KR-102962844-B1 - Electrocatalyst for Water Electrolysis, Water Electrolysis System Using the Same, and Method for Producing Hydrogen Using the Same

Abstract

The present invention relates to a water electrolysis catalyst, a water electrolysis system using the same, and a method for producing hydrogen using the same. A water electrolysis catalyst according to one embodiment of the present invention comprises: a core made of a metal oxide; and a shell formed to surround the outside of the core.

Inventors

• 장혜진

Assignees

• 주식회사 라피스타

Dates

Publication Date

20260511

Application Date

20250702

Claims (20)

1. A core made of metal oxide; and A shell formed to surround the outside of the above core; As a water electrolysis catalyst comprising, The above core is a metal oxide composite containing nickel (Ni) and iron (Fe), and The above shell comprises cerium oxide ( CeO2 ), and The above core is a nanoparticle with an average diameter of 5 nm to 100 nm, and The above-mentioned water electrolysis catalyst is in the form of a nanoparticle with a core-shell structure in which the shell is continuously formed around the core. Water electrolysis catalyst.
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4. In paragraph 1, The above core is one in which the mole fraction of Ni metal is 20 to 99 based on the total metal of the core, Water electrolysis catalyst.
5. In paragraph 1, The above core is one in which the mole fraction of Fe metal is 20 to 99 based on the total metal of the core, Water electrolysis catalyst.
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10. In paragraph 1, The above shell has an average thickness of 2 nm to 20 nm, Water electrolysis catalyst.
11. In paragraph 1, A second shell surrounding the outer side of the above shell; including more, Water electrolysis catalyst.
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15. In Paragraph 11, The second shell comprises at least one selected from the group consisting of cerium oxide ( CeO2 ), titanium oxide ( TiO2 ), tungsten oxide ( WO3 ), iron oxide ( Fe2O3 , Fe3O4 ), cobalt oxide ( Co3O4 ), manganese oxide ( MnO2 ), nickel oxide (NiO), molybdenum oxide ( MoO3 ), vanadium oxide ( V2O5 ) , and copper oxide (CuO, Cu2O ). Water electrolysis catalyst.
16. In Paragraph 11, The second shell above has an average thickness of 2 nm to 20 nm or less, Water electrolysis catalyst.
17. In paragraph 1, The above water electrolysis catalyst, in a water electrolysis cell environment under conditions of 0.3 M KOH aqueous solution and 60 ℃, A voltage drop of 50 mV or less even under repetitive current conditions of 1,000 cycles or more at a current density of 1 A/cm², Water electrolysis catalyst.
18. In paragraph 1, The above-mentioned water electrolysis catalyst is, Applied as an oxidation reaction electrode in water electrolysis systems, CO2 electroreduction reactions, fuel cell reactions, electrochemical sensors, or Carbon Capture, Utilization and Storage (CCUS) systems, Water electrolysis catalyst.
19. Water containing alkaline electrolytes; The cathode immersed in the above water; and It includes an anode coated with a water electrolysis catalyst according to claim 1, and A water electrolysis system in which oxygen is generated at the anode and hydrogen at the cathode when a voltage is applied between the anode and the cathode.
20. A water electrolysis system pursuant to Paragraph 19 that decomposes water to produce hydrogen generation and oxygen generation reactions, Hydrogen production method.

Description

Electrocatalyst for Water Electrolysis, Water Electrolysis System Using the Same, and Method for Producing Hydrogen Using the Same The present invention relates to a water electrolysis catalyst, a water electrolysis system using the same, and a method for producing hydrogen using the same. In water electrolysis, the oxygen evolution reaction (OER) has a more complex reaction mechanism and more reaction steps compared to the hydrogen evolution reaction (HER), resulting in a slower reaction rate; consequently, it acts as a major factor determining the overall rate of the water electrolysis reaction. Therefore, research on oxygen evolution reaction (OER) catalysts and electrodes is actively underway to improve the overall reaction efficiency of water electrolysis. Iridium (Ir)-based catalysts are representative catalysts for the oxygen evolution reaction (OER). Although they exhibit excellent catalytic activity, their supply is limited due to an annual mining volume of only about 7 tons, and their high price is a major factor in the increase of hydrogen production costs. Accordingly, to ensure the economic viability of water electrolysis systems, the development of highly active non-precious metal-based catalysts to replace iridium is actively underway. Representative non-precious metal OER catalysts include nickel-iron oxide (NiFeOx) and cobalt oxide (CoOx). However, as metal components are leached out during the electrochemical reaction process, catalytic activity gradually decreases, which is a major cause of the deterioration in the durability of the water electrolysis system. For water electrolysis devices to be widely applied across various industries, the development of electrodes possessing both high performance and high durability is essential, and to this end, various studies are actively underway to improve the activity and stability of catalysts. Various strategies such as metal oxide composition optimization, surface structure control, doping, and surface modification are being studied, and some achievements in improving catalyst activity and durability have actually been reported. However, unresolved challenges remain, such as structural degradation of catalysts during long-term operation, the leaching of metal ions, and stability issues at the electrode-electrolyte interface, which still limits the ability to secure catalyst and electrode technologies that simultaneously satisfy commercial-level performance and durability. As one strategy to overcome these limitations, cerium (Ce) is attracting attention as a material for electrochemical reactions based on its excellent oxygen storage capacity. Cerium can facilitate the transfer of electrons and oxygen ions through the reversible electron transition characteristics of Ce³⁺ / Ce⁴⁺ , which can assist in catalytic reactions or contribute to enhancing the structural stability of metal oxide catalysts. In particular, it has been reported to play a role in suppressing metal leaching or regulating oxygen reaction pathways on the surface. However, excessive cerium content can lead to side effects such as reduced electrical conductivity or blockage of reaction sites. In fact, research is underway to enhance the durability and activity of catalysts by synthesizing cerium in the form of complex oxides by combining it with nickel, iron, cobalt, etc., by dispersing or adsorbing cerium oxide nanoparticles on the surface, or by applying cerium via doping. The aforementioned background technology is one that the inventor possessed or acquired in the process of deriving the disclosure of the present invention, and it cannot be considered as prior art disclosed to the general public prior to the filing of this application. FIG. 1 is a schematic cross-sectional view of a water electrolysis catalyst according to one embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a water electrolysis catalyst according to another embodiment of the present invention. FIG. 3 is a schematic diagram of a water electrolysis cell according to an embodiment of the present invention. Figure 4 is a graph showing the results before and after the Accelerated Stress Test of the water electrolysis cells of the embodiments and comparative examples of the present invention. Figures 5 and 6 are scanning electron microscope (SEM) images of an oxygen evolution reaction (OER) catalyst according to an embodiment of the present invention. Figures 7 and 8 are transmission electron microscope (TEM) images of an oxygen evolution reaction (OER) catalyst according to an embodiment of the present invention. FIG. 9 is a diagram showing the transmission electron microscope-based energy dispersive X-ray spectral analysis (TEM-EDS) results of an oxygen evolution reaction (OER) catalyst according to an embodiment of the present invention. Hereinafter, embodiments are described in detail with reference to the attached drawings. However, various modifications may be made to the em