KR20230170176A - electrochemical catalysts and manufacturing method thereof - Google Patents

Abstract

The present invention can be implemented as a two-dimensional metal nanosheet with a high specific surface area to enable sufficient use of metal catalyst materials with excellent electrical conductivity, and at the same time, the manufacturing process is simple, making it easy to mass-synthesize, and ultra-thin films and large areas can be realized, making the catalyst We provide an electrochemical catalyst that can replace platinum by maximizing its utilization and a method for manufacturing the same.

Description

Electrochemical catalysts and manufacturing method thereof}

The present invention relates to an electrochemical catalyst and a method for manufacturing the same. More specifically, the present invention relates to an electrochemical catalyst and a method for manufacturing the same. In more detail, it is implemented as a two-dimensional metal nanosheet with a high specific surface area, so that the characteristics of a metal catalyst material with excellent electrical conductivity are fully utilized, and the manufacturing process is simple, enabling mass production. It relates to an electrochemical catalyst that is easy to synthesize, can be implemented in an ultra-thin film, and has a large area, thereby maximizing its utility as an electrochemical catalyst and replacing platinum, and a method for manufacturing the same.

As the world's population increases, the use of fossil fuels has continued to increase. These fossil fuels emit substances that have a negative impact on global warming, such as carbon dioxide, and there is a problem of depletion of reserves, so there is a need for alternative energy sources. Research on this has continued. Accordingly, hydrogen, which has high energy density and is environmentally friendly, was introduced as an alternative to fossil fuels, and the electrochemical catalyst material used to produce this hydrogen mainly uses platinum, but has the disadvantages of low energy efficiency and high price. There is a need to develop an easily available and highly active electrochemical catalyst to replace platinum.

Accordingly, various electrochemical catalysts are being researched. In particular, metal catalyst materials are attracting attention as electrochemical catalysts that can replace platinum because they have superior electrical conductivity compared to other compounds. However, the electrochemical metal catalysts introduced to date have limited utility due to the following problems.

First, metal catalyst materials reported to date include Fe, Ru, Co, Ni, Rh, etc., but when these metal catalyst materials are manufactured as electrochemical catalysts, there is a problem in that they do not exhibit catalytic efficiency sufficient to replace platinum. More specifically, since electrochemical catalysts are mainly active through surface reactions, research to increase the contact area with the reactants, that is, the specific surface area, should be supported due to the nature of these catalytic reactions. Conventional electrochemical catalysts using the above metal catalyst materials should be supported. Since catalysts have no choice but to be manufactured in the form of zero-dimensional particles or one-dimensional nanorods, there is a problem in that the excellent electrical conductivity of the metal catalyst material cannot be maximized and fully utilized.

Second, in order to solve the above-mentioned problem, attempts were made to improve the specific surface area by manufacturing an electrochemical catalyst having a two-dimensional nanosheet shape rather than a zero-dimensional particle or one-dimensional nanorod shape, but the experimental process was complicated and mass synthesis was difficult. Due to this difficult problem, there is a significant limitation in practical application, and furthermore, even if an electrochemical catalyst using a metal catalyst material is implemented in the form of a two-dimensional nanosheet, the nanosheet has no choice but to be manufactured as thick as several tens of nm or more, and its size is also limited to several tens of nm. There is a problem that it is difficult to implement ultra-thin nanosheets with nanometers or more.

Accordingly, it can be implemented as a two-dimensional nanosheet with a high specific surface area so that metal catalyst materials with excellent electrical conductivity can be fully utilized. At the same time, the manufacturing process is simple, making it easy to mass synthesize, and ultra-thin films and large areas can be realized, increasing the utilization of catalysts. Research on electrochemical catalysts that can maximize is urgently needed.

Republic of Korea Public Notice 2013-0005885 (2015.01.27)

The present invention was created to overcome the above-mentioned problems, and the problem to be solved by the present invention is to sufficiently maintain the characteristics of a metal catalyst material with excellent electrical conductivity by implementing an electrochemical catalyst in the form of a two-dimensional metal nanosheet with a high specific surface area. The purpose is to provide an electrochemical catalyst that can replace platinum and a manufacturing method thereof by maximizing its use as an electrochemical catalyst as it is easy to mass-synthesize due to its simple manufacturing process and can be used in ultra-thin films and large areas.

In order to solve the above-described problems, the present invention includes the following steps: (1) preparing a metal oxide nanosheet precursor; (2) heat-treating the metal oxide nanosheet precursor in a hydrogen and argon gas atmosphere to produce a two-dimensional metal nanosheet; A method for producing an electrochemical catalyst comprising:

Additionally, according to an embodiment of the present invention, step (2) may be characterized as forming holes on the surface of the two-dimensional metal nanosheet.

In addition, the metal oxide nanosheet precursor in step (1) is Re, V, Os, Ru, Ta, Ir, Nb, W, Ga, Mo, In, Cr, Rh, Mn, Co, Fe, Au, Cu. , a metal selected from the group consisting of Ag, or an alloy thereof, or a metal oxide containing ruthenium oxide, vanadium oxide, manganese oxide, cobalt oxide, or a combination thereof. It may be characterized as being derived from one or more selected from the group.

Additionally, step (2) may be characterized as heat treatment at 100 to 700°C.

In addition, step (2) may be characterized as a step of heat treatment in an atmosphere of 1 to 99% hydrogen and argon gas.

Additionally, the present invention provides an electrochemical catalyst containing a two-dimensional metal nanosheet with holes on the surface.

In addition, the two-dimensional metal nanosheet is a group consisting of Re, V, Os, Ru, Ta, Ir, Nb, W, Ga, Mo, In, Cr, Rh, Mn, Co, Fe, Au, Cu, and Ag. It is derived from any one or more selected from the group consisting of metals selected from or alloys thereof, or is selected from the group consisting of metal oxides including ruthenium oxide, vanadium oxide, manganese oxide, cobalt oxide, or a combination thereof. It can be characterized as being derived from more than one source.

Additionally, the thickness of the two-dimensional metal nanosheet may be 0.01 to 10 nm.

Additionally, the size of the two-dimensional metal nanosheet may be 1 to 10,000 nm.

Additionally, the electrochemical catalyst may be used as a catalyst in a hydrogen evolution reaction (HER).

The present invention can implement an electrochemical catalyst in the form of a two-dimensional metal nanosheet with a high specific surface area, making full use of the characteristics of a metal catalyst material with excellent electrical conductivity, and at the same time, the manufacturing process is simple, making it easy to mass synthesize, ultra-thin film, large-scale Since the area can be realized, it is possible to manufacture an electrochemical catalyst that can replace platinum by maximizing its utilization as an electrochemical catalyst.

1 is an SEM image showing a two-dimensional metal nanosheet according to the present invention.
Figure 2 is a graph showing the results of X-ray diffraction pattern analysis of a two-dimensional metal nanosheet according to the present invention.
3 and 4 are TEM images showing two-dimensional metal nanosheets according to the present invention.
Figure 5 is a graph showing the XANES/EXAFS results of the two-dimensional metal nanosheet according to the present invention.
Figure 6 is a graph showing the HER catalytic activity results of the two-dimensional metal nanosheet according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. The present invention may be implemented in many different forms and is not limited to the embodiments described herein.

As described above, conventional electrochemical catalysts that utilize the excellent electrical conductivity of metal catalyst materials have difficulties in increasing the specific surface area, complicated manufacturing processes, and are not easy to mass-produce, which limits their practical use.

Accordingly, the present invention is an electrochemical catalyst comprising the steps of (1) preparing a metal oxide nanosheet precursor (2) heat treating the metal oxide nanosheet precursor in a hydrogen and argon gas atmosphere to produce a two-dimensional metal nanosheet. A solution to the above-mentioned problem was sought by providing a manufacturing method.

Through this, the present invention can be implemented as a two-dimensional nanosheet with a high specific surface area to enable sufficient use of metal catalyst materials with excellent electrical conductivity. At the same time, the manufacturing process is simple, making it easy to mass synthesize, and ultra-thin films and large areas can be realized, making it possible to produce catalysts. By maximizing its utilization, an electrochemical catalyst that can replace platinum can be manufactured.

In the present invention, a nanosheet may be a two-dimensional nanomaterial that is not in the shape of a particle or rod, but has a certain area and a nanoscale dimension, for example, a thickness of 100 nm or less.

Hereinafter, the method for producing the electrochemical catalyst according to the present invention will be described in detail.

The method for producing an electrochemical catalyst according to the present invention includes the steps of (1) preparing a metal oxide nanosheet precursor, (2) heat treating the metal oxide nanosheet precursor in a hydrogen and argon gas atmosphere to produce a two-dimensional metal nanosheet. Includes.

Step (1) of the present invention is to prepare a metal oxide nanosheet precursor to take advantage of the excellent electrical conductivity of the metal catalyst material.

In general, metal catalyst materials have excellent electrical conductivity compared to other compounds, so they are attracting attention as electrochemical catalysts that can replace platinum. Such metal catalyst materials include metals selected from the group consisting of Re, V, Os, Ru, Ta, Ir, Nb, W, Ga, Mo, In, Cr, Rh, Mn, Co, Fe, Au, Cu, and Ag. Alternatively, it may be at least one selected from the group consisting of alloys thereof, or at least one selected from the group consisting of metal oxides including ruthenium oxide, vanadium oxide, manganese oxide, cobalt oxide, or a combination thereof. In one embodiment according to the present invention, the metal catalyst precursor material is RuO ₂ , MnO ₂ , Mn ₃ O ₇ , Mn _1-x Co _x O ₂ (0 < x ≤ 0.4), VO ₂ , CoO ₂ , FeO ₂ , It may include ReO ₂ , IrO ₂ , InO, or a combination thereof.

In step (1) of manufacturing the metal oxide nanosheet precursor using the metal catalyst material, a conventionally known metal oxide nanosheet manufacturing method can be used as long as it is suitable for the purpose of the present invention. As a non-limiting example of this, the metal catalyst material, the oxide of the metal catalyst material, and the material containing sodium are sufficiently stirred and heat treated at a temperature of 600 to 1200 ° C. for more than 10 hours in an inert atmosphere such as a nitrogen atmosphere, argon atmosphere, or vacuum. After obtaining the metal oxide, it is treated with acid to synthesize a hydrogen ion-substituted derivative, and then peeled again in an aqueous solution to produce a metal oxide nanosheet precursor.

Meanwhile, the metal oxide nanosheet precursor stacked through hydrogen ions may have a layered structure. According to a preferred example of the present invention, when the metal catalyst material is ruthenium oxide, the metal oxide nanosheet precursor is ruthenium oxide. It may be a precursor and may have a layered structure of RuO ₂ -RuO ₂ .

Next, step (2) is a step of manufacturing a two-dimensional metal nanosheet by heat treating the metal oxide nanosheet precursor in a hydrogen and argon gas atmosphere.

In general, metal catalyst materials include Fe, Ru, Co, Ni, Rh, etc., as described above, but when these metal catalyst materials are manufactured as electrochemical catalysts, there is a problem in that they do not exhibit catalytic efficiency sufficient to replace platinum. More specifically, since electrochemical catalysts are mainly active through surface reactions, research to increase the contact area with reactants, i.e., specific surface area, should be supported due to the nature of these catalytic reactions. Conventional electrochemical catalysts using the metal catalyst materials should be supported. Since catalysts have no choice but to be manufactured in the form of zero-dimensional particles or one-dimensional nanorods, there is a problem in that the excellent electrical conductivity of the metal catalyst material cannot be maximized and fully utilized.

In addition, the metal catalyst material shows a tendency to aggregate due to the nature of the metal particles, which can cause problems of reducing the accessible surface area and catalytic activity. When electrochemical catalysts are manufactured by conventionally manufacturing metals in nano sizes, these materials There is a problem in that it does not mix uniformly and does not exhibit sufficient catalytic activity, greatly reducing its utility.

Accordingly, the present invention is capable of producing a two-dimensional nanosheet form, while preventing agglomeration of particles and maximizing the specific surface area, thereby greatly improving catalyst efficiency.

More specifically, referring to FIG. 1, it can be seen that ruthenium oxide, a metal nanosheet precursor, according to a preferred embodiment of the present invention, has a two-dimensional nanosheet shape, and ruthenium nanosheets, an electrochemical catalyst manufactured thereby, also It can be seen that it has a two-dimensional nanosheet shape. Likewise, referring to Figure 5, it can be seen from the XANES/EXAFS results that a complete phase transition occurred from the precursor ruthenium oxide nanosheet to the pure ruthenium metal phase.

In other words, the electrochemical catalyst according to the present invention has a two-dimensional nanosheet shape rather than a zero-dimensional particle or one-dimensional nanorod shape, so all constituent elements can participate in the reaction, thereby widening the reaction specific surface area. Accordingly, the catalytic efficiency of the metal catalyst material can be maximized.

To this end, in step (2), heat treatment may be performed at a temperature of 100 to 700° C. in a hydrogen and argon gas atmosphere. Through the heat treatment, the metal oxide nanosheet precursor prepared in step (1) is reduced under hydrogen reaction to obtain a two-dimensional metal nanosheet composed only of pure metal.

More specifically, referring to Figure 2, the two-dimensional ruthenium nanosheets synthesized from ruthenium oxide as a metal oxide nanosheet precursor according to a preferred embodiment of the present invention at a heat treatment temperature of 100 degrees to 700 degrees are all pure ruthenium (HCP structure). It can be seen that Ru) metal was synthesized. At this time, if the heat treatment temperature in step (2) is less than 100°C, there may be a problem in which the metal oxide nanosheet precursor is not sufficiently reduced. Additionally, if the heat treatment temperature in step (2) above exceeds 700°C, there may be a problem in that the shape of the nanosheet cannot be maintained as holes are formed on the surface of the nanosheet too large due to the high heat treatment temperature.

In addition, step (2) may be characterized as a step of heat treatment in an atmosphere of 1 to 99% hydrogen and argon gas. At this time, if less than 1% of hydrogen or argon gas is used, there may be a problem in that the metal oxide nanosheets are not sufficiently reduced and cannot be synthesized into metal nanosheets.

Meanwhile, the present invention enables the implementation of a two-dimensional metal nanosheet shape as described above through the heat treatment conditions of step (2), and at the same time, it is possible to manufacture an electrochemical catalyst with an ultra-thin film/large area. In other words, conventionally, the thickness of the metal nanosheet used as an electrochemical catalyst had to be manufactured to be tens of nm or more, so an ultra-thin sheet structure could not be realized, and its size could only be manufactured in an area of a few nm, improving the specific surface area. There was a problem that catalyst efficiency could not be maximized due to limitations in ordering. In addition, when the catalytic activity increasing metal is manufactured in the form of a conventional nano-sized sheet, there are not enough reaction sites for hydrogen to react, so the catalytic activity is lowered, making it difficult to use it as an electrochemical catalyst.

In contrast, in the present invention, as shown in FIGS. 1 and 2, the metal nanosheet can be manufactured with a thickness of 0.01 to 10 nm, more preferably 0.01 to 1 nm, through step (2). The size of the metal nanosheet can also be 1 to 10,000 nm, more preferably 100 to 10,000 nm, allowing the specific surface area, which has a significant impact on catalytic efficiency as an electrochemical catalyst, to be significantly increased.

In addition, the present invention can solve the above-mentioned catalytic activity problem by forming holes on the surface of the two-dimensional metal nanosheet through step (2). In other words, since all the constituent elements of the electrochemical catalyst according to the present invention are exposed to the surface, the reactivity can be significantly improved due to greater contact with reactants in catalytic reactions mainly involving surface reactions.

More specifically, referring to FIG. 3, it can be seen that the electrochemical catalysts prepared under different temperature conditions according to the present invention all have a two-dimensional nanosheet shape and have holes. That is, the two-dimensional nanosheet according to the present invention can not only realize a two-dimensional nanosheet shape through heat treatment in a hydrogen and argon gas atmosphere in step (2), but also form holes on the surface of the two-dimensional nanosheet, thereby creating holes. The effect of increasing the specific surface area can be further improved.

In addition, the present invention can control catalyst efficiency by controlling the size of the hole to suit the use of the electrochemical catalyst according to the present invention. More specifically, referring to Figures 3 and 4, it can be seen that as the heat treatment temperature increases, the hole size on the nanosheet surface gradually increases.

Ultimately, the present invention enables the implementation of an ultra-thin film/large-area two-dimensional nanosheet shape that can optimize the specific surface area of the electrochemical catalyst through the heat treatment step in a hydrogen and argon gas atmosphere in step (2), and furthermore, 2 The efficiency of the catalyst can be maximized by forming holes on the surface of the three-dimensional nanosheet and controlling their size.

Furthermore, by solving the problems of conventional metal nanosheets, which have complex experimental processes and difficult mass synthesis, it is possible to manufacture two-dimensional nanosheets with a simple heat treatment step under specific temperature conditions, greatly improving economic efficiency and usability. You can.

Next, the electrochemical catalyst according to the present invention will be described. However, to avoid duplication, description is omitted for parts where the manufacturing method and technical idea of the electrochemical catalyst are the same.

The electrochemical catalyst according to the present invention includes a two-dimensional metal nanosheet with holes on the surface and a hexagonal close-packed (HCP) crystal structure.

The two-dimensional metal nanosheet is selected from the group consisting of Re, V, Os, Ru, Ta, Ir, Nb, W, Ga, Mo, In, Cr, Rh, Mn, Co, Fe, Au, Cu, and Ag. It is derived from any one or more selected from the group consisting of metals or alloys thereof, or one or more selected from the group consisting of metal oxides including ruthenium oxide, vanadium oxide, manganese oxide, cobalt oxide, or a combination thereof. It may have originated from .

In addition, the two-dimensional nanosheet can be manufactured with a thickness of 0.01 to 10 nm, more preferably 0.01 to 1 nm, and the size of the two-dimensional metal nanosheet is also 1 to 10,000 nm, more preferably 100 nm. It can be implemented in large areas ranging from 10,000 nm to 10,000 nm.

The electrochemical catalyst according to the present invention can be used as a catalyst in a hydrogen evolution reaction (HER).

More specifically, referring to FIG. 6, it can be seen that the synthesized two-dimensional ruthenium nanosheets have significantly better hydrogen generation catalytic activity than bulk ruthenium particles, especially in the case of two-dimensional ruthenium nanosheets synthesized at 100 to 300 ° C. It can be seen that it exhibits catalytic activity similar to that of a platinum catalyst.

Through this, the present invention can be implemented as a two-dimensional nanosheet with a high specific surface area to enable sufficient use of metal catalyst materials with excellent electrical conductivity. At the same time, the manufacturing process is simple, making it easy to mass synthesize, and ultra-thin films and large areas can be realized, making it possible to produce catalysts. It can be seen that it is possible to manufacture an electrochemical catalyst that can replace platinum by maximizing its utilization.

Hereinafter, the present invention will be described in more detail through examples. However, the following examples do not limit the scope of the present invention, and should be interpreted to aid understanding of the present invention.

Example 1

(1) Preparation of metal oxide nanosheet precursor

Add 0.476g of Na ₂ CO ₃ (Company: Daejung), 0.897g of RuO ₂ (Company: Alfa Aesar), and 0.227g of Ru (Company: Alfa Aesar) into mortar, grind them, make pellets, and place them in an alumina bottle. Put the alumina bottle in the gas furnace, flow Ar gas, react at 900℃ for 12 hours at a temperature increase rate of 100℃ per hour, and naturally cool to room temperature. Add 100 ml of 1M Na ₂ S ₂ O ₈ (Company: Sigma Aldrich) per 1 g of solid-phase synthesized sample and react at room temperature for 72 h. Afterwards, excess Na ₂ S ₂ O ₈ is washed away with distilled water and dried in an oven at 50°C. Add 100ml of 1M HCl (Company: Samchun) per 1g of dried sample and stir and change daily for 3 days. Afterwards, 0.5 ml of 40 wt% TBAOH (Tetrabutylammonium hydroxide) (Company: Sigma Aldrich) and 125 ml of distilled water were added per 0.5 g of the sample obtained by washing and drying with distilled water until neutral, and stirred at room temperature for 10 days. The synthesized solution was filtered using a centrifuge to filter out the precipitate, and the exfoliated RuO ₂ nanosheets were synthesized.

(2) Preparation of two-dimensional metal nanosheets

The RuO ₂ nanosheet obtained in step (1) was heat-treated for 3 hours in a 5% H ₂ /Ar (100 cc) gas atmosphere at a temperature of 100°C to prepare a two-dimensional ruthenium nanosheet composed only of pure ruthenium metal.

Examples 2 to 7

It was manufactured in the same manner as in Example 1, but heat treatment was performed by changing the heat treatment temperature in step (2) to 100 to 700°C.

Comparative Example 1

As a comparative example, ruthenium oxide nanosheets prepared in step (1) of Example 1, rather than pure ruthenium nanosheets, were prepared.

Experimental Example 1 - Hydrogen Evolution Reaction (HER) performance measurement.

2 mg of the electrochemical catalyst prepared in Examples 1 to 7 and Comparative Example 1 was dissolved in 0.8 ml of tertiary distilled water and 0.2 ml of isopropanol (Samjeon Reagent) solution, and then dissolved in 5 wt% Nafion (Sigma-Aldrich) solution 20. Add μl and disperse through ultrasonic waves (Company: JAC-3010). Take 10 μl of the dispersed solution and sample it on a Glassy Carbon (GC) Rotating Disk Electrode (RDE) electrode (Company: ALS). A SCE electrode is used as the reference electrode and a Pt wire is used as the counter electrode. The measurement was performed using RRDE-3A Rotating Ring Disk Electrode Apparatus (Company: ALS) to test the catalytic activity of the hydrogen generation reaction in 0.5MH ₂ SO ₄ electrolyte purged with N ₂ for more than 30 minutes, and this is shown in FIG. 6.

Referring to FIG. 6, it can be seen that the synthesized two-dimensional ruthenium nanosheets have significantly better hydrogen generation catalytic activity than the bulk ruthenium particles. In particular, in the case of two-dimensional ruthenium nanosheets synthesized at 100 to 300 ° C, the platinum catalyst and It can be seen that similar catalytic activity is shown.

Experimental Example 2 - X-ray diffraction pattern analysis

For Examples 1 to 7, the X-ray diffraction patterns were analyzed (X-ray diffraction - Company: Rigaku MiniFlex600) and are shown in Figure 2.

Referring to FIG. 2, the two-dimensional ruthenium nanosheets synthesized from ruthenium oxide as a metal oxide nanosheet precursor according to a preferred embodiment of the present invention at a heat treatment temperature of 100 to 700 degrees are all pure ruthenium (Ru) having an hcp structure. It can be seen that the metal was synthesized.

Experimental Example 3- SEM image

For Examples 1 to 7 and Comparative Example 1, scanning electron microscope images (Field Emission-Scanning Electron Microscopy - Company: JEOL JSM-7001F) were confirmed and shown in Figure 1.

Referring to Figure 1, it can be seen that ruthenium oxide, a metal nanosheet precursor, has a two-dimensional nanosheet shape, and the ruthenium nanosheet, an electrochemical catalyst manufactured through this, also has a two-dimensional nanosheet shape. there is.

Experimental Example 4-TEM Image

Transmission electron microscopy (JEOL F200) images of Examples 1 to 7 and Comparative Example 1 were confirmed and shown in Figures 3 and 4.

Referring to Figures 3 and 4, it can be seen that the electrochemical catalysts prepared under different temperature conditions according to the present invention all have a two-dimensional nanosheet shape and have holes. That is, the two-dimensional nanosheet according to the present invention can not only realize a two-dimensional nanosheet shape through heat treatment in a hydrogen and argon gas atmosphere in step (2), but also form holes on the surface of the two-dimensional nanosheet, thereby creating holes. It can be seen that the specific surface area increase effect can be further improved.

Experimental Example 5 - XANES and EXAFS

Examples 1 to 7 and Comparative Example 1 were measured using X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) (Pohang Radiation Light Accelerator), and the results are shown in FIG. 5.

Referring to Figure 5, it can be seen from the XANES/EXAFS results that the precursor ruthenium oxide nanosheet has completely undergone a phase transition to the pure ruthenium metal phase.

Claims (10)

(1) preparing a metal oxide nanosheet precursor;
(2) heat-treating the metal oxide nanosheet precursor in a hydrogen and argon gas atmosphere to produce a two-dimensional metal nanosheet; A method for producing an electrochemical catalyst comprising.
According to paragraph 1,
Step (2) is a method of producing an electrochemical catalyst, characterized in that it is a step of forming holes on the surface of the two-dimensional metal nanosheet.
According to paragraph 1,
The metal oxide nanosheet precursor in step (1) is Re, V, Os, Ru, Ta, Ir, Nb, W, Ga, Mo, In, Cr, Rh, Mn, Co, Fe, Au, Cu, and Ag. A method for producing an electrochemical catalyst, characterized in that it is derived from a metal selected from the group consisting of a metal or an alloy thereof, or a metal oxide including ruthenium oxide, vanadium oxide, manganese oxide, cobalt oxide, or a combination thereof.
According to paragraph 1,
Step (2) is a method for producing an electrochemical catalyst, characterized in that the step is heat treatment at 100 to 700 ° C.
According to paragraph 1,
Step (2) is a method of producing an electrochemical catalyst, characterized in that heat treatment in an atmosphere of 1 to 99% hydrogen and argon gas.
An electrochemical catalyst containing two-dimensional metal nanosheets with holes on the surface.
According to clause 6,
The two-dimensional metal nanosheet is selected from the group consisting of Re, V, Os, Ru, Ta, Ir, Nb, W, Ga, Mo, In, Cr, Rh, Mn, Co, Fe, Au, Cu, and Ag. It is derived from any one or more selected from the group consisting of metals or alloys thereof, or from one or more metal oxides including ruthenium oxide, vanadium oxide, manganese oxide, cobalt oxide, or combinations thereof. An electrochemical catalyst characterized by its origin.
According to clause 6,
An electrochemical catalyst wherein the two-dimensional metal nanosheet has a thickness of 0.01 to 10 nm.
According to clause 6,
An electrochemical catalyst wherein the two-dimensional metal nanosheet has a size of 1 to 10,000 nm.
The electrochemical catalyst selected in any one of claims 5 to 9 is,
An electrochemical catalyst characterized by being used as a catalyst in a hydrogen evolution reaction (HER).