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KR-20260066979-A - GAS DIFFUSION ELECTRODES FOR ELECTROCHEMICAL CARBON DIOXIDE REDUCTION AND MANUFACTURING METHOD THEREFOR

KR20260066979AKR 20260066979 AKR20260066979 AKR 20260066979AKR-20260066979-A

Abstract

The present invention relates to a gas diffusion electrode for electrochemical carbon dioxide reduction and a method for manufacturing the same. The gas diffusion electrode for carbon dioxide reduction according to the present invention has the advantage of being able to smoothly discharge moisture and salt components formed on the electrode and maintain high carbon dioxide reduction performance for a long period by ensuring a smooth supply of carbon dioxide. In addition, the excellent physical strength of the nickel foam used as a support layer facilitates the expansion of the electrode area, making it suitable for industrial application.

Inventors

  • 박기태
  • 도영진
  • 오준원
  • 하준수
  • 김승우

Assignees

  • 건국대학교 산학협력단

Dates

Publication Date
20260512
Application Date
20241105

Claims (20)

  1. porous metal substrate layer; A porous layer comprising a carbon compound and a hydrophobic polymer formed on the above porous metal substrate layer; and A gas diffusion electrode for carbon dioxide reduction comprising a catalyst layer formed on the above-mentioned porous layer.
  2. In Article 1, The above gas diffusion electrode is a gas diffusion electrode having a gas permeability of 200 cm³ / cm² /sec/kPa or more under dry carbon dioxide supply conditions.
  3. In Article 1, The above gas diffusion electrode is a gas diffusion electrode having a gas permeability of 10 cm³ / cm² /sec/kPa or more under carbon dioxide supply conditions containing moisture corresponding to a relative humidity of 100% or more.
  4. In Article 1, The above porous metal is a gas diffusion electrode that is a porous metal containing nickel.
  5. In Article 1, The above porous metal substrate layer is a gas diffusion electrode having a pore size of 100 to 1000 μm.
  6. In Article 1, The above porous metal substrate layer is a gas diffusion electrode coated with a hydrophobic polymer.
  7. In either Article 1 or Article 6, A gas diffusion electrode in which the hydrophobic polymer is one or more selected from the group consisting of polytetrafluoroethylene (PTFE), polypropylene (PP), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polyperfluoroalkoxy (PFA), ethylene tetrafluoroethylene (ETFE), polyoxymethylene (POM), and polyimide (PI).
  8. In Article 1, A gas diffusion electrode in which the carbon compound is one or more selected from carbon black, graphite, and carbon fiber.
  9. In Article 1, A gas diffusion electrode in which the carbon compound and hydrophobic polymer of the above-mentioned porous layer are in a weight ratio of 9:1 to 7:3.
  10. In Article 1, A gas diffusion electrode having a BET specific surface area of the above porous layer of 50 m² /g to 300 m² /g.
  11. In Article 1, The above porous layer is a gas diffusion electrode having a pore size of 10 to 300 μm.
  12. In Article 1, The catalyst layer above is a gas diffusion electrode comprising silver (Ag) and Nafion.
  13. In Article 12, A gas diffusion electrode in which the silver (Ag) and Nafion of the catalyst layer are in a weight ratio of 9.5:0.5 to 5:5.
  14. In Article 1, The catalyst layer is a gas diffusion electrode having a contact angle of 125° or more.
  15. In Article 1, The catalyst layer is a gas diffusion electrode having a pore size of 10 to 300 μm.
  16. In Article 1, The above gas diffusion electrode is a gas diffusion electrode having an electrical conductivity of 300 to 400 S/m.
  17. A step of manufacturing a porous metal substrate layer by coating a nickel foam with a hydrophobic polymer; A step of preparing a porous layer by coating a slurry solution mixed with a carbon compound and a hydrophobic polymer onto a porous metal substrate layer; and A method for manufacturing a gas diffusion electrode for carbon dioxide reduction according to claim 1, comprising the step of preparing a catalyst layer by coating a slurry solution mixed with silver and Nafion ionomer onto a porous layer.
  18. In Article 17, The above hydrophobic polymer is one or more selected from the group consisting of polytetrafluoroethylene (PTFE), polypropylene (PP), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polyperfluoroalkoxy (PFA), ethylene tetrafluoroethylene (ETFE), polyoxymethylene (POM), and polyimide (PI).
  19. In Article 17, The above carbon compound is one or more selected from carbon black, graphite, and carbon fiber.
  20. In Article 17, In the step of manufacturing the above porous metal substrate layer, A method further comprising the step of heat-treating at 300 to 350°C after coating with a hydrophobic polymer.

Description

Gas diffusion electrodes for electrochemical carbon dioxide reduction and method for manufacturing the same The present invention relates to a gas diffusion electrode for electrochemical carbon dioxide reduction and a method for manufacturing the same. Electrochemical carbon dioxide reduction technology is a technology that uses electric energy with carbon dioxide as a raw material to produce useful compounds such as carbon monoxide (CO), synthesis gas, formic acid (HCOOH), ethylene (C₂H), and ethanol (C₂H₅OH). In conventional electrochemical carbon dioxide reduction reactions, carbon-based gas diffusion electrodes are mainly used to facilitate electron movement and to smoothly supply the reactant, carbon dioxide, to the catalyst layer (Patent Document 0001, Patent Document 0002). Conventional gas diffusion electrodes consist of a microporous layer formed from carbon black powder, such as Vulcan XC-72, on a support such as carbon paper or carbon cloth having large pores, and a catalyst layer is coated on the microporous layer to be used as an electrode. Although these carbon-based electrodes exhibit excellent performance in the initial stages of use, over time, the hydrophobicity of the electrode decreases, causing moisture and salt to accumulate on the electrode, resulting in a flooding phenomenon that hinders the supply of carbon dioxide to the catalyst layer. Due to this flooding phenomenon, the supply of carbon dioxide, which is a reactant, is inhibited, and the rate of the electrochemical carbon dioxide reduction reaction is limited. Furthermore, as water surrounding the catalyst participates in the reduction reaction instead of carbon dioxide and causes a hydrogen evolution reaction, the Faraday efficiency of the electrochemical carbon dioxide reduction reaction decreases. Consequently, the flooding phenomenon continuously degrades the carbon dioxide reduction performance of carbon-based gas diffusion electrodes, hindering the commercialization of electrochemical carbon dioxide conversion technology. Previous research results have been reported that channels ranging in size from several to several hundred micrometers are created in the microporous layer through a pore-forming agent (Non-patent Literature 0001) or laser perforation (Non-patent Literature 0002) to facilitate the supply of carbon dioxide and the discharge of water, thereby mitigating flooding problems; however, this process is a factor that increases the manufacturing cost of the electrode. Figure 1 shows the manufacturing process of a gas diffusion electrode according to the present invention, a schematic diagram of the gas diffusion electrode, and a surface SEM image. Figure 2 shows SEM images before and after coating the pore layer and the catalyst layer during the manufacturing process of the gas diffusion electrode according to the present invention. Figure 3 is a graph of CO production Faraday efficiency and operating voltage according to current density of comparative examples and embodiments according to the present invention. Figure 4 is a graph of long-term operation data for 50 hours at 200 mA/ cm² of the comparative example and the embodiment according to the present invention. Figure 5 is a graph of contact angle measurements before and after 50 hours of long-term operation of the comparative example and the embodiment according to the present invention. FIG. 6 is a graph of gas permeability measured under dry carbon dioxide supply conditions and carbon dioxide supply conditions containing moisture corresponding to a relative humidity of 100% or more according to the comparative example and embodiment of the present invention. Figure 7 is a graph of the electrical conductivity measurement results of the comparative example and the embodiment according to the present invention. The present invention will be described in detail below. The present invention comprises a porous metal substrate layer; A porous layer comprising a carbon compound and a hydrophobic polymer formed on the above porous metal substrate layer; and A gas diffusion electrode for carbon dioxide reduction is provided, comprising a catalyst layer formed on the above-mentioned porous layer. The porous metal may include nickel, and most preferably, may be in the form of nickel foam. Nickel foam is a porous solid material composed of nickel metal and has a porous form similar to a sponge. The porous metal substrate layer may have a pore size of 100 to 1000 μm. When the pore size of the substrate layer is less than 100 μm, the movement of reactants and products may not be smooth, and when the pore size exceeds 1000 μm, there is a problem of reduced electrical conductivity. The above porous metal substrate layer can be coated with a hydrophobic polymer. In the present invention, the hydrophobic polymer may be one or more selected from the group consisting of polytetrafluoroethylene (PTFE), polypropylene (PP), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF)