Electrochemical carbon dioxide reduction device

Abstract

The present invention relates to an electrochemical carbon dioxide reduction device comprising: a membrane electrode assembly in which a cathode, an ion-exchange membrane and an anode are sequentially stacked; a first bipolar plate provided on the cathode; and a second bipolar plate provided on the anode, wherein the cathode has a first catalyst layer comprising a Pt catalyst and a second catalyst layer comprising a catalyst of Ag and / or Au, each being disposed on the ion-exchange membrane, the first catalyst layer being disposed adjacent to a fluid inlet of the first bipolar plate, and the second catalyst layer being disposed adjacent to a fluid outlet of the first bipolar plate.

Description

Electrochemical carbon dioxide reduction device

[0001] The present invention relates to an electrochemical carbon dioxide reduction device.

[0002] The indiscriminate use of fossil fuels has caused carbon dioxide emissions that have led to significant problems for human society, such as the greenhouse effect and ecosystem disruption. To overcome this, research is being conducted on methods that utilize carbon dioxide conversion technologies not only for storage but also for converting carbon dioxide into useful resources for consumption across various sectors. Technologies for carbon dioxide conversion include photochemical, electrochemical, and biochemical methods; among these, the electrochemical method is expected to be the most suitable for commercialization. The electrochemical method has the advantage of enabling the conversion of carbon dioxide into various compounds (HCOOH, CH4, CO, C2H4) depending on the type of catalyst, voltage intensity, and reaction conditions, while also allowing for the control of compound selectivity.

[0003] However, commercialization of the electrochemical carbon dioxide reduction method faces significant challenges due to the difficulty in controlling the type and amount of the generated compounds. Therefore, research is needed on means to easily control the type and amount of compounds produced in electrochemical carbon dioxide reduction.

[0004] [Prior Art Literature]

[0005] [Patent Literature]

[0006] Republic of Korea Published Patent Application No. 10-2022-0078863

[0007] The present invention aims to provide an electrochemical carbon dioxide reduction device capable of easily controlling the type and production ratio of compounds obtained through the reduction of carbon dioxide.

[0008] However, the technical problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned problems will be clearly understood by a person skilled in the art from the description below.

[0009] One embodiment of the present invention comprises: a membrane electrode assembly in which a cathode, an ion exchange membrane, and an anode are sequentially stacked; a first bipolar plate provided on the cathode; and a second bipolar plate provided on the anode.

[0010] The present invention provides an electrochemical carbon dioxide reduction apparatus wherein the cathode comprises a first catalyst layer comprising a Pt catalyst and a second catalyst layer comprising at least one of Ag and Au, each disposed on the ion exchange membrane, wherein the first catalyst layer is disposed adjacent to a fluid inlet of the first bipolar plate and the second catalyst layer is disposed adjacent to a fluid outlet of the first bipolar plate.

[0011] The electrochemical carbon dioxide reduction apparatus according to the present invention has the advantage of being able to easily control the type and amount of compounds generated from carbon dioxide. Specifically, the electrochemical carbon dioxide reduction apparatus according to the present invention can obtain synthesis gas in which the mixing ratio of hydrogen and carbon monoxide is controlled by controlling the area of ​​the first catalyst layer and the second catalyst layer of the cathode, which are compounds generated by the reduction of carbon dioxide.

[0012] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by a person skilled in the art from the description below.

[0013] Figure 1 shows the configuration and fluid flow of an electrochemical carbon dioxide reduction device according to one embodiment of the present invention.

[0014] Figure 2 shows the carbon monoxide generation current density and Faraday efficiency for carbon monoxide according to the amount of Ag catalyst loaded on the cathode in the reference example.

[0015] Figure 3 shows the selectivity ratio of hydrogen / carbon monoxide according to the area ratio of the first catalyst layer and the second catalyst layer according to the embodiment.

[0016] Figure 4 shows the reaction voltage according to the carbon dioxide reduction reaction time of the electrochemical carbon dioxide reduction device according to the example and comparative example.

[0017] In this specification, when a part is described as "comprising" a certain component, it means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0018] In this specification, when a member is described as being located "on" another member, this includes not only cases where a member is in contact with another member, but also cases where another member exists between the two members.

[0019] The electrochemical carbon dioxide reduction reaction is a technology in which various compounds (e.g., carbon monoxide, formic acid, methane, ethylene, ethanol, etc.) are produced depending on the type of metal used as the electrode when voltage is applied to the electrode. Conventional research on electrochemical carbon dioxide reduction has focused on the development of catalysts capable of increasing selectivity for carbon monoxide in order to obtain carbon monoxide with excellent commercial value. Furthermore, research has shown that it is advantageous to produce a mixed gas by incorporating a predetermined amount of hydrogen into carbon monoxide according to the purpose, and then use this as a raw material to produce products of higher added value. The inventors conducted research to obtain a mixed gas of carbon monoxide and hydrogen with a desired compositional ratio without the incorporation of separate hydrogen through a carbon dioxide reduction process, and as a result, have completed the present invention. Specifically, when a single catalyst layer was prepared by mixing a catalyst capable of obtaining carbon monoxide from carbon dioxide with a different catalyst capable of obtaining hydrogen from carbon monoxide, the production amounts of carbon monoxide and hydrogen were not maintained at a constant level, and the compositional ratio of the generated gases could not be controlled. Accordingly, it was confirmed that the compositional ratio of the generated mixed gas can be easily controlled by a simple method of separating the catalyst for producing carbon monoxide and the catalyst for producing hydrogen within the catalyst layer through the reduction of carbon dioxide and adjusting their surface areas.

[0020] The present invention will be described in detail below.

[0021] One embodiment of the present invention comprises: a membrane electrode assembly in which a cathode, an ion exchange membrane, and an anode are sequentially stacked; a first bipolar plate provided on the cathode; and a second bipolar plate provided on the anode.

[0022] The present invention provides an electrochemical carbon dioxide reduction apparatus wherein the cathode comprises a first catalyst layer comprising a Pt catalyst and a second catalyst layer comprising at least one of Ag and Au, each disposed on the ion exchange membrane, wherein the first catalyst layer is disposed adjacent to a fluid inlet of the first bipolar plate and the second catalyst layer is disposed adjacent to a fluid outlet of the first bipolar plate.

[0023] According to one embodiment of the present invention, the first catalyst layer and the second catalyst layer may be arranged parallel to each other as layers of the same level on the ion exchange membrane. Specifically, the first catalyst layer and the second catalyst layer are each provided on the ion exchange membrane, and adjacent sides between the first catalyst layer and the second catalyst layer may be provided in contact with each other.

[0024] According to one embodiment of the present invention, the first catalyst layer may include a first catalyst particle that primarily generates hydrogen through a reduction reaction of carbon dioxide. Additionally, the second catalyst layer may include a second catalyst particle that primarily generates carbon monoxide through a reduction reaction of carbon dioxide.

[0025] According to one embodiment of the present invention, the first catalyst particle may be a Pt particle or a mixture of a Pt particle and another metal particle, or an alloy particle of Pt and another metal. Specifically, the first catalyst particle may be a Pt particle. The Pt particle may be supported on a carrier, wherein the carrier may be a porous carbon material carrier. Commercially available Pt / C particles may be used as the Pt particle.

[0026] According to one embodiment of the present invention, the second catalyst particle may be an Ag particle or an Au particle, or a mixture thereof. Additionally, the second catalyst particle may be an alloy particle comprising at least one metal among Ag and Au. Specifically, according to one embodiment of the present invention, the second catalyst particle may be an Ag particle. The second catalyst particle may utilize a commercially available metal particle comprising the metal element.

[0027] According to one embodiment of the present invention, the first catalyst layer is positioned adjacent to the fluid inlet of the first bipolar plate and first reacts with water vapor introduced along with carbon dioxide (and / or water vapor delivered through an ion exchange membrane via water supplied through an anode) to produce hydrogen, and then sequentially reacts with carbon dioxide in the second catalyst layer to produce carbon monoxide. Through such arrangement of the first and second catalyst layers, it is possible to prevent carbon monoxide resulting from the reduction of carbon dioxide in the second catalyst layer from reaching the first catalyst layer and poisoning the Pt particles within the first catalyst layer.

[0028] According to one embodiment of the present invention, water vapor introduced into the cathode can generate hydrogen in the first catalyst layer of the cathode through the following reaction equation 1.

[0029] [Reaction Equation 1]

[0030] 2H2O + 2e - → H2 + 2OH -

[0031] Furthermore, the remaining carbon dioxide that is not reduced in the first catalyst layer moves to the second catalyst layer of the cathode and can produce carbon monoxide through the following reaction equation 2.

[0032] [Reaction Equation 2]

[0033] CO2 + 2e - + 2H2O → CO + 2OH -

[0034] FIG. 1 illustrates the configuration and fluid flow of an electrochemical carbon dioxide reduction apparatus according to one embodiment of the present invention. Specifically, FIG. 1 illustrates the reduction of carbon dioxide by introducing an electrolyte solution (e.g., KHCO3 aqueous solution) into the anode (30) through the fluid inlet of the second bipolar plate (300), introducing carbon dioxide into the cathode (21, 22), and applying electricity. Specifically, it illustrates the reduction of carbon dioxide by introducing carbon dioxide (and water vapor) into the first catalyst layer (21) of the cathode through the fluid inlet of the first bipolar plate (200) and applying electricity so that carbon dioxide can be sequentially reduced in the second catalyst layer (22) of the cathode, thereby producing a synthesis gas containing hydrogen and carbon monoxide through the fluid outlet of the bipolar plate (200).

[0035] According to one embodiment of the present invention, the first catalyst layer and the second catalyst layer may each further include an ionomer. Specifically, the first catalyst layer and the second catalyst layer may include the same ionomer or different ionomers. The ionomer acts as a binder for the first catalyst layer and the second catalyst layer and can position catalyst particles within each catalyst layer so that each catalyst layer can function as a double layer.

[0036] According to one embodiment of the present invention, the ionomer may mean a polymer or copolymer containing both electrically neutral repeating units and ionized repeating units. The ionized repeating units are covalently bonded to the polymer backbone. Generally, the proportion of ionized units may be in the range of about 1 mol% to about 90 mol%. Specifically, the ionomer may be an anion exchange ionomer. More specifically, the anion exchange ionomer may include anion exchange groups such as 1st to tertiary amino groups, quaternary ammonium bases, pyridyl groups, imidazole groups, quaternary pyridinium bases and / or quaternary imidazolium bases. The anion exchange groups may enable charge balance by anions. The ionomer may also include a polymer composition containing quaternary ammonium, sulfonium, phosphagenium, and guanidinium residues or salts attached or immobilized as functional groups. The above ionomer may be completely or partially fluorinated, or may be a polymer comprising a sulfonate, sulfonimide, phosphate, a phosphonic acid group and / or a sulfonic group. For example, the ionomer may be perfluorosulfonic acid (PSFA) (e.g., Nafion®), perfluoroalkyl sulfonimide ionomer (PFSI), polytetrafluoroethylene (PTFE) (e.g., Teflon®), polyvinylidene fluoride (PVDF), polystyrene sulfonic acid (PSSA), poly(trifluoromethanesulfonic acid) (PTFMSA), poly(acrylic acid) (PAA), poly(methacrylic acid) (PMAA), poly(vinyl alcohol-sodium acrylate copolymer) (poly(vinyl alcohol-co-sodium acrylate)), polybenzimidazole (PBI), FLEMION®, SELEMION®, and / or Sustainion®.

[0037] According to one embodiment of the present invention, in the first catalyst layer and / or the second catalyst layer, the ionomer may be included in an amount of 10 wt% to 30 wt%. Within the above content range, the ionomer can effectively fix the catalyst particles within each catalyst layer, form the catalyst layer, and allow carbon dioxide to be supplied appropriately to the catalyst particles.

[0038] According to one embodiment of the present invention, the catalyst loading amount of the first catalyst layer and the second catalyst layer may be 0.25 mg / cm² to 0.5 mg / cm² or less, respectively. If the catalyst loading amount is less than the above range, the reduction reaction of carbon dioxide may not be sufficiently carried out in each catalyst layer due to a lack of catalytic reaction active area in the first and / or second catalyst layers. Furthermore, if the catalyst loading amount exceeds the above range, the amount of catalyst in the first and / or second catalyst layers is excessive and may obstruct the flow of supplied carbon dioxide, and accordingly, the current density and / or Faraday efficiency may decrease in the carbon dioxide reduction reaction.

[0039] According to one embodiment of the present invention, the thickness of the first catalyst layer and the second catalyst layer may each be 10 μm to 100 μm, specifically 20 μm to 70 μm, or 30 μm to 50 μm. Within the thickness range, the first and second catalyst layers can maximize the reduction efficiency of carbon dioxide to produce a desired product gas in each catalyst layer.

[0040] As described above, the electrochemical carbon dioxide reduction apparatus according to the present invention can easily control the ratio of the generated gas resulting from carbon dioxide reduction by adjusting the area of ​​the first catalyst layer and the second catalyst layer of the cathode. For example, the ratio of hydrogen and carbon monoxide, which are the generated gases, can be controlled by adjusting the area ratio of the first catalyst layer and the second catalyst layer to a variety of values, such as 0.4:1 to 9:1. Specifically, since a synthesis gas containing hydrogen and carbon monoxide in a volume ratio of approximately 1.8:1 to 2.3:1 is commercially easy to utilize, the area ratio of the first catalyst layer and the second catalyst layer can be adjusted to 5:1 to 8:1, or 5.5:1 to 7.5:1, in order to produce such a synthesis gas.

[0041] According to one embodiment of the present invention, a gas diffusion layer may be further included between the cathode and the first bipolar plate. The gas diffusion layer may be a conductive porous body, such as a carbon porous body like carbon paper, carbon cloth, or glass-shaped carbon, or a metal porous body like metal mesh or foamed metal. However, it is not limited thereto, and the gas diffusion layer may use commercially available materials or products.

[0042] According to one embodiment of the present invention, the ion exchange membrane comprises an ion exchange resin, and the ion exchange resin may be a polycation and / or a polyanion. The ion exchange membrane may induce carbon dioxide reduction in an electrochemical carbon dioxide reduction device by allowing the counterions of the charged functional groups in the ion exchange resin to move through the ion exchange membrane matrix under the influence of the application of electrical energy and / or a concentration gradient.

[0043] According to one embodiment of the present invention, the ion exchange membrane may be a cation exchange membrane obtained by sulfonating a styrene-divinylbenzene copolymer, a cation exchange membrane based on a copolymer of tetrafluoroethylene and perfluorosulfonylethoxyvinyl ether with sulfonic acid groups introduced therein, a cation exchange membrane composed of a copolymer of tetrafluoroethylene and a perfluorovinyl ether having carboxyl groups in its side chain, or a cation exchange membrane based on an aromatic polysulfone copolymer with sulfonic acid groups introduced therein. Additionally, the ion exchange membrane may be an anion exchange membrane based on a copolymer of styrene-divinylbenzene with chloromethyl groups introduced and amination, an anion exchange membrane based on a copolymer of vinylpyridine-divinylbenzene with quaternary pyridium, or an anion exchange membrane based on an aromatic polysulfone copolymer with chloromethyl groups introduced and amination. Specifically, according to one embodiment of the present invention, the ion exchange membrane may be an anion exchange membrane. However, it is not limited thereto, and any ion exchange membrane known in the art may be appropriately applied depending on the application.

[0044] According to one embodiment of the present invention, the cathode may not contain a liquid electrolyte. By not supplying a liquid electrolyte to the cathode, there is an advantage in that the process of separating liquid and gas to obtain synthesis gas produced through carbon dioxide reduction can be omitted. In addition, there is an advantage in that the carbon dioxide reduction process can be performed through a relatively high available reaction current by preventing the supplied carbon dioxide from dissolving in the liquid electrolyte to perform the reduction process.

[0045] According to one embodiment of the present invention, the anode may be supplied with an aqueous solution containing an electrolyte, and the moisture supplied through the anode may be partially transferred to the cathode in a gaseous state through an ion exchange membrane to increase the reaction efficiency at the cathode.

[0046] According to one embodiment of the present invention, the anode may comprise at least one metal among Ru, Ir, and Ti. As described above, water is introduced toward the anode, and oxygen may be generated in the anode layer according to an electrochemical carbon dioxide reduction reaction.

[0047] According to one embodiment of the present invention, the first and second bipolar plates each include a fluid inlet, a fluid path through which fluid can move, and a fluid outlet, and the incoming fluid moves through the fluid path (through a gas diffusion layer) and can supply fluid to the cathode and anode, respectively. The first and second bipolar plates are not particularly limited and products commonly used in the industry may be applied.

[0048] Hereinafter, the present invention will be described in detail with reference to examples to specifically explain the invention. However, the embodiments according to the present invention may be modified in various different forms, and the scope of the present invention is not to be interpreted as being limited to the embodiments described below. The embodiments of this specification are provided to more completely explain the present invention to those with average knowledge in the art.

[0049] [Reference Example]

[0050] To determine the optimal catalyst loading amount of the cathode, the following experiment was performed.

[0051] Approximately 75 wt% of Ag catalyst particles (Ag, CAS.No: 7440-22-4, Avension) and approximately 25 wt% of ionomer (Sustainion® XA-9 Alkaline Ionomer) were placed in a Teflon beaker with 30 mL of ethanol solvent and mixed using a horn sonicator for about 30 minutes to obtain a homogeneous coating solution. The density of Ag catalyst particles supported on the final catalyst layer was 0.15 mg / cm³. 2 to 1.3 mg / cm² 2After preparing various amounts of Ag catalyst particles in the coating solution so as to be, the solution is heated to a temperature of approximately 70°C and the coating solution is 15 x 15 cm 2 A catalyst electrode was formed by spray coating on carbon paper.

[0052] 9 x 9 cm 2 An anion exchange membrane of size X37-50 (DIOXIDE MATERIALS) was stored in a 1M KOH solution for 24 hours to OH - After substituting with functional groups, a carbon paper supported with iridium oxide was placed as an anode on one side of the anion exchange membrane, and a previously prepared catalyst electrode was placed as a cathode on the other side of the anion exchange membrane to manufacture a membrane electrode assembly.

[0053] Then, a bipolar plate with an engraved flow path formed on each side of the prepared membrane electrode assembly, a gasket, and an end-plate were sequentially arranged and assembled to manufacture an electrochemical carbon dioxide reduction device.

[0054] In the prepared carbon dioxide reduction apparatus, carbon dioxide gas was supplied to the cathode at a flow rate of 300 sccm, and a 0.1 M aqueous KHCO3 electrolyte solution was supplied to the anode at a flow rate of 20 sccm. Electrochemical carbon dioxide reduction was performed by applying a voltage in the range of 3.1 V to 3.6 V using a power supply. At this time, the H2 / CO mixed gas generated on the MEA surface was qualitatively and quantitatively analyzed using gas chromatography. Furthermore, the concentration of each product was quantified using a calibration curve, the number of charges consumed in the reaction with the corresponding compound was obtained and plotted as the Faraday efficiency, which is the ratio to the total reaction charge, and the ratio of the two gas products was compared.

[0055] Figure 2 shows the carbon monoxide generation current density and Faraday efficiency for carbon monoxide according to the amount of Ag catalyst loaded on the cathode in the reference example. According to the results in Figure 2, the amount of Ag catalyst loaded on the carbon paper is 0.15 mg / cm² 2 In the case corresponding to this, the CO generation current density is 140 mA / cm² due to insufficient reaction active area. 2 It was measured as . The loading of Ag catalyst was 0.28 mg / cm² 2 0.30 mg / cm² 2 When deposited within the range, the CO generation current density is 201 mA / cm² 2 At 196 mA / cm 2 As it increased within the range, CO production also increased. Also, the Ag catalyst loading was 0.28 mg / cm² 2 0.30 mg / cm² 2 When deposited within the specified range, the CO Faraday efficiency, which represents the electronic efficiency used in the CO production reaction from CO2 reduction, also increased to 96% and 97%, indicating that the reaction was carried out with superior efficiency. However, the Ag catalyst loading was 0.30 mg / cm² 2 Exceeding 0.45 mg / cm² 2 In this case, the current density and Faraday efficiency are 186 mA / cm², respectively. 2 and decreased to 95%. In addition, the loading of the Ag catalyst was higher at 0.52 mg / cm² 2 The current density and Faraday efficiency at are 182 mA / cm², respectively. 2 and showed results reduced to 91%, with the Ag catalyst loading being 1.3 mg / cm² 2 In the case of 73 mA / cm 2 Low catalytic activity with a current density and a Faraday efficiency of 25% was observed. This can be understood as the activity being inhibited because, when the loading amount of Ag catalyst is excessively high, it blocks the microporous layer (MPL) of the carbon paper, thereby hindering the flow of carbon dioxide from the back side.

[0056] Through this, it was found that controlling the loading amount of catalyst particles in the cathode catalyst layer to 0.25 mg / cm² to 0.5 mg / cm² or less can maximize catalytic activity.

[0057] [Example]

[0058] Approximately 80 wt% of Pt / C catalyst particles (Pt 10 wt%, CAS.No: 7440-06-4, Alfa Aesar) and approximately 20 wt% of ionomer (Sustainion® XA-9 Alkaline Ionomer) were placed in a Teflon beaker with 30 mL of ethanol solvent and mixed for approximately 30 minutes using a horn sonicator to obtain a homogeneous first coating solution.

[0059] Then, about 80 wt% of Ag catalyst particles (Ag, CAS.No: 7440-22-4, Avension) and about 20 wt% of ionomer (Sustainion® XA-9 Alkaline Ionomer) were placed in a Teflon beaker with 30 mL of ethanol solvent and mixed for about 30 minutes using a horn sonicator to obtain a homogeneous second coating solution.

[0060] Leave the area adjacent to the fluid inlet of the bipolar plate empty with a mask of 15 x 15 cm 2A first catalyst layer was formed by placing it on carbon paper, heating it to a temperature of about 70°C, and applying a first coating solution so that the catalyst loading amount was about 30 mg / cm². Then, a mask was placed so that the remaining area of ​​the carbon paper (the area in contact with the first catalyst layer and adjacent to the fluid outlet of the bipolar plate) was empty, and a second coating solution was applied to form a second catalyst layer so that the catalyst loading amount was about 30 mg / cm² while heating it to a temperature of about 70°C, thereby manufacturing a catalyst electrode (cathode). At this time, the area ratio of the first catalyst layer and the second catalyst layer was adjusted to 9:1 to 0.43:1, respectively, and an electrochemical carbon dioxide reduction device was manufactured as in the reference example above, and a carbon dioxide reduction reaction was performed.

[0061] FIG. 3 shows the selectivity ratio of hydrogen / carbon monoxide according to the area ratio of the first catalyst layer and the second catalyst layer according to the embodiment. FIG. 3 shows that the mixing ratio of hydrogen and carbon monoxide generated through the electrochemical carbon dioxide reduction device according to the embodiment is proportional to the area ratio of the first catalyst layer and the second catalyst layer of the cathode (R 2 =0.9988). Through this, it was confirmed that the gas mixing ratio in the synthesis gas can be easily controlled by adjusting the area ratio of the first catalyst layer and the second catalyst layer of the cathode according to the purpose. For example, it was confirmed that in order to obtain a synthesis gas with a volume ratio of hydrogen to carbon monoxide of about 2:1, it is necessary to adjust the area of ​​the first catalyst layer and the second catalyst layer to about 6:1.

[0062] [Comparative Example]

[0063] Except for manufacturing a catalyst electrode (cathode) by swapping the positions of the first catalyst layer and the second catalyst layer in the example, an electrochemical carbon dioxide reduction device was manufactured as in the reference example above, and a carbon dioxide reduction reaction was performed.

[0064] Figure 4 shows the reaction voltage according to the carbon dioxide reduction reaction time of an electrochemical carbon dioxide reduction device according to the example and comparative example. As can be seen in Figure 4, in the comparative example where the carbon dioxide reduction reaction is performed first at the cathode, a higher voltage than in the example is required to produce H2 / CO synthesis gas at the same rate, and it can be seen that a higher reaction voltage is required as time passes. In contrast, in the case of the example, it can be seen that a stable low overvoltage is maintained over time. This can be interpreted as being due to the carbon monoxide poisoning of the Pt / C catalyst particles caused by carbon monoxide preferentially generated by the Ag catalyst particles at the cathode of the comparative example, which leads to a decrease in catalytic activity. In contrast, in the case of the example, by adjusting the arrangement of the first catalyst layer and the second catalyst layer so that the Pt / C catalyst preferentially performs carbon dioxide reduction and the Ag catalyst particles subsequently perform carbon dioxide reduction, the carbon monoxide poisoning of the Pt / C catalyst particles was prevented, and a stable reaction voltage could be maintained as shown in Figure 4.

[0065] [Explanation of the symbol]

[0066] 100: Membrane electrode assembly

[0067] 10: Ion exchange membrane

[0068] 21: First catalyst layer of the cathode

[0069] 22: Second catalytic layer of the cathode

[0070] 30: Anode

[0071] 200: 1st bipolar plate

[0072] 300: Second bipolar plate

Claims

1. A membrane electrode assembly having a cathode, an ion exchange membrane, and an anode sequentially stacked; a first bipolar plate provided on the cathode; and a second bipolar plate provided on the anode; comprising, The above cathode comprises a first catalyst layer including a Pt catalyst and a second catalyst layer including at least one of Ag and Au catalysts, each disposed on the ion exchange membrane. The first catalyst layer is disposed adjacent to the fluid inlet of the first bipolar plate, and the second catalyst layer is disposed adjacent to the fluid outlet of the first bipolar plate. Electrochemical carbon dioxide reduction device.

2. In Claim 1, An electrochemical carbon dioxide reduction device in which the first catalyst layer and the second catalyst layer each further comprise an ionomer.

3. In Claim 2, An electrochemical carbon dioxide reduction device having catalyst loading amounts of the first catalyst layer and the second catalyst layer of 0.25 mg / cm² to 0.5 mg / cm² or less, respectively.

4. In Claim 1, An electrochemical carbon dioxide reduction device having an area ratio of the first catalyst layer and the second catalyst layer of 5:1 to 8:

1.

5. In Claim 1, An electrochemical carbon dioxide reduction device in which the above ion exchange membrane is an anion exchange membrane.

6. In Claim 1, An electrochemical carbon dioxide reduction device in which the above cathode does not contain a liquid electrolyte.

7. In Claim 1, An electrochemical carbon dioxide reduction device further comprising a gas diffusion layer between the cathode and the first bipolar plate.

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