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EP-4741052-A1 - OXYGEN GENERATING OXIDE CATALYST FOR ANION EXCHANGE MEMBRANE WATER ELECTROLYSIS AND PREPARATION METHOD THEREFOF

EP4741052A1EP 4741052 A1EP4741052 A1EP 4741052A1EP-4741052-A1

Abstract

The present disclosure relates to an oxygen evolution reaction(OER) oxide catalyst for anion exchange membrane(MEM) water electrolysis doped with various metal atoms using a coprecipitation method, and a preparation method thereof.

Inventors

  • KIM, GIL HO
  • CHAE, GYU SIK
  • CHOI, YENA

Assignees

  • Hanwha Solutions Corporation

Dates

Publication Date
20260513
Application Date
20240805

Claims (16)

  1. An oxidation catalyst for anion exchange membrane water electrolysis comprising a spinel-based oxide of the following Chemical Formula 1: [Chemical Formula 1] Ni 1 -a X a [ Co 2 -b-c Y b Z c ] O 4 in Chemical Formula 1, (0≤a<1), (0≤b<2), and (0≤c≤2), with the proviso that both b and c are not 0, the metal (X) is Co, Fe, Mn, Mg, Zn, or Cu, the metal (Y) is Ni, Fe, or Mn, the metal (Z) is Ni, Fe, or Mn, and the metals (Y) and (Z) are different from each other.
  2. The oxidation catalyst for anion exchange membrane water electrolysis according to claim 1, wherein: the oxidation catalyst for anion exchange membrane water electrolysis comprises a spinel-based oxide of the following Chemical Formula 1-1 or Chemical Formula 1-2: [Chemical Formula 1-1] Ni 1 -a X a [ Co 2 -b' Y b' ] O 4 [Chemical Formula 1-2] Ni [ Co 2-b"-c" Y b" Z c" ] O 4 in Chemical Formula 1-1, (0<a<1), and (0<b'<2), in Chemical Formula 1-2, (0<b"<2), and (0<c"<2), and the metals X, Y, and Z in Chemical Formula 1-1 and Chemical Formula 1-2 are the same as defined in claim 1.
  3. The oxidation catalyst for anion exchange membrane water electrolysis according to claim 2, wherein: in Chemical Formula 1-1, (0.4≤a≤0.6), and (0.4≤b'≤0.6).
  4. The oxidation catalyst for anion exchange membrane water electrolysis according to claim 2, wherein: in Chemical Formula 1-2, (0.2≤b"≤0.3), and (0.8<c"<0.9).
  5. The oxidation catalyst for anion exchange membrane water electrolysis according to claim 1, wherein: in Chemical Formula 1, the metal (X) is Cu, the metal (Y) is Fe or Mn, and the metal (Z) is Ni.
  6. The oxidation catalyst for anion exchange membrane water electrolysis according to claim 1, comprising one or more spinel-based oxides selected from the group consisting of Ni 0.5 Cu 0.5 (Co 1.5 Fe 0.5 )O 4 , Ni 0.5 Cu 0.5 (Co 1.5 Mn 0.5 )O 4 , and Ni(Co 0.9 Fe 0.24 Ni 0.86 )O 4 .
  7. The oxidation catalyst for anion exchange membrane water electrolysis according to claim 1, the catalyst has a particle size span ((D 90 - D 10 )/D 50 ) of 1.0 or more and 5.0 or less.
  8. The oxidation catalyst for anion exchange membrane water electrolysis according to claim 1, wherein: the catalyst has a tap density of 1 g/mL or less.
  9. The oxidation catalyst for anion exchange membrane water electrolysis according to claim 1, wherein: the catalyst exhibits an overvoltage of 310 to 360 mV at a current density of 10 mA cm -2 .
  10. A preparation method of an oxidation catalyst for anion exchange membrane water electrolysis, the method comprising the steps of: coprecipitating a plurality of metal salts in a water solution having a pH of 11 or more in the presence of a complexing agent to form a catalyst precursor; and calcining the catalyst precursor at a temperature of 600°C or less to form a spinel-based oxide of the following Chemical Formula 1: [Chemical Formula 1] Ni 1 -a X a [ Co 2 -b-c Y a Z c ] O 4 in Chemical Formula 1, (0≤a<1), (0≤b<2), and (0≤c≤2), with the proviso that both b and c are not 0, the metal (X) is Co, Fe, Mn, Mg, Zn, or Cu, the metal (Y) is Ni, Fe, or Mn, the metal (Z) is Ni, Fe, or Mn, and the metals (Y) and (Z) are different from each other.
  11. The preparation method of an oxidation catalyst for anion exchange membrane water electrolysis according to claim 10, wherein: in Chemical Formula 1, the metal (X) is Cu, the metal (Y) is Fe or Mn, and the metal (Z) is Ni.
  12. The preparation method of an oxidation catalyst for anion exchange membrane water electrolysis according to claim 1, wherein: the complexing agent includes at least one selected from the group consisting of ammonium hydroxide(NH 4 OH), ammonium sulfate((NH 4 ) 2 SO 4 ), ammonium nitrate(NH 4 NO 3 ), and ammonium phosphate monobasic((NH 4 ) 2 HPO 4 ).
  13. The preparation method of an oxidation catalyst for anion exchange membrane water electrolysis according to claim 10, wherein: the plurality of metal salts each have the form of an acid addition salt of a metal or a hydrate thereof.
  14. An anode for anion exchange membrane water electrolysis comprising the oxidation catalyst according to claim 1 formed on a gas diffusion layer.
  15. The anode for anion exchange membrane water electrolysis according to claim 14, wherein the oxidation catalyst is included in an amount of 0.1 to 10 mg/cm 2 per unit area of the gas diffusion layer.
  16. An anion exchange membrane water electrolysis system comprising: a polymer electrolyte layer; a cathode located on one side of the polymer electrolyte layer; and the anode according to claim 14 located on the other side of the polymer electrolyte layer so that the catalyst layer is in contact with the polymer electrolyte layer.

Description

[TECHNICAL FIELD] CROSS-REFERENCE TO RELATED APPLICATION(S) This application claims the benefit of Korean Patent Application No. 10-2023-0103598 filed on August 8, 2023 with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. The present disclosure relates to an oxygen generating oxide catalyst for anion exchange membrane water electrolysis having excellent catalytic activity, uniform particle size distribution, and large surface area, and a preparation method thereof, and an anode for anion exchange membrane water electrolysis and an anion exchange membrane water electrolysis system including the same. [BACKGROUND] Water electrolysis technology, which produces hydrogen by electrolyzing water, was initiated in the 1800s. This technology has been commercially utilized since the 1920s. In recent years, as a necessity for renewable energy has greatly increased, the production of low-carbon, green hydrogen has been attracting attention as a solution thereof. Representative water electrolysis technologies include an alkaline water electrolysis(AWE) and a proton exchange membrane water electrolysis(PEMWE). The alkaline water electrolysis uses inexpensive nickel-based electrodes and porous membranes and thus has a price competitiveness. However, the gap between the porous diaphragm and the electrodes is wide, which results in high resistance and low current density. In addition, the stack volume is large, the operating cost is high, and the application of the porous diaphragm makes it difficult to rapidly change the current density, which hardly links to renewable energy sources. The cation exchange membrane electrolysis system is MW-scale. The cation exchange membrane water electrolysis can be operated at high current density. It can be designed in a compact manner, have high hydrogen purity, and can keep initial output pressure and minimum load low. It also has a fast response speed, and thus is suitable for linking with renewable energy. Despite these advantages, it requires the use of catalysts and bipolar plates made of precious metals in order to prevent corrosion, and thus the production cost is high. Thus, as a technology to replace the alkaline water electrolysis system and the cation exchange membrane water electrolysis system, an anion exchange membrane water electrolysis system has been proposed. The anion exchange membrane water electrolysis system can be designed in a compact manner, and it operates in the same atmosphere as the alkaline water electrolysis system, which makes it possible to use non-precious metal materials. Therefore, this anion exchange membrane water electrolysis system can take the advantage of both the alkaline water electrolysis system and the cation exchange membrane water electrolysis system. However, in order to improve the performance of such an anion exchange membrane water electrolysis system, in an oxidation electrode(ANODE) where an oxygen evolution reaction involving a larger overvoltage, for example, the reaction of the following reaction formula occurs, the use of an oxidation catalyst that not only exhibits excellent electrical conductivity and catalytic activity but also has high durability is required:         [Reaction Formula 1]      4OH- → O2 + 2H2O + 4e- Considering that the above anion exchange membrane water electrolysis system is operated at a low temperature of about 100°C or less, precious metal catalysts such as IrO2 or RuO2 have been considered as oxidation catalysts that meet the above requirements. However, these precious metal catalysts have high unit prices, which makes it difficult to take advantage of the anion exchange membrane water electrolysis system. Thus, in recent years, studies for applying spinel-based compounds has become active. Pure spinel(AB2O4) structure oxides have high intrinsic activity and excellent durability, but they fail to exhibit the same performance in actual systems. In addition, they have low electrical conductivity, and thus make them difficult to use as oxygen evolution reaction(OER) catalysts for anion exchange membrane(AEM) water electrolysis. To overcome this, a solid state method, sol-gel method, and a precipitation method, which add various dopants, have been proposed, but it is difficult to adjust the catalyst particles, and some particles have a high specific gravity, making it difficult to prepare a slurry. Further, it is difficult to synthesize a spinel structure having various metal atoms in a certain ratio. Therefore, there is a need develop a method for efficiently synthesizing various metal atoms and a multi-component spinel structure oxide catalyst having high water electrolysis performance and uniform particle size produced thereby. [Prior Art Literature] (Patent literature 1) Chinese Patent Publication No. 115224293 [DETAILED DESCRIPTION OF THE INVENTION] [Technical Problem] The present disclosure has been designed to solve the above-ment