Catalyst structure, method for manufacturing same, and water decomposition device comprising same

Abstract

A method for manufacturing a catalyst structure according to the present invention comprises the steps of: preparing a rhenium (Re) precursor, a first doping metal precursor, a second doping metal precursor, and a solvent; manufacturing a base source by providing the rhenium precursor, the first doping metal precursor, and the second doping metal precursor to the solvent and mixing same; manufacturing a preliminary catalyst structure by synthesizing the base source by a solvothermal synthesis process; and heat-treating the preliminary catalyst structure in a reducing atmosphere to manufacture a catalyst structure comprising rhenium, a first doping metal, a second doping metal, and carbon.

Description

Catalyst structure, method for manufacturing the same, and water splitting device including the same

[0001] The present invention relates to a catalyst structure, a method for manufacturing the same, and a water splitting device including the same, and more specifically, to a catalyst structure including a first doping metal and a second doping metal on the surface of a rhenium nanocluster, a method for manufacturing the same, and a water splitting device including the same.

[0002] The catalyst structure used in the water splitting device refers to a material that catalyzes the hydrogen production reaction.

[0003] Catalytic structures are used to accelerate and catalyze these reactions, thereby increasing reaction rates and enhancing reaction efficiency. Accordingly, various catalysts have been researched and developed, and the efficiency and stability of these catalysts play a crucial role in the success of hydrogen production technology and the development of economically effective methods.

[0004] Catalytic structures include a variety of metals, metal compounds, nanomaterials, and composites. These materials are used to enhance chemical reaction activity, improve the electrochemical properties of hydrogen production reactions, and protect metal catalysts from poisoning by heavy metal toxins.

[0005] For example, Korean Patent Registration Publication No. 10-2075923 discloses a method for producing a polymer composite electrocatalyst for water electrolysis, characterized by including a first step of oxidizing the surface of aluminum powder, a second step of precipitating the surface-oxidized aluminum powder and CNT powder of the first step into an organic acid solution and mixing them, a third step of thermally compressing the material of the second step to produce Al-CNT plate-shaped pellets and drying them to thermally decompose the organic acid, a fourth step of producing an Al-CNT polymer composite material by compounding the Al-CNT plate-shaped pellets produced in the third step with a polymer plastic, a fifth step of forming a polymer composite electrocatalyst for water electrolysis using the electrically conductive Al-CNT polymer composite material produced in the fourth step, and a sixth step of oxidizing, expanding, and aging the aluminum powder in the polymer composite electrocatalyst by an anodic oxidation method.

[0006] The technical problem to be solved by the present invention is to provide a method for manufacturing a catalyst structure having improved electrocatalytic properties in an alkaline environment.

[0007] Another technical problem to be solved by the present invention is to provide a catalyst structure with reduced activation energy for adsorption of water molecules and dissociation of water molecules in an alkaline environment.

[0008] Another technical problem to be solved by the present invention is to provide a catalyst structure with improved HER efficiency in an alkaline environment.

[0009] Another technical problem to be solved by the present invention is to provide a catalyst structure with an improved HER rate in an alkaline environment.

[0010] Another technical problem that the present invention seeks to solve is to provide a method for manufacturing a catalyst structure with reduced manufacturing process costs.

[0011] Another technical problem that the present invention seeks to solve is to provide a method for manufacturing a catalyst structure with a shortened manufacturing time.

[0012] Another technical problem that the present invention seeks to solve is to provide a method for manufacturing a catalyst structure that is easy to mass-produce.

[0013] The technical problems to be solved by the present invention are not limited to those described above.

[0014] To solve the above technical problem, the present invention provides a method for manufacturing a catalyst structure.

[0015] According to one embodiment, the method for manufacturing the catalyst structure may include the steps of preparing a rhenium (Re) precursor, a first doping metal precursor, a second doping metal precursor, and a solvent, providing and mixing the rhenium precursor, the first doping metal precursor, and the second doping metal precursor in the solvent to manufacture a base source, synthesizing the base source by a solvothermal synthesis method to manufacture a preliminary catalyst structure, and heat-treating the preliminary catalyst structure in a reducing atmosphere, thereby manufacturing a catalyst structure including rhenium, a first doping metal, a second doping metal, and carbon.

[0016] According to one embodiment, the first doping metal precursor and the second doping metal precursor provided in the solvent may be provided in an amount of more than 2.5 mol% and less than 10 mol% relative to the rhenium precursor.

[0017] In one embodiment, the reducing atmosphere may include a mixture of gases comprising argon gas and hydrogen gas in a lower proportion than the argon gas.

[0018] According to one embodiment, the heat treatment temperature of the solvent thermal synthesis may be 200°C to 250°C, and the heat treatment time may be 2 hours to 2.5 hours, and the heat treatment temperature of the preliminary catalyst structure may be 500°C to 900°C, and the heat treatment time may be 4 hours to 6 hours.

[0019] In one embodiment, the solvent may include THF, the rhenium precursor may include Re2O7, the first doping metal precursor may include Pt(acac)2, and the second doping metal precursor may include Ni(acac)2.

[0020] According to one embodiment, the base source may include providing the rhenium precursor, the first doping metal precursor, and the second doping metal precursor to the solvent, mixing them, and leaving them to stand, thereby producing a gel.

[0021] In order to solve the above technical problem, the present invention provides a catalyst structure manufactured by the above-described method for manufacturing a catalyst structure.

[0022] According to one embodiment, the catalyst structure may include a rhenium nanocluster in which a plurality of rhenium (Re) nanoparticles are aggregated, a first doping metal doped on the surface of the rhenium nanocluster, and a second doping metal doped at a lower ratio than the first doping metal, and the plurality of rhenium nanoparticles may be connected to each other by amorphous carbon.

[0023] In one embodiment, the rhenium nanoparticles may include a metal having a lower electronegativity than the first doping metal and the second doping metal.

[0024] According to one embodiment, the first doping metal may include Pt, and the second doping metal may include Ni.

[0025] In one embodiment, when analyzing the catalyst structure, the peaks for the Pt 4f and Ni 2P spectra may be shifted in a negative direction compared to a reference catalyst structure including Pt and C.

[0026] According to one embodiment, when the catalyst structure is analyzed by XRD, the D band (1368 cm -1 ) and G band (1580 cm -1 ) may include observation of a peak corresponding to the amorphous carbon.

[0027] In order to solve the above technical problem, the present invention provides a water splitting device to which the above-described catalyst structure is applied.

[0028] According to one embodiment, the water splitting device may include the above-described catalyst structure, and may include reducing the activation energy for a step of adsorbing water molecules on the surface of the catalyst structure due to the first doping metal and the second doping metal of the catalyst structure in an alkaline environment, a step of dissociating the water molecules adsorbed on the surface of the catalyst structure, and a step of providing electrons to a pair of hydrogen ions adsorbed on the surface of the catalyst structure to generate hydrogen gas.

[0029] A method for producing a catalyst structure according to the present invention may include a step of preparing a rhenium precursor, a first doping metal precursor, a second doping metal precursor, and a solvent, a step of providing and mixing the rhenium precursor, the first doping metal precursor, and the second doping metal precursor in the solvent to produce a base source, a step of synthesizing the base source by a solvothermal synthesis method to produce a preliminary catalyst structure, and a step of heat-treating the preliminary catalyst structure in the reducing atmosphere, thereby producing the catalyst structure including rhenium, the first doping metal, the second doping metal, and carbon.

[0030] In the step of manufacturing the base source, the first doping metal precursor and the second doping metal precursor provided in the solvent may be provided in an amount of more than 2.5 mol% and less than 10 mol% relative to the rhenium precursor. As a result, the catalyst structure having a reduced overvoltage and Tafel Slope value, i.e., improved electrocatalytic properties, may be provided.

[0031] And, in the step of manufacturing the catalyst structure by heat-treating the preliminary catalyst structure in the reducing atmosphere, the reducing atmosphere can be provided by a mixed gas including argon gas and hydrogen gas in a lower ratio than the argon gas. Accordingly, the preliminary catalyst structure can be easily reduced. As a result, the catalyst structure can be provided with a reduced overvoltage and Tafel Slope value of the catalyst structure, i.e., with improved electrocatalytic properties.

[0032] The catalyst structure manufactured by the above-described method for manufacturing the catalyst structure may include a rhenium nanocluster in which a plurality of rhenium nanoparticles are aggregated, the first doping metal doped onto the surface of the rhenium nanocluster, and the second doping metal doped at a lower ratio than the first doping metal. In addition, the plurality of rhenium nanoparticles may be connected to each other by amorphous carbon.

[0033] The first doping metal of the catalyst structure can promote the adsorption of hydrogen atoms and the reduction of hydrogen cations on the surface of the catalyst structure in an alkaline environment. In addition, the second doping metal of the catalyst structure can exist as a metal oxide or metal hydroxide including the second doping metal in an alkaline environment. Accordingly, an area affin for oxygen atoms on the surface of the catalyst structure can be increased. In addition, the rhenium nanoparticles of the catalyst structure can have a lower electronegativity than the first doping metal and the second doping metal. Accordingly, the rhenium nanoparticles of the catalyst structure can have a partially positive charge.

[0034] Therefore, due to the rhenium nanoparticles, the first doping metal, and the second doping metal of the catalyst structure, the activation energy for the adsorption and dissociation of water molecules generated on the surface of the catalyst structure in an alkaline environment can be reduced. As a result, the HER efficiency of the catalyst structure can be improved in an alkaline environment. Accordingly, the catalyst structure can be applied to a water splitting device.

[0035] Figure 1 is a flowchart illustrating a method for manufacturing a catalyst structure according to an embodiment of the present invention.

[0036] FIG. 2 is a drawing for explaining a rhenium (Re) precursor, a first doping metal precursor, a second doping metal precursor, and a solvent according to an embodiment of the present invention.

[0037] FIG. 3 is a drawing for explaining a method for manufacturing a base source according to an embodiment of the present invention.

[0038] FIG. 4 is a drawing for explaining a method for manufacturing a preliminary catalyst structure by synthesizing a base source using a solvent-thermal synthesis method according to an embodiment of the present invention.

[0039] FIG. 5 is a drawing for explaining a method of manufacturing a catalyst structure by heat-treating a preliminary catalyst structure according to an embodiment of the present invention.

[0040] FIG. 6 is a drawing for explaining the structure of a catalyst structure according to an embodiment of the present invention.

[0041] Figure 7 is a drawing for explaining the hydrogen gas generation process of a water splitting device to which a catalyst structure according to an experimental example of the present invention is applied.

[0042] Figure 8 is a drawing for explaining the structural features of a catalyst structure according to Experimental Example 1 of the present invention.

[0043] FIG. 9 is a drawing for comparing the electrocatalytic performance for HER (Hydrogen Evolution Reaction) of catalyst structures according to Comparative Example 1 and Experimental Examples 1 to 4 of the present invention.

[0044] FIG. 10 is a drawing for explaining HER (Hydrogen Evolution Reaction) in an alkaline environment through electrochemical analysis of catalyst structures according to Comparative Example 1 and Experimental Examples 1 to 4 of the present invention.

[0045] Figure 11 is a HAADF-STEM (High-angle annular dark field scanning transmission electron microscopy) photograph and EDS mapping result of a catalyst structure according to Experimental Example 1 of the present invention.

[0046] Figure 12 is an image analyzing the electrostatic potential of the surface of a catalyst structure according to Experimental Example 1 of the present invention.

[0047] FIG. 13 is a drawing for comparing the overvoltage and Tafel Slope of the catalyst structures according to Experimental Example 1 and Experimental Example 1-1 of the present invention.

[0048] Fig. 14 is a graph for comparing the overvoltage and Tafel Slope of the catalyst structures according to Experimental Example 1 and Experimental Examples 1-2 to 1-5 of the present invention.

[0049] Figure 15 is a table summarizing the XPS analysis results before / after 10,000 cycles of HER for the catalyst structure according to Experimental Example 1 of the present invention.

[0050] FIG. 16 is a graph for comparing the overvoltage of catalyst structures according to Experimental Examples 1-1, 1-6, and 1-7 of the present invention.

[0051] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the technical concept of the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed content is thorough and complete and to sufficiently convey the spirit of the present invention to those skilled in the art.

[0052] In this specification, when a component is referred to as being on another component, it means that it can be formed directly on the other component, or a third component may be interposed between them. In addition, in the drawings, the thicknesses of films and regions are exaggerated for the purpose of effectively explaining the technical contents.

[0053] Also, although terms such as first, second, and third have been used to describe various components in various embodiments of this specification, these components should not be limited by these terms. These terms are only used to distinguish one component from another. Thus, what is referred to as a first component in one embodiment may be referred to as a second component in another embodiment. Each embodiment described and illustrated herein also includes its complementary embodiments. Also, the term "and / or" has been used herein to mean including at least one of the components listed before and after.

[0054] In the specification, singular expressions include plural expressions unless the context clearly dictates otherwise. In addition, terms such as "comprise" or "have" are intended to specify the presence of a feature, number, step, component, or combination thereof described in the specification, and should not be construed as excluding the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof. In addition, in the present specification, "connection" is used to mean both indirectly connecting multiple components and directly connecting them.

[0055] In addition, when describing the present invention below, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description will be omitted.

[0056]

[0057] FIG. 1 is a flowchart for explaining a method for manufacturing a catalyst structure according to an embodiment of the present invention, FIG. 2 is a diagram for explaining a rhenium (Re) precursor, a first doping metal precursor, a second doping metal precursor, and a solvent according to an embodiment of the present invention, FIG. 3 is a diagram for explaining a method for manufacturing a base source according to an embodiment of the present invention, FIG. 4 is a diagram for explaining a method for manufacturing a preliminary catalyst structure by synthesizing a base source by a solvent-thermal synthesis method according to an embodiment of the present invention, FIG. 5 is a diagram for explaining a method for manufacturing a catalyst structure by a method for heat-treating a preliminary catalyst structure according to an embodiment of the present invention, and FIG. 6 is a diagram for explaining the structure of a catalyst structure according to an embodiment of the present invention.

[0058] Referring to FIGS. 1 and 2, a rhenium precursor (100), a first doping metal precursor (210), a second doping metal precursor (220), and a solvent (300) are prepared (S100).

[0059] The above rhenium precursor (100) can be used as a precursor for forming rhenium nanoparticles (610) of a catalyst structure (600) described below, and rhenium nanoclusters in which a plurality of the above rhenium nanoparticles (610) are aggregated. For example, the rhenium precursor (100) can include Re2O7.

[0060] The first doping metal precursor (210) and the second doping metal precursor (220) may be used as precursors for forming the first doping metal (621) and the second doping metal (622), respectively, on the surface of the rhenium nanocluster of the catalyst structure (600). For example, the first doping metal precursor (210) may include Pt(acac)2. For example, the second doping metal precursor (220) may include Ni(acac)2.

[0061] The solvent (300) may react with the rhenium precursor (100) to undergo ring-opening polymerization. Accordingly, the base source (400) described below may have a gel form. For example, the solvent (300) may include THF (Tetrahydrofuran).

[0062] Referring to FIGS. 1 and 3, the base source (400) is manufactured by providing and mixing the rhenium precursor (100), the first doping metal precursor (210), and the second doping metal precursor (220) into the solvent (300) (S200).

[0063] The above base source (400) can be manufactured in a gel form by inducing the ring-opening polymerization described above by leaving the mixed precursor, which is a mixture of the solvent (300), the rhenium precursor (100), the first doped metal precursor (210), and the second doped metal precursor (200), at room temperature. For example, the leaving time of the mixed precursor can be 24 hours.

[0064] According to one embodiment, the first doped metal precursor (210) and the second doped metal precursor (220) provided in the solvent (300) may be provided in an amount of more than 2.5 mol% and less than 10 mol% relative to the rhenium precursor (100). As a result, the overvoltage and Tafel Slope value of the catalyst structure (600) may be reduced. That is, the electrocatalytic properties of the catalyst structure (600) may be improved. For example, the mol% of the first doped metal precursor (210) and the second doped metal precursor (220) provided in the solvent (300) may be the same.

[0065] In contrast, when the first doping metal precursor (210) and the second doping metal precursor (220) provided in the solvent (300) are provided in an amount of 2.5 mol% or less or 10 mol% or more relative to the rhenium precursor (100), the overvoltage and Tafel Slope values ​​of the catalyst structure (600) may increase. That is, the electrocatalytic properties of the catalyst structure (600) may decrease.

[0066] Therefore, according to the method for manufacturing the catalyst structure (600) in the embodiment of the present application, the first doping metal precursor (210) and the second doping metal precursor (220) provided to the solvent (300) may be provided in an amount of more than 2.5 mol% and less than 10 mol% relative to the rhenium precursor (100). As a result, the catalyst structure (600) with reduced overvoltage and Tafel Slope values, i.e., improved electrocatalytic properties, may be provided.

[0067] In addition, since the first doping metal precursor (210) is provided in the solvent (300) in an amount of more than 2.5 mol% and less than 10 mol% relative to the rhenium precursor (100), the amount of the generally expensive first doping metal precursor (210) can be reduced. For example, the first doping metal precursor may be Pt(acac)2. Accordingly, the manufacturing cost of the catalyst structure (600) is reduced, and mass production of the catalyst structure (600) can be facilitated.

[0068] Referring to FIGS. 1 and 4, a preliminary catalyst structure (500) is manufactured by synthesizing the base source (400) using a solvent thermal synthesis method (S300).

[0069] Solvent-thermal synthesis can be performed by additionally providing the solvent (300) to the base source (400) and performing heat treatment. Accordingly, the preliminary catalyst structure (500) in powder form can be manufactured. For example, the heat treatment temperature of the solvothermal synthesis can be 200°C to 250°C. For example, the heat treatment time of the solvothermal synthesis can be 2 hours to 2.5 hours. Accordingly, the manufacturing time of the preliminary catalyst structure (500) can be shortened. As a result, the manufacturing time of the catalyst structure (600) is shortened, and mass production of the catalyst structure (600) can be facilitated.

[0070] Referring to FIGS. 1 and 5, the catalyst structure (600) including rhenium, the first doping metal (621), the second doping metal (622), and carbon is manufactured by a method of heat-treating the preliminary catalyst structure (400) in a reducing atmosphere (S400).

[0071] In the above reducing atmosphere, the preliminary catalyst structure (400) can be manufactured into the catalyst structure (600) by being heat-treated at a higher temperature and for a longer time than the heat-treatment temperature and time of the solvent thermal synthesis. For example, the heat-treatment temperature of the preliminary catalyst structure (400) can be 500°C to 900°C. For example, the heat-treatment time of the preliminary catalyst structure (400) can be 4 hours to 6 hours.

[0072] In one embodiment, the reducing atmosphere may be provided by a mixed gas. The mixed gas may include argon gas and hydrogen gas in a lower ratio than the argon gas. For example, the ratio of the argon gas and the hydrogen gas may be 95:5. Accordingly, the preliminary catalyst structure (500) may be easily reduced. As a result, the overvoltage and Tafel slope value of the catalyst structure (600) may be reduced. In other words, the electrocatalytic properties of the catalyst structure (600) may be improved.

[0073] In contrast, when the reducing atmosphere is provided by the argon gas, the preliminary catalyst structure (500) is not easily reduced, so the overvoltage and Tafel Slope value of the catalyst structure (600) may increase. That is, the electrocatalytic properties of the catalyst structure (600) may decrease.

[0074] Therefore, according to the method for manufacturing the catalyst structure (600) in the embodiment of the present application, the reducing atmosphere can be provided by the mixed gas including the argon gas and the hydrogen gas having a lower ratio than the argon gas. Accordingly, the preliminary catalyst structure (500) can be easily reduced. As a result, the catalyst structure (600) with a reduced overvoltage and Tafel Slope value, i.e., improved electrocatalytic properties can be provided.

[0075] In conclusion, the method for manufacturing the catalyst structure (600) according to an embodiment of the present application may include a step of preparing the rhenium precursor (100), the first doping metal precursor (210), the second doping metal precursor (220), and the solvent (300), a step of providing and mixing the rhenium precursor (100), the first doping metal precursor (210), and the second doping metal precursor (220) in the solvent (300) to manufacture the base source (300), a step of synthesizing the base source (300) by a solvothermal synthesis method to manufacture the preliminary catalyst structure (400), and a step of heat-treating the preliminary catalyst structure (400) in the reducing atmosphere, thereby manufacturing the catalyst structure (600) including rhenium, the first doping metal (621), the second doping metal (622), and carbon.

[0076] In the step of manufacturing the base source (300), the first doping metal precursor (220) and the second doping metal precursor (220) provided to the solvent (300) may be provided in an amount of more than 2.5 mol% and less than 10 mol% relative to the rhenium precursor (100). As a result, the catalyst structure (600) with reduced overvoltage and Tafel Slope values, i.e., improved electrocatalytic properties, may be provided.

[0077] And, in the step of manufacturing the catalyst structure (600) by heat-treating the preliminary catalyst structure (400) in the reducing atmosphere, the reducing atmosphere can be provided by the mixed gas including the argon gas and the hydrogen gas having a lower ratio than the argon gas. Accordingly, the preliminary catalyst structure (500) can be easily reduced. As a result, the catalyst structure (600) with reduced overvoltage and Tafel Slope value of the catalyst structure (600), i.e., improved electrocatalytic properties can be provided.

[0078] Referring to FIG. 6, the structure of the catalyst structure (600) is described.

[0079] The catalyst structure (600) may include a rhenium nanocluster in which a plurality of rhenium nanoparticles (610) are aggregated, the first doping metal (621) doped on the surface of the rhenium nanocluster, and the second doping metal (622) doped at a lower ratio than the first doping metal (621). For example, the average diameter of the rhenium nanoparticles (610) may be 25 nm. For example, the average diameter of the rhenium nanoclusters may be 400 nm. For example, the first doping metal (621) may be platinum (Pt). For example, the second doping metal (622) may be nickel (Ni). For example, the doping ratio of the first doping metal (621) may be 6.79 atom%. For example, the doping ratio of the second doping metal (622) may be 0.57 atm%. In addition, a plurality of rhenium nanoparticles (610) may be connected to each other by amorphous carbon (630) to form the rhenium nanocluster. Accordingly, the charge transport efficiency of the catalyst structure (600) may be improved. For example, the shape of the rhenium nanocluster may be Berry Type.

[0080] The first doping metal (631) of the catalyst structure (600) can promote the adsorption of hydrogen atoms and the reduction of hydrogen cations on the surface of the catalyst structure (600) in an alkaline environment. In addition, the second doping metal (622) of the catalyst structure (600) can exist as a metal oxide or metal hydroxide including the second doping metal (622) in an alkaline environment. Accordingly, an area affinity for oxygen atoms on the surface of the catalyst structure (600) can be increased. For example, the metal oxide can be NiO. For example, the metal hydroxide can be NiOOH and Ni(OH)2. In addition, the rhenium nanoparticles (610) of the catalyst structure can have a lower electronegativity than the first doping metal (621) and the second doping metal (622). For example, the electronegativity of the rhenium nanoparticles (610) may be 1.91. For example, the electronegativity of the first doping metal (621) may be 2.28. For example, the electronegativity of the second doping metal (622) may be 1.93. Accordingly, the rhenium nanoparticles (610) of the catalyst structure (600) may have a partial positive charge.

[0081] Therefore, due to the rhenium nanoparticles (610), the first doping metal (621), and the second doping metal (622) of the catalyst structure (600), the activation energy for the adsorption of water molecules and the dissociation of water molecules generated on the surface of the catalyst structure (600) in an alkaline environment can be reduced. As a result, the HER (hydrogen evolution reaction) efficiency of the catalyst structure (600) can be improved in an alkaline environment.

[0082] The first doping metal (621) and the second doping metal (622) doped on the surface of the rhenium nanocluster of the catalyst structure (600) can be observed during EDS Mapping analysis of the catalyst structure (600), as described later in FIG. 8 h. In addition, the first doping metal (621) and the second doping metal (622) doped on the surface of the rhenium nanocluster of the catalyst structure (600) can be observed during XPS analysis of the catalyst structure (600), as described later in FIG. 8 i to k. The peaks corresponding to the 0-valent rhenium of the above rhenium nanocluster can be observed at 40.73 eV and 43.16 eV, the peaks corresponding to the +4-valent rhenium can be observed at 41.67 eV and 44.13 eV, and the peaks corresponding to the +6-valent rhenium can be observed at 46.2 eV and 48.63 eV. In addition, the peaks corresponding to the 0-valent of the first doping metal (621) can be observed at 70.67 eV and 74 eV, and the peaks corresponding to the +2-valent of the first doping metal (621) can be observed at 72.35 eV and 75.68 eV. In addition, it can be seen that the peak corresponding to the 0-valence of the second doping metal (622) is observed at 852.8 eV and 870.1 eV, the peak corresponding to the +2-valence of the second doping metal (622) is observed at 855.8 eV and 873.7 eV, and the peak corresponding to the Sat. Peak of the second doping metal (622) is observed at 860.8 eV and 879.1 eV.

[0083] And, the amorphous carbon (630) connecting the plurality of rhenium nanoparticles (610) of the catalyst structure (600) to each other can be observed during XRD analysis of the catalyst structure (600), as described later in d of Fig. 8. The peak corresponding to the amorphous carbon (630) is the D band (1368 cm -1 ) and G band (1580 cm -1 ) can occur.

[0084] In conclusion, the catalyst structure (600) according to an embodiment of the present application may include a plurality of rhenium nanoparticles (610) aggregated into a rhenium nanocluster, a first doping metal (621) doped on the surface of the rhenium nanocluster, and a second doping metal (622) doped at a lower ratio than the first doping metal (621). In addition, the plurality of rhenium nanoparticles (610) may be connected to each other by the amorphous carbon (630).

[0085] The first doping metal (631) of the catalyst structure (600) can promote the adsorption of hydrogen atoms and the reduction of hydrogen cations on the surface of the catalyst structure (600) in an alkaline environment. In addition, the second doping metal (622) of the catalyst structure (600) can exist as the metal oxide or metal hydroxide including the second doping metal (622) in an alkaline environment. Accordingly, an area affin for oxygen atoms on the surface of the catalyst structure (600) can increase. In addition, the rhenium nanoparticles (610) of the catalyst structure (600) can have a lower electronegativity than the first doping metal (621) and the second doping metal (622). Accordingly, the rhenium nanoparticles (610) of the catalyst structure (600) can have a partially positive charge.

[0086] Therefore, due to the rhenium nanoparticles (610), the first doping metal (621), and the second doping metal (622) of the catalyst structure (600), the activation energy for the adsorption and dissociation of water molecules generated on the surface of the catalyst structure (600) in an alkaline environment can be reduced. As a result, the HER efficiency of the catalyst structure (600) can be improved in an alkaline environment. Accordingly, the catalyst structure (600) can be applied to a water splitting device.

[0087]

[0088] Hereinafter, with reference to FIG. 7, the process of generating hydrogen gas in a water splitting device to which a catalyst structure according to an embodiment of the present invention is applied is described.

[0089] Figure 7 is a drawing for explaining the hydrogen gas generation process of a water splitting device to which a catalyst structure according to an experimental example of the present invention is applied.

[0090] Referring to FIG. 6, a catalyst structure (600) is provided, which includes a rhenium nanocluster in which a plurality of rhenium nanoparticles (610) are aggregated, a first doping metal (621) doped on the surface of the rhenium nanocluster, and a second doping metal (622) doped at a lower ratio than the first doping metal (621), and in which the plurality of rhenium nanoparticles (610) are connected to each other by amorphous carbon (630).

[0091] Referring to FIG. 7, in an alkaline environment, the hydrogen gas generation process of the water splitting device to which the catalyst structure (600) is applied includes, as shown in FIG. 7, a step in which water molecules (710, 720) are adsorbed on the surface of the catalyst structure (600), a step in which the water molecules (710, 720) are dissociated on the surface of the catalyst structure (600), and a step in which hydrogen (720) cations (H) are formed on the surface of the catalyst structure (600). + ) is adsorbed, and a pair of hydrogen (720) cations (H) are formed on the surface of the catalyst structure (600). + ) may include a step of providing electrons to generate hydrogen gas (H2).

[0092] A step in which the water molecules (710, 720) are adsorbed on the surface of the catalyst structure (600), a step in which the water molecules (710, 720) are dissociated on the surface of the catalyst structure (600), and a step in which a pair of hydrogen (720) cations (H) are formed on the surface of the catalyst structure (600) +) in the step of generating hydrogen gas (H2) by receiving electrons, the activation energy for each step can be reduced by the first doping metal (621), the second doping metal (622), and the rhenium nanoparticles (610) of the catalyst structure (600). Accordingly, the overall activation energy for the hydrogen gas generation process of the water splitting device can be reduced. Due to this, the HER efficiency and speed of the water splitting device can be improved in an alkaline environment.

[0093]

[0094] Hereinafter, specific experimental examples and characteristic evaluation results of catalyst structures according to embodiments of the present invention are described.

[0095]

[0096] Catalyst structure according to Experimental Example 1

[0097] Re2O7 was prepared as a rhenium precursor, Pt(acac)2 was prepared as a first doping metal precursor, Ni(acac)2 was prepared as a second doping metal precursor, and THF was prepared as a solvent.

[0098] The rhenium precursor (0.192 g), the first doped metal precursor (0.008 g, 5 mol% relative to the rhenium precursor), and the second doped metal precursor (0.005 g, 5 mol% relative to the rhenium precursor) were provided in the solvent (1 mL), mixed, and left at room temperature for 24 hours to prepare a gel-like base source.

[0099] After dissolving the above base source (1 g) in the above solvent, it was synthesized by a solvent-thermal synthesis method at 250°C for 2 hours and 30 minutes, washed with the above solvent, and dried to prepare a preliminary catalyst structure in a powder state.

[0100] The above preliminary catalyst structure was prepared in a mixed gas (argon gas: hydrogen gas = 95:5) atmosphere at 500°C (5°C min). -1 ) was heat treated for 4 hours to manufacture a catalyst structure.

[0101]

[0102] Catalyst structure according to Experimental Example 1-1

[0103] A catalyst structure was manufactured in the same manner as in Experimental Example 1, except that the preliminary catalyst structure was heat-treated in an argon gas atmosphere.

[0104]

[0105] Catalyst structure according to Experimental Example 1-2

[0106] A catalyst structure was prepared in the same manner as in Experimental Example 1, except that the first doping metal precursor and the second doping metal precursor were provided in a solvent (1 mL) at 2.5 mol% relative to the rhenium precursor, respectively.

[0107]

[0108] Catalyst structure according to Experimental Example 1-3

[0109] A catalyst structure was prepared in the same manner as in Experimental Example 1, except that the first doping metal precursor and the second doping metal precursor were provided in a solvent (1 mL) at 10 mol% relative to the rhenium precursor, respectively.

[0110]

[0111] Catalyst structure according to Experimental Example 1-4

[0112] A catalyst structure was prepared in the same manner as in Experimental Example 1, except that the first doping metal precursor and the second doping metal precursor were provided in a solvent (1 mL) at 15 mol% relative to the rhenium precursor, respectively.

[0113]

[0114] Catalyst structure according to Experimental Example 1-5

[0115] A catalyst structure was prepared in the same manner as in Experimental Example 1, except that the first doping metal precursor and the second doping metal precursor were provided in a solvent (1 mL) at 20 mol% relative to the rhenium precursor.

[0116]

[0117] Catalyst structure according to Experimental Example 1-6

[0118] A catalyst structure was manufactured in the same manner as in Experimental Example 1, except that the second doping metal precursor was provided in a solvent (1 mL) at 10 mol% relative to the rhenium precursor and the preliminary catalyst structure was heat-treated in an argon gas atmosphere.

[0119]

[0120] Catalyst structure according to Experimental Example 1-7

[0121] A catalyst structure was manufactured in the same manner as in Experimental Example 1, except that the second doping metal precursor was provided in a solvent (1 mL) at 15 mol% relative to the rhenium precursor and the preliminary catalyst structure was heat-treated in an argon gas atmosphere.

[0122]

[0123] Catalyst structure according to Experimental Example 2

[0124] A catalyst structure was prepared in the same manner as in Experimental Example 1, except that the second doping metal precursor was not provided in the solvent (1 mL).

[0125]

[0126] Catalyst structure according to Experimental Example 3

[0127] A catalyst structure was prepared in the same manner as in Experimental Example 1, except that the first doping metal precursor was not provided in the solvent (1 mL).

[0128]

[0129] Catalyst structure according to Experimental Example 4

[0130] Commercial Pt / C was used as a catalyst structure.

[0131]

[0132] Catalyst structure according to comparative example

[0133] A catalyst structure was prepared in the same manner as in Experimental Example 1, except that the first doping metal precursor and the second doping metal precursor were not provided in the solvent (1 mL).

[0134] Rhenium precursor (g)First doping metal precursor (mol% relative to rhenium precursor)Second doping metal precursor (mol% relative to rhenium precursor)Ar:H2 ratioLegend displayed on graphExperimental example 10.1925595:5Pt-Ni@Re / CExperimental example 1-10.19255100:0Pt-Ni@Re / C-ArExperimental example 1-20.1922.52.595:52.5mol%Experimental example 1-30.192101095:510mol%Experimental example 1-40.192151595:515mol%Experimental example 1-50.192202095:520mol%Experimental example 1-60.192510100:0Pt(5mol%)-Ni(10mol%)Experimental example 1-70.192515100:0Pt(5mol%)-Ni(15mol%)Experimental Example 20.1925-95:5Pt@Re / CExperimental Example 30.192-595:5Ni@Re / CExperimental Example 4---95:5Pt / CComparative Example 10.192--95:5Re / C

[0135]

[0136] Figure 8 is a drawing for explaining the structural features of a catalyst structure according to Experimental Example 1 of the present invention.

[0137] Referring to Fig. 8a, the structure of the catalyst structure according to Experimental Example 1 is schematically illustrated. Referring to Fig. 8b and c, the catalyst structure according to Experimental Example 1 was photographed using SEM. Referring to Fig. 8d, the catalyst structure according to Experimental Example 1 was analyzed using Raman spectra. Referring to Fig. 8e, the catalyst structure according to Experimental Example 1 was analyzed using PXRD (Powder X-ray diffraction). Referring to Fig. 8f and g, the catalyst structure according to Experimental Example 1 was photographed using HR-TEM (High-resolution transmission electron microscopy). Referring to Fig. 8h, the catalyst structure according to Experimental Example 1 was photographed using HAADF-STEM (High-angle annular dark field scanning transmission electron microscopy), and EDS mapping analysis was performed on the photographed photographs. Referring to i to j of Fig. 8, the catalyst structure according to Experimental Example 1 was analyzed by XPS.

[0138] As can be seen from Figure 8a, the catalyst structure according to Experimental Example 1 has a structure in which Pt and Ni are dispersed on the surface of Re nanoclusters. In addition, it can be seen that the plurality of Re nanoparticles constituting the Re nanocluster have a structure in which they are connected to each other by amorphous carbon.

[0139] As can be seen in b and c of Fig. 8, the Re nanoclusters have a Berry Type morphology with an average diameter of 400 nm. In addition, the average diameter of the Re nanoparticles is 25 nm.

[0140] As can be seen in Fig. 8d, the D band (1368 cm -1 ) and G band (1580 cm-1 ) it can be seen that a peak corresponding to the amorphous carbon is observed. Therefore, it can be seen that a plurality of the Re nanoparticles are connected to each other by the amorphous carbon.

[0141] As can be seen in Fig. 8e, the crystal structure of the catalyst structure according to Experimental Example 1 has a hexagonal unit cell and a P63 / mmc space group similar to the crystal structure of Re metal. (a = b = 2.76Å, c = 4.46Å, α = β = 90°, γ = 120°)

[0142] As can be seen in f and g of Fig. 8, the Re nanoparticles are single crystals, and it can be seen that a 2.40 Å-sized empty space exists between the (1000) plane and the (0001) plane of the Re nanoparticles.

[0143] As can be seen in Fig. 8h, it can be seen that the surface of the Re nanocluster composed of a plurality of the Re nanoparticles is doped with Pt and Ni.

[0144] As can be seen from i in Fig. 8, in the Re spectrum, Re 0 Peaks corresponding to Re are observed at 40.73 eV and 43.16 eV, and 4+ Peaks corresponding to Re are observed at 41.67 eV and 44.13 eV, and 6+ It can be seen that the corresponding peaks were observed at 46.2 eV and 48.63 eV.

[0145] As can be seen from j in Fig. 8, in the Pt 4f spectrum, Pt 0 Peaks corresponding to Pt are observed at 70.67 eV and 74 eV. 2+ It can be seen that the corresponding peaks were observed at 72.35 eV and 75.68 eV.

[0146] As can be seen from k in Fig. 8, in the Ni 2p spectrum, Ni 0Peaks corresponding to Ni are observed at 852.8 eV and 870.1 eV, and 2+ It can be seen that peaks corresponding to the Sat. Peak are observed at 855.8 eV and 873.7 eV, and peaks corresponding to the Sat. Peak are observed at 860.8 eV and 879.1 eV.

[0147] As can be seen from j and k of Fig. 8, the catalyst structure according to Experimental Example 1 shows that the peaks for the Pt 4f spectrum and the Ni 2p spectrum are shifted in the negative direction compared to the conventional reference catalyst structures (Pt / C, PtNi / SWNT, and metal-doped Pt3Ni / C nanoparticles). This factor is interpreted to be due to the relatively strong electron transfer from Pt and Ni due to the Re nanoclusters having lower electronegativity than Pt and Ni.

[0148]

[0149] FIG. 9 is a drawing for comparing the electrocatalytic performance for HER (Hydrogen Evolution Reaction) of catalyst structures according to Comparative Example 1 and Experimental Examples 1 to 4 of the present invention.

[0150] Referring to a and b of FIG. 9, the catalyst structures according to Comparative Example 1 and Experimental Examples 1 to 4 were loaded onto a Glassy Carbon Rotating Disk to manufacture working electrodes according to Comparative Example 1 and Experimental Examples 1 to 4. Then, using the working electrodes according to Comparative Example 1 and Experimental Examples 1 to 4, a Graphite Rod as a counter electrode, and Hg / HgO (in 1 M NaOH solution) as a reference electrode, in an environment of pH 14, a Scan Rate of 2 mVs -1LSV (Linear Scan Voltammetry) was measured under the condition. Referring to Fig. 9c, the LSV graph of the working electrode according to Comparative Example 1 and Experimental Examples 1 to 4 measured in Fig. 9a and b is represented as a Tafel Plot. Referring to Fig. 9d, the exchange current value (0.624 mAcm) at 0 mV vs. RHE is plotted on the LSV graph of the working electrode according to Experimental Example 1 measured in Fig. 9a. -2 ) and the active site value of Re on the (0001) plane (1.596 x 1016 site / cm -2), the TOF (Turnover Frequency) value for the working electrode according to Experimental Example 1 was calculated. Referring to FIG. 9 e, the TOF value is plotted against the overvoltage values ​​(0 mV, 36 mV, 89 mV) of the working electrode according to Experimental Example 1 in a graph. Referring to FIG. 9 f, except that the working electrode according to Experimental Example 1-1 was manufactured by loading the catalyst structure according to Experimental Example 1 onto a Glassy Carbon Plate, LSV (Black Line) was measured in the initial state before performing 10,000 cycles of HER under the conditions described in FIG. 9 a, and LSV (Red Line) was measured after performing 10,000 cycles of HER, and the graph was presented. And, in order to evaluate the reproducibility of the working electrode according to Experimental Example 1-1, five working electrodes according to Experimental Example 1-1 were prepared, and the current density generated for 48 hours under an overvoltage condition of -500 mV was measured, and the average current density value and standard deviation of the working electrodes according to five Experimental Examples 1-1 were presented in a graph. Referring to Fig. 9g, Nikel foam (NF) was used as the working electrode according to Comparative Example 1-1, and the working electrode according to Experimental Example 1-2 was manufactured by loading the catalyst structure according to Experimental Example 1 onto Nickel foam (NF), and the working electrode according to Experimental Example 4-1 was manufactured by loading the catalyst structure according to Experimental Example 4 onto Nickel foam (NF), and LSV was measured under the conditions described in Fig. 9a.Referring to FIG. 9h, the working electrode according to Comparative Example 1-1, the working electrode according to Experimental Example 1-2, and the working electrode according to Experimental Example 4-1 described in FIG. 9g were used as cathode electrodes, Nikel foam (NF) was used as an anode electrode, and an anion exchange membrane was placed between the cathode electrode and the anode electrode, thereby manufacturing an H-type Cell according to Comparative Example 1-1, an H-type Cell according to Experimental Example 1-2, and an H-type Cell according to Experimental Example 4-1. Then, using the H-type Cell according to Comparative Example 1-1, Experimental Example 1-2, and Experimental Example 4-1, water decomposition was performed in a 1 M KOH environment, and the current density according to voltage was measured. Referring to FIG. 9i, using the H-type Cell according to Experimental Example 1-2 described in FIG. 9h, in a 1 M KOH environment, -0.4 V vs. The amount of hydrogen gas produced over time while decomposing water under RHE(η400) conditions was measured, and the Faradaic efficiency ((measured hydrogen production amount / theoretically calculated hydrogen production amount) x 100) was calculated.

[0151] As can be seen from a and b of FIG. 9, the overvoltage of the working electrode according to Experimental Example 1 is 36 mV (η10), the overvoltage of the working electrode according to Experimental Example 4 is 49 mV (η10), the overvoltage of the working electrode according to Comparative Example 1 is 136 mV (η10), the overvoltage of the working electrode according to Experimental Example 2 is 97 mV (η10), and the overvoltage of the working electrode according to Experimental Example 3 is 55 mV (η10). Therefore, it can be seen that the overvoltage of the working electrode according to Experimental Example 1 is the lowest.

[0152] As can be seen from c in Fig. 9, the Tafel Slope value of the working electrode according to Comparative Example 1 is 81 mV dec. -1And, the Tafel Slope value of the working electrode according to Experimental Example 1 is 30 mV dec. -1 And, the Tafel Slope value of the working electrode according to Experimental Example 2 is 60 mV dec. -1 And, the Tafel Slope value of the working electrode according to Experimental Example 3 is 44 mV dec. -1 And, the Tafel Slope value of the working electrode according to Experimental Example 4 is 40 mV dec. -1 It can be seen that. Therefore, it can be seen that the Tafel Slope value of the working electrode according to Experimental Example 1 is the lowest. Accordingly, it can be seen that the working electrode according to Experimental Example 1 has the best electrocatalytic properties for HER.

[0153] As can be seen in d of Fig. 9, the TOF value of the working electrode according to Experimental Example 1 is 0.12 s. -1 You can see that.

[0154] As can be seen in Fig. 9e, the working electrode according to Experimental Example 1 has a TOF value of 0.12 s at an overvoltage of 0 mV. -1 , and the TOF value at an overvoltage of 36 mV is 1.96 s. -1 , and the TOF value is 10.0 s at an overvoltage of 89 mV. -1 You can see that.

[0155] As can be seen in Fig. 9f, the working electrode according to Experimental Example 1-1 shows a current density decrease of 5.5% at 500 mV after 10,000 cycles of HER. Therefore, it can be seen that the working electrode according to Experimental Example 1 has stability for long-term HER cycles. In addition, it can be seen that the working electrode according to Experimental Example 1 shows a decrease of 1.99% (standard deviation 6.07) in average current density after 48 hours compared to the initial average current density under -500 mV overvoltage conditions.

[0156] As can be seen in Fig. 9g, the working electrode according to Experimental Example 1-2 has a current density of 5,113 mAcm at an overvoltage of 1 V. -2 It can be seen that the working electrode according to Experimental Example 1-2 is 1,000 mAcm -2 At current density, the overvoltage is 419 mV and the TOF value is 195.6 S. -1 You can see that.

[0157] As can be seen in h of Fig. 9, the H-type cell according to Experimental Example 1-2 has the lowest voltage at which water decomposition begins and the highest current density. Therefore, it can be seen that the H-type cell according to Experimental Example 1-2 has higher activity for water decomposition than the H-type cell according to Comparative Example 1-1 and Experimental Example 4-1.

[0158] As can be seen from i in Fig. 9, the H-type cell according to Experimental Example 1-2 generated 72 mL of hydrogen gas in 1 hour, and the Faradaic efficiency was found to be 98.63%. In addition, it can be seen that the amount of hydrogen gas generated (72.94 mL) theoretically calculated using the ideal gas equation for the H-type cell according to Experimental Example 1-2 and the amount of hydrogen gas generated (72 mL) actually measured are substantially similar.

[0159] Catalyst structure graph legend display Working electrode according to Experimental Example 1 Glassy Carbon Rotating Disk Catalyst structure according to Experimental Example 1 Pt-Ni@Re / C Working electrode according to Experimental Example 1-1 Glassy Carbon Plate Catalyst structure according to Experimental Example 1 - Working electrode according to Experimental Example 1-2 Nickel foam Catalyst structure according to Experimental Example 1 Pt-Ni@Re / ClNF Working electrode according to Experimental Example 2 Glassy Carbon Rotating Disk Catalyst structure according to Experimental Example 2 Pt@Re / C Working electrode according to Experimental Example 3 Glassy Carbon Rotating Disk Catalyst structure according to Experimental Example 3 Ni@Re / C Working electrode according to Experimental Example 4 Glassy Carbon Rotating Disk Catalyst structure according to Experimental Example 4 Pt / C Working electrode according to Experimental Example 4-1 Nickel foam Catalyst structure according to Experimental Example 4 Pt / ClNF Working electrode according to Comparative Example 1 Glassy Carbon Rotating Disk According to Comparative Example 1 Working electrode according to catalyst structure Re / C comparison example 1-1 Nickel foam-Bare NF

[0160] Classification Cathode Anode Graph Legend Display H-Type Cell according to Experimental Example 1-2 Working Electrode according to Experimental Example 1-2 Nickel foamNF ll Pt-Ni@Re / C l NF H-Type Cell according to Experimental Example 4-1 Working Electrode according to Experimental Example 4-1 Nickel foamNF ll Pt / Cl NF H-Type Cell according to Comparison Example 1-1 Working Electrode according to Comparison Example 1-1 Nickel foamNF ll NF

[0161]

[0162] FIG. 10 is a drawing for explaining HER (Hydrogen Evolution Reaction) in an alkaline environment through electrochemical analysis of catalyst structures according to Comparative Example 1 and Experimental Examples 1 to 4 of the present invention.

[0163] Referring to FIG. 10a, EIS (Electrochemical Impedance Spectroscopy) analysis was performed on the catalyst structures according to Comparative Example 1 and Experimental Examples 1 to 4 under the conditions of 10 mHz to 100 kHz (AC amplitude 5 mV) with an overvoltage of 200 mV in a 1 M KOH environment. Referring to FIG. 10b, for the catalyst structures according to Experimental Examples 1 and 4, in a CO-saturated 1 M KOH environment, a constant overvoltage was provided for a constant period of time to adsorb CO on the surface of the catalyst structures according to Experimental Examples 1 and 4. Then, after removing the CO gas remaining in the CO-saturated KOH using pure argon gas, CV (Cyclic Voltammogram) was measured on the catalyst structures according to Experimental Examples 1 and 4. Referring to c of Fig. 10, for the catalyst structures according to Experimental Examples 1 and 4, CV (Cyclic Voltammogram) was measured in a 1M KOH environment (pH 14) to determine H updThe peaks were compared. Referring to Fig. 10d, in an alkaline environment, an experiment on HER was performed for each temperature condition for the catalyst structures according to Experimental Examples 1 and 4, and the activation energy of the catalysts according to Experimental Examples 1 and 4 was calculated using the Arrhenius equation. Referring to Fig. 10e, in an alkaline environment, the change in Gibbs free energy for H, OH, and H2O adsorbed on the (0001) plane of the catalyst structures according to Comparative Examples 1, 1, and 2, and the (111) plane of the catalyst structure according to Experimental Example 4 was calculated using DFT (Density Functional Theory). Referring to Fig. 11f, in an alkaline environment, the Gibbs free energy change for the step (M) in which water molecules are adsorbed on the (0001) plane of the catalyst structure according to Comparative Example 1, Experimental Example 1, and Experimental Example 2 and the (111) plane of the catalyst structure according to Experimental Example 4, the transition state (TS) for dissociation of water molecules, the step d in which dissociated hydrogen is adsorbed, and the step h in which hydrogen gains electrons and is desorbed were calculated using DFT.

[0164] As can be seen in Fig. 10a, the charge transfer resistance value R of the catalyst structure according to Experimental Example 1 ct is 5.9Ω, and the solution resistance value is R s It can be seen that R of the catalyst structure according to Experimental Example 4 is 1.8Ω. ct As the resistance is 13.1Ω, it can be seen that the catalyst structure according to Experimental Example 1 has a superior charge transport efficiency than the catalyst structure according to Experimental Example 4. This factor is interpreted to be due to the electrical interconnection between the Re nanoparticles and the amorphous carbon constituting the Re nanoclusters doped with Pt and Ni in the catalyst structure according to Experimental Example 1.

[0165] As can be seen in Fig. 10b, the oxidation peak corresponding to CO of the catalyst structure according to Experimental Example 1 is shifted in the negative direction compared to the catalyst structure according to Experimental Example 4. Accordingly, it can be seen that the catalyst structure according to Experimental Example 1 has a higher dissociation efficiency of water molecules than the catalyst structure according to Experimental Example 4.

[0166] As can be seen in c of Fig. 10, the catalyst structure according to Experimental Example 1 has a higher H corresponding to hydrogen desorption than the catalyst structure according to Experimental Example 4. upd It can be seen that the peak shifts in the negative direction. Therefore, it can be seen that the catalyst structure according to Experimental Example 1 is easier to desorb hydrogen than the catalyst structure according to Experimental Example 4. Accordingly, the catalyst structure according to Experimental Example 1 is easier to desorb hydrogen than the catalyst structure according to Experimental Example 4 in that the desorbed hydrogen combines with water molecules to form H3O, which is a source of hydrogen gas. + It can be seen that more is generated. Accordingly, the catalyst structure according to Experimental Example 1 can improve the HER rate even in an alkaline environment.

[0167] As can be seen from d of Fig. 10, the activation energy (16.2 kJ / mol) of the catalyst structure according to Experimental Example 1 is lower than the activation energy (20.7 kJ / mol) of the catalyst structure according to Experimental Example 4. This factor is that the catalyst structure according to Experimental Example 1 is lower than the catalyst structure according to Experimental Example 4 in terms of H3O. + - It is interpreted that this is because the reduction process was optimized, reducing the energy barrier of the entire HER.

[0168] As can be seen in Fig. 10e, the Gibbs free energy change for H2O adsorbed on the surface of the catalyst structure according to Experimental Example 1 is the lowest. Accordingly, it can be seen that H2O is most easily adsorbed on the surface of the catalyst structure according to Experimental Example 1. This factor is interpreted to be due to the fact that the interaction of H2O molecules with H is enhanced due to the Pt and Ni doped on the surface of the Re nanoclusters of the catalyst structure according to Experimental Example 1.

[0169] As can be seen from f of Fig. 10, in the HER of the catalyst structure according to Experimental Example 1, the Gibbs free energy changes for the step (M) in which water molecules are adsorbed, the transition state (TS) for dissociation of water molecules, and the step h in which hydrogen acquires electrons and is desorbed are the lowest.

[0170]

[0171] Figure 11 is a HAADF-STEM (High-angle annular dark field scanning transmission electron microscopy) photograph and EDS mapping result of a catalyst structure according to Experimental Example 1 of the present invention.

[0172] Referring to Fig. 11a, a HAADF-STEM image of the catalyst structure according to Experimental Example 1 was photographed. Referring to Fig. 11b, the HAADF-STEM image of the catalyst structure according to Experimental Example 1 taken in Fig. 11a was subjected to EDS Mapping analysis for Re, Pt, and Ni elements.

[0173] As can be seen from a and b of Fig. 11, the Re element of the catalyst structure according to Experimental Example 1 is 92.67 atom%, the Pt element is 6.79 atom%, and the Ni element is 0.57 atom%.

[0174]

[0175] Figure 12 is an image analyzing the electrostatic potential of the surface of a catalyst structure according to Experimental Example 1 of the present invention.

[0176] Referring to Fig. 12, the electrostatic potential for Re, Pt, and Ni atoms on the surface of the catalyst structure according to Experimental Example 1 was analyzed.

[0177] As can be seen in Fig. 12, the electrostatic potential of the Pt atom of the catalyst structure according to Experimental Example 1 is -0.72e, the electrostatic potential of the Ni atom is -0.11e, and the electrostatic potential of the Re atom is -0.05e to +0.02e. Therefore, it can be seen that the electrostatic potential of the Pt atom of the catalyst structure according to Experimental Example 1 has the most negative electrostatic potential. Due to this, the H of the OH adsorbed on the surface of the catalyst structure according to Experimental Example 1 + Among the Pt, Ni, and Re atoms, it can be seen that hydrogen interacts most strongly with the Pt atom. Accordingly, it can be seen that hydrogen is easily adsorbed on the surface of the catalyst structure according to Experimental Example 1.

[0178]

[0179] FIG. 13 is a drawing for comparing the overvoltage and Tafel Slope of the catalyst structures according to Experimental Example 1 and Experimental Example 1-1 of the present invention.

[0180] Referring to a and b of Fig. 13, LSV measurements were performed for the catalyst structures according to Experimental Example 1 and Experimental Example 1-1 under the conditions described in a of Fig. 9. Referring to c of Fig. 13, the LSV graphs for the catalyst structures according to Experimental Example 1-1 and Experimental Example 1 measured in a and b of Fig. 13 are represented as Tafel Plots.

[0181] As can be seen from a and b of Fig. 13, the overvoltage of the catalyst structure according to Experimental Example 1 is 36 mV (η10), and the overvoltage of the catalyst structure according to Experimental Example 1-1 is 42 mV (η10).

[0182] As can be seen in c of Fig. 13, the Tafel Slope of the catalyst structure according to Experimental Example 1 is 30 mVdec. -1 And, the Tafel Slope of the catalyst structure according to Experimental Example 1-1 is 33 mVdec. -1 You can see that.

[0183] Therefore, it can be seen that the catalyst structure according to Experimental Example 1 has superior electrocatalytic properties for HER than the catalyst structure according to Experimental Example 1-1.

[0184] Accordingly, in the method for manufacturing a catalyst structure according to the present invention, it can be seen that the method of creating a reducing atmosphere with a mixed gas (Ar:H2=95:5) for the preliminary catalyst structure is a method for improving the electrocatalytic properties for HER for the catalyst structure.

[0185]

[0186] Fig. 14 is a graph for comparing the overvoltage and Tafel Slope of the catalyst structures according to Experimental Example 1 and Experimental Examples 1-2 to 1-5 of the present invention.

[0187] Referring to FIG. 14a, LSV was measured for the catalyst structures according to Experimental Example 1 and Experimental Examples 1-2 to 1-5 under the conditions described in FIG. 9a. Referring to FIG. 14b, a Tafel plot was plotted using the LSV graphs for the catalyst structures according to Experimental Example 1 and Experimental Examples 1-2 to 1-5 measured in FIG. 14a. Referring to FIG. 14c, the overvoltage of the catalyst structures according to Experimental Example 1 and Experimental Examples 1-2 to 1-5 was plotted using the LSV graphs for the catalyst structures according to Experimental Example 1 and Experimental Examples 1-2 to 1-5 measured in FIG. 14a. Referring to d of Fig. 14, the Tafel Slope was calculated using the Tafel Plot for the catalyst structures according to Experimental Example 1 and Experimental Examples 1-2 to 1-5 of b of Fig. 14 and presented as a graph.

[0188] As can be seen from a to d of FIG. 14, the overvoltage of the catalyst structure according to Experimental Example 1 is 36 mV (η10), the overvoltage of the catalyst structure according to Experimental Example 1-2 is 58 mV (η10), the overvoltage of the catalyst structure according to Experimental Example 1-3 is 44 mV (η10), the overvoltage of the catalyst structure according to Experimental Example 1-4 is 51 mV (η10), and the overvoltage of the catalyst structure according to Experimental Example 1-5 is 50 mV (η10). In addition, the Tafel Slope of the catalyst structure according to Experimental Example 1 is 30 mV dec. -1 And, the Tafel Slope of the catalyst structure according to Experimental Example 1-2 is 36 mVdec. -1 And, the Tafel Slope of the catalyst structure according to Experimental Example 1-3 is 33 mVdec. -1 And, the Tafel Slope of the catalyst structure according to Experimental Example 1-4 is 35 mVdec. -1And, the Tafel Slope of the catalyst structure according to Experimental Example 1-5 is 37 mVdec. -1 You can see that.

[0189] Therefore, it can be seen that the electrocatalytic properties for HER of the catalyst structure according to Experimental Example 1 are the best.

[0190] Accordingly, in the method for manufacturing a catalyst structure according to the present invention, it can be seen that the method of controlling the first doping metal precursor and the second doping metal precursor provided to the solvent to be more than 2.5 mol% and less than 10 mol% relative to the rhenium precursor is a method for improving the electrocatalytic properties of the catalyst structure for HER.

[0191]

[0192] Figure 15 is a table summarizing the XPS analysis results before / after 10,000 cycles of HER for the catalyst structure according to Experimental Example 1 of the present invention.

[0193] Referring to Fig. 15, the catalyst structure according to Experimental Example 1 was analyzed by XPS in the initial state before 10,000 cycles of HER, and the catalyst structure according to Experimental Example 1 was analyzed by XPS after 10,000 cycles of HER were performed.

[0194] As can be seen in Fig. 15, in the Re 4f spectrum, the Re of the catalyst structure according to Experimental Example 1 0 , Re 4+ , and Re 6+ It can be seen that the ratio is substantially maintained after 10,000 cycles of HER. And, in the Pt 4f spectrum, the Pt of the catalyst structure according to Experimental Example 1 0 , and Pt 2+ It can be seen that the ratio is practically maintained after 10,000 cycles of HER. Also, in the Ni 2p spectrum, Ni 0 , and Ni 2+It can be seen that the ratio is practically maintained after 10,000 cycles of HER.

[0195] Therefore, it can be seen that the catalyst structure according to Experimental Example 1 has stability for a long-term HER cycle.

[0196]

[0197] FIG. 16 is a graph for comparing the overvoltage of catalyst structures according to Experimental Examples 1-1, 1-6, and 1-7 of the present invention.

[0198] Referring to Fig. 16, LSV (Linear Scan Voltammetry) was measured in an environment of pH 14 for the catalyst structures according to Experimental Examples 1-1, 1-6, and 1-5.

[0199] As can be seen in Fig. 16, among the experimental examples, the overvoltage of the catalyst structure according to Experimental Example 1-1 is the lowest.

[0200] Therefore, in the method for manufacturing a catalyst structure according to the present invention, it can be seen that the method of providing the first doping metal precursor and the second doping metal precursor to the solvent in the same mol% as the rhenium precursor is a method for reducing the overvoltage of the catalyst structure.

[0201]

[0202] While the present invention has been described in detail using preferred embodiments, the scope of the present invention is not limited to the specific embodiments described above, and should be interpreted in accordance with the appended claims. Furthermore, those skilled in the art will appreciate that numerous modifications and variations are possible without departing from the scope of the present invention.

[0203] Since the catalyst structure according to the present invention is applicable to a water splitting device, it can be used in the energy industry, automobile industry, chemical industry, steel industry, and power storage industry where water splitting devices are used.

Claims

1. A step of preparing a rhenium (Re) precursor, a first doping metal precursor, a second doping metal precursor, and a solvent; A step of providing the rhenium precursor, the first doping metal precursor, and the second doping metal precursor to the solvent and mixing them to prepare a base source; A step of manufacturing a preliminary catalyst structure by synthesizing the above base source by a solvothermal synthesis method; and A method for producing a catalyst structure, comprising a step of producing a catalyst structure comprising rhenium, a first doping metal, a second doping metal, and carbon by heat-treating the above-mentioned preliminary catalyst structure in a reducing atmosphere.

2. In paragraph 1, A method for producing a catalyst structure, comprising providing the first doping metal precursor and the second doping metal precursor provided in the solvent in an amount of more than 2.5 mol% and less than 10 mol% relative to the rhenium precursor.

3. In paragraph 1, A method for manufacturing a catalyst structure, wherein the reducing atmosphere is composed of a mixed gas containing argon gas and hydrogen gas in a lower proportion than the argon gas.

4. In paragraph 1, The heat treatment temperature of the above solvent thermal synthesis is 200°C to 250°C, and the heat treatment time is 2 hours to 2.5 hours. A method for manufacturing a catalyst structure, wherein the heat treatment temperature of the above-mentioned preliminary catalyst structure is 500°C to 900°C, and the heat treatment time is 4 hours to 6 hours.

5. In paragraph 1, The above solvent includes THF, The above rhenium precursor comprises Re2O7, The above first doping metal precursor comprises Pt(acac)2, The second doping metal precursor is a method for producing a catalyst structure including Ni(acac)2.

6. In paragraph 1, A method for producing a catalyst structure, comprising: providing the base source, the rhenium precursor, the first doping metal precursor, and the second doping metal precursor to the solvent, mixing them, and leaving them to form a gel.

7. Rhenium nanoclusters in which multiple rhenium (Re) nanoparticles are aggregated; and Including a first doping metal doped on the surface of the rhenium nanocluster and a second doping metal doped at a lower ratio than the first doping metal, A catalyst structure comprising a plurality of the above rhenium nanoparticles connected to each other by amorphous carbon.

8. In paragraph 7, The above rhenium nanoparticles are a catalyst structure including a first doping metal and a second doping metal having a lower electronegativity than the first doping metal.

9. In paragraph 8, The above first doping metal includes Pt, The second doping metal is a catalyst structure including Ni.

10. Including the catalyst structure according to Article 7, A water splitting device comprising, in an alkaline environment, a step of adsorbing water molecules onto the surface of the catalyst structure due to the first doping metal and the second doping metal of the catalyst structure, a step of dissociating the water molecules adsorbed onto the surface of the catalyst structure, and a step of generating hydrogen gas by providing electrons to a pair of hydrogen ions adsorbed onto the surface of the catalyst structure, wherein the activation energy is reduced.

11. Rhenium nanoclusters composed of multiple rhenium (Re) nanoparticles; and Including platinum (Pt) doped on the surface of the above rhenium nanocluster and nickel (Ni) doped at a lower ratio than the platinum, A plurality of the above rhenium nanoparticles are connected to each other by amorphous carbon, A catalyst structure having peaks for Pt 4f and Ni 2P spectra shifted in a negative direction compared to a reference catalyst structure containing Pt and C during XPS analysis.

12. In paragraph 11, when analyzing XRD, the D band (1368 cm -1 ) and G band (1580 cm -1 ) A catalyst structure including a peak corresponding to the amorphous carbon observed in the above.

Images