300mA / cm 2 The carbon dioxide electrolyzer was operated under the same conditions as in Example 1, except that the operation was carried out as follows.

[0052] Comparative Example 1 A carbon dioxide electrolyzer was operated under the same conditions as in Example 1, except that an anion exchange membrane was used instead of a cation exchange membrane and no acidic solution storage tank was included.

[0053] Comparative Example 2 A carbon dioxide electrolyzer was operated under the same conditions as in Example 2, except that an anion exchange membrane was used instead of a cation exchange membrane and no acidic solution storage tank was included.

[0054] Comparative Example 3 A carbon dioxide electrolyzer was operated under the same conditions as in Example 3, except that an anion exchange membrane was used instead of a cation exchange membrane and no acidic solution storage tank was included.

[0055] Comparative Example 4 A carbon dioxide electrolysis apparatus was operated under the same conditions as in Example 1, except that no acid solution storage tank was included.

[0056] Comparative Example 5 A carbon dioxide electrolysis apparatus was operated under the same conditions as in Example 2, except that no acid solution storage tank was included.

[0057] Comparative Example 6 A carbon dioxide electrolysis apparatus was operated under the same conditions as in Example 3, except that no acid solution storage tank was included.

[0058] Experimental example The products of the carbon dioxide reduction reaction used in the carbon dioxide electrolysis devices according to Examples 1 to 3 and Comparative Examples 1 to 6 were analyzed by gas chromatography. The amount of carbon dioxide initially charged was compared with the amount of carbon dioxide produced, and the amount of carbon dioxide lost without being electrochemically reduced was measured. The Faraday efficiencies of carbon monoxide and hydrogen were also measured according to the following measurement method, and the measured properties are listed in Table 1 below.

[0059] (1) Carbon dioxide loss rate (CO2Loss, %) The composition of the gas was measured by GC (Gas Chromatography) analysis in the exhaust flow path. The exhausted gas flow rate (mL / min) was multiplied by the percentage of carbon dioxide (%) measured by GC analysis to calculate the flow rate of CO2 exhausted after electrochemical conversion (Q CO2 This was taken as the initial injection flow rate (QCO2 The total amount of CO2 used (CO2 used, %) was measured by comparing it with the CO2 conversion rate during the CO2 reduction reaction (i). Because the CO conversion ratio was 1:1 during the CO2 reduction reaction, the CO2 loss was calculated as the remainder after subtracting the amount of CO2 converted from the amount of CO2 used under the assumption that the flow rate of carbon monoxide gas (Qco) measured by GC analysis was the same as the amount of CO2 electrochemically converted (CO2conv, %). The measured value was calculated using the following mathematical formula 1.

[0060]

number

[0061] (2) Carbon monoxide Faraday efficiency (%) The gas composition was measured by GC (Gas Chromatography) analysis at the outlet flow path, and the Faraday efficiency was calculated using the following formula:

[0062]

number

[0063] In the above mathematical formula 2, Q is the flow rate in the discharge channel, F is the Faraday constant, p is the pressure, T is the measurement temperature, and R is the ideal gas constant. total ) is the value of the total current applied over time, and the current to the product (i product ) is the volume of gas measured by GC analysis (V product ) is the value calculated from

[0064] (3) Hydrogen Faraday efficiency (%) The hydrogen faradaic efficiency was measured and then calculated in the same manner as in (2) carbon monoxide faradaic efficiency.

[0065] [Table 1]

[0066] Referring to Table 1, it can be seen that Examples 1 to 3, which include an acidic solution storage tank, maintain the same level of carbon monoxide faradaic efficiency and have a very low carbon dioxide loss rate compared to Comparative Examples 1 to 6, which do not include an acidic solution storage tank.

[0067] In other words, the electrolysis device of the present invention, which includes an acidic solution storage tank, further separates carbon dioxide from carbonate, significantly reducing the loss of carbon dioxide converted to carbonate and achieving high electrolysis efficiency.In contrast, when an anion exchange membrane is used as in Comparative Examples 1 to 3, or a cation exchange membrane is used as in Comparative Examples 4 to 6, but an acidic solution storage tank is not included, it can be confirmed that a large amount of carbon dioxide is converted to carbonate and lost, resulting in a decrease in electrolysis efficiency. [Explanation of symbols]

[0068] 11 Anode 13 Cathode 15 Separator 20 Acid solution storage tank 30 Discharge flow path 60 Gas-liquid separator

Claims

1. an electrolysis cell including a gas diffusion layer, a cathode, a separator, an anode, and an electrolyte; an acid solution storage tank connected to a discharge flow path that discharges a product from the cathode, the acid solution storage tank being located outside the electrolysis cell; The electrolysis apparatus, wherein the separator is a cation separator.

2. 2. The electrolysis apparatus of claim 1, wherein the acid solution storage tank contains an acid solution containing one or more selected from the group consisting of phosphoric acid, hydrochloric acid, sulfuric acid, nitric acid, acetic acid, citric acid, and oxalic acid.

3. The electrolyte is Cs ２ CO ３ , CsHCO ３ , Cs ２ SO ４ , CsCl, CsNO ３ , K. ２ CO ３ , KHCO ３ , K. ２ SO ４ , K. ３ P.O. ４ , KCl, KNO ３ , Na ２ CO ３ , NaHCO ３ , Na ２ SO ４ , Na ３ P.O. ４ , NaCl, and NaNO ３ 2. The electrolysis apparatus according to claim 1, wherein the aqueous solution contains one or more selected from the group consisting of:

4. 2. The electrolysis device according to claim 1, wherein the electrolysis cell is a zero-gap membrane electrode assembly cell in which the gas diffusion layer, the cathode, the separator, and an anode having an anolyte flow path formed therein are stacked in this order.

5. A product produced by the electrolysis reaction at the cathode is transferred to the acid solution storage tank through the discharge channel; 10. The electrolysis apparatus of claim 1, wherein the products include carbon monoxide, water vapor, and salts.

6. 6. The electrolysis apparatus of claim 5, wherein carbon dioxide produced from the salt in the acid solution storage tank is supplied to the electrolysis cell.

7. 6. The electrolysis apparatus of claim 5, wherein the salt is a carbonate.

8. 2. The electrolysis device according to claim 1, which electrolyzes carbon dioxide.

9. 9. The electrolysis apparatus according to claim 8, wherein the carbon dioxide is supplied to the electrolysis cell in a state containing water vapor.

10. 2. The electrolysis device according to claim 1, wherein carbon dioxide is electrolyzed to produce one or more selected from the group consisting of carbon monoxide, ethylene, methane, formic acid, hydrocarbons, aldehydes, and alcohols.

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