KR102247335B1 - Electrocatalyst using tofu and manufacturing method for the same - Google Patents

Abstract

According to the present invention, disclosed are an electrocatalyst using tofu and a method for manufacturing the same. The method for manufacturing an electrocatalyst using tofu according to an embodiment of the present invention includes the steps of: heating and stirring soybean water; adding a metal solution containing a transition metal to the heated and stirred soybean water to manufacture tofu containing the transition metal; pulverizing the tofu after drying; and carbonizing the pulverized tofu through a heat treatment process to manufacture an electrocatalyst.

Description

Electrocatalyst using tofu and its manufacturing method {ELECTROCATALYST USING TOFU AND MANUFACTURING METHOD FOR THE SAME}

The present invention relates to an electrocatalyst using tofu and a method of manufacturing the same.

Oxygen reduction reaction (ORR) and oxygen generation reaction (OER) proceed very slowly in the cathode of the electrodes of fuel cells and metal-air batteries, and the use of a catalyst is essential.

Most of the catalysts are commercialized only in precious metals, but due to the high cost of raw materials, they are a major obstacle to the commercialization of fuel cells and metal-air batteries.

In order to replace this, it has been reported that the M-N-C catalyst synthesized by doping carbon with nitrogen and a transition metal is active in ORR and OER reactions.

However, since the M-N-C catalyst requires precise synthesis conditions for each step, mass production is difficult, which causes a rise in catalyst price.

Therefore, in order to lower the price of the catalyst, mass production is possible and the catalyst must have excellent performance.

Korean Patent Application Publication No. 10-2011-0070353, "Polymer electrolyte including a non-platinum cathode catalyst for a polymer electrolyte fuel cell, an electrode including the cathode catalyst, and a membrane-electrode assembly including an electrode and a membrane-electrode assembly Fuel cell" Japanese Patent Publication No. 5116512, "High performance, high durability, non-precious metal fuel cell catalyst"

An embodiment of the present invention is to provide an electrocatalyst using tofu that can express excellent catalytic properties due to a large specific surface area due to the network structure of the protein, and a method for producing the same, using tofu containing a protein formed by condensation polymerization. .

In an embodiment of the present invention, an electrocatalyst is prepared using tofu, and unlike the conventional noble metal-based catalyst, the manufacturing cost is inexpensive and the tofu capable of expressing catalytic performance equal to or higher than the conventional noble metal-based catalyst is used. It is intended to provide an electrocatalyst and a method for manufacturing the same.

An embodiment of the present invention is to provide an electrocatalyst using a tofu capable of mass-producing an electrocatalyst and a method for manufacturing the same, since it is only necessary to provide an additional high-temperature heat treatment system while using a conventional tofu production process line when manufacturing an electrocatalyst.

An embodiment of the present invention is to provide an electrocatalyst using tofu and a method for manufacturing the same, which is carbonized through a heat treatment process and has a large number of pores formed on the surface, and thus can have a high specific surface area.

An embodiment of the present invention is to provide an electrocatalyst using tofu and a method of manufacturing the same, which can improve the catalytic performance of the electrocatalyst by controlling the size or number of pores of the electrocatalyst through a carbonization process through a heat treatment process. .

An embodiment of the present invention is to provide an electrocatalyst using tofu and a method of manufacturing the same, capable of manufacturing an eco-friendly electrocatalyst using tofu.

An embodiment of the present invention has excellent catalytic performance by preparing an electrocatalyst doped with a transition metal, so that when used as a positive electrode in a fuel cell, an oxygen generation reaction (OER), an oxygen reduction reaction (ORR), and a hydrogen generation reaction (HER) It is intended to provide an electrocatalyst using tofu that can improve the activity of and a method for producing the same.

The method for producing an electrocatalyst using tofu according to the present invention comprises the steps of heating and stirring soybean water; Preparing tofu containing the transition metal by adding a metal solution containing a transition metal to the heated and stirred soybean water; Pulverizing after drying the tofu; And carbonizing the pulverized tofu through a heat treatment process to prepare an electrocatalyst.

According to the method of manufacturing an electrocatalyst using tofu according to an embodiment of the present invention, the transition metal may be chelate-bonded with the protein contained in the soybean water.

According to the method of manufacturing an electrocatalyst using tofu according to an embodiment of the present invention, the concentration of the metal solution may be 0.003M to 0.021M.

According to the method of manufacturing an electrocatalyst using tofu according to an embodiment of the present invention, the transition metal is cobalt (Co), nickel (Ni), iron (Fe), zinc (Zn), tin (Sn), and manganese (Mn). ) May include at least one of.

According to the method of manufacturing an electrocatalyst using tofu according to an embodiment of the present invention, the metal solution contains two different transition metals, and the two different transition metals are in a molar ratio of 1:1 to 1:2. It may be included in the metal solution.

According to the method of manufacturing an electrocatalyst using tofu according to an embodiment of the present invention, the metal solution contains three different transition metals, and the three different transition metals are 1:1:1 to 1:1: It may be included in the metal solution in a molar ratio of 2.

According to the manufacturing method of an electrocatalyst using tofu according to an embodiment of the present invention, an additive including at least one of _{potassium hydroxide (KOH) and zinc chloride (ZnCl 2) is added to the pulverized tofu during the heat treatment process.} can do.

According to the method of manufacturing an electrocatalyst using tofu according to an embodiment of the present invention, a weight ratio of the pulverized tofu and the additive may be 1:2 to 1:3.

According to the method of manufacturing an electrocatalyst using tofu according to an embodiment of the present invention, the temperature of the heat treatment process may be in the range of 800°C to 1500°C.

According to the method of manufacturing an electrocatalyst using tofu according to an embodiment of the present invention, the time of the heat treatment process may be 30 minutes to 2 hours.

According to the manufacturing method of an electrocatalyst using tofu according to an embodiment of the present invention, after the step of preparing the electrocatalyst by carbonizing the pulverized tofu through a heat treatment process, the step of leaching the electrocatalyst may be further included. I can.

The electrocatalyst using tofu according to the present invention is characterized in that it is manufactured according to the electrocatalyst using tofu according to an embodiment of the present invention.

According to the electrocatalyst using tofu according to an embodiment of the present invention, the electrocatalyst may have a nanoporous structure or a mesoporous structure.

According to the electrocatalyst using tofu according to an embodiment of the present invention, the specific surface area of the electrocatalyst may be 800m ² /g to 3000m ² /g.

According to an exemplary embodiment of the present invention, a tofu containing a protein formed by condensation polymerization is used, and the specific surface area is large due to the network structure of the protein, so that excellent catalytic properties can be expressed.

According to an exemplary embodiment of the present invention, an electrocatalyst is prepared using tofu, and unlike a conventional noble metal-based catalyst, the manufacturing cost is inexpensive and catalytic performance equivalent to or higher than that of a conventional noble metal-based catalyst can be expressed.

According to an embodiment of the present invention, mass production of the electrocatalyst is possible because only a high-temperature heat treatment system is required while using a conventional tofu production process line when manufacturing an electrocatalyst.

According to an embodiment of the present invention, it is carbonized through a heat treatment process, and a plurality of pores are formed on the surface, so that a high specific surface area may be obtained.

According to an embodiment of the present invention, the size or number of pores of the electrocatalyst can be adjusted through a carbonization process through a heat treatment process, thereby improving catalytic performance of the electrocatalyst.

According to an embodiment of the present invention, by manufacturing an electrocatalyst using tofu, it is possible to manufacture an eco-friendly electrocatalyst.

According to an embodiment of the present invention, by preparing an electrocatalyst doped with a transition metal and having excellent catalytic performance, when used as a positive electrode in a fuel cell, an oxygen generation reaction (OER), an oxygen reduction reaction (ORR), and a hydrogen generation reaction ( HER) activity can be improved.

1 is a flow chart showing a method of manufacturing an electrocatalyst using tofu according to an embodiment of the present invention.
2A to 2D are images showing the appearance of the electrocatalysts of Examples 1 to 3.
3A is a scanning electron microscopy (SEM) image showing a state before activation of the electrocatalyst of Example 1, and FIG. 3B is a SEM image showing a state after activating the electrocatalyst of Example 4.
4 is a graph showing the results of evaluating an oxygen evolution reaction (OER) for Example 4 and a control example.
5 is a graph showing the results of evaluating an oxygen reduction reaction (ORR) in Example 4. FIG.
6A is a graph showing the results of measuring specific surface areas of Examples 4 and 5 using a Brunauer-Emmett-Teller (BET) device, and FIG. 6B is a graph showing the pore size of Examples 4 and 5 It is a graph showing one result.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and contents described in the accompanying drawings, but the present invention is not limited or limited by the embodiments.

The terms used in the present specification are for describing exemplary embodiments and are not intended to limit the present invention. In this specification, the singular form also includes the plural form unless specifically stated in the phrase. As used in the specification, “comprises” and/or “comprising” do not exclude the presence or addition of one or more other elements or steps to the mentioned elements or steps.

As used herein, "an embodiment", "example", "side", "example" and the like should be construed as having any aspect or design described better or advantageous than other aspects or designs. It is not.

In addition, the term'or' means an inclusive OR'inclusive or' rather than an exclusive OR'exclusive or'. That is, unless otherwise stated or clear from context, the expression'x uses a or b'means any one of natural inclusive permutations.

In addition, the singular expression ("a" or "an") used in this specification and the claims generally means "one or more" unless otherwise stated or unless it is clear from the context that it relates to the singular form. Should be interpreted as.

The terms used in the description below have been selected as general and universal in the related technical field, but there may be other terms depending on the development and/or change of technology, customs, preferences of technicians, and the like. Therefore, terms used in the following description should not be understood as limiting the technical idea, but should be understood as illustrative terms for describing embodiments.

In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in this case, detailed meanings will be described in the corresponding description. Therefore, terms used in the following description should be understood based on the meaning of the term and the contents throughout the specification, not just the name of the term.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used with meanings that can be commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not interpreted ideally or excessively unless explicitly defined specifically.

On the other hand, in the description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted. In addition, terms used in the present specification are terms used to properly express an embodiment of the present invention, which may vary depending on the intention of users or operators, or customs in the field to which the present invention belongs. Therefore, definitions of these terms should be made based on the contents throughout the present specification.

1 is a flow chart showing a method of manufacturing an electrocatalyst using tofu according to an embodiment of the present invention.

Referring to Figure 1, the method of manufacturing an electrocatalyst using tofu according to an embodiment of the present invention includes the step of heating and stirring the bean water (S110), and the transition by adding a metal solution containing a transition metal to the heated and stirred bean water. Manufacturing tofu containing metal (S120), pulverizing the tofu after drying (S130), and carbonizing the pulverized tofu through a heat treatment process to produce an electrocatalyst (S140). .

In step S110, the soybean water may be soymilk obtained by crushing and filtration by submerging after sorting and washing the beans.

The bean water may be prepared by a generally widely known method for producing bean water.

Specifically, since the beans may contain impurities such as weed seeds, stones, and deteriorated beans during harvest, the impurities may be removed through a screening process of beans prior to step S110.

Depending on the embodiment, the soybean is immersed in water through a sorting process, and then the floating matter is removed, and dirt, soil, and heat-resistant microorganisms adhered to the surface of the soybean may be removed by grinding the water two to three times.

According to an embodiment, after the sorting process, a immersion process for smoothing the tissue of the beans may be performed.

The soybean as a raw material for soybeans may be soybean, which is a general raw material for commercially available tofu, and the type of soybeans capable of producing tofu is not limited.

The soybean water contains water, protein, fat, carbohydrates and minerals, of which proteins include carbon (C), hydrogen (H), oxygen (O), and nitrogen (N).

In addition, the bean water contains phytic acid containing phosphorus (P), and may contain sulfur (S) contained in amino acids.

The step S110 may extract proteins, fats and other components from the soybean water while heating and stirring the soybean water, and may kill microorganisms present in the soybean water.

According to an embodiment, the heating and stirring process of step S110 may heat the bean water to 80° C. while stirring at 250 rpm or more.

In step S120, a metal solution containing a transition metal is added to the heated and agitated bean water, and the bean water is solidified by the transition metal to prepare tofu containing the transition metal.

In the step S120, according to an embodiment, the metal solution is added dropwise to the heated and stirred soybean water and stirred so that it is well mixed to prepare tofu containing the transition metal.

The metal solution containing the transition metal plays the same role as a coagulant used in a general tofu manufacturing process, and may include at least one transition metal ionized by a solvent.

For example, the metal solution _{may be any one of CoCl 2} , NiCl ₂ , FeCl ₂ , ZnCl ₂ and Ni(NO ₃ ) ₂ , but is not limited to the material.

The transition metal contained in the tofu may increase the catalytic activity of the electrocatalyst, and may coagulate the soybean meal by chelate-binding proteins or amino acids contained in the soybean meal.

The chelate bond formed between the protein contained in the bean water and the transition metal can prevent the transition metal from agglomeration by the heat treatment process of step S140, which will be described later, thereby increasing the surface area of the transition metal and the activation of the electrocatalyst. There are many points, and catalyst efficiency can be improved.

The transition metal may be a divalent cation or trivalent cation upon ionization, dissociation of the hydrogen in the carboxyl group (-COOH) contained in the two or more protein molecules or two or more amino acid -COO ^- and a divalent transition metal Or, it can form a large protein by chelate bonding with a trivalent cation.

According to an embodiment, the transition metal may include at least one of cobalt (Co), nickel (Ni), iron (Fe), zinc (Zn), tin (Sn), and manganese (Mn), and the material Is not limited to.

At this time, the sublimation temperature of zinc is low, so that a mesopore can be formed in the electrocatalyst, and a detailed description thereof will be described later.

In order to solidify the heated and stirred bean water, the metal solution may have a concentration of 0.003M to 0.021M.

When the concentration of the metal solution is less than 0.003M, the amount of the transition metal contained in the metal solution is small, so that the heat-stirred soybean water cannot sufficiently coagulate with the protein or amino acid in the heat-stirred soybean water. There may be problems that do not exist.

When the concentration of the metal solution exceeds 0.021M, the transition metals that cannot be combined with proteins or amino acids contained in the soybean water may be aggregated, and catalytic activity as metal oxide is generated by oxidation in the heated and stirred soybean water. There may be a problem of dropping.

According to an embodiment, the metal solution may contain two different transition metals.

For example, the metal solution may include cobalt (Co) and nickel (Ni), cobalt (Co) and iron (Fe), iron (Fe) and nickel (Ni), and the It is not limited to the type.

According to an embodiment, the two different transition metals may be included in the metal solution in a molar ratio of 1:1 to 1:2.

According to an embodiment, the metal solution may contain three different transition metals.

For example, the metal solution may contain cobalt (Co), nickel (Ni), and zinc (Zn), or may contain cobalt (Co), nickel (Ni) and iron (Fe), and is limited to the above types. It doesn't work.

The zinc is a material having a low sublimation temperature, and when zinc is included among three different transition metals included in the metal solution, an electrocatalyst having a mesoporous structure may be prepared in step S140, which will be described later.

Specifically, when the metal solution containing three different transition metals contains zinc having a low sublimation temperature, zinc sublimates in the heat treatment process of step S140, which will be described later, thereby generating pores as much as the space occupied by zinc. I can.

For this reason, it is possible to prepare an electrocatalyst having a mesoporous structure having a larger pore size than the case of containing three different transition metals without including zinc.

According to an embodiment, assuming that the three different transition metals are A, B, and C, respectively, the transition metals A, B, and C are A:B:C=1:1:1 to A:B:C= It may be included in the metal solution in a molar ratio of 1:1:2.

For example, in the case of containing A = cobalt, B = nickel, and C = zinc as the three different transition metals, the metal solution in a molar ratio of A:B:C=Co:Ni:Zn=1:1:2 Can be included in

In step S130, the tofu containing the transition metal may be dried and pulverized to prepare a powder-shaped tofu.

The process of drying the tofu may be a freeze drying process. For example, the tofu containing the transition metal is frozen in a refrigerator for 1 hour and then put into a freeze dryer and freeze-dried for 3 days under a temperature of -50°C and a pressure of 30 mTorr. I can make it.

The process of crushing the dried tofu includes a jaw crusher, a gyratory crusher, a crushing roll, a bowl mill, a roller mill, and an atritioin mil. , Rod mill, ball mill, pebble mill, tube mill, compartment mill, hammer mill with internal classification, Any one of a fluid-energy mill, an agitated mill, a cube cutter, and a slitter may be used, and the method is not limited thereto.

According to an embodiment, the process of centrifuging the tofu containing the transition metal before step S130, discarding the supernatant, and dispersing it by adding distilled water, is repeated 4 to 5 times to react with the protein and amino acids of the soybean water. It is possible to perform a process of removing untranslated metal.

In step S140, an electrocatalyst with pores may be prepared by carbonizing the pulverized tofu through a heat treatment process.

In the heat treatment process, hydrogen (H) and oxygen (O) among the components of the pulverized tofu are sublimated by heat treatment of the tofu pulverized at high temperature, and only carbon (C), nitrogen (N) and a transition metal remain, and the transition metal A doped metal-nitrogen-carbon (MNC) electrocatalyst can be prepared.

In addition, the heat treatment process may increase the specific surface area of the electrocatalyst by sublimating hydrogen (H) and oxygen (O) among the pulverized tofu components to form pores in the electrocatalyst.

In addition, in the heat treatment process, phosphorus (P) and sulfur (S) among the components of the pulverized tofu are heat treated to convert carbon (C) of the pulverized tofu to phosphorus (P) and sulfur (S) having many free electrons. By doping with, it is possible to increase the conductivity and catalytic reaction activity of the electrocatalyst.

In addition, in the heat treatment process, phosphorus (P) contained in the pulverized tofu is combined with the transition metal to generate a metal phosphate, thereby improving the catalytic reaction of the electrocatalyst by the metal phosphate and generating oxygen. The reaction (OER) and hydrogen evolution reaction (HER) can be activated.

Depending on the embodiment, the heat treatment process may be performed at a temperature increase rate of 2°C/min in an atmosphere furnace.

In the heat treatment process, the number or size of pores of the electrocatalyst may be controlled by adjusting a heat treatment temperature and a heat treatment time.

Specifically, the heat treatment process may be performed at a temperature of 800°C to 1500°C.

If the temperature of the heat treatment process is less than 800°C, hydrogen and oxygen contained in the tofu may not be sufficiently sublimated, and if zinc is included as a transition metal, zinc does not sublimate, so that an electrocatalyst having a mesoporous structure can be prepared. There is no problem.

When the temperature of the heat treatment process exceeds 1500° C., there is a problem in that the transition metal is sublimated and cannot function as an electrocatalyst.

In addition, the heat treatment process may be performed for 30 minutes to 2 hours.

If the time of the heat treatment process is less than 30 minutes, hydrogen and oxygen in the tofu may not be sufficiently sublimated, and if the time of the heat treatment process exceeds 2 hours, elements other than carbon may be sublimated, resulting in loss of catalytic activity. .

According to an embodiment, in order to control the pores of the electrocatalyst during the heat treatment process, an additive including at least one of _{potassium hydroxide (KOH) and zinc chloride (ZnCl 2) is added to the pulverized tofu to form a mesoporous structure.} By preparing the catalyst, the electrocatalyst can be activated.

Among the additives, potassium hydroxide may oxidize carbon contained in the pulverized tofu in the heat treatment process to generate carbon dioxide, and may form mesopores in the oxidized portion of the carbon.

Among the additives, zinc chloride may be mixed with the pulverized tofu and then sublimated during the heat treatment process to form mesopores.

The pulverized tofu and the additive may be mixed in a weight ratio of 1:2 to 1:3.

If the weight ratio is less than 1:2, sufficient mesopores cannot be formed in the electrocatalyst, and if the weight ratio is more than 1:3, the additive reacts excessively with carbon contained in the pulverized tofu, and rather the electrocatalyst The specific surface area of can be reduced.

According to an embodiment, the additive may be added together with the metal solution when the metal solution is added to the heated and stirred bean water in step S120.

At this time, the bean water and the additive may be mixed in a weight ratio of 1:2 to 1:3.

The manufacturing method of an electrocatalyst using tofu according to an embodiment of the present invention uses tofu containing a protein formed by condensation polymerization, and has a large specific surface area due to the network structure of the protein, so that excellent catalytic properties can be expressed.

In addition, the manufacturing method of an electrocatalyst using tofu according to an embodiment of the present invention uses tofu, so unlike conventional noble metal-based catalysts, the manufacturing cost is inexpensive and catalytic performance is equal to or higher than that of conventional noble metal-based catalysts. Can be expressed.

In addition, since the method of manufacturing an electrocatalyst using tofu according to an embodiment of the present invention only requires an additional high-temperature heat treatment system while using a conventional tofu production process line, mass production of the electrocatalyst is possible.

In addition, the method of manufacturing an electrocatalyst using tofu according to an embodiment of the present invention can control the size or number of pores of the electrocatalyst through a carbonization process through a heat treatment process, thereby improving catalytic performance of the electrocatalyst.

Hereinafter, an electrocatalyst manufactured according to a method of manufacturing an electrocatalyst using tofu according to an embodiment of the present invention will be described.

Since the electrocatalyst using tofu according to an embodiment of the present invention includes components of a method of manufacturing the electrocatalyst using tofu according to an embodiment of the present invention, a redundant description will be omitted.

The electrocatalyst using tofu according to an embodiment of the present invention is an M-N-C electrocatalyst, and may have a nanoporous structure by being carbonized by a heat treatment process.

According to an embodiment, the electrocatalyst using tofu according to an embodiment of the present invention may have a mesoporous structure when zinc having a low sublimation temperature is included as a transition metal.

The electrocatalyst using the tofu according to an embodiment of the present invention is carbonized through a heat treatment process, and thus a plurality of pores are formed on the surface thereof, and thus may have a high specific surface area.

Specifically, the specific surface area of the electrocatalyst using tofu according to an embodiment of the present invention may be 800m ² /g to 3000m ² /g.

Such an electrocatalyst using tofu according to an embodiment of the present invention can be used as a cathode for fuel cells and metal-air batteries, and can also be used for wastewater treatment by using the effect of adsorbing heavy metals of proteins in the tofu.

In addition, the electrocatalyst using tofu according to an embodiment of the present invention is eco-friendly because it is manufactured using tofu.

The electrocatalyst using tofu according to an embodiment of the present invention uses tofu containing a protein formed by condensation polymerization, and has a large specific surface area due to the network structure of the protein, so that excellent catalytic properties can be expressed.

In addition, the electrocatalyst using tofu according to an embodiment of the present invention is doped with a transition metal and has excellent catalytic performance, so when used as a positive electrode in a fuel cell, an oxygen generation reaction (OER), an oxygen reduction reaction (ORR), and hydrogen generation It can improve the activity of the reaction (HER).

In addition, since the electrocatalyst using tofu according to an embodiment of the present invention is carbonized by a heat treatment process and has a large specific surface area, excellent catalytic performance can be expressed.

Hereinafter, an electrocatalyst using tofu was prepared according to Examples and Comparative Examples, and then characteristics were evaluated to demonstrate the characteristics and effects of the electrocatalyst using tofu.

Example

[Example 1]

48.5 mL of bean water was heated to 80° C. while stirring at 250 rpm using a magnetic stirrer.

1.5 mL of a _{0.003M CoCl 2} solution, which is a metal solution, was added dropwise to the heated soybean water and stirred.

_{After adding all the CoCl 2} solution to the heated soybean water, the mixture was stirred for 10 minutes.

Thereafter, it was placed in a conical tube and centrifuged at 2,000 rpm for 1 minute, and the supernatant was discarded, and then distilled water was added thereto and the process of dispersing was repeated 5 times to prepare tofu.

The prepared tofu was frozen in a refrigerator for 1 hour and then put in a freeze dryer and freeze-dried for 3 days at a temperature of -50°C and a pressure of 30 mTorr.

After pulverizing and pulverizing the freeze-dried tofu, the temperature was raised to 900°C at a temperature increase rate of 2°C/min in an atmosphere furnace, and heat treatment was performed for 2 hours under the condition of an argon gas flow rate of 5 mL/min. Was prepared.

[Example 2]

An electrocatalyst was prepared in the same manner as in [Example 1], except that a _{NiCl 2} solution was used as the metal solution.

[Example 3]

An electrocatalyst was prepared in the same manner as in [Example 1], except that _{FeCl 2} solution was used as the metal solution.

[Example 4]

An electrocatalyst was prepared in the same manner as in [Example 1], except that the freeze-dried tofu was pulverized and powdered and then mixed with KOH at a weight ratio of 1:2 to activate the electrocatalyst by performing a heat treatment process. I did.

[Example 5]

The electrocatalyst was prepared in the same manner as in [Example 2], except that the freeze-dried tofu was pulverized and powdered and then _{mixed with ZnCl 2} in a weight ratio of 1:2 to activate the electrocatalyst by performing a heat treatment process. Was prepared.

[Control example]

Conventionally used noble metal catalyst RuO ₂ .

The examples 1 to 5 are summarized in Table 1 below according to the types of transition metals and process conditions.

[Table 1]

2A to 2D are images showing the appearance of the electrocatalysts of Examples 1 to 3.

Specifically, FIG. 2A is an image showing the shape of the tofu pulverized before heat treatment of Example 1, FIG. 2B is an image showing the shape of the pulverized tofu before heat treatment of Example 2, and FIG. 2C is This is an image showing the shape of the pulverized tofu before heat treatment in Example 3, and FIG. 2D is an image showing the shape of the electrocatalyst prepared after heat treatment of the pulverized tofu of Example 1 above.

Referring to FIGS. 2A to 2D, it can be seen that an electrocatalyst was manufactured using tofu containing a transition metal through Examples 1 to 3 above.

FIG. 3A is a scanning electron microscopy (SEM) image showing a state before activation of the electrocatalyst of Example 1, and FIG. 3B is a SEM image showing a state after activating the electrocatalyst of Example 4.

First, referring to FIG. 3A, it can be seen that before activating the electrocatalyst of Example 1, pores are not visibly formed on the surface, but are formed in a very fine size.

On the other hand, referring to FIG. 3B, it can be seen that mesopores were formed on the surface of the electrocatalyst due to activation by KOH with respect to the electrocatalyst of Example 4.

Therefore, in the electrocatalyst of the present invention, mesopores may be formed by additives during a high-temperature heat treatment process.

4 is a graph showing the results of evaluating the oxygen evolution reaction (OER) for Example 4 and Control Example.

4 is a graph evaluating the OER activity of Example 4 and Control Example at 10 mA, and'Tofu-Co-NC900' shown in FIG. 4 means the electrocatalyst of Example 4 having a ^{specific surface area of 900 m 2 /g, and} ,'Tofu-Co-NC800' means the electrocatalyst of Example 4 having a ^{specific surface area of 800m 2 /g.}

Referring to FIG. 4, it can be seen that the overpotential values of Example 4 and the control example are similar, and thus similar OER activity is shown.

Accordingly, it can be seen that the electrocatalyst of Example 4 exhibits catalytic performance similar to that of the reference example, which is a conventional noble metal catalyst.

5 is a graph showing the results of evaluating an oxygen reduction reaction (ORR) in Example 4. FIG.

Figure 5 is a graph showing the evaluation of the ORR activity of Example 4 in a 0.1M potassium hydroxide (KOH) solution, shown in Figure 5 'Activated Co2P-NSPC' means the electrocatalyst of Example 4.

Referring to FIG. 5, the half wave potential of Example 4 is 0.79V, which is close to 1V, indicating that it is acting as an ORR catalyst with excellent performance.

6A is a graph showing the results of measuring specific surface areas of Examples 4 and 5 using a Brunauer-Emmett-Teller (BET) device, and FIG. 6B is a graph showing the pore size of Examples 4 and 5 It is a graph showing one result.

_{At this time,'Co 2} P-NSPC' shown in FIGS. 6A and 6B refers to the electrocatalyst of Example 4 activated by KOH, and'Ni-NSPC' is of Example 5 activated by _{ZnCl 2.} It means an electrocatalyst.

First, referring to FIG. 6A, as a result of measuring the specific surface area of Example 4 using a BET device, the specific surface area of Example 4 is 2349 m ² /g, and the specific surface area of Example 5 is 1210 m ² /g I can confirm that it is.

In addition, it can be seen that the graph outline for Example 5 was not made of a single line, so that mesopores were formed in Example 5.

Accordingly, it can be confirmed that the electrocatalyst according to the embodiment of the present invention has a large specific surface area by being activated by an additive during a high-temperature heat treatment process to form mesopores.

6B shows the results of calculating the pore sizes of the fourth and fifth embodiments based on the results of FIG. 6A. Referring to FIG. 6B, the pore size of the fifth embodiment is the same as that of the fourth embodiment. Compared to that, it can be seen that the mesopores were formed in Example 5, which is consistent with the results of FIG. 6A.

As described above, although the present invention has been described by limited embodiments and drawings, the present invention is not limited to the above embodiments, and various modifications and variations from these descriptions for those of ordinary skill in the field to which the present invention pertains. This is possible. Therefore, the scope of the present invention is limited to the described embodiments and should not be defined, but should be defined by the claims to be described later as well as those equivalent to the claims.

Claims (13)

Heating and stirring the bean water;
Preparing tofu containing the transition metal by adding a metal solution containing a transition metal to the heated and stirred soybean water;
Pulverizing after drying the tofu; And
Including the step of producing an electrocatalyst by carbonizing the pulverized tofu through a heat treatment process,
The method of drying the tofu is a method of manufacturing an electrocatalyst using tofu, characterized in that freeze drying.
The method of claim 1,
The transition metal is a method for producing an electrocatalyst using tofu, characterized in that the chelate bond with the protein contained in the soybean water.
The method of claim 1,
The method for producing an electrocatalyst using tofu, characterized in that the concentration of the metal solution is 0.003M to 0.021M.
The method of claim 1,
The transition metal comprises at least one of cobalt (Co), nickel (Ni), iron (Fe), zinc (Zn), tin (Sn), and manganese (Mn). Manufacturing method.
The method of claim 4,
The metal solution contains two different transition metals,
The method of producing an electrocatalyst using tofu, wherein the two different transition metals are contained in the metal solution in a molar ratio of 1:1 to 1:2.
The method of claim 4,
The metal solution contains three different transition metals,
The method of manufacturing an electrocatalyst using tofu, wherein the three different transition metals are contained in the metal solution in a molar ratio of 1:1:1 to 1:1:2.
The method of claim 1,
The method of manufacturing an electrocatalyst using tofu, characterized in that an additive including at least one of potassium hydroxide (KOH) and zinc chloride (ZnCl _{2) is added to the pulverized tofu during the heat treatment process.}
The method of claim 7,
The method of manufacturing an electrocatalyst using tofu, characterized in that the weight ratio of the pulverized tofu and the additive is 1:2 to 1:3.
The method of claim 1,
The method of manufacturing an electrocatalyst using tofu, characterized in that the temperature of the heat treatment process is 800°C to 1500°C.
The method of claim 1,
The time of the heat treatment process is a method of producing an electrocatalyst using tofu, characterized in that 30 minutes to 2 hours.
An electrocatalyst using tofu prepared according to any one of claims 1 to 10.
The method of claim 11,
The electrocatalyst is an electrocatalyst using tofu, characterized in that it has a nanoporous structure or a mesoporous structure.
The method of claim 11,
The electrocatalyst using tofu, characterized in that the specific surface area of the electrocatalyst is 800m ² /g to 3000m ^{2 /g.}

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