Electrolysis device

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 the outside of the electrolysis cell through a discharge flow path for discharging a product from the cathode, wherein the separator is a cation separator.

Description

electrolysis device

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0077536, filed June 16, 2023, the entire contents of which are incorporated herein by reference.

[0003]

[0004] Technology field

[0005] The present invention relates to an electrolytic device that electrochemically reduces carbon dioxide.

[0006]

[0007] Carbon dioxide is a greenhouse gas that causes global warming and must be reduced. Known methods for reducing carbon dioxide include capture, chemical conversion, and electrochemical conversion. Among these, electrochemical conversion allows for precise control of the composition of other synthetic gases, offering greater economic benefits than simply removing carbon dioxide. Furthermore, electrolysis of carbon dioxide with water can yield carbon monoxide, ethylene, methane, formic acid, formate, various hydrocarbons, and organic compounds such as aldehydes and alcohols.

[0008] The process of electrochemically decomposing carbon dioxide is similar to the electrolysis technology of water, but since the activity of the electrochemical reaction improves in a strongly alkaline atmosphere, a KOH aqueous solution of a certain concentration is generally used as an electrolyte. When water is supplied to the anode and current is applied, the water is decomposed into hydrogen ions and electrons along with the generation of oxygen gas. The electrons move to the cathode through an external conductor, and the hydrogen ions move to the cathode through an ion-selective membrane. At this time, the moved electrons react with the carbon dioxide and water supplied to the cathode to produce carbon monoxide and hydroxide ions (OH). -) is decomposed into hydrogen ions (H ) of the anode, and the generated hydroxide ions are converted into hydrogen ions (H ) of the anode. + ) reacts with the electrons to produce water, thereby becoming electrically neutral. Through the above process, the electrochemical decomposition reaction of carbon dioxide is completed. At this time, the water supplied together with the carbon dioxide reacts with the electrons transferred separately from the carbon monoxide production reaction and is electrolyzed to produce hydrogen gas and simultaneously produce hydroxide ions. This reaction of water and electrons can be said to be a competitive reaction with the carbon monoxide production reaction. Since the above reactions are electrochemical reactions, the amount of carbon monoxide produced and the hydrogen / carbon dioxide ratio can be easily controlled by controlling the voltage.

[0009] Meanwhile, in the conventional electrolysis device, OH is generated by a side reaction at the cathode during the carbon dioxide electrolysis process. - is generated, and the above OH - It reacts again with the supplied carbon dioxide to form carbonate (HCO3 - ) occurs. Therefore, the conventional electrolysis device had a problem in that the supplied carbon dioxide was not converted into the desired product and instead generated carbonate, resulting in a loss of carbon dioxide. In addition, the conventional electrolysis device had a problem in that the efficiency of the electrolysis was reduced because the carbonate passed through the anion exchange membrane and diffused to the anode, and carbon dioxide was generated through an oxidation reaction at the anode.

[0010] (Patent Document 001) KR 10-2018-0133688 A

[0011]

[0012] The problem to be solved by the present invention is to provide an electrolysis device that can prevent the loss of carbon dioxide converted into carbonate and improve the yield of products by separating carbon dioxide again from carbonate generated by a side reaction during carbon dioxide electrolysis.

[0013]

[0014] The present invention provides an electrolysis device.

[0015] (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 acid solution storage tank connected to a discharge path for discharging a product from the cathode outside the electrolysis cell, wherein the separator is a cation separation membrane.

[0016] (2) The present invention provides an electrolysis device in which, in the above (1), the acid solution storage tank contains an acid solution including at least one selected from the group consisting of phosphoric acid, hydrochloric acid, sulfuric acid, nitric acid, acetic acid, citric acid, and oxalic acid.

[0017] (3) The present invention provides an electrolysis device in which, in the above (1) or (2), the electrolyte is an aqueous solution containing at least one selected from the group consisting of Cs2CO3, CsHCO3, Cs2SO4, CsCl, CsNO3, K2CO3, KHCO3, K2SO4, K3PO4, KCl, KNO3, Na2CO3, NaHCO3, Na2SO4, Na3PO4, NaCl and NaNO3.

[0018] (4) The present invention provides an electrolytic device in which, in any one of the above (1) to (3), the electrolytic cell is a zero-gap membrane electrode assembly cell in which the gas diffusion layer, the cathode, the separator, and the anode having an anode fluid path formed therein are sequentially stacked.

[0019] (5) The present invention provides an electrolysis device in which a product generated by an electrolytic reaction at the cathode in any one of the above (1) to (4) is transferred to the acid solution storage tank through the discharge path, and the product includes carbon monoxide, water vapor, and salt.

[0020] (6) The present invention provides an electrolysis device in which carbon dioxide generated from the salt in the acid solution storage tank is supplied to the electrolysis cell in the above (5).

[0021] (7) The present invention provides an electrolysis device according to (5) or (6), wherein the salt is a carbonate.

[0022] (8) The present invention provides an electrolysis device that electrolyzes carbon dioxide in any one of the above (1) to (7).

[0023] (9) The present invention provides an electrolysis device in which, in the above (8), the carbon dioxide is supplied to the electrolysis cell in a state including water vapor.

[0024] (10) The present invention provides an electrolytic device in any one of the above (1) to (9), wherein the electrolytic device electrolyzes carbon dioxide to produce at least one selected from the group consisting of carbon monoxide, ethylene, methane, formic acid, hydrocarbons, aldehydes, and alcohols.

[0025]

[0026] 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 a salt generated by a side reaction in the acid solution storage tank.

[0027] In addition, the electrolysis device of the present invention can improve the electrolysis efficiency of carbon dioxide by reducing the loss of carbon dioxide, thereby increasing the yield of the product.

[0028]

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

[0030]

[0031] Hereinafter, the present invention will be described in more detail to facilitate understanding. The terms and words used in this specification and claims should not be interpreted based on their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention, they should be interpreted in a way that aligns with the technical spirit of the present invention.

[0032] The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

[0033] In this specification, it should be understood that the terms “include,” “comprising,” or “having” are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0034]

[0035] The present invention provides an electrolysis device comprising an electrolysis cell including a gas diffusion layer, a cathode (13), a separation membrane (15), an anode (11), and an electrolyte, and an acid solution storage tank (20) connected to a discharge path (30) for discharging a product from the cathode (13) outside the electrolysis cell, wherein the separation membrane (15) is a cation separation membrane.

[0036] According to one embodiment of the present invention, the electrolysis device can be utilized in all fields of electrochemical conversion, and the electrolysis device can be a device capable of producing useful chemical substances through electrochemical conversion such as a fuel cell or water electrolysis, and a device capable of reducing and converting carbon dioxide and NOx. Specifically, the electrolysis device can be an electrochemical conversion device that converts carbon dioxide into carbon monoxide and ethylene.

[0037]

[0038] As described in the background technology above, the electrolysis cell having a structure in which an electrolyte flows through the front surface of the conventional cathode generates OH by a side reaction during the reduction process of carbon dioxide. - It reacts again with carbon dioxide to form carbonate (HCO3 - ) and thus had a problem of carbon dioxide loss, and the problem could be solved by flowing an acidic electrolyte across the front of the cathode, but in this case, additional resistance was generated by the acidic electrolyte, which caused an additional problem of voltage increase. In addition, an anion exchange membrane was mainly used as a separator included in the carbon dioxide electrolysis cell, and although the anion exchange membrane has excellent carbon dioxide conversion efficiency due to fast ion transfer, it has very low mechanical strength, and since the carbonate passes through the anion exchange membrane and diffuses to the anode and generates carbon dioxide through an oxidation reaction at the anode, it had a problem of lowering the efficiency of the electrolysis.

[0039] Accordingly, the inventor of the present invention has developed an electrolysis device capable of reducing the loss of supplied carbon dioxide by separating carbon dioxide again from the generated carbonate without diffusing the generated carbonate to the anode (11). Specifically, the electrolysis device includes an electrolysis cell and an acid solution storage tank (20) connected to the outside of the electrolysis cell. The electrolysis device includes the cathode (13) and the anode (11), and a gas diffusion layer may be disposed in close contact with the cathode (13), and may include a separation membrane (15) and an electrolyte disposed between the cathode (13) and the anode (11). In addition, the electrolysis device according to the present invention may include an electrolysis cell having a structure of a zero-gap membrane electrode assembly to be described later. The electrolytic cell having the above zero-gap membrane electrode assembly structure has a structure in which the electrolyte does not flow in the front portion of the cathode (13) but only in the front portion of the anode (11), thereby solving the additional problem of voltage increasing during the electrolysis reaction. In addition, the electrolytic cell includes a cation exchange membrane, thereby preventing the generated carbonate from being transferred to the anode (11).

[0040]

[0041] Figure 1 is a schematic diagram of a carbon dioxide electrolysis device according to the present invention.

[0042] According to one embodiment of the present invention, the cathode (13) is connected to a supply line through which a reactant is supplied, and a discharge conduit (30) through which a product generated after electrolysis is discharged. The reactant may be carbon dioxide, and the carbon dioxide may be in a gaseous state and may include water vapor at about 40 to 60°C. In addition, the product is generated by electrolysis of the carbon dioxide, and may be at least one selected from the group consisting of carbon monoxide, ethylene, methane, formic acid, hydrocarbons, aldehydes, and alcohols. Unreacted carbon dioxide, water vapor, and carbonates generated by side reactions may be further discharged together with the product discharged from the discharge conduit (30).

[0043] Referring to the above drawing 1, the acid solution storage tank (20) is connected to the discharge path (30), and carbon dioxide can be separated again from the carbonate by the acid solution filled in the acid solution storage tank (20). Specifically, the hydrogen ions (H) of the acid solution contained in the acid solution storage tank (20) + ) and carbonate (HCO3 - ) can react to produce water and carbon dioxide. In addition, the acid solution storage tank (20) may include an acid solution including 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 may react with the produced carbonate to regenerate carbon dioxide, and the electrolysis device of the present invention further includes an acid solution storage tank (20) compared to a conventional electrolysis device, thereby regenerating carbon dioxide from carbonate, thereby improving electrolysis efficiency and reducing the amount of carbon dioxide lost to carbonate.

[0044] According to one embodiment of the present invention, the separation membrane (15) may be a cation separation membrane (15), and specifically, a Nafion separation membrane (15). The cation separation membrane (15) may serve to prevent the carbonate generated at the cathode (13) from diffusing toward the anode (11). Furthermore, when the separation membrane (15) is an anion separation membrane (15), since the carbonate is diffused toward the anode (11), the transport of the carbonate to the acid solution storage tank (20) may not be smooth, which may lower the overall electrolysis efficiency and increase carbon dioxide loss.

[0045] According to one embodiment of the present invention, the electrolyte may be an acidic or neutral electrolyte, and may contain cations (Na + , K + , Cs + ) may be an aqueous solution. For example, it may be Cs2CO3, CsHCO3, Cs2SO4, CsCl, CsNO3, K2CO3, KHCO3, K2SO4, K3PO4, KCl, KNO3, Na2CO3, NaHCO3, Na2SO4, Na3PO4, NaCl, NaNO3.

[0046] 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 an anode (11) liquid path are sequentially laminated. Specifically, the zero-gap membrane electrode assembly may be formed in the form of a very thin plate film in which the gas diffusion layer, the cathode (13), the separator (15), and the anode (11) having an anode (11) liquid path are sequentially laminated in order to increase driving voltage and current efficiency.

[0047] Conventional electrolysis cells have a gap structure in which the electrodes and the separator are spaced apart by a few millimeters, but the zero gap is a sandwich-type electrolysis cell in which the cathode electrode and the anode negative electrode are in contact with each other with the separator in between, thereby eliminating the gap between the electrodes and the separator. The zero gap-type electrolysis cell can reduce the solution ion resistance due to the presence of an electrolyte and reduce the increase in mass transfer resistance due to the generated gas when implementing a large-area electrode.

[0048] In addition, the electrolyte flowing toward the cathode (13) side is called cathode (13) liquid, and the electrolyte flowing toward the anode (11) side is called anode (11) liquid. The zero-gap membrane electrode assembly may not include the cathode (13) liquid, but may include only the anode (11) liquid. The zero-gap membrane electrode assembly may have the advantage of minimizing the gap between the cathode (13), the anode (11), and the separator (15), thereby speeding up the transport of ions, reducing the overvoltage, and increasing the efficiency of the current. In addition, in this case, separators may be arranged on both sides of the zero-gap membrane electrode assembly to form one cell.

[0049] According to one embodiment of the present invention, the discharge path (30) transports the product generated by the electrolytic reaction at the cathode (13) to the acid solution storage tank (20), and the product may include carbon dioxide, carbon monoxide, water vapor, and salt. In addition, the carbon dioxide generated in the acid solution storage tank (20) may be supplied to the electrolysis cell.

[0050] Carbon dioxide is separated from carbonate in the acid solution storage tank (20), and the generated carbon dioxide can be supplied to the cathode (13) again through a supply line. The electrolysis device of the present invention separates carbon dioxide from carbonate by the acid solution storage tank (20), and circulates the carbon dioxide to the electrolysis cell, thereby reducing the loss of carbon dioxide and increasing the electrolysis efficiency.

[0051]

[0052] Hereinafter, the decomposition principle of the electrolysis device and each component of the electrolysis device will be described.

[0053] The above electrolysis refers to decomposing a substance through a redox reaction by applying a direct current voltage to a decomposition reaction that does not occur spontaneously. The anode acts as an oxidation electrode, oxidizing water to generate oxygen, and at this time, hydrogen ions are generated. The hydrogen ions generated at the anode are transferred to the cathode through the electrolyte, and the cathode acts as a reduction electrode, so that reactants introduced to the cathode can react with electrons and hydrogen ions transferred from the anode to generate products. In addition, the separator may be disposed between the anode and the cathode. The separator may be composed of an inert material that does not participate in the electrochemical reaction itself, but may provide a path for ions to move between the anode and the cathode and serve to isolate physical contact between the anode and the cathode.

[0054] In addition, the anode and the cathode of the electrolysis device of the present invention may each include a catalyst layer. In addition, water vapor supplied together with carbon dioxide in the cathode region generates a reduction product through an electroreduction reaction on the cathode surface. Therefore, the cathode may include a gas diffusion layer to evenly 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. In addition, the hydrophobic gas diffusion layer effectively prevents moisture condensation, thereby ensuring a continuous and uniform supply of carbon dioxide and allowing the electrolysis reaction to proceed smoothly. In addition, the catalyst layer may have a surface such as a porous structure so as to exhibit good gas permeability characteristics on the surface.

[0055]

[0056] According to one embodiment of the present invention, the anode may include a catalyst active in the electrolysis of water, and the catalyst layer of the anode may include at least one 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, for an oxygen evolution reaction. Specifically, the anode in the electrolysis device of the present invention may include titanium (Ti) coated with iridium oxide (IrO2).

[0057] In addition, since the carbon dioxide reduction reaction occurring at the cathode competes with the hydrogen evolution reaction, a catalyst that requires a high voltage for the hydrogen evolution reaction and is active in the carbon dioxide reduction reaction may be included. The catalyst layer of the cathode may include at least one selected from the group consisting of Sn, a Sn alloy, Al, Au, Ag, C, Cd, Co, Cr, Cu, a Cu alloy, Ga, Hg, In, Mo, Nb, Ni, NiCo2O4, a Ni alloy, a Ni-Fe alloy, Pb, Rh, Ti, V, W, Zn, and mixtures thereof for the hydrogen evolution reaction. Specifically, the cathode in the electrolysis device of the present invention may include silver (Ag).

[0058] In addition, as described above, the separation membrane may include a cation exchange membrane (CEM), and specifically, may be a Nafion exchange membrane. In the case of the cation exchange membrane, it may act as a bonding membrane that prevents the reducing substance generated at the cathode through catalytic action from moving to the anode and being oxidized, and may be a separation phase that inhibits the permeation of anions and allows cations such as hydrogen ions (H+) to pass through.

[0059]

[0060] In addition, the electrolyte may be an electrolyte according to the present invention as described above, and specifically, may be an acidic electrolyte, and more specifically, may be an aqueous solution containing cesium hydrocarbonate. The electrolyte composition may contain the electrolyte in an amount of 0.1 to 15.0 M, preferably 0.25 to 10.0 M. The concentration of the electrolyte is related to the generation efficiency of the product (the generation efficiency of the target product relative to the applied current density) and the voltage. The higher the concentration of the electrolyte, the lower the generation voltage, required voltage, or overvoltage. However, the above-described conditions are preferable in order to minimize the increase in manufacturing cost and the generation of additional products due to side reactions.

[0061] In addition, the gas diffusion layer may use a porous body using a carbon material such as carbon fiber cloth, carbon fiber felt, or carbon fiber paper, or a metal porous body made of a thin metal plate with a mesh structure such as expanded metal or metal mesh, and in the electrolysis device of the present invention, the gas diffusion layer may use carbon fiber cloth.

[0062] According to one embodiment of the present invention, the electrolysis device can be used in all fields requiring electrochemical conversion, and in particular, can electrochemically decompose carbon dioxide to obtain a desired product, and specifically, the electrolysis device can electrolyze carbon dioxide to produce one or more selected from the group consisting of carbon monoxide, ethylene, methane, formic acid, hydrocarbons, aldehydes, and alcohols.

[0063]

[0064] Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0065]

[0066] Example 1

[0067] A carbon dioxide electrolysis device having the operating conditions described below was operated. The carbon dioxide electrolysis device was operated, which included a membrane electrode assembly having a zero-gap structure in which an anode, a cation separation membrane (type: Nafion®212), a cathode, and a gas diffusion layer were sequentially laminated, and an acid solution storage tank connected to the outside of the cathode and the membrane electrode assembly and filled with an acid solution (85%, H3PO4).

[0068] Reaction current density: 100 mA / cm 2 (Constant current operation)

[0069] Reaction voltage: 1~4 V

[0070] Reaction temperature: 40 ℃

[0071] Reaction pressure: 1 atm (atmospheric pressure)

[0072] Anode catalyst: IrO2on Ti mesh

[0073] Cathode catalyst: Ag powder

[0074] Electrode area: 100 cm 2

[0075] Gas diffusion layer: Sigracet 39BB

[0076] Anode electrolyte: 1.0 M CsHCO3 (25 ml / min)

[0077] Cathode reactant: 40 ℃ Humidified CO2 gas (200 ccm)

[0078] 40 ℃ Humidified CO2 gas supply flow rate: 200 ml / min

[0079]

[0080] Example 2

[0081] The reaction current density is 200 mA / cm 2A carbon dioxide electrolysis device was operated under the same conditions as Example 1, except that it was performed in .

[0082]

[0083] Example 3

[0084] The reaction current density is 300 mA / cm 2 A carbon dioxide electrolysis device was operated under the same conditions as Example 1, except that it was performed in .

[0085]

[0086] Comparative Example 1

[0087] A carbon dioxide electrolysis device was operated under the same conditions as Example 1 except that an anion exchange membrane was used instead of a cation exchange membrane and an acid solution storage tank was not included.

[0088]

[0089] Comparative Example 2

[0090] A carbon dioxide electrolysis device was operated under the same conditions as Example 2 except that an anion exchange membrane was used instead of a cation exchange membrane and an acid solution storage tank was not included.

[0091]

[0092] Comparative Example 3

[0093] A carbon dioxide electrolysis device was operated under the same conditions as Example 3 except that an anion exchange membrane was used instead of a cation exchange membrane and an acid solution storage tank was not included.

[0094]

[0095] Comparative Example 4

[0096] A carbon dioxide electrolysis device was operated under the same conditions as Example 1 except that an acid solution storage tank was not included.

[0097]

[0098] Comparative Example 5

[0099] A carbon dioxide electrolysis device was operated under the same conditions as Example 2 except that an acid solution storage tank was not included.

[0100]

[0101] Comparative Example 6

[0102] A carbon dioxide electrolysis device was operated under the same conditions as Example 3 except that an acid solution storage tank was not included.

[0103]

[0104] Experimental example

[0105] The products resulting from the carbon dioxide reduction reaction in the carbon dioxide electrolysis devices according to Examples 1 to 3 and Comparative Examples 1 to 6 were analyzed by gas chromatography. At this time, the amount of carbon dioxide initially injected and the amount of carbon dioxide generated were compared to measure the amount of carbon dioxide lost without being electrochemically reduced. In addition, the Faraday efficiency of carbon monoxide and hydrogen was measured according to the following measurement method, and the measured characteristics are listed in Table 1 below.

[0106]

[0107] (1) Carbon dioxide loss rate (CO2 Loss, %)

[0108] The gas composition in the exhaust path was measured by GC (Gas-Chromatography) analysis. The flow rate of CO2 emitted after electrochemical conversion (Q) was calculated by multiplying the emitted gas flow rate (mL / min) by the ratio of carbon dioxide (%) measured by GC analysis. CO2 .f) was measured and the initial input flow rate (Q CO2.i) was compared to the total amount of CO2 used (CO2used, %). Since the conversion ratio of CO in the CO2 reduction reaction is 1:1, the flow rate of carbon monoxide gas (Qco) measured by GC analysis was assumed to be the same as the amount of CO2 electrochemically converted (CO2conv, %), and the remainder after subtracting the conversion amount from the CO2 used was calculated as CO2loss. The measured value was calculated using the following mathematical equation 1.

[0109] [Mathematical Formula 1]

[0110]

[0111]

[0112] (2) Carbon monoxide Faraday efficiency (%)

[0113] The gas composition in the exhaust stream was measured using gas chromatography (GC) analysis. In addition, the Faraday efficiency was calculated using the following equation.

[0114] [Equation 2]

[0115]

[0116] In the above mathematical expression 2, Q is the flow rate in the exhaust path, F is the Faraday constant, p is the pressure, T is the measured temperature, and R is the ideal gas constant. The total current (i total ) is the value of the total current applied over time, and the current for the product (i product ) is the volume of gas measured through GC analysis (V product ) is the value calculated from.

[0117]

[0118] (3) Hydrogen Faraday efficiency (%)

[0119] The above hydrogen Faraday efficiency was measured and calculated in the same manner as the carbon monoxide Faraday efficiency (2) above.

[0120]

[0121] Current density (mA / cm) 2 ) Membrane type / Inclusion of acid solution storage tank (O / X) Hydrogen Faradaic efficiency (%) Carbon monoxide Faradaic efficiency (%) Carbon dioxide loss rate (%) Example 1100 Cation exchange membrane / O0.80 100.15 4.72 Example 2200 Cation exchange membrane / O0.90 91.75 4.09 Example 3300 Cation exchange membrane / O3.3 184.10 4.41 Comparative example 1100 Anion exchange membrane / X0.56 100.19 11.04 Comparative example 2200 Anion exchange membrane / X0.67 95.39 20.46 Comparative example 3300 Anion exchange membrane / X0.86 92.04 29.57 Comparative example 4100 Cation Exchange membrane / X2.85100.1914.01Comparative example 5200Cation exchange membrane / X2.2292.0129.00Comparative example 6300Cation exchange membrane / X6.3181.3341.37

[0122] Referring to Table 1 above, it can be seen that in Examples 1 to 3 including an acid solution storage tank, the carbon monoxide Faraday efficiency is maintained at the same level as in Comparative Examples 1 to 6 not including the acid solution storage tank, while the carbon dioxide loss rate is significantly lower.

[0123] That is, the electrolytic device of the present invention can significantly reduce the loss of carbon dioxide converted into carbonate and achieve high electrolysis efficiency by separating carbon dioxide again from carbonate by including an acidic solution storage tank. In contrast, even 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, if an acidic solution storage tank is not included, it can be confirmed that the amount of carbon dioxide lost by being converted into carbonate is large, resulting in a decrease in electrolysis efficiency.

[0124] 11: Anode

[0125] 13: Cathode

[0126] 15: Membrane

[0127] 20: Acid solution storage tank

[0128] 30: Emission Euro

[0129] 60: Gas-liquid separator

Claims

1. An electrolysis cell comprising a gas diffusion layer, a cathode, a separator, an anode, and an electrolyte; and An acid solution storage tank is included outside the electrolysis cell and is connected to a discharge path for discharging a product from the cathode, An electrolysis device wherein the above separation membrane is a cationic separation membrane.

2. In claim 1, An electrolysis device wherein the acid solution storage tank contains an acid solution comprising at least one selected from the group consisting of phosphoric acid, hydrochloric acid, sulfuric acid, nitric acid, acetic acid, citric acid, and oxalic acid.

3. In claim 1, An electrolysis device wherein the electrolyte is an aqueous solution containing at least one selected from the group consisting of Cs2CO3, CsHCO3, Cs2SO4, CsCl, CsNO3, K2CO3, KHCO3, K2SO4, K3PO4, KCl, KNO3, Na2CO3, NaHCO3, Na2SO4, Na3PO4, NaCl and NaNO3.

4. In claim 1, An electrolysis device in which the above electrolysis cell is a zero-gap membrane electrode assembly cell in which the gas diffusion layer, the cathode, the separator, and the anode having an anode liquid path formed therein are sequentially stacked.

5. In claim 1, The product generated by the electrolytic reaction at the cathode is transported to the acid solution storage tank through the discharge path, An electrolytic device wherein the above products include carbon monoxide, water vapor and salt.

6. In claim 5, An electrolysis device in which carbon dioxide generated from the salt in the acid solution storage tank is supplied to the electrolysis cell.

7. In claim 5, An electrolytic device wherein the above salt is a carbonate.

8. In claim 1, The above electrolysis device is an electrolysis device that electrolyzes carbon dioxide.

9. In claim 8, An electrolysis device in which the carbon dioxide is supplied to the electrolysis cell in a state including water vapor.

10. In claim 1, The above electrolysis device is an electrolysis device that electrolyzes carbon dioxide to produce at least one selected from the group consisting of carbon monoxide, ethylene, methane, formic acid, hydrocarbons, aldehydes, and alcohols.

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