KR102624681B1 - Oxygen evolution reaction catalyst for polymer electrolyte membrane(pem) water electrolysis and fabrication method thereof - Google Patents

Abstract

The polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst of the present invention forms a mesoporous material made of aggregates of metal oxide particles. In the mesoporous body made of an aggregate of metal oxide particles, the metal oxide includes ruthenium (Ru), and the first peak of the Bragg 2θ angle with respect to the CuK-alpha characteristic X-ray wavelength of 1.541 Å is between 25 and 30 degrees. , the second peak appears between 32 and 37 degrees, and the ratio of the intensity of the second peak to the intensity of the first peak exceeds 1.

Description

Polymer electrolyte (PEM) water electrolysis oxygen evolution reaction catalyst and method for producing the same

The present invention relates to polymer electrolyte (PEM) water electrolysis, and particularly to an oxygen evolution reaction catalyst and a method for producing the same.

Technologies for producing hydrogen from pure water using electrical energy are divided into alkaline water electrolysis, polymer electrolyte membrane (PEM) water electrolysis, and high-temperature water vapor electrolysis using solid oxides. Alkaline water electrolysis technology uses an aqueous alkaline solution such as potassium hydroxide (KOH) as an electrolyte and uses a separation membrane to separate hydrogen and oxygen, and has operating conditions below 100°C.

Polymer electrolyte (PEM) water electrolysis technology uses a polymer electrolyte (PEM) membrane as an electrolyte and a separator, and is characterized by operating conditions below 200°C depending on the stability of the polymer membrane.

In addition, high-temperature water vapor electrolysis technology using solid oxide is a technology that uses an oxide film with hydrogen or oxygen ion conductivity as an electrolyte and a separation membrane, and is characterized by high temperature operating conditions of 700 to 900°C.

Among low-temperature water electrolysis methods, alkaline water electrolysis technology has the advantage of relatively low equipment costs, but when linked with highly intermittent renewable energy, the rate of performance decline is faster than that of polymer electrolyte (PEM) water electrolysis because it is operated at a low current density. , it has the disadvantage of not being able to respond quickly when power output fluctuates significantly. Meanwhile, high-temperature water vapor electrolysis technology using solid oxides has the problem of expensive materials and the high cost of creating a high-temperature environment.

Accordingly, the development of water electrolysis technology using polymer electrolyte (PEM), which is advantageous in equipment cost, production cost, and performance competition, is being actively conducted. PEM electrolysis is capable of operating at high current densities, making the device compact, the structure of the electrolytic cell and system is simple, and it is not corrosive, ensuring a long lifespan.

Polymer Electrolyte Membrane Electrolysis (PEM Electrolysis) consists of an anode, a cathode, and an ion exchange membrane (electrolyte function) that separates the generated hydrogen and oxygen gases and allows hydrogen ions to move from the anode to the cathode. Similar to PEM fuel cells, PEM electrolysis uses a precious metal catalyst (Platinum, Iridiuimi, Ruthenium) and a fluorocarbon-based ionomer as a polymer solid electrolyte. In PEM electrolysis, each electrode reaction is as follows.

Anode: 2H ₂ O → 4H+ + 4e ^- + O ₂

Cathode: 4H ⁺ + 4e ^- → 2H ₂

Since PEM electrolysis uses a solid acid polymer electrolyte with a pH of 2 to 4, acid-resistant platinum-based catalysts are mainly used. Meanwhile, among the electrode materials used in PEM electrolyzers, the oxygen generation reaction catalyst is a noble metal-based catalyst and requires a large amount of catalyst. In detail, ruthenium metal has the highest efficiency as an anode oxygen generation reaction catalyst, but has a durability problem in that the metal is eluted in an acidic electrolyte. Accordingly, iridium metal, which has relatively low catalytic activity but is highly durable, is mainly used as a catalyst, and binary or ternary catalysts containing iridium are being developed. However, iridium is an expensive precious metal and has the problem of increasing manufacturing costs.

In this regard, the present invention provides a new oxygen generation reaction catalyst material to reduce the cost of PEM electrolyzers and presents an oxygen generation reaction catalyst material with improved catalytic activity and durability.

One object of the present invention is to provide a polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst and a manufacturing method thereof that can reduce costs by reducing the cost of the oxygen generation reaction catalyst in the process of polymer electrolyte (PEM) water electrolysis technology. It is for.

Another object of the present invention is to provide a polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst with improved durability and catalytic activity of the oxygen generation reaction catalyst in the process of polymer electrolyte (PEM) water electrolysis technology, and a method for manufacturing the same.

The polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst of the present invention forms a mesoporous material made of aggregates of metal oxide particles. In the mesoporous body made of an aggregate of metal oxide particles, the metal oxide includes ruthenium (Ru), and the first peak of the Bragg 2θ angle with respect to the CuK-alpha characteristic X-ray wavelength of 1.541 Å is between 25 and 30 degrees. , the second peak appears between 32 and 37 degrees, and the ratio of the intensity of the second peak to the intensity of the first peak exceeds 1.

In an embodiment, the mesoporous body made of an aggregate of the metal oxide particles further includes a metal impurity, and the metal impurity is per number of metal atoms of the metal oxide out of the entire mesoporous body made of the aggregate of the metal oxide particles. It is characterized in that it ranges from 5 to 15 in percentage (at%).

In an embodiment, the metal impurity is tin (Sn).

In an embodiment, the mesoporous body made of an aggregate of metal oxide particles is characterized by a specific surface area of 95 m ² /g or more.

In addition, the present invention provides a polymer electrolyte water electrolysis (PEM water electrolysis) system including an anode including the above-described polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst; It includes a cathode and a polymer electrolyte (PEM), wherein a first reaction equation is performed at the anode, a second reaction equation is performed at the cathode, and the polymer electrolyte (PEM) is composed of oxygen gas generated at the anode and the It is characterized by separating hydrogen gas generated at the cathode and allowing hydrogen ions generated at the anode to move to the cathode.

[First reaction equation] 2H ₂ O → 4H+ + 4e ^- + O ₂

[Second reaction equation] 4H ⁺ + 4e ^- → 2H ₂

In addition, the method for producing a polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst of the present invention includes preparing a precursor mixture containing a metal salt; Impregnating ordered mesoporous silica (OMS) with a precursor mixture at a predetermined concentration to form a silica-precursor complex; Drying the silica-precursor complex; A heat treatment step of heat treating the dried silica-precursor composite to form a mesoporous material made of aggregates of metal oxide particles; removing the structured mesoporous silica containing the mesoporous body; and drying the mesoporous body from which the structured mesoporous silica has been removed. The mesoporous body contains a metal oxide, and the first peak of the Bragg 2θ angle with respect to the CuK-alpha characteristic X-ray wavelength of 1.541 Å appears between 25 and 30 degrees, and the second peak appears between 32 and 37 degrees. It is characterized in that the ratio of the intensity of the second peak to the intensity of the first peak exceeds 1.

In an embodiment, it is characterized in that it contains the metal salt ruthenium (Ru).

In an embodiment, the metal oxide includes ruthenium oxide (RuO ₂ ).

In an embodiment, the precursor mixture further includes metal impurities.

In an embodiment, the metal impurity is tin (Sn).

In an embodiment, the mesoporous body is characterized in that the metal impurity is in the range of 5 to 15 in atomic percentage (at%) per number of metal atoms of the metal oxide in the entire mesoporous body made of an aggregate of the metal oxide particles. do.

In an embodiment, the concentration of the predetermined concentration of the precursor mixture is characterized in that the weight of the metal salt is 5 to 10 parts by weight per 100 parts by weight of the precursor mixture.

In an example, the step of drying the silica-precursor complex is characterized in that it is performed for 10 to 12 hours at a temperature range of 70 to 90 ° C.

In an embodiment, the heat treatment step of forming the mesoporous body is characterized in that it is performed for 5 to 6 hours at a temperature range of 250 to 300 ° C.

In an embodiment, the mesoporous body made of an aggregate of metal oxide particles is characterized by a specific surface area of 95 m ² /g or more.

In an embodiment, the step of forming a silica-precursor composite and the step of drying the silica-precursor composite are performed multiple times before the heat treatment step of forming the mesoporous body.

The polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst of the present invention is a mesoporous body made of aggregates of metal oxide particles and is manufactured by the nano-replicate method to have a large reaction area with a specific surface area of 95 m ² /g or more. You can have Accordingly, there is an advantage in that costs can be reduced because the amount of catalyst used can be reduced.

In addition, the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst of the present invention is a mesoporous body made of aggregates of metal oxide particles, the metal oxide contains ruthenium (Ru), and the CuK-alpha characteristic X-ray wavelength of 1.541 Å The first peak of the Bragg 2θ angle appears between 25 and 30 degrees, the second peak appears between 32 and 37 degrees, and the ratio of the intensity of the second peak to the intensity of the first peak is Since it exceeds 1, the (101) plane is more developed than the (110) plane. The development of the (101) plane has the advantage of showing excellent oxygen generation reaction activity in the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst and improving durability.

Figure 1 is a flow chart showing the manufacturing method of the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst of the present invention.
Figure 2 is a conceptual diagram showing the formation process of the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst of the present invention.
Figure 3 is a conceptual diagram of the polymer electrolyte water electrolysis (PEM water electrolysis) system of the present invention.
Figure 4 shows the results of X-ray diffraction analysis of the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst formed from aggregates of metal oxide particles of Examples 1, 3, and Comparative Examples.
Figure 5 shows the specific surface area analysis results based on the nitrogen adsorption and desorption results of Examples 1 to 5 and Comparative Examples.
Figure 6 shows the results of activity analysis for the oxygen generation reaction of Examples 1 to 5 and Comparative Examples.
Figure 7 shows the results of linear scanning potential method for the oxygen generation reaction of Examples 1 to 5 and Comparative Examples.

Hereinafter, embodiments disclosed in the present specification will be described in detail with reference to the attached drawings. However, identical or similar components will be assigned the same reference numbers regardless of reference numerals, and duplicate descriptions thereof will be omitted. Additionally, in describing the embodiments disclosed in this specification, if it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed in this specification, the detailed descriptions will be omitted. In addition, the attached drawings are only for easy understanding of the embodiments disclosed in this specification, and the technical idea disclosed in this specification is not limited by the attached drawings, and all changes included in the spirit and technical scope of the present invention are not limited. , should be understood to include equivalents or substitutes.

Terms containing ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

Singular expressions include plural expressions unless the context clearly dictates otherwise.

In this application, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Figure 1 is a flow chart showing the manufacturing method of the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst of the present invention.

Referring to Figure 1, the method for producing a polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst includes preparing a precursor mixture (S100), forming a silica-precursor complex (S200), and drying the silica-precursor complex. It includes a step (S300), a heat treatment step of forming a mesoporous body (S400), a step of removing structured mesoporous silica (S500), and a step of drying the mesoporous body (S600).

The present invention is a method of synthesizing a mesoporous body using a nano-replication method using structured mesoporous silica. In detail, this is a method in which the mesoporous silica is used as a template, the solutionized precursor of the desired material is filled into the pores of the mold, crystallization is achieved through heat treatment, and then the silica is removed.

In the step of preparing the precursor mixture (S100), the precursor mixture may include a metal salt. In an embodiment, the solvent of the precursor mixture may be water. Additionally, the metal salt may include ruthenium (Ru). Polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalysts containing ruthenium have the advantage of being more active than conventionally used iridium (Ir) catalysts. In detail, the metal salt may be a salt that contains ruthenium (Ru) and is soluble in a water-based solvent.

As described above, when the solvent of the precursor mixture is water, the synthesis of a polymer electrolyte (PEM) water electrolysis oxygen evolution reaction catalyst can be successfully achieved by a nano-replication method based on structured mesoporous silica (OMS). You can. When the solvent is an organic solvent or an alcohol-based solvent, structuring is performed in the step of forming a silica-precursor complex (S200), drying the silica-precursor complex (S300), or heat treatment step of forming a mesoporous body (S400), which will be described later. The pore structure of the mesoporous silica is damaged, making it impossible to obtain the desired type of polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst.

In the step of forming a silica-precursor complex (S200), structured mesoporous silica (OMS) may be impregnated with a predetermined concentration of the precursor mixture. The structured mesoporous silica is a silica template material with a three-dimensional structure in which one-dimensional micropores are connected to each other. It is a molecular sieve material with a three-dimensional connection structure and can have various cubic structures.

In one embodiment the structured mesoporous silica may be KIT-6. Furthermore, the mesoporous silica may be at least one of KIT-6, SBA-15, SBA-16, and MCM-48. Additionally, as described above, since the precursor mixture is water-based, the surface of the structured mesoporous silica can be pretreated to make it hydrophobic.

Accordingly, as the structured mesoporous silica is impregnated with the precursor mixture, the precursor mixture is accommodated in pores formed in the structured mesoporous silica to form a silica-precursor complex.

In order for the precursor mixture to be easily accommodated in the structured mesoporous silica, the precursor mixture may have a predetermined concentration. In detail, the concentration of the precursor mixture at a predetermined concentration may be 5 to 10 parts by weight of the metal salt per 100 parts by weight of the precursor mixture. If the weight part of the metal salt is less than 5, the amount of the metal salt accommodated in the pores formed in the structured mesoporous silica decreases, resulting in difficulties in subsequent processes. On the other hand, when the weight part of the metal salt exceeds 10, the concentration of the precursor mixture increases, which may make it difficult to fill the pores formed in the structured mesoporous silica.

Furthermore, the precursor mixture may further include metal impurities. In detail, the metal impurity may be tin (Sn). A polymer electrolyte (PEM) water electrolysis oxygen evolution reaction catalyst containing tin as an impurity may increase oxygen evolution reaction activity.

The subsequent step of drying the silica-precursor complex (S300) may be performed at a temperature range of 70 to 90° C. for 10 to 12 hours. Accordingly, the solvent of the precursor mixture may be evaporated and the metal salt or metal impurity may be filled on the silica-precursor complex described above.

In the step (S300) of drying the silica-precursor complex, the drying temperature and time may be within a range where metal salts or metal impurities in the precursor mixture do not react and change into other forms such as oxides or complexes.

Furthermore, after performing the step of drying the silica-precursor complex (S300), some of the pores formed in the structured mesoporous silica are filled with the metal salt or metal impurity, but the new pores created by evaporation of the solvent after drying are filled with the metal salt or metal impurity. To fill the silica-precursor complex described above, the step (S200) may be performed again.

That is, the step of forming the silica-precursor complex (S200) and the step of drying the silica-precursor complex (S300) may be performed multiple times. In one embodiment, the step of forming the silica-precursor complex (S200) and the step of drying the silica-precursor complex (S300) may each be performed twice. At this time, the manufacturing sequence of the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst is a step of preparing a precursor mixture (S100), followed by forming a first silica-precursor complex, drying the first silica-precursor complex, and 2. It may include forming a silica-precursor complex and drying the second silica-precursor complex. In addition, the step of forming the silica-precursor complex (S200) and the step of drying the silica-precursor complex (S300) are not limited in number and may be performed multiple times.

The heat treatment step (S400) for forming the mesoporous body may be performed for 5 to 6 hours at a temperature range of 250 to 300°C. If the heat treatment temperature is lower than 250°C, the mesoporous body may not be properly formed. On the other hand, if the heat treatment temperature is higher than 350°C, the uniformity of the resulting mesoporous body may decrease, and the activity of the catalyst may decrease without increasing the durability of the resulting mesoporous body.

In the heat treatment step (S400) of forming a mesoporous body, the precursor material is converted to a metal oxide to form a mesoporous material made of aggregates of metal oxide particles. At this time, oxygen may be supplied in the heat treatment step to convert it into a metal oxide. Accordingly, the heat treatment step may be performed in an air atmosphere containing oxygen. Furthermore, the metal oxide may include ruthenium oxide (RuO ₂ ).

Mesoporous pores of the aggregate of the metal oxide particles may have pores of 2 to 50 nm. That is, aggregates of the metal oxide particles may be filled in the pores of the structured mesoporous silica.

It includes removing the structured mesoporous silica (S500) and drying the mesoporous body (S600). In the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst, the structured mesoporous silica cannot electrochemically act as a catalyst and is therefore preferably removed. Accordingly, a solvent capable of selectively removing the structured mesoporous silica may be used. This may be a solution containing hydrofluoric acid (HF) or sodium hydroxide (NaOH). The structured mesoporous silica may be converted into silicate by alkali melting or carbonate melting, or may be removed by hydrofluoric acid to form SiF ₄ . Accordingly, mesoporous bodies composed of aggregates of the metal oxide particles can be separated.

The mesoporous body composed of the separated aggregates of the metal oxide particles can be dried and used as a polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst. The step of drying the mesoporous body (S600) may be performed for 10 to 12 hours at a temperature range of 70 to 90°C. At this time, for rapid drying, the aggregates of the metal oxide particles may be dried in a reduced pressure atmosphere.

Furthermore, in the mesoporous body made of an aggregate of metal oxide particles, the first peak representing the (110) plane of the Bragg 2θ angle for the CuK-alpha characteristic X-ray wavelength of 1.541 Å appears between 25 and 30 degrees, and (101 ) The second peak representing the plane appears between 32 and 37 degrees. 'Intensity of the second peak/Intensity of the first peak', which is the ratio of the intensity of the second peak to the intensity of the first peak, exceeds 1. In detail, when the precursor material is converted to a metal oxide in the heat treatment step (S400) of forming a mesoporous body, the crystallization rate of the (101) plane of the metal oxide is formed faster than the crystallization rate of the (110) plane.

In other words, it can be seen that a specific surface develops due to the difference in crystal growth rate. The polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst prepared by the method for producing the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst of the present invention is as described above. It can be seen that the (101) plane of the metal oxide is more developed than the (110) plane. Such development of the (101) surface can show excellent oxygen generation reaction activity and improve durability in a polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst. This can be explained in detail in the description of comparative examples and examples described later.

In addition, the mesoporous body made of an aggregate of the metal oxide particles may have an atomic percentage (at%) of metal impurities in the range of 5 to 15 per total number of atoms of the metal oxide particles. When the concentration of the metal impurity is 5 at.% or more, the metal impurity is eluted during the oxygen evolution reaction, which has the effect of increasing the activity by increasing the specific surface area of the catalyst. On the other hand, when the concentration of the metal impurities exceeds 15 at.%, the degree of elution of the metal impurities is severe and may break the overall structure of the metal oxide, resulting in a decrease in activity.

In addition, the mesoporous body made of the metal oxide aggregate has a specific surface area of 95 m ² /g or more and may have a specific surface area sufficient to electrochemically serve as a catalyst.

Figure 2 is a conceptual diagram showing the formation process of the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst of the present invention.

Referring to FIG. 2, a porous template material such as structured mesoporous silica is impregnated with a metal salt, dried and heat treated, and the template material is removed to form a polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst.

Figure 3 is a conceptual diagram of the polymer electrolyte water electrolysis (PEM water electrolysis) system 10 of the present invention.

Referring to Figure 3, the present invention includes an anode (10), a cathode (20), and a polymer electrolyte (PEM) (30) containing the above-described polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst. It can be included. In detail, the first reaction equation below may be performed at the anode 10, and the second reaction equation may be performed at the cathode 20.

[First reaction equation] 2H ₂ O → 4H+ + 4e ^- + O ₂

[Second reaction equation] 4H ⁺ + 4e ^- → 2H ₂

Furthermore, the polymer electrolyte (PEM) 30 separates oxygen gas generated at the anode 10 and hydrogen gas generated at the cathode 20. Additionally, the polymer electrolyte (PEM) 30 may be formed so that hydrogen ions generated at the anode 10 can move to the cathode 20. In addition, the positive electrode 10 and the negative electrode 20 may be provided with a current distributor 40 containing a material such as titanium fiber or titanium mesh.

Hereinafter, an example prepared by the method for producing the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst of the present invention will be described.

<Example 1>

A precursor mixture was prepared by stirring a water-soluble ruthenium precursor in water. At this time, 10 parts by weight of ruthenium precursor is prepared per 100 parts by weight of the precursor mixture.

Structured mesoporous silica is impregnated with the precursor mixture to form a silica-precursor complex. The structured mesoporous silica was KIR-6 and was pretreated to be hydrophobic.

The silica-precursor complex was dried at 80°C for 12 hours. Subsequently, the structured mesoporous silica was impregnated with the precursor mixture again to accommodate the precursor mixture in the pores of the structured mesoporous silica. Additionally, the repeatedly formed silica-precursor complex was dried at 80°C for 12 hours.

The dried silica-precursor composite is heat-treated at 300° C. for 6 hours to form a mesoporous material made of aggregates of metal oxide particles. The heat treatment was carried out in an air atmosphere.

Next, the structured mesoporous silica was removed with a hydrofluoric acid or sodium hydroxide solution, and the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst formed of aggregates of metal oxide particles was collected and dried at 80°C for 12 hours.

<Example 2>

A polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst formed of an aggregate of metal oxide particles was prepared in the same manner as in Example 1, but metal impurities were added to the precursor mixture. In detail, the metal impurity is tin (Sn), and the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst formed from an aggregate of the metal oxide particles of Example 2 is a mesoporous body made of an aggregate of metal oxide particles. Tin per metal atom was manufactured to be 1 at% in atomic percentage (at%).

<Example 3>

A polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst formed from aggregates of metal oxide particles was prepared in the same manner as in Example 2, except that the polymer electrolyte (PEM) water electrolysis oxygen generation reaction formed from aggregates of metal oxide particles was prepared in Example 3. The catalyst was manufactured so that the tin content (at%) per metal atom of the metal oxide was 5 at% in the entire mesoporous body consisting of an aggregate of metal oxide particles.

<Example 4>

A polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst formed from aggregates of metal oxide particles was prepared in the same manner as in Example 2, except that the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst formed from aggregates of metal oxide particles was prepared in Example 4. The catalyst was manufactured so that the tin content per metal atom of the metal oxide was 10 at% in terms of atomic percentage (at%) of the entire mesoporous body consisting of an aggregate of metal oxide particles.

<Example 5>

A polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst formed from aggregates of metal oxide particles was prepared in the same manner as in Example 2, except that the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst formed from aggregates of metal oxide particles was prepared in Example 5. The catalyst was manufactured so that the tin content (at%) per total number of atoms in the mesoporous body made of aggregates of metal oxide particles was 15 at%.

<Comparative example>

The polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst formed from an aggregate of metal oxide particles in the comparative example was commercially available ruthenium oxide (RuO ₂ ).

Figure 4 shows the results of X-ray diffraction analysis of the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst formed from aggregates of metal oxide particles of Examples 1, 3, and Comparative Examples.

Referring to FIG. 4, the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst formed from an aggregate of metal oxide particles of Examples 1, 3, and Comparative Examples has a first peak representing the (110) plane of the Bragg 2θ angle of 20. It appears between 25 and 25 degrees, and the second peak representing the (101) plane appears between 32 and 37 degrees.

Depending on the manufacturing method of the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst formed from aggregates of metal oxide particles, the speed of the crystal plane of the metal oxide varies, and this is determined by the intensity of the first and second peaks described above. It appears.

In Examples 1 and 3, the intensity of the second peak is greater than the intensity of the first peak. That is, 'intensity of the second peak/intensity of the first peak', which is the ratio of the intensity of the second peak to the intensity of the first peak, exceeds 1.

This is because in the heat treatment step of forming the mesoporous body, the precursor material is converted to a metal oxide, and the crystallization rate of the (101) plane of the metal oxide is formed faster than the crystallization rate of the (110) plane. In other words, it can be seen that a specific plane develops due to the difference in crystal growth rate. In the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst of Examples 1 and 3, the (101) plane of the metal oxide is stronger than the (110) plane. It can be seen that it is developing further. This development of the (101) plane affects excellent oxygen generation reaction activity and improved durability in the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst described later.

Figure 5 shows the specific surface area analysis results based on the nitrogen adsorption and desorption results of Examples 1 to 5 and Comparative Examples.

Referring to Figure 5, it can be seen that the specific surface area of Examples 1 to 5 increased compared to the comparative example. In particular, since the examples have a specific surface area of 95 m ² /g or more, the amount of catalyst used can be reduced.

Figure 6 shows the results of activity analysis for the oxygen generation reaction of Examples 1 to 5 and Comparative Examples, and Figure 7 shows the results of linear scanning potential analysis for the oxygen generation reaction of Examples 1 to 5 and Comparative Examples.

Referring to Figures 6 and 7, the overvoltage appears in a similar range when reaching 5 mA/cm ² in the examples and comparative examples, but it can be seen that the activity for the oxygen evolution reaction is excellent at the overvoltage when reaching 10 mA/cm ² there is.

In particular, in the case of tin (Sn) doped medium porous RuO ₂ for oxygen generation, it is most appropriate when 5 atom% or more and 10 atom% or less is applied. If the metal impurity is less than 5 at.%, there is a problem that the metal impurity is eluted during the oxygen evolution reaction and the specific surface area of the catalyst is reduced, thereby reducing activity. On the other hand, when the metal impurity exceeds 15 at.%, the degree of elution of the metal impurity is so severe that the overall structure of the metal oxide can be broken, leading to a decrease in activity.

The polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst, its manufacturing method, and the polymer electrolyte water electrolysis (PEM water electrolysis) system described above are not limited to the configuration and method of the above-described embodiments, but are essential elements of the present invention. It is obvious to those skilled in the art that it can be embodied in another specific form without departing from its characteristics.

Additionally, the above detailed description should not be construed as limiting in any respect and should be considered illustrative. The scope of the present invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present invention are included in the scope of the present invention.

Claims (17)

In the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst,
Forming a mesoporous material made of aggregates of metal oxide particles,
The mesoporous body made of aggregates of the metal oxide particles,
The metal oxide includes ruthenium (Ru),
CuK-alpha characteristics The first peak of the Bragg 2θ angle for the X-ray wavelength of 1.541 Å appears between 25 and 30 degrees,
The second peak appears between 32 and 37 degrees,
The ratio of the intensity of the second peak to the intensity of the first peak exceeds 1,
The mesoporous body composed of aggregates of the metal oxide particles further contains metal impurities,
The metal impurity is tin (Sn),
Polymer electrolyte (PEM) water electrolysis oxygen generation, wherein the metal impurity per number of metal atoms of the metal oxide in the entire mesoporous body made of aggregates of the metal oxide particles is in the range of 5 to 15 in atomic percentage (at%). reaction catalyst. delete delete According to paragraph 1,
A polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst, characterized in that the mesoporous body made of an aggregate of metal oxide particles has a specific surface area of 95 m ² /g or more. An anode comprising the polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst of claim 1 or 4;
cathode; and
Contains a polymer electrolyte (PEM),
The first reaction equation is performed at the anode,
The second reaction equation is performed at the cathode,
The polymer electrolyte (PEM) separates oxygen gas generated at the anode and hydrogen gas generated at the cathode, and is formed to enable hydrogen ions generated at the anode to move to the cathode. ) system.
[First reaction equation] 2H ₂ O → 4H+ + 4e ^- + O ₂
[Second reaction equation] 4H ⁺ + 4e ^- → 2H ₂ Preparing a precursor mixture containing a metal salt;
Impregnating ordered mesoporous silica (OMS) with a precursor mixture at a predetermined concentration to form a silica-precursor complex;
Drying the silica-precursor complex;
A heat treatment step of heat treating the dried silica-precursor composite to form a mesoporous material made of aggregates of metal oxide particles;
removing the structured mesoporous silica containing the mesoporous body; and
Comprising the step of drying the mesoporous body from which the structured mesoporous silica has been removed,
The mesoporous body,
Contains metal oxides,
CuK-alpha characteristics The first peak of the Bragg 2θ angle for the X-ray wavelength of 1.541 Å appears between 25 and 30 degrees,
The second peak appears between 32 and 37 degrees,
The ratio of the intensity of the second peak to the intensity of the first peak exceeds 1,
The precursor mixture further contains metal impurities,
The metal impurity is tin (Sn),
The mesoporous body is a polymer electrolyte (PEM) characterized in that the metal impurity ranges from 5 to 15 in atomic percentage (at%) per number of metal atoms of the metal oxide in the entire mesoporous body made of aggregates of the metal oxide particles. ) Manufacturing method of water electrolysis oxygen generation reaction catalyst. According to clause 6,
A method for producing a polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst, wherein the metal salt contains ruthenium (Ru). According to clause 6,
The metal oxide is a method of producing a polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst containing ruthenium oxide (RuO ₂ ). delete delete delete According to clause 6,
A method for producing a polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst, characterized in that the concentration of the precursor mixture of the predetermined concentration is 5 to 10 parts by weight of the metal salt per 100 parts by weight of the precursor mixture. According to clause 6,
A method for producing a polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst, characterized in that the surface of the structured mesoporous silica is pretreated to make it hydrophobic. According to clause 6,
A method for producing a polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst, characterized in that the step of drying the silica-precursor complex is performed for 10 to 12 hours at a temperature range of 70 to 90 ° C. According to clause 6,
A method for producing a polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst, characterized in that the heat treatment step of forming the mesoporous body is performed for 5 to 6 hours at a temperature range of 250 to 300 ° C. According to clause 6,
A method for producing a polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst, wherein the mesoporous body made of an aggregate of metal oxide particles has a specific surface area of 95 m ² /g or more. According to clause 6,
Preparation of a polymer electrolyte (PEM) water electrolysis oxygen generation reaction catalyst, characterized in that the step of forming a silica-precursor complex and the step of drying the silica-precursor complex are performed multiple times before the heat treatment step of forming the mesoporous body. method.

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