Catalyst for water electrolysis electrode, method for producing catalyst for water electrolysis electrode, and water electrolysis electrode

Abstract

The present disclosure relates to a catalyst for a water electrolysis electrode, a method for manufacturing the catalyst for a water electrolysis electrode, and a water electrolysis electrode, the catalyst for a water electrolysis electrode according to an embodiment may include: a carbon structure doped with a first element and a second element; and alloy nanoparticles doped with the first element, the alloy nanoparticles being supported on the surface of the carbon structure, the first element being iron (Fe).

Description

Technical Field

[0001] This disclosure relates to a catalyst for a water electrolysis electrode, a method for manufacturing the catalyst for a water electrolysis electrode, and a water electrolysis electrode. Background Technology

[0002] Hydrogen energy, as a clean energy source, has attracted much attention as one of the powerful alternative energy sources for solving energy problems in the long term. Among hydrogen production methods, water electrolysis, which uses electricity to separate water into hydrogen and oxygen and does not emit carbon dioxide, is relatively environmentally friendly and has therefore received much attention. It can also make a significant contribution to achieving carbon neutrality.

[0003] On the one hand, in the water electrolysis reaction, there is an oxygen evolution reaction (OER) generated at the oxygen evolution electrode and a hydrogen evolution reaction generated at the hydrogen evolution electrode in the water electrolysis system. In acidic and alkaline media respectively, the half-cell reaction and the overall reaction can be represented as shown in the following chemical formulas 1 and 2.

[0004]

Chemical Formula 1

Chemical Formula 2

[0005] Therefore, there is a need to develop catalysts for water electrolysis electrodes that can replace precious metal catalysts or reduce the content of precious metals while having high hydrogen evolution reaction performance, specifically catalysts for hydrogen evolution electrodes. Summary of the Invention

[0006] According to one aspect of this disclosure, a non-precious metal water electrolysis electrode catalyst with low transition metal loading and excellent hydrogen evolution reaction performance can be provided, as well as a water electrolysis electrode including the water electrolysis electrode catalyst.

[0007] According to another aspect of this disclosure, a method for manufacturing a catalyst for a water electrolysis electrode can be provided, which can effectively manufacture a catalyst for a water electrolysis electrode.

[0008] The catalyst for the water electrolysis electrode according to this disclosure may include: a carbon structure doped with a first element and a second element; and alloy nanoparticles doped with the first element, wherein the alloy nanoparticles are loaded on the surface of the carbon structure, and the first element is iron (Fe).

[0009] In a catalyst for a water electrolysis electrode according to one embodiment, the carbon structure may include at least one selected from the group consisting of carbon black, carbon nanotubes, carbon nanofibers, carbon nanoribbons, fullerenes, graphene, graphene nanoplatelets, and graphite.

[0010] In a catalyst for a water electrolysis electrode according to one embodiment, the second element may be nitrogen.

[0011] In a catalyst for a water electrolysis electrode according to one embodiment, the alloy nanoparticles may be nickel-cobalt (Ni-Co) alloy nanoparticles.

[0012] In a catalyst for a water electrolysis electrode according to one embodiment, the nickel-cobalt alloy nanoparticles may contain an excess of cobalt compared to nickel.

[0013] In one embodiment of the catalyst for a water electrolysis electrode, the catalyst may be an Fe-NC type catalyst supported on nickel-cobalt alloy nanoparticles doped with iron (Fe).

[0014] In a catalyst for a water electrolysis electrode according to one embodiment, the first element may contain 0.01% to 0.10% by weight based on the total weight of the catalyst for the water electrolysis electrode.

[0015] The method for manufacturing a catalyst for a water electrolysis electrode according to the present disclosure may include: contacting a carbon precursor with a first element precursor solution to form a carbon complex doped with the first element; and immersing the carbon complex doped with the first element in a metal precursor solution, wherein the first element is iron (Fe), and the metal precursor solution includes two or more transition metal precursors that are different from each other.

[0016] In a method for manufacturing a catalyst for a water electrolysis electrode according to an embodiment, the carbon precursor may include at least one selected from the group consisting of carbon black, carbon nanotubes, carbon nanofibers, carbon nanoribbons, fullerene, graphene, graphene nanoplatelets, and graphite.

[0017] In a method for manufacturing a catalyst for a water electrolysis electrode according to an embodiment, the first elemental precursor solution may include at least one or a mixture thereof selected from the group consisting of iron chloride, iron nitrate, iron acetate, iron sulfate, iron trifluoromethanesulfonate, iron citrate, iron acetylacetonate, and iron pyrophosphate.

[0018] In a method for manufacturing a catalyst for a water electrolysis electrode according to one embodiment, the step of forming a carbon complex doped with the first element may involve nitrogen treatment of the carbon precursor followed by contact with a precursor solution of the first element.

[0019] In a method for manufacturing a catalyst for a water electrolysis electrode according to one embodiment, the metal precursor solution may include a nickel (Ni) precursor and a cobalt (Co) precursor.

[0020] In a method for manufacturing a catalyst for a water electrolysis electrode according to one embodiment, the method may further include a step of heat-treating the metal precursor solution containing a carbon complex doped with the first element under an inert atmosphere.

[0021] In a method for manufacturing a catalyst for a water electrolysis electrode according to one embodiment, the heat treatment step may be a heat treatment at a temperature of 600°C to 1000°C for 30 minutes to 2 hours.

[0022] According to the water electrolysis electrode disclosed herein, it may include: a substrate; and a catalyst for water electrolysis electrode loaded on the substrate, wherein the catalyst for water electrolysis electrode includes a carbon structure doped with a first element and a second element and alloy nanoparticles doped with the first element, the alloy nanoparticles being loaded on the surface of the carbon structure, and the first element being iron (Fe).

[0023] In a water electrolysis electrode according to one embodiment, the alloy nanoparticles may be nickel-cobalt (Ni-Co) alloy nanoparticles.

[0024] In a water electrolysis electrode according to one embodiment, the catalyst used in the water electrolysis electrode may be an Fe-NC type catalyst supported on nickel-cobalt alloy nanoparticles doped with iron (Fe).

[0025] In a water electrolysis electrode according to one embodiment, the first element may be present in an amount of 0.01% to 0.10% by weight, based on the total weight of the catalyst used in the water electrolysis electrode.

[0026] In a water electrolysis electrode according to one embodiment, the catalyst loading of the water electrolysis electrode may be 0.1 mg / cm³. 2 Up to 5.0 mg / cm 2 .

[0027] In a water electrolysis electrode according to one embodiment, the Tafel slope may be less than 200 mV / dec.

[0028] According to one aspect of this disclosure, a non-precious metal water electrolysis electrode catalyst with low transition metal loading and excellent hydrogen evolution reaction performance can be provided, as well as a water electrolysis electrode including the water electrolysis electrode catalyst.

[0029] According to another aspect of this disclosure, a method for manufacturing a catalyst for a water electrolysis electrode can be provided, which can effectively manufacture a catalyst for a water electrolysis electrode. Attached Figure Description

[0030] Figure 1 This is a diagram illustrating an example of the surface structure of a catalyst for a water electrolysis electrode according to an embodiment of the present disclosure.

[0031] Figure 2 This is a block diagram illustrating an example of a method for preparing a catalyst for a water electrolysis electrode according to an embodiment of the present disclosure.

[0032] Figure 3 These are TEM images and EDS mapping results of the catalyst used in the water electrolysis electrode of the embodiment.

[0033] Figure 4 This is a graph showing the XRD pattern of the catalyst used in the water electrolysis electrode of an embodiment.

[0034] Figure 5 This is a diagram illustrating an example of a three-electrode system configured for evaluating electrochemical properties.

[0035] Figure 6 The graphs are used to evaluate the hydrogen evolution reaction performance of the water electrolysis electrodes of Examples 1, 3, and 4, and are presented as current density vs. voltage curves.

[0036] Figure 7 The graphs are used to evaluate the hydrogen evolution reaction performance of the water electrolysis electrodes of Examples 1, 3, and 4, and are presented as overpotential vs. logarithmic current density curves.

[0037] Figure 8 This is a diagram showing an example of the surface structure of the catalyst used in the water electrolysis electrode of Comparative Example 3.

[0038] Figure label: 10: Catalyst for water electrolysis electrode; 100: First element; 200: Second element; 300: Carbon structure; 400: Alloy nanoparticles. Detailed Implementation

[0039] The embodiments described in this specification can be modified into various different forms, therefore the technology according to one embodiment is not limited to the embodiments described below. Furthermore, unless otherwise defined in this specification, the use of "comprising," "having," "containing," or "having" a certain constituent element throughout the specification means that other constituent elements may be included, and that factors, materials, or processes not further listed are not excluded.

[0040] In this specification, unless otherwise explicitly stated, "identical" or "uniform" can mean that they are identical or uniform to each other within an acceptable margin of error. For example, "identical" in the form of a structural or physical property measurement not only means that the two individuals being compared are completely identical, but also that they are identical within a margin of error. On the one hand, "identical" in the form of a physical property measurement can mean that the difference between the measurements of individuals is approximately less than 5%, specifically less than 3%, and more specifically less than 1%.

[0041] The numerical ranges used in this specification include upper and lower limits and all values ​​within those limits, increments logically derived from the form and width of the defined range, all values ​​with double limits, and all possible combinations of upper and lower limits of numerical ranges defined in different forms.

[0042] Unless otherwise defined in this specification, “about” can be considered as a value within 30%, 25%, 20%, 15%, 10% or 5% of the value explicitly stated.

[0043] In this specification, the use of terms such as "first," "second," and "third" preceding a certain constituent element is merely to avoid confusion regarding the constituent elements they refer to, and is unrelated to the order, importance, or hierarchical relationship between the constituent elements. For example, it is also possible to realize an invention that does not include the first constituent element but only includes the second constituent element.

[0044] In this specification, "contact" or "making contact" can refer to a situation where one entity comes into direct physical / chemical contact with another entity, or more specifically, a situation where one entity comes into contact with yet another entity through another entity as a medium, without limitation. On the one hand, it is preferable that one entity comes into contact with another entity in a way that enables a physical / chemical interaction between them, but it is not necessarily limited to this.

[0045] The term "salt" as used in this specification can refer to, without limitation, the ionic form of a compound or chemical structure, including cationic or anionic compounds, for the purpose of forming electrically neutral compounds or structures.

[0046] The term "water electrolysis" as used in this specification can refer to, without limitation, a reaction or series of processes that use electrical energy to decompose water (H2O) into gaseous hydrogen (H2) and oxygen (O2).

[0047] The present disclosure is described in detail below. However, it is merely an example, and the present disclosure is not limited to the specific implementation described as an example.

[0048] Catalysts for water electrolysis electrodes Figure 1 This is a diagram illustrating an example of the surface structure of a catalyst for a water electrolysis electrode according to an embodiment of the present disclosure.

[0049] According to one embodiment of the present disclosure, a catalyst 10 for a water electrolysis electrode may include: a carbon structure 300 doped with a first element 100 and a second element 200; and alloy nanoparticles 400 doped with the first element 100, the alloy nanoparticles 400 being loaded on the surface of the carbon structure 300, wherein the first element 100 is iron (Fe).

[0050] In one embodiment, the catalyst 10 for the water electrolysis electrode may include a carbon structure 300 doped with a first element 100 and a second element 200 and alloy nanoparticles 400 doped with the first element 100.

[0051] In one embodiment, the alloy nanoparticles 400 may be loaded onto the surface of the carbon structure 300.

[0052] In one embodiment, the carbon structure 300 may be a carbon structure doped with a first element 100 and a second element 200.

[0053] In one embodiment, the carbon structure 300 can be a nanometer-scale or micrometer-scale structure. On the one hand, in an exemplary embodiment, the carbon structure can be any type of structure, including one-dimensional and two-dimensional structures. As an example, the carbon structure 300 can be defined by various shapes such as spheres, fibers, discs, wires, webs, pillars, rods, ribbons, plates, walls, and tubes.

[0054] In an exemplary embodiment, the carbon structure 300 is not necessarily limited to this and can be formed in the range of 0.1 nm to 1000 μm, specifically 0.1 nm to 100 μm, more specifically in the range of 0.1 nm to 1000 nm or 0.1 nm to 500 nm.

[0055] In one embodiment, the carbon structure 300 may include at least one selected from the group consisting of carbon black, carbon nanotubes, carbon nanofibers, carbon nanoribbons, fullerenes, graphene, graphene nanoplatelets, and graphite. However, it is not necessarily limited to this, and the carbon structure 300 may specifically include carbon black.

[0056] In one embodiment, the carbon black may be a concept including at least one of acetylene black, ketjen black, and Super P.

[0057] In one embodiment, the graphite can be the concept of natural graphite, artificial graphite, or a mixture thereof without limiting its meaning.

[0058] In one embodiment, as described later, the carbon structure 300 may exist in a composite form generated by physicochemical treatment of a precursor. The precursor may be a carbon precursor. The carbon precursor may include, but is not necessarily limited to, at least one selected from the group consisting of carbon black, carbon nanotubes, carbon nanofibers, carbon nanoribbons, fullerenes, graphene, graphene nanoplatelets, and graphite; the carbon precursor may specifically include carbon black.

[0059] The composite carbon structure 300 can have, for example, a hetero-doped structure in which one or more of the individual carbon atoms constituting the structure are replaced or intercalated with hetero-element. In a specific embodiment, the carbon structure 300 can be a composite carbon structure doped with a first element 100 and a second element 200.

[0060] Figure 1 This is a diagram showing an example of the surface of the carbon structure 300. Figure 1 In the example shown, the surface of a carbon structure 300 according to one embodiment is illustrated in a honeycomb structure with each element located at each vertex. Figure 1 As shown, carbon atoms are mainly located at the vertices of this structure.

[0061] refer to Figure 1 A portion of the carbon atoms is replaced or inserted by a first element 100 or a second element 200. Through this substitution or insertion as described above, a portion of the existing honeycomb structure may be deformed in at least a portion of the region where the substitution or insertion occurs and its adjacent regions. In contrast, even through this substitution or insertion as described above, the existing honeycomb structure can remain unchanged in at least a portion of the region where the substitution or insertion occurs and its adjacent regions.

[0062] In one embodiment, as described above, the first element 100 can be iron (Fe). The first element 100 can be doped onto both the carbon structure 300 and the alloy nanoparticles 400.

[0063] In an exemplary embodiment, the first element 100 is doped onto the carbon structure 300 and / or the alloy nanoparticles 400 respectively, so that it can be contained in each in trace amounts.

[0064] In one embodiment, the second element 200 may be nitrogen.

[0065] In nitrogen-doped carbon structures, the nitrogen-doped regions can provide active sites. On one hand, the first element 100, specifically iron (Fe) as a single atom, can exist in a form that coordinates with the doped nitrogen atoms.

[0066] In the embodiments described above, the first element 100 may be contained in a form that coordinates with the second element 200.

[0067] In an exemplary embodiment, the carbon structure can be an Fe-NC structured carbon structure.

[0068] Refer again Figure 1 In one embodiment, the alloy nanoparticles 400 can be loaded onto the surface of the carbon structure 300.

[0069] In one embodiment, the alloy nanoparticles 400 may be doped with the first element 100.

[0070] In one embodiment, the alloy nanoparticles 400 can be nanoscale particles without limitation. As an example, it can refer to at least one region having nanoscale dimensions or an example of a structure having a specific size. The alloy nanoparticles 400 can be single-crystal, polycrystalline, amorphous, or a combination thereof.

[0071] In an exemplary embodiment, the alloy nanoparticles 400 are not necessarily limited to this, and may have an average particle size of 0.1 nm to 100 nm. Alternatively, specifically, the average particle size of the alloy nanoparticles may be 0.5 nm or more, 1 nm or more, 2 nm or more, 5 nm or more, 7 nm or more, 10 nm or more, 12 nm or more, 15 nm or more, or 20 nm or more, or less than 90 nm, less than 80 nm, less than 75 nm, less than 70 nm, less than 65 nm, less than 55 nm, less than 50 nm, less than 45 nm, less than 40 nm, less than 35 nm, or less than 30 nm.

[0072] In one embodiment, the alloy nanoparticles may be alloy nanoparticles composed of alloys of dissimilar metal elements.

[0073] In one embodiment, the alloy nanoparticle 400 may be an alloy nanoparticle composed of an alloy of at least two transition metal elements.

[0074] In one embodiment, the alloy nanoparticle 400 may be an alloy nanoparticle composed of at least two fourth-period transition metal elements.

[0075] In one embodiment, the alloy nanoparticle 400 may be a nickel-cobalt (Ni-Co) alloy nanoparticle.

[0076] In one embodiment, the nickel-cobalt alloy nanoparticles may contain an excess of cobalt compared to nickel.

[0077] In one embodiment, the nickel-cobalt alloy nanoparticles may contain more than 5 times the amount of cobalt compared to nickel by weight. In specific embodiments, they may contain more than 6 times, 6.5 times, 7 times, 7.5 times, or 8 times the amount of cobalt compared to nickel by weight.

[0078] Refer again Figure 1 In one embodiment, the alloy nanoparticle 400 may be an alloy nanoparticle doped with the first element 100.

[0079] In a specific embodiment, the first element 100 may be iron.

[0080] Therefore, in one embodiment, the alloy nanoparticle 400 can be an iron-doped alloy nanoparticle.

[0081] In one embodiment, the iron-doped nickel-cobalt alloy nanoparticles may be alloy nanoparticles doped with trace amounts of iron.

[0082] In one embodiment, the catalyst 10 for the water electrolysis electrode can be an Fe-NC type catalyst supported on nickel-cobalt alloy nanoparticles doped with iron (Fe).

[0083] In one embodiment, the alloy nanoparticles 400 can induce a reaction specificity different from the past through the interaction between the constituent elements. In a specific embodiment, the alloy nanoparticles 400 can induce a reaction specificity different from the past for the hydrogen evolution reaction through the interaction between iron, nickel, and cobalt.

[0084] In one embodiment, the alloy nanoparticles 400 can be uniformly loaded on the surface of the carbon structure 300.

[0085] On the one hand, as described above, in the carbon structure 300, specifically, a transition metal element, specifically a first element 100 as iron, can be coordinated and bonded in a region doped with a second element 200 as nitrogen. This region can provide an active site. Alloy nanoparticles containing an excess of nickel-cobalt located near this site can interact with the first element 100, specifically iron, doped at or near this site. Through the interaction described above, the hydrogen evolution reaction performance can be further improved.

[0086] In one embodiment, the first element 100 may be present in an amount of 0.01% to 0.10% by weight, based on the total weight of the catalyst 10 for the water electrolysis electrode. Alternatively, in a specific embodiment, the content of the first element 100 may be 0.02% or more by weight, 0.03% or more by weight, 0.04% or more by weight, or 0.05% by weight, or less than 0.09% by weight, 0.08% by weight, 0.07% by weight, or 0.06% by weight. That is, in the catalyst 10 for the water electrolysis electrode, the first element 100 may be present in an amount of 0.01% to 0.10% by weight, and in a specific embodiment, may be 0.02% or more by weight, 0.03% or more by weight, 0.04% or more by weight, or 0.05% or more by weight, or less than 0.09% by weight, 0.08% by weight, or 0.07% by weight.

[0087] In one embodiment, the first element 100 may contain 0.10% to 0.50% by weight, based on the total weight of the alloy nanoparticles 400. Alternatively, in a specific embodiment, the content of the first element 100 may be 0.20% or more, 0.25% or more, or 0.30% by weight, or less than 0.45% by weight or less than 0.40% by weight. That is, in the alloy nanoparticles 400, the first element 100 may contain 0.10% to 0.50% by weight, and in a specific embodiment, it may contain 0.20% or more, 0.25% or more, or 0.30% or more, or less than 0.45% by weight or less than 0.40% by weight.

[0088] In one embodiment, the second element 200 may be present from 0.1% to 1.0% by weight, based on the total weight of the catalyst 10 for the water electrolysis electrode. Alternatively, in a specific embodiment, the content of the second element 200 may be 0.2% or more by weight, 0.3% or more by weight, 0.4% or more by weight, or 0.5% by weight, or less than 0.9% by weight, 0.8% by weight, or 0.7% by weight. That is, in the catalyst 10 for the water electrolysis electrode, the second element 200 may be present from 0.1% to 1.0% by weight, and in a specific embodiment, it may be present from 0.2% to 0.3% to 0.4% to 0.5% by weight, or less than 0.9% by weight, 0.8% by weight, or 0.7% by weight.

[0089] In one embodiment, as described above, when the alloy nanoparticles are nickel-cobalt alloy nanoparticles, the catalyst 10 for the water electrolysis electrode may include 0.1% to 2.0% by weight of nickel. In specific embodiments, it may include more than 0.3% by weight, more than 0.5% by weight, more than 0.7% by weight, more than 0.8% by weight, or more than 0.9% by weight, or less than 1.9% by weight, less than 1.8% by weight, less than 1.6% by weight, less than 1.4% by weight, less than 1.2% by weight, or less than 1.1% by weight.

[0090] In one embodiment, as described above, when the alloy nanoparticles are nickel-cobalt alloy nanoparticles, the catalyst 10 for the water electrolysis electrode may include 1% to 12% cobalt. In specific embodiments, it may include more than 3%, more than 5%, more than 6%, or more than 7%, or less than 11%, less than 10%, less than 9.5%, or less than 9%.

[0091] Method for manufacturing catalysts for water electrolysis electrodes Figure 2 This is a block diagram illustrating an example of a method for preparing a catalyst for a water electrolysis electrode according to an embodiment of the present disclosure.

[0092] According to an embodiment of the present disclosure, a method for manufacturing a catalyst for a water electrolysis electrode may include: step S10 of contacting a carbon precursor with a first element precursor solution to form a carbon complex doped with the first element; and step S20 of immersing the carbon complex doped with the first element in a metal precursor solution, wherein the first element is iron (Fe) and the metal precursor solution includes two or more transition metal precursors that are different from each other.

[0093] In one embodiment, in step S10, the carbon precursor can be brought into contact with a first element precursor solution to form a carbon complex doped with the first element.

[0094] As mentioned above, in one embodiment, the carbon precursor may include at least one selected from the group consisting of carbon black, carbon nanotubes, carbon nanofibers, carbon nanoribbons, fullerenes, graphene, graphene nanoplatelets, and graphite. However, it is not necessarily limited to this, and the carbon precursor may also specifically include carbon black.

[0095] In one embodiment, the carbon black may be a concept including at least one of acetylene black, ketjen black, and Super P.

[0096] In one embodiment, the graphite can be the concept of natural graphite, artificial graphite, or a mixture thereof without limiting its meaning.

[0097] In one embodiment, the carbon precursor may be a carbon precursor prepared by acid treatment. In a specific embodiment, the carbon precursor may be prepared by contacting it with an acidic solution and then drying it.

[0098] In one embodiment, a strong acid such as nitric acid, sulfuric acid, or hydrochloric acid, or a mixture thereof, can be used as the acidic solution. On one hand, the carbon precursor can be contacted with the acidic solution for 12 to 36 hours. Specifically, contact can be achieved by impregnating the carbon precursor with the acidic solution or by spraying the acidic solution onto the carbon precursor.

[0099] In one embodiment, the carbon precursor described above can be brought into contact with a first element precursor solution.

[0100] In one embodiment, the first element precursor solution may include a transition metal precursor. In a specific embodiment, the first element precursor solution may include an iron precursor.

[0101] In one embodiment, the transition metal precursor may include a transition metal salt. In a specific embodiment, the iron precursor may include an iron salt.

[0102] In one embodiment, the first element precursor solution may include at least one or a mixture thereof selected from the group consisting of iron chloride, iron nitrate, iron acetate, iron sulfate, iron trifluoromethanesulfonate, iron citrate, iron acetylacetonate, and iron pyrophosphate. However, it is not necessarily limited to this, and the first element precursor solution may also specifically be an aqueous solution of iron chloride.

[0103] The first element precursor solution can act as an oxidizing agent. The first element can be incorporated into the carbon precursor by contacting the first element precursor solution with the carbon precursor. Specifically, iron can be incorporated into the carbon precursor through the process described above.

[0104] In one embodiment, the carbon precursor can be added to the first element precursor solution and stirred to bring the carbon precursor into contact with the first element precursor solution, thereby doping the carbon precursor with the first element. However, this is not a limitation; for example, the stirring can be carried out for more than 1 hour, more than 2 hours, more than 3 hours, or less than 6 hours. On the other hand, it is not a limitation; for example, the contact can be carried out at a temperature between 10°C and 50°C.

[0105] In one embodiment, step S10 of forming a carbon complex doped with the first element may involve nitrogen-treating the carbon precursor and then contacting it with a solution of the first element precursor.

[0106] In one embodiment, step S10 may include step S11 of nitrogen-treating the carbon precursor.

[0107] In one embodiment, the nitrogen treatment can be performed using a nitrogen source that includes nitrogen atoms within the molecule, such as a nitrogen-containing compound, a compound containing nitrogen and carbon, or other nitrogen-containing organic matter. In a non-limiting embodiment, the nitrogen source can be prepared in a liquid medium or by fluid flow.

[0108] In an exemplary embodiment, the nitrogen source may include pyrrole, polypyrrole, polyvinylpyrrole, methylpolypyrrole, pyrazole, pyridine, vinylpyridine, polyvinylpyridine, pyrimidine, piperazine, imidazole, methylimidazole, aniline, polyaniline, polyimide, polyamide, polyamide-imide, acrylonitrile, polyacrylonitrile, ammonia, urea, adenine, melamine, etc. In an exemplary embodiment, the nitrogen source may include pyrrole and / or polypyrrole.

[0109] In an exemplary embodiment, the carbon precursor can be dispersed in a dispersion medium, and then a nitrogen source as described above can be added to perform the nitrogen treatment. In the embodiment described above, the carbon precursor can be dispersed in a dispersion medium, and then a nitrogen source can be added and stirred to bring the carbon precursor into contact with the nitrogen source, thereby obtaining a nitrogen-treated carbon precursor.

[0110] However, this is not necessarily the case; the dispersion medium can be a mixture of water and C1 to C6 fatty alcohols. Specifically, as described above, the dispersion medium can be a mixture of water and propanol. On the one hand, the mixing ratio of the water and fatty alcohol mixture, based on volume, can be 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, or 8:2, but is not necessarily limited to this.

[0111] However, it is not necessarily limited to this. For example, the stirring can be carried out for more than 10 minutes or more than 20 minutes, or for less than 1 hour, less than 50 minutes, or less than 40 minutes. On the other hand, it is not necessarily limited to this. For example, the contact can be carried out at a temperature between 10°C and 50°C.

[0112] A nitrogen-treated carbon precursor can be obtained through the above S11 step. In a specific embodiment, the nitrogen-treated carbon precursor can be a polypyrrole-carbon composite. The polypyrrole-carbon composite obtained through the above embodiments can be effectively and uniformly doped with nitrogen atoms across its entire surface.

[0113] In the embodiments described above, step S10 may further include step S12, which involves contacting the nitrogen-treated carbon precursor with the first element precursor solution. That is, in the embodiments described above, step S10 may include steps S11 and S12. In a specific embodiment, step S12 may be performed after step S11.

[0114] In one embodiment, step S12 can be achieved by contacting the nitrogen-treated carbon precursor obtained in step S11, as an example of a polypyrrole-carbon composite, with a first element precursor solution to ultimately form a carbon composite doped with the first and second elements, as an example of an iron-doped polypyrrole-carbon composite. The description relating to the carbon composite doped with the first and second elements as described above is the same as the description relating to the aforementioned carbon structure. Similarly, the description relating to contacting the nitrogen-treated carbon precursor in step S12 with the first element precursor solution is the same as the description relating to step S10 as described above, except that a nitrogen-treated carbon precursor is used instead of a carbon precursor. Therefore, repeated descriptions are omitted below.

[0115] A carbon composite doped with the first and second elements can be formed through step S10 in the embodiments described above.

[0116] In one embodiment, in step S20, the carbon complex doped with the first element can be immersed in a metal precursor solution. In a specific embodiment, in step S20, the carbon complex doped with the first element and the second element can be immersed in a metal precursor solution.

[0117] In one embodiment, the metal precursor solution may include two or more transition metal precursors that are different from each other.

[0118] In one embodiment, the metal precursor solution may include two or more fourth-period transition metal precursors that are different from each other.

[0119] In one embodiment, the metal precursor solution may include a nickel (Ni) precursor and a cobalt (Co) precursor. In a specific embodiment, the metal precursor solution may be a solution comprising a nickel precursor and a cobalt precursor.

[0120] In one embodiment, the nickel precursor may include a nickel salt. Non-limiting examples of nickel precursors including the nickel salt include nickel nitrate, nickel sulfate, nickel fluoride, nickel chloride, nickel bromide, nickel acetate, nickel acetylacetonate, nickel citrate, and nickel phosphate.

[0121] In one embodiment, the cobalt precursor may include a cobalt salt. Non-limiting examples of cobalt precursors including the cobalt salt include cobalt nitrate, cobalt sulfate, cobalt fluoride, cobalt chloride, cobalt bromide, cobalt acetate, cobalt acetylacetonate, cobalt citrate, and cobalt phosphate.

[0122] As a non-limiting example, the metal precursor solution contains nickel and cobalt precursors by weight in ratios of 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, or 1:9.

[0123] The solvent in the metal precursor solution can be a fatty alcohol, without limitation. Specifically, C1 to C4 fatty alcohols can be used. In one embodiment, propanol can be used as the solvent, but it is not necessarily limited to this.

[0124] In a non-limiting embodiment, the impregnation can be performed for 10 minutes or more, 30 minutes or more, 1 hour or more, 2 hours or more, or 3 hours or less, or for less than 48 hours, 36 hours or less, 24 hours or less, 20 hours or less, 18 hours or less, or 15 hours or less. In another non-limiting embodiment, the impregnation can be performed by applying heat to the solution at 20°C or more, 30°C or more, 50°C or more, 70°C or more, 90°C or more, 100°C or more, 150°C or more, or 200°C or more.

[0125] In one embodiment, step S20 may involve immersing a carbon composite doped with the first element formed in step S10 in a metal precursor solution as described above, specifically a metal precursor solution including nickel and cobalt precursors, thereby depositing nickel and cobalt as alloy nanoparticles on the surface of the carbon composite, ultimately obtaining a carbon structure supported on the surface of the carbon composite. Alternatively, in step S20, the first element doped in the carbon composite may be a portion of iron that migrates to the alloy nanoparticles supported in the carbon composite. Finally, through steps S10 and S20 as described above, a catalyst for a water electrolysis electrode comprising a carbon structure doped with a first element and a second element, and alloy nanoparticles doped with the first element supported on the surface of the carbon structure, can be manufactured.

[0126] In one embodiment, the method may further include step S30: heat-treating the metal precursor solution impregnated with the carbon complex doped with the first element under an inert atmosphere. That is, the method for manufacturing a catalyst for a water electrolysis electrode according to an embodiment of the present disclosure may include step S30: heat-treating the metal precursor solution impregnated with the carbon complex in step S20 under an inert atmosphere. Steps S20 and S30 may be performed sequentially, or at least a portion of each step may be performed in parallel.

[0127] In one embodiment, step S30 can be performed in an inert atmosphere. For example, it can be performed in an inert atmosphere formed by inert gases such as nitrogen, helium, or argon. However, it is not limited to this; step S30 can also be performed in an inert atmosphere formed by nitrogen.

[0128] In one embodiment, step S30 of the heat treatment may be heat treatment at a temperature of 600°C to 1000°C for 30 minutes to 2 hours. That is, step S30 may be heat treatment of the metal precursor solution impregnated with the carbon composite in step S20 at a temperature of 600°C to 1000°C for 30 minutes to 2 hours under a nitrogen atmosphere.

[0129] In a non-limiting embodiment, the heat treatment temperature in step S30 can be above 650°C, above 700°C, or above 750°C, or below 950°C, below 900°C, below 880°C, or below 850°C. In another non-limiting embodiment, the time consumed in step S30 can be above 40 minutes, above 50 minutes, or above 55 minutes, or below 110 minutes, below 100 minutes, below 90 minutes, below 80 minutes, or below 70 minutes.

[0130] In one embodiment, step S30 may involve heat-treating the metal precursor solution impregnated with the carbon composite in step S20 under an inert atmosphere to induce thermal decomposition. This allows for the uniform distribution of the alloy nanoparticles on the surface of the carbon composite, ultimately improving the hydrogen evolution performance of the prepared catalyst.

[0131] Water electrolysis electrode According to one embodiment of the present disclosure, a water electrolysis electrode may include: a substrate; and a catalyst for water electrolysis electrode loaded on the substrate. The catalyst for water electrolysis electrode includes a carbon structure doped with a first element and a second element, and alloy nanoparticles doped with the first element. The alloy nanoparticles are loaded on the surface of the carbon structure. The first element is iron (Fe).

[0132] In one embodiment, the substrate may include at least one of titanium, nickel, cobalt, aluminum, stainless steel, or alloys thereof. However, it is not limited to this; it may include materials available in this art that can maintain conductivity for use in water electrolysis electrodes without limitation.

[0133] In one embodiment, the substrate can have various shapes such as rods, wires, plates, and grids.

[0134] In one embodiment, the catalyst for the water electrolysis electrode may include a carbon structure doped with a first element and a second element, and alloy nanoparticles supported on the surface of the carbon structure, wherein the first element is doped onto the alloy nanoparticles.

[0135] In one embodiment, the catalyst for the water electrolysis electrode may be the water electrolysis electrode catalyst of an embodiment of the present disclosure described above, or a water electrolysis electrode catalyst manufactured according to the manufacturing method of the water electrolysis electrode catalyst of an embodiment of the present disclosure described above.

[0136] In one embodiment, the carbon structure may include at least one selected from the group consisting of carbon black, carbon nanotubes, carbon nanofibers, carbon nanoribbons, fullerenes, graphene, graphene nanoplatelets, and graphite. However, it is not necessarily limited to this, and the carbon structure 300 may specifically include carbon black.

[0137] In one embodiment, the second element may be nitrogen.

[0138] In one embodiment, the alloy nanoparticles may be nickel-cobalt (Ni-Co) alloy nanoparticles.

[0139] In one embodiment, the nickel-cobalt alloy nanoparticles may contain an excess of cobalt compared to nickel.

[0140] In one embodiment, the catalyst for the water electrolysis electrode can be an Fe-NC type catalyst supported on nickel-cobalt alloy nanoparticles doped with iron (Fe).

[0141] In one embodiment, the first element may be present in amounts from 0.01% to 0.10% by weight, based on the total weight of the catalyst used in the water electrolysis electrode. Alternatively, in a specific embodiment, the content of the first element may be 0.02% or more by weight, 0.03% or more by weight, 0.04% or more by weight, or 0.05% or more by weight, or less than 0.09% by weight, 0.08% by weight, or 0.07% by weight. That is, in the catalyst used in the water electrolysis electrode, the first element may be present in amounts from 0.01% to 0.10% by weight, and in a specific embodiment, it may be present in amounts from 0.02% or more by weight, 0.03% or more by weight, 0.04% or more by weight, or 0.05% or more by weight, or less than 0.09% by weight, 0.08% by weight, or 0.07% by weight.

[0142] In one embodiment, the first element 100 may contain 0.10% to 0.50% by weight, based on the total weight of the alloy nanoparticles 400. Alternatively, in a specific embodiment, the content of the first element 100 may be 0.20% or more, 0.25% or more, or 0.30% or more, or less than 0.45% or less than 0.40% by weight. That is, in the alloy nanoparticles 400, the first element 100 may contain 0.10% to 0.50% by weight, and in a specific embodiment, it may contain 0.20% or more, 0.25% or more, or 0.30% or more, or less than 0.45% or less than 0.40% by weight.

[0143] In one embodiment, the second element is present at a concentration of 0.1% to 1.0% by weight, based on the total weight of the catalyst for the water electrolysis electrode. Alternatively, in a specific embodiment, the content of the second element may be 0.2% or more by weight, 0.3% or more by weight, 0.4% or more by weight, or 0.5% or more by weight, or less than 0.9% by weight, 0.8% by weight, or 0.7% by weight. That is, in the catalyst for the water electrolysis electrode, the second element may be present at a concentration of 0.1% to 1.0% by weight, and in a specific embodiment, it may be present at a concentration of 0.2% or more by weight, 0.3% or more by weight, 0.4% or more by weight, or 0.5% or more by weight, or less than 0.9% by weight, 0.8% by weight, or 0.7% by weight.

[0144] In addition, refer to Figure 1 and Figure 2 The foregoing description relating to catalysts for water electrolysis electrodes is applicable and not limited thereto.

[0145] In one embodiment, the water electrolysis electrode may be loaded with a catalyst onto the substrate to form a water electrolysis electrode according to an embodiment of the present disclosure.

[0146] In one embodiment, the loading is not particularly limited as long as it is a method known in the art. As an example, various methods such as depositing, spraying, or coating the catalyst onto the substrate can be contemplated.

[0147] In one embodiment, the catalyst loading of the water electrolysis electrode can be 0.1 mg / cm³. 2 Up to 5.0 mg / cm 2 That is, in one embodiment, the water electrolysis electrode can operate at 0.1 mg / cm³. 2 Up to 5.0 mg / cm 2 The catalyst for the water electrolysis electrode is loaded at a specific loading rate. In a specific embodiment, this loading rate can be 0.2 mg / cm³. 2 Above, 0.3 mg / cm2 Above, 0.5 mg / cm 2 Above, 0.7 mg / cm 2 Above, 0.9mg / cm 2 Above, 1.0 mg / cm 2 Above, 1.2 mg / cm 2 Above or 1.6 mg / cm 2 The above, or 4.8 mg / cm 2 Below, 4.5 mg / cm 2 Below, 4.3 mg / cm 2 Below, 4.0 mg / cm 2 Below, 3.5 mg / cm 2 Below, 3.0 mg / cm 2 Below, 2.7 mg / cm 2 Below or 2.2 mg / cm 2 the following.

[0148] In one embodiment, the Tafel slope of the water electrolysis electrode can be below 200 mV / dec.

[0149] In one embodiment, the Tafel slope may refer to the inclination of a Tafel plot curve based on the polarization results of the hydrogen evolution reaction measured in a 1M KOH solution at a scan rate of 5mV / s.

[0150] The Tafel slope can refer to the value represented by B in a relation defined by the following formula.

[0151] [Relational Formula] η = Blog(j / j0) In this relationship, η is the overvoltage, j is the current density, and j o For exchange current density.

[0152] The smaller the value of the Tafel slope, the more kinetically favorable the hydrogen evolution reaction.

[0153] In a specific embodiment, the Tafel slope can be below 190mV / dec, below 180mV / dec, below 170mV / dec, or below 165mV / dec.

[0154] Water electrolysis system According to one embodiment of the present disclosure, the water electrolysis electrode can be constituted as an element of the water electrolysis system.

[0155] In one embodiment, the water electrolysis system can be provided as an apparatus including a membrane electrode assembly. The membrane electrode assembly may include: a diaphragm; a cathode located in either space separated by the diaphragm; an anode located in another space separated by the diaphragm; and an electrolyte for impregnating or at least contacting the cathode and anode. According to one embodiment of the present disclosure, the water electrolysis electrode can be provided as a cathode within the water electrolysis system.

[0156] In an exemplary embodiment, the membrane can function as an ion exchange membrane (a cation exchange membrane or anion exchange membrane, with an anion exchange membrane as an example). As an example, the membrane can represent a porous polymer membrane, a porous ceramic membrane, etc.

[0157] In an exemplary embodiment, the anode may use a conductive substrate, similar to that in the water electrolysis electrode, and an anode catalyst may be loaded onto the conductive substrate. The anode catalyst may also be a noble metal catalyst, such as iridium or palladium, or a non-noble metal catalyst known in the art, to be conductive without side reactions with the electrolyte, while simultaneously exhibiting low overvoltage in the oxygen evolution reaction.

[0158] In an exemplary embodiment, the electrolyte may be an alkaline electrolyte. However, it is not limited to this; examples of the electrolyte may include lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium bicarbonate, potassium bicarbonate, etc. It is also not limited to this; the pH of the electrolyte may be 9 or higher, 9.5 or higher, 10 or higher, 10.5 or higher, 11 or higher, 11.5 or higher, or 12 or higher.

[0159] The water electrolysis system according to one embodiment can be preferably used in, for example, water electrolysis devices or redox flow batteries, other fuel cells, but is not necessarily limited to these.

[0160] The embodiments of this disclosure are further described below with reference to specific experimental examples. The embodiments and comparative examples included in the experimental examples are merely illustrative of the invention and do not limit the scope of the appended patent claims. Those skilled in the art should understand that various modifications and variations can be made to the embodiments within the scope and technical concept of this disclosure, and such modifications and variations should also fall within the scope of the appended patent claims.

[0161] Manufacturing example (Example) (1) Manufacturing of catalysts for water electrolysis electrodes Vulcan XC-72R carbon black (Fuel cell store) was acid-treated with a mixed solution of 6M NHO3 and 6M H2SO4 for 24 hours, followed by drying to obtain 8g of acid-treated dried carbon black. The obtained 8g of carbon black was dispersed in a 1:1 (v:v) mixture of propanol (Sigma-Aldrich) and distilled water. Then, 100mL of pyrrole monomer (Sigma-Aldrich, 98%) was added to the solution, and the mixture was stirred for 30 minutes. Meanwhile, 0.041mol of iron chloride hexahydrate (Alfa Aesar) was quantitatively dissolved in 50mL of distilled water and added to the stirred suspension. The mixture was stirred again for 4 hours to prepare the iron-doped polypyrrole-carbon complex (Fe-PPyCC).

[0162] On one hand, 0.062 mmol of nickel nitrate hexahydrate (Sigma-Aldrich) and 0.563 mmol of cobalt nitrate hexahydrate (Sigma-Aldrich) were quantitatively dissolved in 20 mL of propanol (Sigma-Aldrich) to prepare a metal precursor solution. 330 mg of the iron-doped polypyrrole-carbon composite prepared above was added to the prepared metal precursor solution, and heating was applied for a sufficient time to allow deposition. Then, under N2 conditions, thermal decomposition was performed at 800 °C for 1 hour to finally produce the catalyst for the water electrolysis electrode.

[0163] (2) Manufacturing of water electrolysis electrodes After adding 10 mg of the aforementioned water electrolysis electrode catalyst and 40 μL of Nafion solution (5 wt.% Nafionsolution, Sigma-Aldrich) to 1.5 mL of isopropanol (IPA) / distilled water (4:1 (v:v)), a uniformly mixed ink was prepared using an ultrasonic disperser.

[0164] The prepared ink was sprayed using an air spray gun at a concentration of 2 mg / cm³. 2 The electrode was loaded onto a substrate (GDL, Sigracet 39 BB, Fuel cell strore) to ultimately manufacture the water electrolysis electrode.

[0165] (Comparative Example 1) (1) Manufacturing of catalysts for water electrolysis electrodes Except for not adding cobalt nitrate hexahydrate, but only dissolving 0.062 mmol of nickel nitrate hexahydrate in 20 mL of propanol to prepare a metal precursor solution, the catalyst for water electrolysis electrode was prepared by the same method as in the example.

[0166] (2) Manufacturing of water electrolysis electrodes In addition to using the catalyst for the water electrolysis electrode manufactured as described above, the water electrolysis electrode is prepared by the same method as in the examples.

[0167] (Comparative Example 2) (1) Manufacturing of catalysts for water electrolysis electrodes Except for not adding nickel nitrate hexahydrate, but only dissolving 0.563 mmol of cobalt nitrate hexahydrate in 20 mL of propanol to prepare a metal precursor solution, the catalyst for water electrolysis electrode was prepared by the same method as in the example.

[0168] (2) Manufacturing of water electrolysis electrodes In addition to using the catalyst for the water electrolysis electrode manufactured as described above, the water electrolysis electrode is prepared by the same method as in the examples.

[0169] (Comparative Example 3) (1) Manufacturing of catalysts for water electrolysis electrodes The iron-doped polypyrrole-carbon composite (Fe-PPyCC) prepared by the same method as in the examples was used as a catalyst for water electrolysis electrodes without any additional post-treatment.

[0170] (2) Manufacturing of water electrolysis electrodes In addition to using the catalyst for the water electrolysis electrode described above, the water electrolysis electrode was prepared by the same method as in the examples, thereby manufacturing the water electrolysis electrode.

[0171] (Comparative Example 4) In addition to using a Pt / C catalyst (40% Platinum on Vulcan XC-72R, Fuel cell store), which is commonly used as a reducing electrode catalyst, as a catalyst for water electrolysis electrode, the water electrolysis electrode was prepared by the same method as in the examples.

[0172] Evaluation example Evaluation Example 1. Evaluation of Physicochemical Catalyst Properties (1) TEM (Transmission Electron Microscopy) / EDS (Energy Dispersive X-ray Spectroscopy) mapping analysis Figure 3 These are TEM images and EDS mapping results of the catalyst used in the water electrolysis electrode of the embodiment.

[0173] The catalyst used in the water electrolysis electrode manufactured in the examples was observed and mapped using a high-resolution transmission electron microscope (JEM-2100F, JEOL LTD) equipped with a HAADF-STEM (High-Angle Annular Dark-Field Scanning Transmission Electron Microscope) detector, and analyzed. Figure 3 It is shown in the figure.

[0174] Analysis results, such as Figure 3 As confirmed in the study, the nanoparticles in the catalyst for the water electrolysis electrode manufactured in the examples have an average size of 25 nm, and they exist in an alloy form with nickel and cobalt present in the same position. Furthermore, it has been confirmed that iron single atoms exist not only in the carbon structure but also in the nickel-cobalt alloy particles.

[0175] (2) XRD (X-ray diffraction) analysis Figure 4 This is a graph showing the XRD pattern of the catalyst used in the water electrolysis electrode of an embodiment.

[0176] The metal crystal planes of the water electrolysis electrode catalyst manufactured in the examples were confirmed using X-ray diffraction analysis (PANalytical B.V). Measurements were performed using Cu Kα rays at 40 kV and 100 mA, with measurements taken at 0.01° intervals and a scan rate of 6° per minute in the range of 10 to 80°. Figure 4 The spectrum measured is shown in the figure.

[0177] Analysis results Figure 4 The main peaks in the graph represent nickel-cobalt alloys with a face-centered cubic (FCC) lattice structure, thus confirming the presence of an alloy of nickel and cobalt in the catalyst for the water electrolysis electrode manufactured in the examples. This confirms that the nanoparticles of the examples are composed of nickel-cobalt alloy nanoparticles. However, the iron doped in the nickel-cobalt alloy nanoparticles according to the examples exists in trace amounts in a single-atom form and was therefore not detected in the spectra according to this evaluation example.

[0178] (3) Elemental content analysis The metal element content of the water electrolysis electrode catalyst manufactured in the examples was analyzed by inductively coupled plasma (ICP) mass spectrometry. For the water electrolysis electrode catalyst manufactured in the examples, the content of metal elements present in the catalyst was analyzed using inductively coupled plasma atomic emission spectrometry (ICP-AES, NexION 300X, PerkinElmer). The analytical results are shown in Table 1 below.

[0179] Table 1

[0180] On one hand, the nitrogen content of the water electrolysis electrode catalyst manufactured in the examples was analyzed using an elemental analyzer. For the water electrolysis electrode catalyst manufactured in the examples, the sample was melted in an electric furnace under a helium atmosphere at a certain power of 4500W using a nitrogen-oxygen-hydrogen analyzer (ONH836, LECO Corp). The released nitrogen gas was analyzed by TCD, thereby analyzing the nitrogen content present in the catalyst. The analysis results are shown in Table 2 below.

[0181] Table 2

[0182] Evaluation Example 2. Evaluation of the Electrochemical Characteristics of Electrodes Figure 5 This is a diagram illustrating an example of a three-electrode system configured for evaluating electrochemical properties.

[0183] Figure 6 The graphs are used to evaluate the hydrogen evolution reaction performance of the water electrolysis electrodes of Examples 1, 3, and 4, and are presented as current density vs. voltage curves.

[0184] Using the water electrolysis electrodes manufactured in the examples and comparative examples as working electrodes 20, the Hg / HgO electrode as a reference electrode 30, and the graphite rod as a counter electrode 40, a configuration is formed. Figure 5 The diagram shows a 3-electrode system. Each electrode is immersed in a 1M KCl solution.

[0185] The performance of the hydrogen evolution reaction was evaluated using the three-electrode systems described above, each employing a water electrolysis electrode manufactured in the examples and comparative examples as the working electrode. The polarization of the hydrogen evolution reaction was measured and evaluated for each three-electrode system at room temperature and a scan rate of 5 mV / s. All measured values ​​were expressed as "vs RHE (reversible hydrogen electrode)". Figure 6 The measurement results are shown in Table 3 below.

[0186] Table 3

[0187] IR Compensation: 80% Refer to this Figure 6 According to Table 3, it can be confirmed that when the current is 200 mA / cm 2 When comparing the hydrogen evolution reaction performance using current density as a benchmark, the catalysts in the examples showed performance similar to that of the catalyst in Comparative Example 4, which is a commonly used platinum catalyst, at 300 mA / cm². 2 When comparing hydrogen evolution reaction performance based on current density, the catalysts of the examples exhibit superior hydrogen evolution reaction performance compared to the catalyst of Comparative Example 4, which is a commonly used platinum catalyst.

[0188] Specifically, it can be confirmed that when using the water electrolysis electrode with the catalyst from the example, in order to obtain 300 mA / cm 2 The current density was achieved with only 0.54V of overvoltage, which is approximately 0.07V lower than the overvoltage of the catalyst in Comparative Example 4, which uses a commonly used platinum catalyst. This suggests that the catalysts in this example exhibit superior performance compared to commonly used platinum catalysts in the hydrogen evolution reaction.

[0189] Figure 7 The graphs are used to evaluate the hydrogen evolution reaction performance of the water electrolysis electrodes of Examples 1, 3, and 4, and are presented using overpotential vs. logarithmic current density curves.

[0190] On the one hand, the following table 4 shows that... Figure 7 The slope of the Tafel plot in the Chinese and comparative examples.

[0191] Table 4

[0192] Refer to this Figure 7As shown in Table 4, the catalysts of the examples exhibit a tilt of approximately 45 mV / dec lower than that of the catalyst in Comparative Example 4, which uses a commonly used platinum catalyst. This suggests that the catalysts of the examples possess kineticly superior performance compared to commonly used platinum catalysts in the hydrogen evolution reaction.

[0193] The evaluation results confirm that the water electrolysis electrode using the catalyst of an embodiment of the present disclosure has superior hydrogen evolution reaction performance compared to electrodes using commonly used platinum catalysts. Referring to (3) of the aforementioned Evaluation Example 1, considering that the catalyst of the embodiment has a transition metal content at 1 / 4 level compared to commonly used platinum catalysts, it can be confirmed that even with a low transition metal loading, the catalyst of an embodiment of the present disclosure can provide a non-precious metal catalyst with superior hydrogen evolution reaction performance compared to existing commonly used precious metal catalysts.

[0194] Figure 8 This is a diagram illustrating an example of the surface structure of the catalyst used in the water electrolysis electrode of Comparative Example 3. Observe... Figure 8 The surface structure shown in the figure is an example. Unlike the examples, in the catalyst of Comparative Example 3, the surface of the carbon structure 300 is not loaded with alloy nanoparticles.

[0195] It can be confirmed that the catalyst in the examples also has excellent hydrogen evolution reaction performance compared with the remaining comparative examples.

[0196] Based on the results described above, it is determined that, according to an embodiment of the present disclosure, the catalyst for the water electrolysis electrode is introduced into the nickel-cobalt alloy nanoparticles, which act as the main active sites of the catalyst, thereby causing a reaction specificity different from the past through the interaction between nickel, cobalt, and iron. In addition, it is determined that the iron single atoms doped on the surface of the carbon structure around the nickel-cobalt alloy nanoparticles also interact further with the alloy nanoparticles, thereby contributing to the performance improvement.

[0197] The above description is merely an example of applying the principles of this disclosure, and other configurations may be included without departing from the scope of this disclosure.

Claims

1. A catalyst for water electrolysis electrode, comprising: a carbon structure body doped with a first element and a second element; and alloy nanoparticles doped with the first element, the alloy nanoparticles being supported on a surface of the carbon structure body, the first element being iron.

2. The catalyst for water electrolysis electrode according to claim 1, wherein the second element is nitrogen.

3. The catalyst for water electrolysis electrode according to claim 1, wherein the catalyst for water electrolysis electrode is a Fe-N-C type catalyst supporting nickel-cobalt alloy nanoparticles doped with iron.

4. The catalyst for water electrolysis electrode according to claim 1, wherein the first element is contained in an amount of 0.01 to 0.10% by weight based on the total weight of the catalyst for water electrolysis electrode.

5. A method for producing a catalyst for water electrolysis electrode, comprising: a step of bringing a carbon precursor into contact with a first element precursor solution, thereby forming a carbon composite doped with a first element; and a step of impregnating the carbon composite doped with the first element in a metal precursor solution, the first element being iron, the metal precursor solution including two or more transition metal precursors different from each other.

6. The method for producing a catalyst for water electrolysis electrode according to claim 5, wherein the metal precursor solution includes a nickel precursor and a cobalt precursor.

7. A water electrolysis electrode, comprising: a substrate; and the catalyst for water electrolysis electrode according to claim 1 supported on the substrate.

8. The water electrolysis electrode according to claim 7, wherein the catalyst for water electrolysis electrode is a Fe-N-C type catalyst supporting nickel-cobalt alloy nanoparticles doped with iron.

9. The water electrolysis electrode according to claim 7, wherein 10. The water electrolysis electrode according to claim 7, wherein the Tafel slope is 200 mV / dec or less. ​ The loading amount of the water electrolysis electrode catalyst is 0.1 mg / cm 2 to 5.0 mg / cm 2 . ​ ​

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