KR20220076414A - Iridium Oxide-Based Electrocatalyst and Preparation Method Thereof - Google Patents

Abstract

The present invention relates to an iridium oxide-based electrochemical catalyst comprising rod-shaped crystalline iridium oxide and particulate amorphous iridium oxide formed on at least a portion of the rod-shaped crystalline iridium oxide. The iridium oxide-based electrochemical catalyst of the present invention may exhibit excellent OER performance and durability.

Description

Iridium oxide-based electrochemical catalyst and its preparation method {Iridium Oxide-Based Electrocatalyst and Preparation Method Thereof}

The present invention relates to an iridium oxide-based catalyst for an electrochemical reaction such as a water electrolysis device/reaction and a method for preparing the same.

As concerns about the depletion of fossil fuels, which accounted for most of the conventional fuel consumption, continue to increase, the demand for research and development of new and renewable energy has been constantly on the rise. As an alternative to this, hydrogen energy, which is a clean energy source, has been proposed. Methods for producing such hydrogen energy include steam reforming, partial oxidation, autothermal reforming and direct cracking using hydrocarbon-based raw materials, thermochemical cracking using non-hydrocarbon-based raw materials, biological cracking, photochemical cracking, and electrolysis. . Among them, the water electrolysis method with high reliability and maturity of technology is receiving the greatest attention, and alkaline water electrolysis, high temperature steam electrolysis, and proton exchange membrane water electrolysis are used as representative methods.

In particular, compared to other water electrolysis methods, Proton Exchange Membrane (PEM) Water Electrolysis has high reactivity, energy density and efficiency as well as miniaturization, and water electrolysis cells can also be manufactured in a stacked type. Thus, the manufacturing process can be simplified, and since pure water is used as a raw material without using an electrolyte, the purity is very high, there is no corrosion problem due to the electrolyte, and the operating pressure can be designed even at hundreds of atmospheres. is being actively carried out.

In the proton exchange membrane water electrolysis method, various electrochemical reactions are used to produce hydrogen energy. Among them, the slow reaction rate in the Oxygen Evolution Reaction (OER) acts as a major factor in the degradation of the performance of the water electrolyzer. is used Until now, only osmium (Os), ruthenium (Ru) and iridium (Ir) metals have been reported to have excellent reactivity as catalysts for oxygen evolution under acidic proton exchange membrane water electrolysis conditions. However, although osmium or ruthenium exhibits excellent catalytic activity in the initial state, it is difficult to use for a long period of time due to low stability.

Therefore, the possibility of applying iridium, which has excellent corrosion resistance while simultaneously satisfying a certain level of catalytic activity and durability even in acidic conditions, is being emphasized. However, studies are being conducted to adjust the structural characteristics.

For example, Zhao et al. reported that one-dimensional nanostructured iridium oxide in the form of a nanotube has improved electron mobility and stability than iridium oxide in the form of simple amorphous particles. (Journal of the electroanalytical Chemistry, 2013, 688, 269-274).

According to the manufacturing method, a nanotube-structured iridium oxide having a cross-sectional diameter of about 50 nm and a maximum average aspect ratio of about 10 was prepared, but there is a limitation in that the electrochemically activated specific surface area is small compared to the conventional amorphous particle shape. .

Therefore, there is a very high need for a technology for preparing an iridium oxide-based electrochemical catalyst having a novel structure of nano-scale with excellent performance and strong durability for application to a cation exchange membrane water electrolysis device.

Electrochemical controlled synthesis and characterization of well-aligned IrO2 nano tube arrays with enhanced eletrocatalytic activity toward oxygen evolution reaction, Journal of the electroanalytical Chemistry, 2013, 688, 269-274

In order to solve the above problems, the present invention is to provide an iridium oxide-based electrochemical catalyst having a novel structure having excellent performance and strong durability for application to a proton exchange membrane water electrolysis device.

The present invention provides an iridium oxide-based electrochemical catalyst comprising rod-shaped crystalline iridium oxide and particulate amorphous iridium oxide formed on the surface of at least a portion of the rod-shaped crystalline iridium oxide.

In addition, the present invention comprises the steps of (a) reacting an iridium precursor compound, an oxate of an alkali metal or alkaline earth metal, and a compound represented by the following Chemical Formula (1) to produce a granular crystalline iridium oxide;

<Formula (1)>

(In Formula (1), A and B are each independently an amine group or a thiol group, and are the same as or different from each other, and n is an integer of 2 to 10.)

(b) calcining the granular crystalline iridium oxide to produce rod-shaped crystalline iridium oxide; and (c) mixing and heating the rod-shaped crystalline iridium oxide, an iridium precursor compound, and a polyhydric alcohol to form a particulate amorphous iridium oxide on the surface of the rod-shaped crystalline iridium oxide; containing, iridium oxide A method for preparing an electrochemical catalyst is provided.

The iridium oxide-based electrochemical catalyst of the present invention may exhibit improved OER performance due to high electrical conductivity.

In addition, the iridium oxide-based electrochemical catalyst of the present invention can have improved durability because the structure is maintained even after an electric current flows over time, and can prevent deterioration of OER performance.

In addition, since the iridium oxide-based electrochemical catalyst of the present invention is excellent in both electrical conductivity and durability, it can be used in a wider range of industries.

1 is a view showing an iridium oxide-based electrochemical catalyst and a method for preparing the same according to the present invention.
2 is a view showing a method for producing a rod-shaped crystalline iridium oxide of the present invention.
3 is a view showing a TEM photograph of an iridium oxide-based electrochemical catalyst in an embodiment of the present invention.
4 is a view showing a TEM photograph of an iridium oxide-based electrochemical catalyst in Comparative Example of the present invention.
5 is a view showing the distribution of the average diameter of the particle type amorphous iridium oxide of the present invention.
6 is a view showing the XRD spectrum of the iridium oxide-based electrochemical catalyst in Examples and Comparative Examples of the present invention.
7 is a view showing the XPS spectrum of the iridium oxide-based electrochemical catalyst in Examples and Comparative Examples of the present invention.
8 is a view showing the XPS spectrum of the iridium oxide-based electrochemical catalyst in Examples and Comparative Examples of the present invention.
9 is a view showing the XPS spectrum of the iridium oxide-based electrochemical catalyst in Examples and Comparative Examples of the present invention.
10 is a view showing the electrical conductivity of the iridium oxide-based electrochemical catalyst in Examples and Comparative Examples of the present invention.
11 is a view showing the results of the electrochemical reaction of the half-cell using the iridium oxide-based electrochemical catalyst in Examples and Comparative Examples of the present invention.
12 is a view showing results according to cyclic voltammetry (CV) of a half cell using an iridium oxide-based electrochemical catalyst in Examples and Comparative Examples of the present invention.
13 is a view showing the results of measuring the durability of the half cell using the iridium oxide-based electrochemical catalyst in Examples and Comparative Examples of the present invention.
14 is a view showing a single cell using the iridium oxide-based electrochemical catalyst of the present invention and a method for manufacturing the same.
15 is a view showing the results of measuring the electrochemical reaction and durability of a single cell using an iridium oxide-based electrochemical catalyst in Examples and Comparative Examples of the present invention.

Hereinafter, the present invention will be described in detail. The terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor may properly define the concept of the term in order to best describe his invention. Based on the principle that there is, it should be interpreted as meaning and concept consistent with the technical idea of the present invention.

In the present invention, "rod-like" may mean a long rod in the direction of any one axis, and specifically, the aspect ratio (the length of the long axis passing through the center of the particle, and perpendicular to the long axis) and the ratio of the length of the minor axis passing through the center of the particle (=length of the major axis/length of the minor axis)) is greater than 1 and less than or equal to 30, and can be distinguished from spherical particles having an aspect ratio of 1 or close thereto. In addition, the plane cut perpendicular to the long axis passing through the center of the particle is not limited to the shape of a circle, an ellipse, a polygon, etc., and the rod type is cylindrical (cylindrical), polygonal column, needle (needle type), etc. It may mean including all shapes.

In the present invention, "crystalline" may mean that a plurality of atoms or molecules are regularly arranged in a certain relationship, and "amorphous" means that the arrangement state of a plurality of atoms or molecules is It may mean that it is determined due to lack of periodic regularity.

In the present invention, "electrical conductivity" means a physical quantity indicating the degree of current flowing on the surface of the iridium oxide-based electrochemical catalyst, and specifically, it may be a number obtained by dividing the current density by the electric field, and the unit is Siemens (S)/centimeter (cm), and may be measured by a terminal measurement method, an electrode measurement method, or the like.

One aspect of the present invention provides an iridium oxide-based electrochemical catalyst comprising rod-shaped crystalline iridium oxide and particulate amorphous iridium oxide formed on at least a portion of the rod-shaped crystalline iridium oxide.

The iridium oxide-based electrochemical catalyst according to an embodiment of the present invention may be formed on the surface of the rod-shaped crystalline iridium oxide in a form in which a plurality of the particulate amorphous iridium oxide are attached to each other or separated from each other, and the particles It is not limited to the distance between the types of amorphous iridium oxide. In addition, the iridium oxide-based electrochemical catalyst may exist independently or in a cluster, but is not limited to the type of existence thereof.

In the present invention, rod-shaped crystalline iridium oxide and particle-shaped amorphous iridium oxide are not simply mixed, but are connected to each other by physical and chemical mutual bonds and exist as a single complex, and various physical Even if force is applied, it can maintain its form as a complex.

The rod-shaped crystalline iridium oxide may be derived from an iridium precursor compound, and the iridium precursor compound is iridium fluoride, iridium chloride, iridium bromide, iridium iodide, iridium acetate, iridium acetyl acetonate, iridium nitrate, and their It may include at least one selected from the group consisting of hydrates.

The rod-shaped crystalline iridium oxide may include at least one selected from the group consisting of Ir ₂ O ₃ , IrO ₂ and IrO ₄ , and in this case, may have the form of a complete rod, and have a particle-like surface on the surface. Amorphous iridium oxide can be well formed to exhibit improved OER performance and durability.

The rod-shaped crystalline iridium oxide is not particularly limited as long as the length corresponds to the nano-scale, but may be 10 to 120 nm, or 40 to 80 nm, and the average diameter of the cut surface in the longitudinal direction is 2 to It may be 5 nm. When the length or average diameter in the above range is satisfied, the iridium oxide-based electrochemical catalyst may exhibit higher electrochemical activity and more improved OER performance and durability.

The rod-shaped crystalline iridium oxide may have an average aspect ratio of 2 to 20, and as the aspect ratio increases, it becomes closer to a needle shape, and as it decreases, it becomes closer to a particle shape. In addition, as the aspect ratio increases, the electrochemically activated specific surface area of the iridium oxide-based electrochemical catalyst further increases, thereby further improving electrical conductivity and OER performance.

The particulate amorphous iridium oxide may be derived from an iridium precursor compound, and the iridium precursor compound is iridium fluoride, iridium chloride, iridium bromide, iridium iodide, iridium acetate, iridium acetyl acetonate, iridium nitrate, and their It may include at least one selected from the group consisting of hydrates.

The particulate amorphous iridium oxide may include IrO _x (0<x<2), and iridium oxide having various bonding ratios of iridium element and oxygen is present in a mixed state. In addition, it may be formed by reducing the iridium precursor compound.

The particle-shaped amorphous iridium oxide may have an average diameter of 0.6 to 1.0 nm, or 0.7 to 0.9 nm, and when the average diameter in the above range is satisfied, a larger number of amorphous iridium oxide on the surface of the rod-shaped crystalline iridium oxide This can be formed to have a stable structure, and the durability of the iridium oxide-based electrochemical catalyst can be further improved.

The particle-shaped amorphous iridium oxide may be formed so that the density per unit area is 0.01 to 0.1 pieces/nm ² on the surface of the rod-shaped crystalline iridium oxide, and when it has a density per unit area in the above range, the The iridium oxide-based electrochemical catalyst can have a more stable structure, and can prevent deterioration of OER performance (here, the density per unit area is assumed to be a rod-shaped crystalline iridium oxide exhibits an approximate cylindrical shape, and the It is calculated by counting the number of particle-type amorphous iridium oxide present on the side surface excluding the top and bottom surfaces with an electron microscope).

The particulate amorphous iridium oxide may be included in an amount of 10 wt% to 30 wt%, or 15 to 25 wt%, based on the rod-shaped crystalline iridium oxide, and when the content in the above range is satisfied, the iridium oxide-based The electrochemical catalyst may have higher electrochemical activity, thereby exhibiting high electrical conductivity and OER performance, and may have a more stable structure to prevent deterioration of OER performance.

According to an embodiment of the present invention, the iridium oxide-based electrochemical catalyst may have an electrical conductivity of 250 to 350 S/cm.

Another aspect of the present invention may be to provide a cation exchange membrane water electrolysis device including an electrode including the iridium oxide-based electrochemical catalyst, and the device or field to which the iridium-based electrochemical catalyst can be applied is limited. it is not going to be

According to one embodiment of the present invention, as shown in FIG. 14 c, the cation exchange membrane water electrolysis device is an oxidation electrode comprising the iridium oxide-based electrochemical catalyst, titanium felt and a titanium block. wealth; A reduction electrode unit comprising a carbon paper (carbon paper) and a graphite block containing a carbon-supported platinum catalyst; and a potentiostat.

The oxidation electrode and the reduction electrode may further include a current collector, and the current collector may be made of a titanium material.

The cation exchange only water electrolysis device may further include hardware outside the oxidation electrode and the reduction electrode, and the hardware may be made of stainless steel.

According to an embodiment of the present invention, water may be supplied to the oxidizing electrode part at a rate of 3 to 7 mL/min, or 5 mL/min, as shown in FIG. 14 c , at this time the oxidizing electrode part Oxygen gas may be generated in, and hydrogen gas may be generated in the reduction electrode part.

In another aspect of the present invention, (a) reacting an iridium precursor compound, an oxate of an alkali metal or alkaline earth metal, and a compound represented by the following Chemical Formula (1) to generate a particulate crystalline iridium oxide;

<Formula (1)>

(In Formula (1), A and B are each independently an amine group or a thiol group, and are the same as or different from each other, and n is an integer of 2 to 10.)

(b) calcining the granular crystalline iridium oxide to produce rod-shaped crystalline iridium oxide; and (c) mixing and heating the rod-shaped crystalline iridium oxide, an iridium precursor compound, and a polyhydric alcohol to form a particulate amorphous iridium oxide on the surface of the rod-shaped crystalline iridium oxide; containing, iridium oxide A method for preparing a system electrochemical catalyst is provided, and the above preparation method is schematically illustrated in FIG. 1 .

According to one embodiment of the present invention, in the step (a), the iridium precursor compound may receive oxygen from an oxate of the alkali metal or alkaline earth metal to form a particle-type crystalline iridium oxide, and the formula ( In the compound represented by 1), it may include a complex formed through a coordination bond between a nitrogen or sulfur atom and iridium. In addition, if the compound represented by Formula (1) is not reacted together in step (a), rod-shaped crystalline iridium oxide cannot be formed in step (b).

The step (a) may include using deionized water as a solvent, stirring at 60 to 100 °C for 1 hour to 3 hours; and drying in a convection oven at 60 to 100° C. for 12 hours or more.

The compound represented by the formula (1) is ethylenediamine, ethylenedithiol, cysteamine, 1,3-diaminopropane, 1,3-propanedithiol, 3-amino-1-propanethiol, 1,4- It may include at least one selected from the group consisting of diaminobutane, 1,4-butanedithiol, and 4-amino-1-butanethiol, and in this case, the average diameter and the average aspect ratio are further improved and uniform Rod-shaped crystalline iridium oxide can be formed, and the OER performance and durability of the iridium oxide-based electrochemical catalyst can be further improved.

The iridium precursor compound is not particularly limited as long as it can donate iridium ions, and iridium halides such as iridium fluoride, iridium chloride, iridium bromide and iridium iodide, or hydrates thereof; iridium acetate (eg, a compound represented by Ir(CH ₃ COO)n, where n may be an integer of 1 to 5), iridium acetyl acetonate, and hydrates thereof; and iridium inorganic acid salts such as iridium nitrate or hydrates thereof; may include at least one selected from the group consisting of, and the iridium chloride is at least one selected from the group consisting of IrCl ₂ , IrCl ₃ , IrCl ₄ It may include one, and when using water as a solvent, it may be more efficient to use IrCl ₃ having excellent solubility in water.

The oxyacid salt of the alkali metal may include at least one selected from the group consisting of sodium nitrate, potassium nitrate, sodium sulfate, potassium sulfate, sodium phosphate and potassium phosphate, and the oxyacid of the alkaline earth metal is calcium nitrate, nitrate It may include at least one selected from the group consisting of magnesium, calcium sulfate, magnesium sulfate, calcium phosphate and magnesium phosphate, and may include sodium nitrate having strong oxidizing properties as in an embodiment of the present invention. , The oxate of the alkali metal or alkaline earth metal is not particularly limited as long as it is an oxate capable of donating oxygen to an iridium atom to produce the iridium-containing particles.

The oxygen acid may include at least one selected from the group consisting of boric acid, hypochlorous acid, chlorous acid, perchloric acid, phosphoric acid, nitrous acid, nitric acid, carbonic acid, sulfurous acid, sulfuric acid, thiosulfuric acid and oxalic acid.

In step (a), the oxalate of an alkali metal or alkaline earth metal, the iridium precursor compound, and the compound represented by Formula (1) are each in a molar ratio of 10 to 40, 0.05 to 5, and 0.1 to 1, or 20 to 30, 0.1 to 1 and 0.2 to 0.5, and when reacted at a compounding ratio in the above numerical range, the average diameter and average aspect ratio of the rod-shaped crystalline iridium oxide can have a further improved structure, , in turn, it is possible to further improve the OER performance and durability of the iridium oxide-based electrochemical catalyst.

According to an embodiment of the present invention, the particle-type crystalline iridium oxide formed in step (a) is rod-shaped crystalline iridium oxide whose average diameter and average aspect ratio are further improved through the calcination process of step (b). may be formed. In addition, the specific geometry, electrochemical activity and stability of the crystalline iridium oxide may vary depending on the calcination temperature and/or calcination time.

The calcination in step (b) may be carried out at 350 to 650 °C, or 400 to 550 °C, and may be carried out for 20 to 120 minutes. When calcination is performed under the conditions of temperature and/or time in the above range, the average diameter and average aspect ratio of the rod-shaped crystalline iridium oxide can have a further improved structure, and OER performance of the iridium oxide-based electrochemical catalyst and durability may be further improved.

According to an embodiment of the present invention, in step (c), the polyhydric alcohol may reduce the iridium precursor compound, through which a particulate amorphous iridium oxide is formed on the surface of the rod-shaped crystalline iridium oxide. it could be

In step (c), the rod-shaped crystalline iridium oxide and the iridium precursor compound may be mixed in a weight ratio of 1:3 to 1:10, and when mixed while satisfying the weight ratio in the above range, iridium oxide-based electrochemical The OER performance and durability of the catalyst can be further improved.

The step (c) is a step of stirring at 15 to 25 ℃ for 24 hours or more; and drying at 70 to 90° C. for 12 hours or more.

The polyhydric alcohol may be any alcohol having two or more hydroxyl groups in the molecule, and may include polyvalent aliphatic, alicyclic, or aromatic alcohol, ethylene glycol, propylene glycol, trimethylolpropane, trimethylolethane, 1,6-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, ditrimethylolpropane, trimethylolpropane , glycerin, may include at least one selected from the group consisting of pentaerythritol, but is not limited thereto. In addition, the polyhydric alcohol is 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxyisopropyl (meth) acrylate, butanediol mono (meth) acrylate, 4- It may be derived from at least one selected from the group consisting of hydroxybutyl (meth)acrylate and caprolactone (meth)acrylate.

The step (c) may be made in a solution having a pH of 10 to 14, and when the pH is in the above range, a larger number of the particulate amorphous iridium oxide may be formed on the surface of the rod-shaped crystalline iridium oxide. And it is possible to further improve the OER performance and durability of the iridium oxide-based electrochemical catalyst.

The step (c) may be carried out under a nitrogen atmosphere, may be carried out at 120 to 200 °C, and may be carried out for 2 to 4 hours.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, these examples are for explaining the present invention in more detail, and the scope of the present invention is not limited thereto.

Preparation of iridium oxide-based electrochemical catalyst

<Example 1>

(1) Preparation of rod-shaped crystalline iridium oxide precursor (granular crystalline iridium oxide)

Iridium chloride (IrCl ₃ ) hydrate (manufactured by Sigma Aldrich) 100 mg, sodium nitrate (NaNO _3, manufactured by Sigma Aldrich) 2 g and cysteamine chloride (manufactured by Sigma Aldrich) 50 mg resistivity 18.3 MΩ ·cm of deionized water (manufactured by Human Corporation) was dissolved in 5 mL, and the solution was stirred at 80° C. for 2 hours, and then dried in a convection oven for 12 hours or more to remove water.

(2) Preparation of rod-shaped crystalline iridium oxide

The powder from which water was removed from the solution was finely pulverized with a mortar, and the pulverized powder was heated to 550° C. at a rate of 5° C. in a 10 mL alumina crucible, and then calcined at 550° C. for 30 minutes. Thereafter, the calcined powder was cooled to room temperature, washed with excess deionized water using a Buchner flask and a filter, and dried, to prepare a rod-shaped crystalline iridium oxide made of IrO ₂ .

The method for preparing rod-shaped crystalline iridium oxide of (1) and (2) is shown in FIG. 2A .

(3) Preparation of particle-shaped amorphous iridium oxide formed on the surface of rod-shaped crystalline iridium oxide

As shown in FIG. 2B , 200 mg of rod-shaped crystalline iridium oxide prepared in (2) was dissolved in ethylene glycol (Ethylene glycol, manufacturer) of pH 12 together with 26.6 mg of iridium chloride hydrate, followed by nitrogen It was heated to a temperature of 160 °C for 3 hours under an atmosphere. Thereafter, the mixture was stirred at room temperature for 24 hours, washed with deionized water, and dried at 80° C. for 12 hours.

Through (1), (2), and (3) above, particle-type amorphous iridium oxide containing 10 wt% of IrO _x (0<x<2) based on rod-type crystalline iridium oxide is the rod-type An iridium oxide-based electrochemical catalyst formed on the surface of crystalline iridium oxide was prepared.

<Example 2>

In the same manner as in Example 1, except that 53.3 mg of iridium chloride hydrate was used instead of 26.6 mg of iridium chloride hydrate in (3) of Example 1, 20% by weight of particle-type amorphous based on rod-type crystalline iridium oxide An iridium oxide-based electrochemical catalyst was prepared in which iridium oxide was formed on the surface of the rod-shaped crystalline iridium oxide.

<Example 3>

In the same manner as in Example 1, except that 79.9 mg of iridium chloride hydrate was used instead of 26.6 mg of iridium chloride hydrate in (3) of Example 1, 30% by weight of particle-type amorphous based on rod-type crystalline iridium oxide An iridium oxide-based electrochemical catalyst was prepared in which iridium oxide was formed on the surface of the rod-shaped crystalline iridium oxide.

<Comparative Example 1>

In the same manner as (1) and (2) of Example 1, an iridium oxide-based electrochemical catalyst comprising only rod-shaped crystalline iridium oxide was prepared.

<Comparative Example 2>

In the same manner as in (3) of Example 1, except that in (3) of Example 1, the rod-type crystalline iridium oxide was not used, iridium oxide consisting only of particle-type amorphous iridium oxide A system electrochemical catalyst was prepared.

<Comparative Example 3>

An iridium oxide-based electrochemical catalyst was prepared in the same manner as in Example 1, except that cysteamine hydrochloride was not used in (1) of Example 1.

<Comparative Example 4>

An iridium oxide-based electrochemical catalyst was prepared in the same manner as in Example 1, except that iridium chloride hydrate was not used in (3) of Example 1.

Observation of structure and composition of iridium oxide-based electrochemical catalyst

<Experimental Example 1- TEM photograph observation of iridium oxide-based electrochemical catalyst>

TEM (Transmission Electron Microscopy) and high-resolution (HR) TEM photos of the iridium oxide-based electrochemical catalysts of Examples 1 to 3 and Comparative Examples 1 to 4 were taken with a TF30 ST (Tecnai) of 300 kV, and the results are shown in FIGS. 3 and 4 is shown.

When referring to the TEM photos of Example 1 (FIG. 3 a), Example 2 (FIG. 3 b-1, b-2), and Example 3 (FIG. 3 c), needle-shaped rod-shaped crystalline oxidation It can be seen that the particulate amorphous iridium oxide is well formed on the iridium, and in particular, it can be confirmed that the largest amount of amorphous iridium oxide is uniformly formed in Example 2.

As shown in a-1 and a-2 of FIG. 4, it can be seen that the catalyst of Comparative Example 1 is made of only rod-shaped crystalline iridium oxide because the process of forming amorphous iridium oxide is omitted, and in FIG. 4b As shown in -1 and b-2, it can be confirmed that the catalyst of Comparative Example 2 is made of only particulate amorphous iridium oxide because the process of preparing crystalline iridium oxide is omitted, and as shown in FIG. , the catalyst of Comparative Example 3 did not use cysteamine hydrochloride in the process of preparing crystalline iridium oxide, so it could be confirmed that the shape was not a rod type, as shown in d-1 and d-2 of FIG. , The catalyst of Comparative Example 4 did not use iridium chloride in the process of forming amorphous iridium oxide, so the reduction of rod-type crystalline iridium oxide itself proceeded excessively. can

Specifically, when referring to the HR TEM images of Comparative Example 1 (a-2 in FIG. 4), Comparative Example 4 (d-2 in FIG. 4), and Example 2 (b-2 in FIG. 3), Comparative Example 1 is It can be seen that, although rod-shaped crystalline iridium oxide having a clear lattice structure was formed, as in Example 2, amorphous iridium oxide was not formed on the surface, and Comparative Example 4 was a rod-shaped crystalline iridium oxide itself. It can be confirmed that the surface is damaged due to the reduction reaction.

In addition, the average length of rod-shaped crystalline iridium oxide in the iridium oxide-based electrochemical catalyst of Example 2 was about 60 nm, and the average diameter was about 3.5 nm, as measured from b-1 b-2 of FIG. 3 . In addition, from b-2 of FIG. 3, the average diameter of particle-type amorphous iridium oxide was calculated and the distribution is shown in FIG. 5, and as shown in FIG. 5, the average diameter is the average formed around 0.8 nm. It can be seen that the distribution is from 0.3 nm to 1.7 nm in the center.

In addition, when the density of particle-shaped amorphous iridium oxide per unit area of the surface of the rod-shaped crystalline iridium oxide of Examples 1 to 3 is calculated from FIG. 3, Example 1 is 0.023 pieces/nm ² , Example 2 0.070 pieces/nm ² , Example 3 showed 0.032 pieces/nm ² , and it was confirmed that in Example 2, amorphous iridium oxide having the largest density was formed. The results are shown in Table 1 below.

Catalyst Density of particle-shaped amorphous iridium oxide per unit area of the surface of rod-shaped iridium oxide Example 1 0.023 pcs/nm ² Example 2 0.070 pcs/nm ² Example 3 0.032 pcs/nm ²

<Experimental Example 2- XRD spectrum observation of iridium oxide-based electrochemical catalyst>

XRD (X-ray diffraction) spectra of Examples 1 to 3 and Comparative Examples 1 to 4 were measured using a high resolution power x-ray diffractometer, SmartLab (manufactured by RIGAKU), and the results are shown in FIG. 6 .

In the case of Examples 1 to 3, it can be seen that all peaks on the x-axis (2θ) appear clearly, and the structure of the catalyst of Comparative Example 1 is similar to Examples 1 to 3, so that the peaks of the XRD spectrum are similarly It can be seen that appeared On the other hand, in the case of Comparative Example 2, it can be confirmed that no peak is formed in the XRD spectrum because crystalline iridium oxide is not formed, and the catalyst of Comparative Example 3 also does not form crystalline iridium oxide in a rod shape (200), ( 220), it can be seen that the peak at the plane is not clear. In addition, it can be seen that the catalyst of Comparative Example 4 had a lower intensity of the overall peak compared to Examples 1 to 3 due to the damaged surface.

On the other hand, in the XRD spectrum shown in FIG. 6, the (110) plane on the x-axis (2θ) corresponds to the plane perpendicular to the longitudinal direction of the iridium oxide-based electrochemical catalyst, so the peak size on the (110) plane By comparison, it can be seen that the relative sizes of the average diameters of the iridium oxide-based electrochemical catalysts prepared in Examples 1 to 3 are compared. In the XRD spectrum, it can be estimated that the average diameter of the iridium oxide-based electrochemical catalyst decreases from the point that the size of the peak at the (110) plane decreases from Example 1 to Example 2 and Example 3.

<Experimental Example 3- Observation of XPS spectrum of iridium oxide-based electrochemical catalyst>

X-ray photoelectron spectroscopy (XPS) spectra of Examples 1 to 3 and Comparative Examples 1 to 4 were measured using (K-alpha, manufactured by Thermo VG Scientific), and the results are shown in FIGS. 7 to 9 .

Referring to the Ir 4f spectrum of XPS (FIG. 7 a), the peak of Comparative Example 2 is formed on the rightmost side, so it can be seen that the oxidation number of iridium in the catalyst is the lowest, indicating that it is metallic, and the peak of Comparative Example 1 is the most Since it is formed on the left side, it can be seen that the oxidation number of iridium in the catalyst is the highest, indicating that it is oxidic. In addition, when referring to the O 1s spectrum of XPS (Fig. 7 b), the peaks of Examples 1 to 3 are both a crystalline peak formed at about 531.6 eV and an amorphous peak formed at about 530.8 eV are clearly formed, crystalline and amorphous Although it can be seen that all of iridium oxide is included, in Comparative Examples 1 and 3, an amorphous peak corresponding to amorphous iridium oxide is hardly formed, and in Comparative Example 2, a crystalline peak corresponding to crystalline iridium oxide is hardly formed. It can be seen that in Comparative Example 4, although both peaks are formed, it can be seen that it is not as clear as in Examples 1 to 3.

In addition, as shown in FIG. 8 , in Comparative Examples 1 and 3, it can be seen that Ir exists only as Ir ⁴⁺ , and it can be estimated that only crystalline iridium oxide of IrO ₂ exists, Examples 1 to In 3 and Comparative Example 4, Ir exists in the form of Ir ³⁺ and Ir ⁴⁺ , so it can be seen that amorphous iridium oxide is also present in addition to the crystalline iridium oxide of IrO ₂ , and in particular, in Example 2, the ratio of Ir ³⁺ is As the highest bar, it can be estimated that the component of amorphous iridium oxide is the largest in Example 2, and it can be seen that this is consistent with Example 2 in Table 1 above with the largest number of amorphous iridium oxide.

In addition, as shown in FIG. 9, Comparative Examples 1 and 3 showed that almost no amorphous peak corresponding to amorphous iridium oxide was formed, and Comparative Example 2 showed that almost no crystalline peak corresponding to crystalline iridium oxide was formed. It can be clearly seen, Examples 1 to 3 can be confirmed that the two peaks are formed at almost equal heights.

Observation of electrochemical characteristics of iridium oxide-based electrochemical catalysts

<Experimental Example 4- Measurement of Electrical Conductivity of Iridium Oxide-Based Electrochemical Catalyst>

In order to measure the OER performance of the iridium oxide-based electrochemical catalyst, the electrical conductivity of the catalysts of Example 2, Comparative Example 1, Comparative Example 3 and Comparative Example 4 was measured at 25° C. according to the 4 point probe method, and the results were It is shown in Figure 10.

As shown in FIG. 10 , Comparative Examples 3 and 4 did not even reach an electrical conductivity of 150 S/cm, whereas the catalysts of Examples 2 and 1 had an electrical conductivity of about 300 S/cm and 350 S/cm, respectively. It can be seen that the electrical conductivity shows higher suitability as an electrochemical catalyst, and in Experimental Examples 5 and 6 to be described later, it can be confirmed that the performance of the electrode prepared with the catalyst of Example 2 is more excellent.

Preparation of working electrode and half cell containing iridium oxide-based electrochemical catalyst

<Preparation Example 1-1>

A catalyst ink was prepared by mixing 24.5 mg of the iridium oxide-based electrochemical catalyst of Example 1, 2.74 ml of isopropanol, 1.24 ml of deionized water, and 20 μL of a 5% Nafion solution, and 10 μL of the catalyst ink was dropped to give a catalyst of 0.25 mg/cm ² was loaded into the GC RDE to prepare a working electrode.

the working electrode, a counter electrode of Pt wire, and a reference electrode of 3 M NaCl Ag/AgCl (RE-5B, BASi), and the three electrochemical electrodes are glassy carbon (GC) disk electrodes (GC RDE). , diameter: 5 mm, PINE instrument) using a rotating potentiometer (potentiostat, CHI 760E, CH instrument) was prepared.

<Preparation Examples 1-2 to 1-7>

Instead of the iridium oxide-based electrochemical catalyst of Example 1 in Preparation Example 1-1, the iridium oxide-based electrochemical catalyst of Examples 2, 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4, respectively Electrodes and half cells of Preparation Examples 1-2 to 1-7 were prepared in the same manner as in Preparation Example 1-1, except that

Measurement of OER Performance and Durability of Iridium Oxide-Based Electrochemical Catalyst (1)- Half-cell Analysis

The electrochemical reaction of the half-cells of Preparation Examples 1-1 to 1-7 was measured, and the results are shown in FIGS. 11 and 12 . At this time, 100 ml of 1M H2SO4 was used as the electrolyte, the temperature of the electrochemical cell was maintained at 25°C using a water bath, and all potentials were measured using a reversible hydrogen electrode (RHE). RHE was measured by performing hydrogen evolution and oxidation reaction of a platinum rotating disk electrode (Pt RDE, diameter: 5 mm, PINE instrument, 1600 rpm) in an electrolyte saturated with hydrogen. All half-cell electrochemical reactions were performed in Ar-saturated electrolyte, and before measurement, catalysts were activated by performing 50 cycles of CV (cyclic voltammetry) of 0.05V to 1.5V at a scan rate of 500mV/s for 50 cycles.

The initial OER performance of the half-cell was evaluated by Linear Sweep Voltammetry (LSV), Electrochemical Impedance Spectroscopy (EIS), and Cyclic Voltammetry (CV).

LSV was done in the range of 1.35V to 1.7V with a scan rate of 10 mV/s. Mass activity is the current density divided by the mass of the iridium oxide-based electrochemical catalyst, and specific activity is the current density divided by the specific surface area of the iridium oxide-based electrochemical catalyst, 0.25 mgcatalysts/cm ² , Ar-saturated 1M H ₂ SO ₄ (aq), GC RDE with 1600 rpm rotation was measured under the measurement conditions and voltage of 1.55V. In addition, the specific current density (Specific current density) was calculated by dividing the current density by ECSA. The gravimetric activity, specific activity, and specific current density mean the current density with respect to the unit mass and unit surface area of the catalyst, and can be viewed as another indicator for determining whether the electrochemical activity as a catalyst, that is, the OER performance is excellent. EIS was performed at 1.6V, at frequencies ranging from 10 ^-2 to 10 ⁶ .

CV was obtained from 8 different scan rates (5, 10, 20, 30, 40, 50, 60, 70 mV/s), and a linear relationship for the current-scan was obtained from it, where the slope was is the double layer capacitance (C _DL ) in the non-Faraday current region. The electrochemical surface area (ECSA) was calculated by dividing C _DL by the specific capacitance, C _s (ECSA=C _DL /C _s ). Meanwhile, the C _s value in 1M H ₂ SO ₄ (aq) when the GC RDE electrolyte was used was calculated as 0.065 mF/cm ² .

The durability of the half-cell was measured by the method of chronopotentiometry. Specifically, the overvoltage when the half-cell was operated for 120 minutes at a current density of 10 mA/cm ² was measured. In addition, after the chronopotentiometer measurement for 2 hours at the current density was performed, the LSV was measured again under the same conditions to measure the change in performance, and durability was measured by comparing it with the initial LSV result.

<Experimental Example 5-1-OER performance measurement of half-cell>

The current density of the half cells of Preparation Examples 1-1 to 1-7, 10 mA/cm ² Overpotential, mass activity, specific current density, specific activity It is shown in Figure 11 a to e. In addition, in FIGS. 11 a to f, the graphs corresponding to Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 are Preparation Example 1-1 and Preparation Example, respectively. It corresponds to the graph of the half cell of 1-2, Preparation Example 1-3, Preparation Example 1-4, Preparation Example 1-5, Preparation Example 1-6, Preparation Example 1-7.

11 a and c, in the case of current density and gravimetric activity, Preparation Example 1-5 exhibited the highest LSV slope and the highest gravimetric activity of about 120A g _catalyst ^-1 , and Preparation Example 1- 2, Preparation Example 1-3, Preparation Example 1-1 showed the next highest LSV slope and high gravimetric activity in that order. In addition, as shown in d and e of FIG. 11 , in the case of specific current density and specific activity, Preparation Example 1-2 showed the highest LSV slope and the highest specific activity of 57A g _catalyst ^-1 , and Preparation Example 1- 5, Preparation Example 1-3, Preparation Example 1-1 showed the next highest LSV slope and specific activity in that order. The specific current density was the highest in Preparation Example 1-2, but the current density was the highest in Preparation Example 1-5 because the electrochemical surface area of Preparation Example 1-5 was very high compared to Preparation Example 1-2, and rather OER performance can be seen that Preparation Example 1-2 is superior to Preparation Example 1-5. Meanwhile, in Preparation Examples 1-4, 1-6, and 1-7, the measurement results of current density, specific current density, gravimetric activity, and specific activity all showed lower results compared to Preparation Examples 1-1 to 1-3, and the OER It can be seen that the performance is inferior to Preparation Examples 1-1 to 1-3.

In addition, as shown in d of FIG. 11 , Preparation Examples 1-7 had the greatest overvoltage at about 335 mV at 10 mA/cm ² , and Preparation Examples 1-1 to 1-3 had a good level of 290 to 305 mV. It can be seen that the The low OER performance of Preparation Examples 1-7 is due to the structure being damaged due to the reduction of crystalline iridium oxide itself.

On the other hand, according to FIG. 11 g showing the measurement result of CV (cyclic voltammetry) of Preparation Example 1-5, the catalyst of Preparation Example 1-5 was a particulate amorphous iridium oxide (IrO _x (0 < x < 2) ))), so it initially shows a peak near 0.25 V, and as the CV cycle proceeds, IrO _x is oxidized to IrO ₂ , etc., and it can be seen that the peak around 0.25 V disappears.

In addition, according to FIG. 10 f showing the results of measuring the current density according to the number of particle-shaped amorphous iridium oxide formed on the rod-shaped crystalline iridium oxide, Preparation Example 1-4 in which the amorphous iridium oxide was hardly formed Alternatively, compared to the catalyst of Preparation Example 1-7, it can be seen that the catalysts of Preparation Examples 1-1, 1-3, and 1-2 exhibit higher current densities, and current with respect to the number of amorphous iridium oxide It can also be confirmed that the density shows a tendency in direct proportion.

In addition, for the half cells of Preparation Examples 1-1 to 1-7, different scan rates (5; purple, 10; violet, 20; royal, 30; blue, 40) in the non-faradaic current region ; green, 50; yellow, 60; orange, and 70; red The results of cyclic voltammetry (Cyclic Voltammetry) measured with mV/s) are shown in FIG. 12, and the calculated ECSA values are shown in Table 2 below. .

Catalyst ECSA(m ² g _catalyst ^-1 ) Preparation 1-1 166.2 Preparation 1-2 180.0 Preparation 1-3 166.2 Preparation Example 1-4 150.8 Preparation 1-5 255.4 Preparation 1-6 143.1 Preparation 1-7 255.4

<Experimental Example 5-2-Durability Measurement of Half Cell>

For the half cells of Preparation Examples 1-2, Preparation Examples 1-5, and Preparation Examples 1-6, the results of measuring the overvoltage according to the operating time of the half-cell according to the chromopotentiometric measurement are shown in FIG. 13A , , the measurement results of LSV before and after half-cell operation are shown in FIG. 13B . In addition, in FIGS. 13 a and b, the graphs corresponding to Example 2, Comparative Example 2, and Comparative Example 3 correspond to the graphs of the half cells of Preparation Examples 1-2, Preparation Examples 1-5, and Preparation Examples 1-6, respectively. do.

As shown in FIG. 13A , in Preparation Examples 1-5 and Preparation Examples 1-6, it can be seen that the overvoltage continues to increase as the operation time passes, but in Preparation Examples 1-2, the overvoltage is increased regardless of the operation time. It can be seen that there is no increase. As shown in b of FIG. 13 , in Preparation Examples 1-5 and Preparation Examples 1-6, it can be seen that the slope of the LSV significantly decreased before and after the OER operation, so that the performance was deteriorated, but in Preparation Example 1-2, the slope It can be seen that the degree of reduction is very small and the OER performance is maintained.

Preparation of oxide electrode and single cell containing iridium oxide-based electrochemical catalyst

<Preparation Example 2-1>

As shown in FIG. 14 a, the catalyst ink prepared by dissolving 40.0 mg of the iridium oxide-based electrochemical catalyst of Example 1 in 3.75 ml of isopropanol, 1.25 ml of deionized water, and 100 μL of 5% Nafion solution was prepared using Nafion 212 After coating on one side of the membrane, an oxide electrode was prepared by bonding a titanium block. In addition, a catalyst ink prepared by dissolving 40.0 mg of a Pt/C catalyst (manufactured by Premetek) in 3.75 ml of isopropanol, 1.25 ml of deionized water, and 60 μL of 5% Nafion solution was applied to the other side of the Nafion 212 membrane. A reduction electrode was prepared by bonding paper (manufactured by JTNG).

And, as shown in FIG. 14b , the oxidation electrode and the reduction electrode were respectively coupled with stainless steel hardware to the outside to prepare a Membrane Electrode Assembly (MEA) having an area of 5.0 cm ² . A titanium material was used as the current collector of the oxidation electrode and the reduction electrode, and the flow channel was manufactured in a parallel type.

<Preparation Examples 2-2 to 2-7>

In Preparation Example 2-1, instead of the iridium oxide-based electrochemical catalyst of Example 1, the iridium oxide-based electrochemical catalyst of Examples 2, 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4, respectively Oxidized electrodes and single cells of Preparation Examples 2-2 to 2-7 were prepared in the same manner as in Preparation Example 2-1, except that

Measurement of OER Performance and Durability of Iridium Oxide-Based Electrochemical Catalyst (2)- Single Cell Analysis

The electrochemical reaction of the single cells of Preparation Examples 2-1 to 2-4, 2-6 and 2-7 was measured, and the results are shown in FIG. 15, and Examples in FIGS. 15 a to d Graphs corresponding to 1, Example 2, Example 3, Comparative Example 1, Comparative Example 3, and Comparative Example 4 are, respectively, Preparation Example 2-1, Preparation Example 2-2, Preparation Example 2-3, Preparation Example 2-4 , corresponds to the graph of the single cell of Preparation Example 2-6, Preparation Example 2-7. The temperature of the electrochemical cell was maintained at 80 °C, and the single cell was operated while supplying deionized water preheated to a temperature of 80 °C to the oxidation electrode at a rate of 5.0 mL/min.

The initial OER performance of the single cell was evaluated by galvanostatic measurement, and specifically, the voltage was measured at an interval of 0.1 A/cm ² at a current density in the range of 0 to 3A/cm ² , respectively, and a polarization curve (polarization curve) was obtained. In addition, as the voltage at each current density, the average value of the values measured for 3 minutes was used.

The durability of the single cell was measured by the chronopotentiometer method, and specifically, the overvoltage when the single cell was operated for 90 hours at a current density of 3 A/cm ² was measured. In addition, after the chronopotentiometer measurement for 90 hours at the current density was performed, a polarization curve was obtained again under the same conditions for the measurement of performance change, and the durability was measured by comparing it with the original polarization curve.

<Experimental Example 6-1- OER performance measurement of single cell>

For the single cells of Preparation Examples 2-1 to 2-4, 2-6, and 2-7, according to FIG. 15 a, which is shown by measuring the polarization curve, in the case of Preparation Example 2-2 at 2.0A/cm ² It can be seen that the voltage was about 1.65 V, indicating the lowest voltage, and Preparation Examples 2-3 and 2-1 were the next lowest. In the case of Preparation Example 2-7, the voltage at 2.0A/cm ² exceeded 1.80 V, and the OER performance was the most inferior.

In addition, with respect to the single cells of Preparation Examples 2-1 to 2-4, 2-6 and 2-7, 1A/cm ² According to FIG. 15 b, which shows the result of measuring the overvoltage at a current density of In the single cells of 2-1 to 2-3, the overvoltage was measured to be 375 mV or less, indicating that the degree was good, but in the single cells of Preparation Examples 2-4, 2-6, and 2-7, the overvoltage was It can be seen that the OER performance is inferior when measured above 400 mV.

<Experimental Example 6-2- Measurement of durability of single cells>

For the single cells of Preparation Example 2-2, Preparation Example 2-4, and Preparation Example 2-6, the results of measuring overvoltage according to the single cell operation time at a current density of 3A/cm ² are shown in FIG. 15c . , and the results of measuring the polarization curves before and after single-cell operation are shown in d of FIG. 15 .

As shown in c of FIG. 15 , in Preparation Example 2-2, the voltage was maintained at 1.8V even when the single-cell operation time exceeded 90 hours, and it was found that OER performance and durability were the best, but Preparation Example 2 -4 maintained a good level of OER performance and durability by maintaining the 1.9V level, and in Preparation Example 2-6, the voltage continued to increase even at 2.0V as time passed, confirming that the OER performance and durability were inferior.

In addition, as shown in d of FIG. 15 , in Preparation Example 2-2, the change in the slope of the polarization curve before and after single cell operation was the smallest, so the deterioration of OER performance was very small, whereas in Preparation Example 2-6, the slope change was very As a result, it can be seen that the degradation of OER performance is very large.

Claims (20)

An iridium oxide-based electrochemical catalyst comprising rod-shaped crystalline iridium oxide and particulate amorphous iridium oxide formed on at least a portion of the rod-shaped crystalline iridium oxide. The method according to claim 1,
The rod-type crystalline iridium oxide and the particle-type amorphous iridium oxide exist as a single complex connected to each other by a physical and chemical mutual bond, an iridium oxide-based electrochemical catalyst. The method according to claim 1,
The rod-shaped crystalline iridium oxide is Ir ₂ O ₃ , IrO ₂ And IrO ₄ The iridium oxide-based electrochemical catalyst comprising at least one selected from the group consisting of. The method according to claim 1,
The particle-type amorphous iridium oxide is IrO _x (0<x<2) to include, the iridium oxide-based electrochemical catalyst. The method according to claim 1,
The particle-type amorphous iridium oxide is contained in an amount of 10% to 30% by weight based on the rod-type crystalline iridium oxide, an iridium oxide-based electrochemical catalyst. The method according to claim 1,
The rod-type crystalline iridium oxide has a length of 10 to 120 nm, an iridium oxide-based electrochemical catalyst. The method according to claim 1,
The rod-shaped crystalline iridium oxide has an average diameter of a cut surface in the longitudinal direction of 2 to 5 nm, an iridium oxide-based electrochemical catalyst. The method according to claim 1,
The rod-shaped crystalline iridium oxide has an average aspect ratio of 2 to 20, an iridium oxide-based electrochemical catalyst. The method according to claim 1,
The particle-type amorphous iridium oxide has an average diameter of 0.6 to 1.0 nm, an iridium oxide-based electrochemical catalyst. The method according to claim 1,
The particle-type amorphous iridium oxide has a density per unit area of 0.01 to 0.1 pieces/nm ² of the surface of the rod-type crystalline iridium oxide, an iridium oxide-based electrochemical catalyst. The method according to claim 1,
An iridium oxide-based electrochemical catalyst having an electrical conductivity of 250 to 350 S/cm. A cation exchange membrane water electrolysis device comprising an electrode comprising the iridium oxide-based electrochemical catalyst of any one of claims 1 to 11. (a) reacting an iridium precursor compound, an oxate of an alkali metal or alkaline earth metal, and a compound represented by the following Chemical Formula (1) to produce a particulate crystalline iridium oxide;

(In Formula (1), A and B are each independently an amine group or a thiol group, and are the same as or different from each other, and n is an integer of 2 to 10.)
(b) calcining the granular crystalline iridium oxide to produce rod-shaped crystalline iridium oxide; and
(c) mixing and heating the rod-shaped crystalline iridium oxide, an iridium precursor compound, and a polyhydric alcohol to form a particulate amorphous iridium oxide on the surface of the rod-shaped crystalline iridium oxide; A method for preparing an electrochemical catalyst. 14. The method of claim 13,
The compound represented by Formula (1) is an iridium oxide-based electrochemical catalyst comprising at least one selected from the group consisting of cysteamine, 3-amino-propanethiol and 4-amino-1-butanethiol manufacturing method. 14. The method of claim 13,
The iridium precursor compound includes at least one selected from the group consisting of iridium fluoride, iridium chloride, iridium bromide, iridium iodide, iridium acetate, iridium acetyl acetonate, iridium nitrate, and hydrates thereof, iridium oxide A method for preparing an electrochemical catalyst. 14. The method of claim 13,
The method for producing an iridium oxide-based electrochemical catalyst, wherein the alkali metal oxyacid includes at least one selected from the group consisting of sodium nitrate, potassium nitrate, sodium sulfate, potassium sulfate, sodium phosphate and potassium phosphate. 14. The method of claim 13,
The method for producing an iridium oxide-based electrochemical catalyst, wherein the alkaline earth metal oxygenate includes at least one selected from the group consisting of calcium nitrate, magnesium nitrate, calcium sulfate, magnesium sulfate, calcium phosphate and magnesium phosphate. 14. The method of claim 13,
The method for producing an iridium oxide-based electrochemical catalyst, wherein the calcination in step (b) is carried out at 350 to 650 ℃. 14. The method of claim 13,
The polyhydric alcohol in step (c) is ethylene glycol, propylene glycol, trimethylolpropane, trimethylolethane, 1,6-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, 1,3-butylene glycol , 1,4-butylene glycol, 1,5-pentanediol, ditrimethylolpropane, trimethylolpropane, glycerin, will include at least one selected from the group consisting of pentaerythritol, iridium oxide-based electrochemical A method for preparing a catalyst. 14. The method of claim 13,
The (c) step is a method for producing an iridium oxide-based electrochemical catalyst that is made in a solution having a pH of 10 to 14.

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