High-entropy chalcogenide glass electrocatalyst for oxygen generation and method for manufacturing same

Abstract

The present invention relates to: a high-entropy chalcogenide glass electrocatalyst for oxygen generation in a proton exchange membrane water electrolyzer; and a method for manufacturing same, wherein high-entropy chalcogenide is formed through a combination of at least five types of transition metal precursor and at least one type of chalcogen precursor and is thus imparted. Accordingly, it is possible to manufacture an electrocatalyst having improved OER performance and stability compared to conventional electrocatalysts.

Description

High-entropy chalcogenide glass catalyst electrode for oxygen generation and method for preparing the same

[0001] The present invention relates to a catalyst electrode for oxygen evolution reaction (OER) in a proton exchange membrane electrolyzer, and more particularly, to a high-entropy chalcogenide glass catalyst electrode and a method for manufacturing the same.

[0002] Water electrolysis technology, which produces hydrogen and oxygen gases by electrolyzing water, is attracting significant attention in the field of renewable energy production and conversion to address increasing energy demand and environmental issues. Proton exchange membrane water electrolysis (PEMWE) is a technology that exchanges hydrogen ions. It exhibits low ohmic resistance and high current density, and its simple system design due to low gas cross-mixing makes it advantageous for mass production of hydrogen energy. PEMWE consists of the hydrogen evolution reaction (HER) at the reduction electrode and the oxygen evolution reaction (OER) at the oxidation electrode, with the OER, a four-step slow electron exchange reaction, determining the efficiency of the overall reaction.

[0003] Furthermore, because the PEMWE reaction cell is formed within an acidic, hydrogen-rich atmosphere, the development of an acid-stable and efficient oxygen-generating catalyst is essential for PEMWE. Currently commercialized OER catalysts for PEMWE are single-metal catalysts based on the rare metals iridium and ruthenium. Their high price and scarcity hinder mass production. Furthermore, their performance deteriorates over time as the metal catalysts are excessively oxidized during the reaction and are eluted into the electrolyte. High-entropy materials containing five or more elements theoretically offer the advantage of suppressing metal leaching even in strong acid environments due to their high entropy-based (electro)chemical stability. However, most research has been limited to high-entropy alloy materials, and nanostructure control and uniformity control are challenging during the high-temperature synthesis process. Furthermore, there are not enough examples of proven (electro)chemical stability when applied as actual oxygen-generating catalysts. Therefore, the development of high-entropy oxygen-generating catalysts that exhibit both high OER activity and stability in acidic environments while using minimal or no precious metals is necessary.

[0004] The first technical task of the present invention is to provide a high-entropy chalcogenide glass catalyst electrode.

[0005] The second technical task is to provide a method for manufacturing a high-entropy glass catalyst electrode containing chalcogen in order to achieve the first technical task.

[0006] To achieve the first technical task described above, the present invention provides a high-entropy chalcogenide glass catalyst electrode for oxygen evolution (OER). The catalyst electrode comprises a chalcogen element and a transition metal. The high-entropy chalcogenide has a porous amorphous glass nanosheet structure including pores on the order of several nm to several tens of nm, and the chalcogen and transition metal are irregularly arranged within the nanosheet.

[0007] To achieve the second technical task described above, the present invention provides a method for manufacturing a high-entropy chalcogenide glass catalyst electrode for oxygen evolution (OER). The catalyst electrode can be manufactured through the steps of electrochemically depositing a transition metal precursor on a carbon electrode using a solvent as an electrolyte, chemically vapor depositing a chalcogen precursor on the carbon electrode on which the transition metal has been electrochemically deposited, and heat treating the electrode to form a chalcogenide, thereby obtaining a glass catalyst electrode.

[0008] It is hereby disclosed that the present invention was derived with the support of the following national research and development project.

[0009] [1. National Research and Development Project Supporting This Invention]

[0010] [Project ID] 1711196953 [Project ID] 00249646

[0011] [Ministry Name] Ministry of Science and ICT [Project Management (Specialized) Institution Name] National Research Foundation of Korea

[0012] [Research Project Name] Individual Basic Research (Ministry of Science and ICT)

[0013] [Research Project Name] Large-Area Synthesis and Composite Properties of Two-Dimensional Single-Crystal Mott-Transition Metal Oxide Nano-Film Materials

[0014] [Contribution rate] 50 / 100 [Name of project performing organization] Dongguk University Industry-Academic Cooperation Foundation

[0015] Research Period: June 1, 2023 - May 31, 2024

[0016]

[0017] [2. National Research and Development Projects Supporting This Invention]

[0018] [Project ID] 1711198900 [Project ID] 2022M3H4A1A04096478

[0019] [Ministry Name] Ministry of Science and ICT [Project Management (Specialized) Institution Name] National Research Foundation of Korea

[0020] [Research Project Name] Nanomaterial Technology Development

[0021] [Research Project Name] Study on Electrode / Electrolyte Interface and Surface Modification for the Development of High-Stability Aqueous Electrolytes for 4V Lithium Secondary Batteries

[0022] [Contribution rate] 50 / 100 [Name of project performing organization] Dongguk University Industry-Academic Cooperation Foundation

[0023] [Research Period] July 1, 2023 - February 29, 2024

[0024] The high-entropy chalcogenide glass catalyst electrode for OER of the present invention can be manufactured at a lower temperature and in a shorter time than the existing high-entropy transition metal-based OER catalyst electrode manufacturing process by forming a high-entropy chalcogenide glass catalyst on a carbon electrode, and can be manufactured on a large area.

[0025] In addition, the high-entropy chalcogenide glass catalyst electrode for OER of the present invention can form an amorphous glass nanostructure rich in defect sites by diffusing a chalcogen precursor into the high-entropy transition metal nanoparticles through chemical vapor deposition, and in the process, a porous nanosheet surface with a large specific surface area is formed, so that the catalytic reaction characteristics can be improved.

[0026] In addition, the chalcogen element used in the present invention has a flexible chemical bond, so that the glass forming ability (GFA) of the system can be easily improved, and an amorphous glass structure can be easily formed. In addition, since the chalcogen element is a metalloid substance with a high oxidation / reduction potential, it has strong resistance to corrosion and oxidation, so that when a high-entropy chalcogenide is used, it can function as an OER catalyst that is stable in acid.

[0027] In addition, the high-entropy glass catalyst containing the chalcogen element can improve the activity of the catalytic reaction by increasing the valence state of the metal element through chemical bonding with the anionic chalcogen element, and when a highly active 3d transition metal and a highly stable 4d, 5d transition metal are included together, the high-entropy chalcogenide glass catalyst has both high activity and stability, and can be used as a catalytic electrode for long-term oxygen generation at high current density in PEMWE (Proton Exchange Membrane Water Electrolysis).

[0028] Furthermore, the high-entropy glass catalyst increases the rate of chemical electrolysis reactions, and the catalyst itself participates in the reaction as part of the electrolysis. However, since the catalyst is not primarily consumed by the reaction itself, it can participate in multiple chemical changes. Furthermore, the high-entropy glass catalyst is not simply a bulk current collector that donates or receives electrons from the electrolysis reaction, but rather changes the chemical state of one or more ions during the catalytic process. Therefore, although the high-entropy glass catalyst may be consumed in small amounts during a specific use, it can be regenerated to its original chemical state. Therefore, it is suitable for manufacturing an oxygen-generating catalyst and electrode used in water electrolysis technology.

[0029] FIG. 1 is a flowchart showing a method for manufacturing a high-entropy chalcogenide glass catalyst electrode according to one embodiment of the present invention.

[0030] Figure 2 is a schematic diagram illustrating a catalyst electrode manufacturing device using a constant current method according to one embodiment of the present invention.

[0031] FIG. 3 is a 3D drawing of a high-entropy chalcogenide glass catalyst formed through chalcogenation of a high-entropy transition metal according to one embodiment of the present invention.

[0032] FIG. 4 is a drawing showing SEM (Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), and EDS (Energy Dispersive Spectroscopy) images of a high-entropy catalyst and a high-entropy chalcogenide glass catalyst according to one embodiment of the present invention.

[0033] FIG. 5 is an XRD (X-Ray Diffraction) pattern graph of a high-entropy catalyst and a high-entropy chalcogenide glass catalyst according to one embodiment of the present invention.

[0034] FIG. 6 is a graph showing the XPS (X-ray Photoelectron Spectroscopy) results of a high-entropy catalyst and a high-entropy chalcogenide glass catalyst according to one embodiment of the present invention.

[0035] Figure 7 is a configuration diagram of a half-cell according to one embodiment of the present invention.

[0036] FIG. 8 is a graph showing the results of an OER performance and stability test of a high-entropy glass catalyst electrode according to one embodiment of the present invention.

[0037] FIG. 9 is a graph showing the XPS results after an OER stability test of a high-entropy glass catalyst according to one embodiment of the present invention.

[0038] FIG. 10 is a graph evaluating OER performance according to the presence or absence of constituent elements of a high-entropy chalcogenide glass catalyst according to one embodiment of the present invention.

[0039] FIG. 11 is a graph evaluating OER stability according to the presence or absence of constituent elements of a high-entropy chalcogenide glass catalyst according to one embodiment of the present invention.

[0040] FIG. 12 is a graph summarizing the OER performance and stability according to the presence or absence of constituent elements of a high-entropy chalcogenide glass catalyst according to one embodiment of the present invention.

[0041] Fig. 13 is a configuration diagram of a PEMWE according to one embodiment of the present invention.

[0042] FIG. 14 is a graph showing the results of evaluating the electrolysis characteristics of PEMWE using a high-entropy chalcogenide glass catalyst as an oxidation electrode according to one embodiment of the present invention.

[0043] The present invention is susceptible to various modifications and takes various forms. Specific embodiments are illustrated in the drawings and described in detail herein. However, this is not intended to limit the present invention to specific disclosed forms, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0044] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0045] The present invention is described in more detail below.

[0046] The high-entropy chalcogenide glass catalyst electrode for oxygen evolution (OER) of the present invention comprises: a porous carbon electrode having a plurality of pores; and a glass catalyst irregularly arranged in the pores of the carbon electrode and on the surface of the carbon electrode, thereby being integrated with the carbon electrode.

[0047] The glass catalyst comprises a chalcogenide represented by the following chemical formula 2, and the glass catalyst is formed in the form of a matrix and / or nanosheet having pores of several nm to several tens of nm in size. In addition, the glass catalyst has an amorphous glass structure.

[0048] [Chemical Formula 2]

[0049] A a B b C c D d E e F f

[0050] In the above chemical formula 2, A, B, C, D, and E are transition metals, and each of A, B, C, D, and E is a different one selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Hf, Ta, W, Re, Os, Ir, Pt, Au, Pb, and Bi. As a preferred embodiment of A, B, C, D, and E, A may be Co, B may be Fe, C may be Ni, D may be Mo, and E may be W, but is not limited thereto.

[0051] In addition, the F in the chemical formula 2 is a chalcogen including at least one selected from S, Se, and Te, and is preferably Te, but is not limited thereto.

[0052] And, each of a, b, c, d, e, and f of the chemical formula 2 has a range of 0.1≤a,b,c,d,e,f≤0.3.

[0053]

[0054] Hereinafter, various embodiments of the present invention will be described in more detail with reference to the attached drawings.

[0055] [Method for preparing a high-entropy chalcogenide glass catalyst electrode]

[0056] Figure 3 is a flowchart showing a method for manufacturing a high-entropy chalcogenide glass catalyst electrode.

[0057] Referring to FIG. 3, a method for manufacturing a glass catalyst electrode of the present invention is manufactured by performing a process including a first step (S10) of dissolving a transition metal precursor in a solvent to form a mixed solution, a step (S20) of manufacturing a deposit (or a high-entropy transition metal catalyst electrode) through electrochemical deposition using the mixed solution as an electrolyte, and a third step (S30) of chemical vapor depositing a chalcogen precursor on the deposit (or the high-entropy transition metal catalyst electrode) to form a chalcogenide represented by chemical formula 2, thereby manufacturing a glass catalyst electrode.

[0058] Each of the transition metal precursors in step 1 is a precursor containing a different transition metal, and each of the transition metal precursors may contain Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Hf, Ta, W, Re, Os, Ir, Pt, Au, Pb or Bi, and it may be preferable to use five or more kinds of transition metal precursors as the transition metal precursors, and it is more preferable to use transition metal precursors containing Fe, Co, Ni, Mo and W as the transition metals, respectively.

[0059] For example, Co(NO3)2·6H2O, Fe(NO3)2·9H2O, Ni(NO3)2·6H2O, Na2MoO4·2H2O, and Na2WO4·2H2O can be used as five transition metal precursors.

[0060] The mixed solution of step 1 is prepared by dissolving the transition metal precursor, preferably five or more kinds of transition metal precursors, in a solvent, and the mixed solution contains each of the transition metals derived from the transition metal precursor at a concentration of 0.005 mM to 0.010 mM, more preferably 0.007 mM to 0.008 mM. When the concentration of each of the transition metals in the mixed solution is less than 0.005 mM or more than 0.010 mM, the ionization degree of the transition metal decreases, which causes a problem in that the overpotential required to obtain an arbitrary current density value increases.

[0061] And, the solvent of the first step may include at least one selected from the group consisting of purified water, ethanol, methanol, acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (NMP), cyclohexane, dichloromethane, dimethyl sulfoxide (DMSO), acetonitrile, pyridine, and amines, and preferably may include purified water.

[0062] The above mixed solution may further include a pH adjuster. The pH adjuster may include at least one selected from sodium hydroxide, potassium hydroxide, lithium hydroxide, triethanolamine (TEA), diethanolamine (DEA), and ethanolamine (EA), and preferably, ethanolamine may be used as the pH adjuster. In addition, by using the pH adjuster, the pH of the mixed solution may be adjusted to 8 to 10, and preferably, the pH of the mixed solution may be adjusted to 8.5 to 9.5.

[0063] Next, the second step is a process of manufacturing a deposit in which high-entropy transition metal nanoparticles are formed on a carbon electrode by performing an electrochemical deposition process using the mixed solution manufactured in the first step as an electrolyte.

[0064] The above high-entropy transition metal nanoparticles are transition metal complexes represented by the following chemical formula 1.

[0065] [Chemical Formula 1]

[0066] A a B b C c D d E e

[0067] In the above chemical formula 1, A, B, C, D, and E are transition metals, and are characterized by being different from each other among Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Hf, Ta, W, Re, Os, Ir, Pt, Au, Pb, and Bi, and it is more preferable to use Fe, Co, Ni, Mo, and W. When Fe, Co, Ni, Mo, and W are used, the OER performance may be the best. a, b, c, d, and e are all 0.1≤a,b,c,d,e≤0.3, and when the values ​​of a, b, c, d, and e are less than 0.1 or exceed 0.3, high-entropy formation is difficult.

[0068] In addition, the electrochemical deposition process can be performed using a general electrochemical deposition device used in the art, and as a preferred embodiment, it can be performed using a catalyst electrode manufacturing device using a constant current method, and a schematic diagram thereof is shown in Fig. 2.

[0069] Referring to Fig. 2, a device for manufacturing a catalyst electrode includes a container (1) for containing an electrolyte (3), a working electrode (5) providing a substrate on which a high-entropy transition metal is to be deposited, and a counter electrode (7). In addition, the working electrode (5) and the counter electrode (7) are connected to a power supply. At this time, the working electrode (5) and the counter electrode (7) are not limited to a carbon substrate (or carbon electrode) having excellent conductivity, and specifically, may be any one of carbon fiber, carbon paper, carbon mesh, and carbon foam.

[0070] And, when current is supplied from the power source, the working electrode (5) can become an electron-rich reduction electrode. At this time, metal ions dissolved in the solution undergo a reduction reaction on the working electrode (5), thereby forming the high-entropy transition metal nanoparticles (20).

[0071] And, the electrochemical deposition is performed for 10 to 20 minutes at a temperature of 20°C to 60°C, with a current density of -30 mA·cm. -2 ~ -70 mA·cm -2 It is performed at a temperature of 40℃ for 15 minutes with a current density of -50 mA·cm -2 It is more preferable to perform the electrochemical deposition process at a temperature lower than 20°C or higher than 60°C, which may make it difficult for transition metal ions to be reduced on the working electrode surface. In addition, if the deposition time is lower than 10 minutes or higher than 20 minutes, or the current density is lower than -30 mA cm -2 Less than or -70 mA·cm -2 When electrochemical deposition exceeds , high-entropy transition metal nanoparticles may not be uniformly obtained at the reduction electrode.

[0072] A preferred example of forming a deposit (or high-entropy transition metal catalyst) in which high-entropy transition metal nanoparticles are formed on a carbon electrode using five types of transition metal precursors in the above 2 steps is as shown in the following reaction scheme 1.

[0073] [Reaction Formula 1]

[0074] aCo(NO3)2·6H2O + bFe(NO3)2·9H2O + cNi(NO3)2·6H2O + dNa2MoO4·2H2O + eNa2WO4·2H2O → Co a Fe b Ni c Mo d W e + 2(a+b+c)(NO3) - + (6a+9b+6c+2d+2e)H2O

[0075] Next, the above-mentioned third step is a process of forming a chalcogenide by chemical vapor deposition of a chalcogen precursor on the deposit manufactured in the second step.

[0076] The above chalcogen precursor comprises at least one chalcogen selected from the group consisting of S, Se, and Te, and it is more preferable to use Te.

[0077] And, as an example of the chalcogen precursor, it may include at least one selected from S powder, Se powder, and Te powder.

[0078] In addition, the amount of the chalcogen precursor used, i.e., the chemical vapor deposition amount, may be about 0.1 mg to 1.0 mg of chalcogen per 2 mg of the deposit formed in step 2, i.e., 5.0 to 50.0 parts by weight of chalcogen per 100 parts by weight of the deposit, preferably 20 to 40 parts by weight. At this time, if the content of the chalcogen precursor or the chemical vapor deposition amount of the chalcogen is less than 5.0 parts by weight or more than 50.0 parts by weight per 100 parts by weight of the deposit, there may be a problem that the high-entropy chalcogenide formed by performing steps 3 and 4 has poor uniformity.

[0079] In addition, the chemical vapor deposition is preferably performed at 250°C to 350°C for 1 to 3 hours, and preferably at 280°C to 320°C for 1.5 to 2 hours. At this time, if the reaction time in the chalcogenization process through chemical vapor deposition is less than 1 hour or more than 3 hours, there may be a problem in obtaining a glass catalyst electrode having uniform porosity. In addition, if the heat treatment temperature is less than 250°C or more than 350°C, an amorphous glass structure may not be formed.

[0080] Step 3 is a process of forming an amorphous glass structure composed of chalcogenide by chalcogenizing the deposit manufactured in Step 2, and the chalcogenization in Step 3 can be expressed by the following reaction formula 2.

[0081] [Reaction Formula 2]

[0082] Co a Fe b Ni c Mo d W e + fA → Co a Fe b Ni c Mo d W e A f

[0083] A in reaction scheme 2 is S, Se or Te.

[0084] The high-entropy chalcogenide formed by performing steps 1 to 4 is represented by the chemical formula 2 described above.

[0085] And, a schematic diagram of an amorphous glass structure formed by chalcogenizing a high-entropy transition metal and forming a high-entropy chalcogenide is shown in Figure 3 in 3D.

[0086] Referring to Fig. 3, a high-entropy transition metal catalyst electrode (100) manufactured through a two-step process includes a porous carbon electrode (10) and high-entropy transition metal nanoparticles (20). At this time, the high-entropy transition metal nanoparticles (20) have a size of several tens of nm to several hundred nm.

[0087] And, when chalcogenization is performed on the high-entropy transition metal catalyst electrode (100) through chemical vapor deposition using a chalcogen precursor, a high-entropy chalcogenide glass catalyst electrode (200) can be obtained in which the high-entropy chalcogenide glass catalyst (30) is formed integrally with the porous carbon electrode by irregularly arranging the pores of the porous carbon electrode (10) having a large number of pores and the surface of the carbon electrode. The high-entropy chalcogenide glass catalyst electrode (200) has a thickness of several nm to several tens of nm and includes pores of several nm to several tens of nm in size.

[0088] The high-entropy chalcogenide glass catalyst electrode of the present invention manufactured in this manner has an excellent oxygen generation effect and is therefore suitable for use as an OER electrode in a proton exchange membrane electrolysis tank.

[0089] Hereinafter, the present invention will be described in more detail through examples. However, the following examples are not intended to limit the scope of the present invention and should be interpreted as being intended to aid understanding of the present invention.

[0090] [Example]

[0091] Example 1: Preparation of a high-entropy chalcogenide glass catalyst electrode

[0092] A mixture containing 0.008 mM each of the transition metal precursors Co(NO3)2·6H2O, Fe(NO3)2·9H2O, Ni(NO3)2·6H2O, Na2MoO4·2H2O, Na2WO4·2H2O, and 1 mL of ethanolamine was added with 39 mL of purified water as a solvent, and stirred to prepare a uniform mixed solution.

[0093] Next, the above mixed solution was heated at a temperature of 40°C for 15 minutes at a current density of -50 mA cm -2 Electrochemical deposition was performed on a porous carbon electrode (MTI Korea) having a large number of pores, thereby producing a deposit (or high-entropy transition metal catalyst) in which transition metal nanoparticles were uniformly distributed in the pores and surface of the carbon electrode.

[0094] Next, 0.5 mg of chalcogen precursor (Te powder) per 2 mg of deposit and the deposit (or high-entropy transition metal catalyst) were reacted together at a temperature of 300°C for 2 hours to manufacture a high-entropy chalcogenide glass catalyst electrode represented by the following chemical formula 2-1.

[0095] [Chemical Formula 2-1]

[0096] A a B b C c D d E e F f

[0097] In the above chemical formula 2-1, A is Co, B is Fe, C is Ni, D is Mo, E is W, and F is Te, and a is 0.16, b is 0.16, c is 0.16, d is 0.16, e is 0.16, and f is 0.16.

[0098]

[0099] Comparative Examples 1-1 to 1-6: Preparation of Non-Chalcogenized High-Entropy Catalyst Electrode

[0100] Comparative Example 1-1 was performed by manufacturing a deposited product, i.e., a high-entropy transition metal catalyst electrode, using the same method as Example 1 but without performing chalcogenization.

[0101] In addition, among the five types of transition metal precursors, high-entropy transition metal catalyst electrodes were manufactured without using any one or more of them as shown in Table 1 below, and Comparative Examples 1-2 to 1-6 were performed, respectively.

[0102]

[0103] Comparative Examples 2-1 to 2-5: Preparation of chalcogenide glass catalyst electrode

[0104] In the same manner as in Example 1, a high-entropy chalcogenide glass catalyst electrode was manufactured, but without using any one or more of Co(NO3)2·6H2O, Fe(NO3)2·9H2O, Ni(NO3)2·6H2O, Na2MoO4·2H2O, and Na2WO4·2H2O as a transition metal precursor, a deposit was manufactured, and then the deposit was subjected to chemical vapor deposition using the same chalcogen precursor to manufacture a chalcogenide glass catalyst electrode, and Comparative Examples 2-1 to 2-5 were performed, respectively. And, the expressions of these glass catalyst electrodes are expressed as shown in Table 1 below.

[0105] Classification expression 5 types of transition metal precursors Unused precursor types Example 1 CoFeNiMoWTe - Comparative example 2-1 CoFeNiMoTeNa2WO4·2H2O Comparative example 2-2 CoFeNiWTeNa2MoO4·2H2O Comparative example 2-3 CoFeMoWTeNi(NO3)2·6H2O Comparative example 2-4 CoNiMoWTeFe(NO3)2·9H2O Comparative example 2-5 FeNiMoWTeCo(NO3)2·6H2O Comparative example 1-1 CoFeNiMoW Chalcogenation × Comparative example 1-2 CoFeNiMoNa2WO4·2H2O / Chalcogen × Comparative example 1-3 CoFeNiWNa2MoO4·2H2O / Chalcogen × Comparative example 1-4 CoFeMoWNi(NO3)2·6H2O / Chalcogenation × Comparative example 1-5CoNiMoWFe(NO3)2·9H2O / Chalcogenation × Comparative example 1-5FeNiMoWCo(NO3)2·6H2O / Chalcogenation × Comparative example 1-6CoFeNiNa2WO4·2H2O, Na2MoO4·2H2O / Chalcogen ×

[0106] Experimental Example 1: SEM, TEM, and EDS Analysis

[0107] SEM analysis was performed on the glass catalyst and transition metal catalyst of each of the catalyst electrodes manufactured in Example 1 and Comparative Example 1-1, and TEM and EDS analyses were performed on the glass catalyst of the high-entropy chalcogenide glass catalyst electrode of Example 1, and the results are shown in Fig. 4.

[0108] Figure 4 (a) is an SEM image of a catalyst manufactured in Comparative Example 1, and (b) is an SEM image of a glass catalyst of an electrode manufactured in Example 1.

[0109] And, (c) is a TEM image of the glass catalyst of the high-entropy chalcogenide glass catalyst electrode manufactured in Example 1, and (d) is an EDS image.

[0110] As shown in Fig. 4, (a) to (b) represent the catalysts manufactured in Comparative Example 1-1 and Example 1, respectively, present on the surface of the carbon electrode.

[0111] Comparative Example 1 showed a spherical nanoparticle shape with a size of several tens to several hundred nm, whereas Example 1 showed a matrix shape or nanosheet shape with a thickness of several nm to several hundred nm, rather than a particle shape.

[0112] (c) shows that the catalyst manufactured in Example 1 contains pores of several nm to several tens of nm in size and has an amorphous glass structure.

[0113] In addition, (d) it was confirmed that the catalyst manufactured in Example 1 had five transition metals and one chalcogen element uniformly distributed. Therefore, when the catalyst was manufactured including a chalcogen precursor, it was confirmed that an amorphous glass structure was formed with improved GFA (Glass forming ability) and that it had a porous matrix structure and / or a porous nanosheet structure.

[0114]

[0115] Experimental Example 2: XRD Analysis

[0116] XRD pattern analysis was performed on the glass catalyst of the high-entropy chalcogenide glass catalyst electrode manufactured in Example 1, and the results are shown in Fig. 5.

[0117] Referring to Fig. 5, no diffraction patterns due to the catalyst crystal structure could be found except for the diffraction patterns due to the carbon electrode at 2θ = 26.5 and 54.6. As confirmed through Fig. 4 (c), it was found that the crystal structure of the catalyst had an amorphous glass structure.

[0118]

[0119] Experimental Example 3: XPS Analysis

[0120] XPS analysis was performed on the glass catalyst and transition metal catalyst of each of the catalyst electrodes manufactured in Example 1 and Comparative Example 1-1, and the results are shown in Fig. 6.

[0121] Figures 6 (a), (b), (c), (d), and (e) are XPS spectra in the Co 2p, Fe 2p, Mo 3d, Ni 2p, and W 4f regions of the catalysts manufactured in Example 1 and Comparative Example 1-1, respectively.

[0122] Figure 6 (f) is a radar graph showing the atomic states of metal elements in the catalysts manufactured in Example 1 and Comparative Example 1-1 calculated from XPS spectra.

[0123] Referring to Fig. 6, the catalyst of the catalyst electrode of Comparative Example 1-1 was confirmed to have binding energies of 778.0 eV and 793.6 eV in the Co 2p region, 707.0 eV and 721.2 eV in the Fe 2p region, 227.0 eV and 231.0 eV in the Mo 3d region, 852.5 eV and 869.8 eV in the Ni 2p region, and 30.9 eV and 33.0 eV in the W 4f region. This indicates a metallic bond of a transition metal element, indicating that the catalyst manufactured in Comparative Example 1 has an alloy structure.

[0124] On the other hand, it was confirmed that the glass catalyst of the glass catalyst electrode manufactured in Example 1 had no or a low ratio of the binding energy in the above region. (f) shows the calculated valence states of the transition metals in the catalysts manufactured in Example 1 and Comparative Example 1-1 obtained from the XPS spectra.

[0125] Through this, it was confirmed that the glass catalyst manufactured in Example 1 had a higher valence state of the metal elements than the metal elements in the catalyst manufactured in Comparative Example 1-1 due to chalcogenization.

[0126]

[0127] Experimental Example 4: Evaluation of Oxygen Evolution Reaction (OER) Characteristics

[0128] The oxygen evolution reaction (OER) performance and stability of the high-entropy chalcogenide glass catalyst electrode prepared in Example 1 were evaluated in a half-cell system.

[0129] The half-cell is a three-electrode system with the above catalyst electrode, Ag / AgCl, and carbon rod as working electrodes, counter electrode Pt, and reference electrode, respectively, and was manufactured in the shape of Fig. 7.

[0130] OER performance evaluation was performed in a 0.5 M H2SO4 electrolyte, an environment similar to proton exchange membrane water electrolysis (PEMWE). In addition, commercially available cobalt oxide (Co3O4) and rare metal iridium oxide (IrO2) catalyst electrodes were utilized to objectively compare their OER performance and stability.

[0131] Figure 8 (a) above is a graph showing OER performance.

[0132] In electrolysis technology, the performance of OER is determined by the overpotential. The overpotential required to obtain a given current density value is determined by the difference between the theoretical potential of OER, 1.23 V, and the potential value at a specific current density value. A lower overpotential value required to obtain a given current density value is considered to have relatively high OER performance.

[0133] In the above Fig. 8 (a), Example 1 showed a lower overpotential than Comparative Example 1-1, cobalt oxide catalyst electrode, and showed an overpotential close to that of rare metal iridium oxide. 10 mAcm -2 Example 1 required an overpotential of 373 mV to deliver a current density of , and Comparative Example 1-1 and the cobalt oxide catalyst electrode required an overpotential of 395 mV and 437 mV, respectively. (b) shows the electrochemical active surface area (ECSA), and Example 1 had an ECSA of 1.425 cm -2 Comparative Example 1 (0.725 cm) -2 ) and cobalt oxide (0.398 cm -2 ) has a wider ECSA than that of the catalyst electrode of Example 1. Therefore, the catalyst electrode of Example 1 has excellent OER performance.

[0134] Figure 8 (c) shows the OER stability test results of Example 1. Current density 10 mA·cm -2 The OER stability was evaluated by measuring the change in potential required to transmit the OER. Example 1 was stable for more than 100 hours, but Comparative Example 1-1, cobalt oxide, and rare metal iridium oxide maintained the OER characteristics for 55.3 hours, 3.5 hours, and 22.2 hours, respectively. Therefore, the excellence of the OER stability of Example 1 was confirmed. (d) evaluates the OER performance before and after the OER stability test of Example 1. Before and after the stability test, the current density was 10 mA cm -2 and 100mA·cm -2The overpotential values ​​required to transmit increased by 0 mV and 28 mV, respectively. Through this, it was confirmed that the OER performance of Example 1 could be stably maintained for a long period of time.

[0135]

[0136] Experimental Example 5: XPS Analysis Before and After Oxygen Evolution Reaction (OER)

[0137] XPS analysis was performed to evaluate the valence states of metal elements before and after OER for the high-entropy chalcogenide glass catalyst electrode (CoFeNiMoWTe) manufactured in Example 1, and the results are shown in Fig. 9.

[0138] Figures 9 (a), (b), (c), (d), and (e) are XPS spectra in the Co 2p, Fe 2p, Mo 3d, Ni 2p, and W 4f regions before and after OER of the catalyst electrode manufactured in Example 1, respectively. Figure 9 (f) is a radar graph showing the change in the atomic state of the metal elements before and after OER of the catalyst electrode manufactured in Example 1, calculated from the XPS spectra.

[0139] Referring to (a)-(e) of Fig. 9, the catalyst electrode manufactured in Example 1 did not show a significant change in binding energy in the Co 2p, Fe 2p, and Ni 2p regions before and after the OER reaction. Since 3d transition metal elements can function as OER active sites, maintaining their valence states well can contribute to improving OER stability. On the other hand, the binding energy in the Mo 3d and W 4f regions decreased in intensity or disappeared except for the sites showing high valence states of 5+ and 6+. Mo 5+ and Mo 6+ 230.5 eV and 234.0 eV and 231.6 eV and 234.9 eV, which represent W 5+ and W 6+The intensities of binding energies of 34.7 eV and 36.7 eV and 35.4 eV and 37.3 eV, which represent the Mo 3d and W 4f regions, increased from 45.3% to 72.4% and from 60.9% to 66.1%, respectively. In addition, Fig. 9 (f) shows the calculated changes in the valence states of the five metal elements in the catalyst electrode manufactured in Example 1 before and after OER obtained from the XPS spectra. The high valence states of 5+ and 6+ of the 4d and 5d transition metals indicate that oxides (hydroxides and oxides) were formed on the surfaces of the elements due to passivation by metal-oxygen bonds. Passivation stabilizes the surface of the metal in a strong oxidizing atmosphere and can contribute to suppressing the corrosion of high-entropy chalcogenide catalyst electrodes. Therefore, it was confirmed that the OER performance of the high-entropy chalcogenide catalyst electrode can be maintained for a long time by maintaining the valence state of highly active metal elements while passivating the highly stable metal elements.

[0140]

[0141] Experimental Example 6: Evaluation of Oxygen Evolution Reaction (OER) Performance According to the Presence or Absence of Composition Elements

[0142] In order to evaluate the influence of the constituent elements of a high-entropy chalcogenide glass catalyst electrode on the catalytic activity, the OER performance of the catalyst electrodes manufactured in Example 1 (CoFeNiMoWTe), Comparative Examples 1-1 to 1-6, and Comparative Examples 2-1 to 2-5 (see Table 1) was evaluated, and the results are shown in (a) and (b) of FIG. 10.

[0143] Referring to Figure 10, it was confirmed that the OER performance tends to increase as the number of highly active 3d transition metals included increases. Furthermore, it was confirmed that the OER performance of a catalyst containing all three 3d transition metals tends to increase as the entropy increases due to the additional inclusion of elements including chalcogens. Through this, it was confirmed that the OER performance of a catalyst electrode is significantly affected by the inclusion of highly active 3d transition metals and entropy.

[0144]

[0145] Experimental Example 7: Evaluation of Oxygen Evolution Reaction (OER) Stability According to the Presence or Absence of Constituent Elements

[0146] In order to evaluate the influence of the constituent elements of the high-entropy chalcogenide glass catalyst electrode of Example 1 on the catalyst stability, the OER stability of the catalyst electrodes (see Table 1) manufactured in Example 1 (CoFeNiMoWTe), Comparative Examples 1-1 to 1-6, and Comparative Examples 2-1 to 2-5 was evaluated, and the results are shown in (a) and (b) of FIG. 11.

[0147] Figures 11 (a) and (b) are graphs evaluating OER stability through a constant current experiment and a graph summarizing the time for which the constant current experiment continued, respectively.

[0148] Referring to Figure 11, it was confirmed that the OER stability tends to increase as the number of highly active 3d transition metals included increases. Furthermore, it was confirmed that the catalyst containing all three 3d transition metals tends to show increased OER stability as the entropy increases due to the additional inclusion of elements including chalcogens. Through this, it was confirmed that the OER stability of the catalyst electrode is significantly affected by the inclusion of highly active 3d transition metals and entropy.

[0149] Figure 12 is a graph evaluating the performance and stability of catalyst electrodes. Referring to Figure 12, it was confirmed that both OER performance and stability improved as more active 3d transition metals were included and as entropy increased.

[0150]

[0151] Manufacturing Example 1: Manufacturing of PEMWE (proton exchange membrane water electrolysis) with a high-entropy chalcogenide glass catalyst electrode as an oxidation electrode

[0152] PEMWE was manufactured using the catalyst electrode of Example 1 as an oxidation electrode.

[0153] The above PEMWE was assembled in the order of an end plate, a bipolar plate, the catalyst electrode, a proton exchange membrane (PEM, Nafion 117, Dupont), a Pt / C catalyst electrode, a bipolar plate, and an end plate, and a schematic diagram of the PEMWE is shown in Fig. 13.

[0154]

[0155] Comparative Manufacturing Example 1

[0156] PEMWE was manufactured with the same composition as Manufacturing Example 1, but instead of Example 1, the transition metal catalyst electrode manufactured in Comparative Example 1-1 was used as the oxidation electrode.

[0157]

[0158] Experimental Example 8: Evaluation of the electrolysis characteristics of a proton exchange membrane electrolyzer (PEMWE)

[0159] The OER performance and stability of a high-entropy chalcogenide glass catalyst electrode manufactured according to one embodiment of the present invention were evaluated in a PEMWE system.

[0160] The PEMWE of Manufacturing Example 1 and Comparative Manufacturing Example 1 were manufactured to include the oxidation electrode of FIG. 13 and the catalyst electrode of Example 1 (CoFeNiMoWTe) and Comparative Example 1 (CoFeNiMoW), respectively. In addition, a commercially available rare metal iridium oxide (IrO2) catalyst electrode was utilized to objectively compare the water electrolysis performance, and the results are shown in FIG. 14 (a).

[0161] Figure 14(a) above is a graph showing the electrolysis performance of PEMWE. The electrolysis performance is determined by the overpotential, and the overpotential required to obtain a given current density value is determined by the difference between the theoretical potential of electrolysis, 1.23 V, and the potential value at a specific current density value. If the overpotential value required to obtain a given current density value is low, the electrolysis performance is judged to be relatively high.

[0162] In (a) of the above Fig. 14, Manufacturing Example 1 showed a lower overpotential than Comparative Manufacturing Example 1, and showed an overpotential close to that of PEMWE containing a rare metal iridium oxide catalyst electrode. 1 Acm -2 To transmit the current density, Manufacturing Example 1 required an overpotential of 0.58 V, and Comparative Manufacturing Example 1 and PEMWE including a rare metal iridium oxide catalyst electrode required overpotentials of 0.64 V and 0.41 V, respectively.

[0163] Figure 14 (b) is a graph showing the electrolysis performance according to temperature of Manufacturing Example 1.

[0164] Using this, the activation energy of Manufacturing Example 1 was calculated and is shown in (c) of Figure 14. The activation energy of Manufacturing Example 1 is 28.73 kJ·mol. -1 Activation energy of comparative manufacturing example 1 (32.53 kJ·mol) -1 ) is lower than that of the activation energy of the rare metal iridium oxide (23.83 kJ mol -1 ) was confirmed to have a value close to .

[0165] Figure 14 (d) is an electrolytic stability test of manufacturing example 1 through a constant current experiment, 1 A cm -2 The change in the overpotential value required to transmit the current density was measured.

[0166] Manufacturing Example 1 showed an increase in overpotential of 30 mV over 100 hours. Therefore, it was confirmed that the PEMWE of Manufacturing Example 1 had excellent water electrolysis performance and stability.

[0167]

[0168] From the above Experimental Examples 1 to 8, it was confirmed that the high-entropy chalcogenide glass catalyst electrode according to Example 1 can have a porous high-entropy chalcogenide glass nanosheet structure according to the chalcogenation reaction of the high-entropy transition metal, and that the OER activity is improved through the structure.

[0169] The chalcogenide compound used in the present invention possesses flexible chemical bonds, facilitating the formation of a glassy structure at low temperatures. Furthermore, chalcogens are metalloid substances with high oxidation / reduction potentials, making them highly resistant to corrosion and oxidation. Furthermore, the use of metal chalcogenides enhances the valence state of the metal, enabling them to function as excellent OER catalysts.

[0170] The high-entropy chalcogenide glass catalyst electrode of the present invention has both high activity and stability when a highly active 3d transition metal and a highly stable 4d, 5d transition metal are included together, and can be used as a catalyst electrode for long-term oxygen generation at high current density in PEMWE.

[0171] Furthermore, the high-entropy chalcogenide glass catalyst electrode of the present invention increases the rate of a chemical electrolysis reaction, and the catalyst itself participates in the reaction as part of the electrolysis. However, since the free catalyst of the glass catalyst electrode is not primarily consumed by the reaction itself, it can participate in multiple chemical changes. Furthermore, the free catalyst is not simply a bulk current collector that donates or receives electrons from the electrolysis reaction, but rather changes the chemical state of one or more ions during the catalytic process. Therefore, the free catalyst can be consumed in small amounts during a specific use, and in many embodiments, can be regenerated to its original chemical state. Therefore, the high-entropy chalcogenide glass catalyst electrode of the present invention is suitable for manufacturing as a catalyst and electrode for oxygen generation used in water electrolysis technology.

[0172]

[0173] [Explanation of symbols]

[0174] 1: Container for electrochemical deposition 3: Electrolyte for electrochemical deposition

[0175] 5: Working electrode for electrochemical deposition 7: Counter electrode for electrochemical deposition

[0176] 100: High-entropy transition metal catalyst electrode 10: Carbon electrode

[0177] 20: High-entropy transition metal nanoparticles

[0178] 200: High-entropy chalcogenide catalyst electrode

[0179] 30: High-entropy chalcogenide nanosheets

Claims

1. A porous carbon electrode having a large number of pores; and A glass catalyst is irregularly arranged on the pores of the carbon electrode and the surface of the carbon electrode, and is integrated with the carbon electrode; The glass catalyst is a high-entropy chalcogenide glass catalyst electrode for oxygen generation, characterized in that it comprises a chalcogenide represented by chemical formula 2; [Chemical Formula 2] A a B b C c D d E e F f In the above chemical formula 2, A, B, C, D, and E are transition metals, each of A, B, C, D, and E is a different one selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Hf, Ta, W, Re, Os, Ir, Pt, Au, Pb, and Bi, the F is a chalcogen including at least one selected from S, Se, and Te, and the a, b, c, d, e, and f all have a range of 0.1≤a,b,c,d,e,f≤0.

3.

2. In paragraph 1, A high-entropy chalcogenide glass catalyst electrode for oxygen generation, characterized in that A in the above chemical formula 2 is Co, B is Fe, C is Ni, D is Mo, E is W, and F is Te.

3. A high-entropy chalcogenide glass catalyst electrode for oxygen generation, characterized in that the glass catalyst is in the form of a matrix or nanosheet in the first paragraph. Step 1: preparing a mixed solution by adding 4.5 or more types of transition metal precursors to a solvent; Step 2: electrochemically depositing the above mixed solution onto a carbon electrode to produce a deposit; and Step 3 of manufacturing a glass catalyst electrode in which a chalcogenide represented by the following chemical formula 2 is formed by chemical vapor deposition of a chalcogen precursor on the above-mentioned deposit; A method for manufacturing a high-entropy chalcogenide glass catalyst electrode for oxygen generation, characterized by performing a process including:

5. In paragraph 4, each of the five or more transition metal precursors is a precursor containing a different transition metal, Each of the above five transition metal precursors comprises Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Hf, Ta, W, Re, Os, Ir, Pt, Au, Pb or Bi, A method for producing a high-entropy chalcogenide glass catalyst electrode for oxygen generation, characterized in that the chalcogen precursor comprises at least one chalcogen selected from the group consisting of S, Se, and Te.

6. A method for manufacturing a high-entropy chalcogenide glass catalyst electrode for oxygen generation, characterized in that in the fourth paragraph, the mixed solution contains each of the five or more transition metal precursors at a concentration of 0.005 mM to 0.01 mM.

7. A method for manufacturing a high-entropy chalcogenide glass catalyst electrode for oxygen generation, characterized in that in the fourth paragraph, the glass catalyst electrode of the third step contains 5.0 to 50.0 parts by weight of chalcogen per 100 parts by weight of the deposit.

8. In paragraph 5, each of the transition metal precursors contains five types of transition metals, A method for manufacturing a high-entropy chalcogenide glass catalyst electrode for oxygen generation, characterized in that the above five transition metals include Fe, Co, Ni, Mo or W.

9. In paragraph 5, A method for producing a high-entropy chalcogenide glass catalyst electrode for oxygen generation, characterized in that the chalcogen precursor comprises Te.

10. A method for manufacturing a high-entropy chalcogenide glass catalyst electrode for oxygen generation, characterized in that in the fourth paragraph, the mixed solution of step 1 further includes a pH adjuster.

11. A method for manufacturing a high-entropy chalcogenide glass catalyst electrode for oxygen generation, characterized in that in the 10th paragraph, the pH adjusting agent comprises at least one selected from sodium hydroxide, potassium hydroxide, lithium hydroxide, triethanolamine (TEA), diethanolamine (DEA), and ethanolamine (EA).

12. In the fourth paragraph, the solvent of step 1 is A method for manufacturing a high-entropy chalcogenide glass catalyst electrode for oxygen generation, characterized in that the solvent is at least one selected from the group consisting of purified water, ethanol, methanol, acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (NMP), cyclohexane, dichloromethane, dimethyl sulfoxide (DMSO), acetonitrile, pyridine, and amines.

13. In paragraph 12, A method for manufacturing a high-entropy chalcogenide glass catalyst electrode for oxygen generation, characterized in that the solvent is purified water.

14. A method for manufacturing a high-entropy chalcogenide glass catalyst electrode for oxygen generation, characterized in that the mixed solution of step 1 in paragraph 4 has a pH of 8 to 10.

15. In paragraph 4, The above electrochemical deposition was performed at 20°C to 60°C and a current density of -30 mAcm. -2 ~ -70mAcm -2 A method for producing a high-entropy chalcogenide glass catalyst electrode for oxygen generation, characterized in that the process is performed for 10 to 20 minutes under conditions.

16. In paragraph 4, A method for manufacturing a high-entropy chalcogenide glass catalyst electrode for oxygen generation, characterized in that the above-mentioned chemical vapor deposition in step 3 is performed at 250°C to 350°C.

17. In paragraph 16, A method for manufacturing a high-entropy chalcogenide glass catalyst electrode for oxygen generation, characterized in that the above chemical vapor deposition is performed for 1 to 3 hours.

18. A proton exchange membrane electrolyzer characterized by including a high-entropy chalcogenide glass catalyst electrode selected from any one of claims 1 to 3 as an oxygen generating electrode (anode).

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