Layered metal phosphide hybrid catalyst, method for preparing same, and water electrolysis apparatus having same

Abstract

Disclosed is a method for preparing a layered metal phosphide hybrid catalyst. The method for preparing a layered metal phosphide hybrid catalyst comprises: a first step for preparing a layered metal double-layer hydroxide nanosheet structure represented by chemical formula 1; and a second step for heat-treating the metal double-layer hydroxide nanosheet structure and a phosphorus (P)-containing precursor material in a reducing atmosphere to convert the layered metal double-layer hydroxide nanosheet structure into a layered metal phosphide hybrid nanosheet structure.

Description

Layered metal phosphide hybrid catalyst, method for producing the same, and water electrolysis device comprising the same

[0001] The present invention relates to a layered metal phosphide hybrid catalyst having catalytic activity for a hydrogen evolution reaction (HER) or an oxygen evolution reaction (OER), a method for producing the same, and a water electrolysis device having the same.

[0002] Due to problems such as the depletion of fossil fuels and environmental pollution, research is being actively conducted on environmentally friendly renewable energy devices that use hydrogen, such as fuel cells, and metal-air secondary batteries that store energy generated from renewable energy devices.

[0003] To produce the above hydrogen in an environmentally friendly manner, water electrolysis devices are widely used, and these water electrolysis devices can produce hydrogen and oxygen from water through an oxygen evolution reaction (OER) that occurs at the anode and a hydrogen evolution reaction (HER) that occurs at the cathode.

[0004] Electrolysis catalysts primarily utilize precious metals, such as platinum, ruthenium, and iridium. While these precious metals are considered ideal electrocatalysts for OER and HER in alkaline solutions, their large-scale production is limited due to high cost, poor stability, and precious metal depletion. To overcome these drawbacks, active research is being conducted on non-precious metal catalysts, such as transition metal-based oxides, phosphates, selenides, sulfides, nitrides, borides, carbides, organometallic compounds, and hydroxides. However, these catalysts suffer from limitations, such as low current values ​​and high overvoltages.

[0005] One object of the present invention is to provide a layered metal phosphide hybrid catalyst having relatively high electronic conductivity and exhibiting high catalytic activity for HER or OER reactions.

[0006] Another object of the present invention is to provide a method for producing the layered metal phosphide hybrid catalyst.

[0007] Another object of the present invention is to provide a water electrolysis device that uses the layered metal phosphide hybrid catalyst as a catalyst for the HER reaction.

[0008] A method for producing a layered metal phosphide hybrid catalyst according to an embodiment of the present invention may include a first step of producing a layered metal bilayer hydroxide nanosheet structure represented by the following chemical formula 1; and a second step of converting the layered metal bilayer hydroxide nanosheet structure into a layered metal phosphide hybrid nanosheet structure by heat-treating the metal bilayer hydroxide nanosheet structure and a phosphorus (P)-containing precursor material in a reducing atmosphere.

[0009] [Chemical Formula 1]

[0010] [M 1 2M 2 1-x Ru x (OH)2][A n- ] x / n· mH2O

[0011] In the above chemical formula 1, M 1 is a first transition metal cation with an oxidation state of +2, and M 2 is a second transition metal cation having an oxidation state of +3, A is an interlayer anion having an oxidation state of -n, x is a real number greater than 0 and less than 1, n is an integer greater than or equal to 1 and less than or equal to 5, and m is a positive real number.

[0012] In one embodiment, the first transition metal cation is Ca 2+ , Mg 2+ , Zn 2+ , Ni2+ , Mn 2+ , Co 2+ , Fe 2+ and Cu 2+ comprising at least one selected from the group consisting of, wherein the second transition metal cation is Fe 3+ , Al 3+ , Cr 3+ , Mn 3+ , Ga 3+ , Co 3+ and Ni 3+ Contains at least one selected from the group consisting of, wherein the interlayer anion is OH - , NO3 - , PO4 3- , HPO4 2- and H2PO4 - It may include one or more selected from the group consisting of .

[0013] In one embodiment, the first step comprises: adding M to an aqueous solvent; 1 Contains first metal salt, M 2 The method may include a step of preparing a mixed solution by dissolving a second metal salt and a ruthenium (Ru) salt; and a step of preparing a layered metal double-layer hydroxide nanosheet structure by adding the mixed solution and an alkaline aqueous solution to an aqueous solution containing the interlayer anion and stirring the mixture under an inert gas atmosphere.

[0014] In one embodiment, the second step may include a step of placing the layered metal bilayer hydroxide nanosheet structure and the phosphorus (P)-containing precursor in a heat treatment vessel and then performing a heat treatment while injecting a reducing gas.

[0015] In one embodiment, in the chemical formula 1, x may be 0.2 or more and 0.4 or less.

[0016] In one embodiment, the phosphorus (P)-containing precursor may include sodium phosphate (NaH2PO2·xH2O).

[0017] In one embodiment, the heat treatment may be performed at a temperature of about 250 to 350°C.

[0018] In one embodiment, the layered metal phosphide hybrid nanosheet structure is M 1 a P, M 2 b P and M 1 m M 2 n It may include a nanosheet formed of one or more phosphides selected from the group consisting of P.

[0019] A layered metal phosphide hybrid catalyst according to an embodiment of the present invention may include nanosheets formed of metal phosphide; and ruthenium dispersed in a monoatomic state on the surface of the nanosheets.

[0020] In one embodiment, the layered metal phosphide hybrid catalyst can be manufactured according to the method for manufacturing the layered metal phosphide hybrid catalyst of the present invention.

[0021] In one embodiment, the metal phosphide comprises at least one selected from a phosphide of the first transition metal, a phosphide of the second transition metal, and a phosphide comprising the first and second transition metals, wherein the first transition metal comprises at least one selected from the group consisting of Ca, Mg, Zn, Ni, Mn, Co, Fe, and Cu, and the second transition metal comprises at least one selected from the group consisting of Fe, Al, Cr, Mn, Ga, Co, and Ni.

[0022] In one embodiment, the mole ratio of the ruthenium salt to the total moles of the ruthenium and the second transition metal may be 20% or more and 40% or less.

[0023] In one embodiment, the nanosheets may have a size of 20 to 600 nm.

[0024] A water electrolysis device according to an embodiment of the present invention includes an ion exchange membrane and a first electrode and a second electrode facing each other with the ion exchange membrane interposed therebetween, wherein the first electrode where a hydrogen evolution reaction (HER) occurs may include a layered metal phosphide hybrid catalyst according to the present invention.

[0025] In one embodiment, the first electrode includes a first catalyst layer disposed adjacent to the ion exchange membrane and a first gas diffusion layer disposed on the outside of the first catalyst layer, and the first catalyst layer may include the layered metal phosphide hybrid catalyst.

[0026] According to the layered metal phosphide hybrid catalyst of the present invention, since ruthenium is dispersed in a monoatomic state on a metal phosphide nanosheet having a high specific surface area and electronic conductivity, it can have high electrochemical catalytic activity for a hydrogen production reaction.

[0027] FIG. 1 is a flowchart illustrating a method for manufacturing a layered metal phosphide hybrid catalyst according to an embodiment of the present invention.

[0028] Figure 2 is a drawing for explaining a water electrolysis device according to an embodiment of the present invention.

[0029] Figure 3 is XRD data of layered metal double layer hydroxide nanosheets of Examples 1-1 to 4-1.

[0030] Figure 4 is FE-SEM element mapping data of the layered metal double layer hydroxide nanosheet of Example 3-1.

[0031] Figure 5 is XRD data of metal phosphide hybrid nanosheets according to Examples 1-2 to 4-2.

[0032] Figure 6 is an FE-SEM image of metal phosphide hybrid nanosheets according to Examples 1-2 to 4-2.

[0033] Figure 7 shows XRD data of metal phosphide hybrids manufactured by subjecting the layered metal double-layer hydroxide nanosheet of Example 3-1 to a phosphide reaction at 250°C, 300°C, and 350°C.

[0034] Figure 8 is a STEM image of the layered metal double-layer hydroxide nanosheet of Example 3-1 and the metal phosphide hybrid of Example 3-2 prepared therefrom.

[0035] Figure 9 is STEM element mapping data of the metal phosphide hybrid nanosheet of Example 3-2.

[0036] Figure 10 is STEM data after FIB treatment of the metal phosphide hybrid nanosheet of Example 3-2.

[0037] Figure 11 shows XPS data of the layered metal double-layer hydroxide nanosheet of Example 3-1 and the metal phosphide hybrid nanosheet of Example 3-2.

[0038] Figure 12 is a graph measuring the electrochemical performance of the metal phosphide hybrid nanosheet catalysts of Examples 1-2 to 4-2.

[0039] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. The present invention may be modified in various ways and may take various forms. Therefore, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, but should be understood to include all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention. In describing each drawing, similar reference numerals are used to indicate similar components. In the attached drawings, the dimensions of structures are shown larger than actual size to ensure clarity of the present invention.

[0040] While terms like "first" and "second" may be used to describe various components, these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, a first component could be referred to as a "second component," and similarly, a second component could also be referred to as a "first component."

[0041] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" indicate the presence of a feature, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, steps, operations, components, parts, or combinations thereof.

[0042] 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 shall not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0043]

[0044] <Method for producing a layered metal phosphide hybrid catalyst and a layered metal phosphide hybrid catalyst produced thereby>

[0045] FIG. 1 is a flowchart illustrating a method for manufacturing a layered metal phosphide hybrid catalyst according to an embodiment of the present invention.

[0046] Referring to FIG. 1, a method for producing a layered metal phosphide hybrid catalyst according to an embodiment of the present invention may include a first step (S110) of producing a layered metal bilayer hydroxide nanosheet structure represented by the following chemical formula 1; and a second step (S120) of heat-treating the metal bilayer hydroxide nanosheet structure and a phosphorus (P)-containing precursor material in a reducing atmosphere to convert the layered metal bilayer hydroxide nanosheet structure into a layered metal phosphide hybrid nanosheet structure.

[0047] [Chemical Formula 1]

[0048] [M 1 2M 2 1-x Ru x (OH)2][A n- ] x / n· mH2O

[0049] In the above chemical formula 1, M 1 is a first transition metal cation with an oxidation state of +2, and M 2 is a second transition metal cation having an oxidation state of +3, and A may be an interlayer anion having an oxidation state of -n. In addition, x is a positive real number satisfying the condition of "0 < x <1", n is an integer greater than or equal to 1 and less than or equal to 5, and m may be a positive real number.

[0050] In the above first step (S110), the layered metal double-layer hydroxide nanosheet structure can be manufactured through a co-precipitation synthesis method.

[0051] In one embodiment, the first step (S110) comprises adding M to an aqueous solvent. 1 Contains first metal salt, M 2A step of preparing a mixed solution by dissolving a second metal salt and a ruthenium (Ru) salt; a step of adding the mixed solution and an alkaline aqueous solution to an aqueous solution containing an interlayer anion and stirring under an inert gas atmosphere, thereby preparing a layered metal double-layer hydroxide nanosheet structure represented by the chemical formula 1; may be included.

[0052] In one embodiment, the first transition metal cation is Ca 2+ , Mg 2+ , Zn 2+ , Ni 2+ , Mn 2+ , Co 2+ , Fe 2+ , Cu 2+ It may include at least one selected from the group consisting of Fe, and the second transition metal cation is Fe 3+ , Al 3+ , Cr 3+ , Mn 3+ , Ga 3+ , Co 3+ , Ni 3+ It may include one or more selected from the group consisting of:

[0053] In one embodiment, the first metal salt may include a first nitride containing the first transition metal cation described above, the second metal salt may include a second nitride containing the second transition metal cation described above, and the ruthenium salt may include a chloride containing a ruthenium ion. For example, when the layered metal bilayer hydroxide nanosheet structure includes Ni-Fe:Ru LDH, the first metal salt may include Ni(NO3). 2· 6H2O may be included, and the second metal salt is Fe(NO3) 3· 9H2O may be included, and the ruthenium salt is RuCl 3· It may contain xH2O.

[0054] In one embodiment, the molar ratio of the ruthenium salt to the total number of moles of the ruthenium salt and the second metal salt may be about 20% or more and 40% or less. For example, the molar ratio of the ruthenium salt to the total number of moles of the ruthenium salt and the second metal salt may be about 25% or more and 35% or less, or about 27% or more and 33% or less.

[0055] In one embodiment, water may be used as the aqueous solvent of the mixed solution. For example, decarbonated distilled water may be used as the aqueous solvent. Here, decarbonated distilled water refers to distilled water obtained by boiling tertiary distilled water in a nitrogen atmosphere and then cooling it, and carbonate ions (CO3) present in general distilled water - ) is removed, so when using it, the interlayer anion NO3 is removed during the process of synthesizing LDH. - can be adjusted.

[0056] In one embodiment, the interlayer anion is OH - , NO3 - , PO4 3- , HPO4 2- , H2PO4 - It may include one or more selected from the group consisting of etc. In one embodiment, the aqueous solution containing the interlayer anion may include an aqueous solution of NaNO3. And the aqueous alkaline solution may include an aqueous solution of about 1 to 3 M of NaOH. Meanwhile, the inert gas atmosphere may be a nitrogen atmosphere.

[0057] In one embodiment, in order to manufacture the layered metal double layer hydroxide nanosheet structure, a step of adding the mixed solution and the alkaline aqueous solution one drop at a time to an aqueous solution containing the interlayer anion to manufacture a reaction solution, and adjusting the pH of the reaction solution to 8.5 to 9.5; stirring the reaction solution in an inert gas atmosphere, thereby producing the M 1 Ion, M 2A step of forming a reactant by reacting ions, Ru ions, and interlayer anions; and a step of freeze-drying the reactant to obtain a layered metal double-layer hydroxide nanosheet structure represented by the chemical formula 1; can be performed. In this case, the M 1 Ion, M 2 ions, Ru ions and interlayer anions react to form the above reactants, so carbonate ions (CO3 2- ) can be removed.

[0058] Through the manufacturing method of the present invention, a layered metal double-layer hydroxide nanosheet structure having nanosheets having a size of about 20 to 600 nm can be manufactured.

[0059] In the second step (S120), the phosphorus (P)-containing precursor is not particularly limited as long as it is a substance capable of phosphizing the metal contained in the metal double-layer hydroxide nanosheet structure. For example, the phosphorus (P)-containing precursor is sodium hypophosphate (NaH2PO). 2· xH2O) may be included.

[0060] In one embodiment, in order to convert the layered metal bilayer hydroxide nanosheet structure into a layered metal phosphide hybrid nanosheet structure, the layered metal bilayer hydroxide nanosheet structure and the phosphorus (P)-containing precursor may be placed in a heat treatment vessel and then heat treatment may be performed while injecting a reducing gas.

[0061] In one embodiment, a mixed gas of hydrogen and argon may be used as the reducing gas, and the heat treatment may be performed at a temperature of about 250 to 350°C for about 2 to 4 hours.

[0062] In one embodiment, for the heat treatment, the layered metal double-layer hydroxide nanosheet structure and the phosphorus (P)-containing precursor may be placed in the heat treatment vessel at a weight ratio of about 1:5 to 1:20.

[0063] In one embodiment, during the heat treatment, the metal hydroxide (M) of the layered metal bilayer hydroxide nanosheet structure 1 2M 2 1-x Ru x (OH)2) is dehydrated and converted to oxide, and then the first and second transition metals (M 1 , M 2 ) can be phosphidated to form a metal phosphide, and the ruthenium (Ru) can be eluted in a single-atom state on the surface of the nanosheet made of the metal phosphide.

[0064] In one embodiment, the metal phosphide is M 1 a P (a is a real number greater than or equal to 1 and less than or equal to 3), M 2 b P (b is a real number greater than or equal to 1 and less than or equal to 3), M 1 m M 2 n It may include one or more selected from P (m, n are each independently real numbers greater than or equal to 1 and less than or equal to 3).

[0065] In one embodiment, during the heat treatment, most of the ruthenium (Ru) contained in the layered metal double-layer hydroxide nanosheet structure, for example, about 90 atomic% or more, about 95 atomic% or more, or about 98 atomic% or more, can be eluted onto the surface of the nanosheet converted to the metal phosphide, and the eluted ruthenium (Ru) can be dispersed and arranged in a monatomic state.

[0066] A layered metal phosphide hybrid catalyst according to an embodiment of the present invention may include nanosheets formed of metal phosphide; and monoatomic ruthenium dispersed on the surface of the nanosheets.

[0067] In one embodiment, the layered metal phosphide hybrid catalyst can be manufactured according to the above manufacturing method.

[0068] In one embodiment, the metal phosphide may include at least one selected from a phosphide of the first transition metal, a phosphide of the second transition metal, and a phosphide comprising the first and second transition metals. In one embodiment, when the first transition metal is nickel (Ni) and the second transition metal is iron (Fe), the metal phosphide may include at least one selected from a nickel phosphide, an iron phosphide, and a nickel-iron phosphide, for example, a nickel phosphide and an iron phosphide.

[0069] In one embodiment, the mole ratio of the ruthenium salt to the total moles of the ruthenium and the second transition metal may be about 20% or more and 40% or less, about 25% or more and 35% or less, or about 27% or more and 33% or less.

[0070] In one embodiment, the nanosheets may have a size of about 20 to 600 nm.

[0071] According to the layered metal phosphide hybrid catalyst of the present invention, since ruthenium is dispersed in a monoatomic state on a metal phosphide nanosheet having a high specific surface area and electronic conductivity, it can have high electrochemical catalytic activity for a hydrogen production reaction.

[0072]

[0073] <Water electrolysis device>

[0074] Figure 2 is a drawing for explaining a water electrolysis device according to an embodiment of the present invention.

[0075] Referring to FIG. 2, a water electrolysis device (100) according to an embodiment of the present invention may include an ion exchange membrane (110), a first electrode (120), and a second electrode (130).

[0076] The ion exchange membrane (110) may be any ion exchange membrane applicable to a known water electrolysis device without limitation. For example, the ion exchange membrane (110) may include a cation exchange membrane or an anion exchange membrane.

[0077] The first electrode (120) and the second electrode (130) may be arranged to face each other with the ion exchange membrane (110) interposed therebetween.

[0078] A hydrogen evolution reaction (HER) can occur at the first electrode (120), and an oxygen evolution reaction (OER) can occur at the second electrode (130).

[0079] The first electrode (120) may include a first catalyst layer (121) disposed adjacent to the ion exchange membrane (110) and a first gas diffusion layer (122) disposed on the outside of the first catalyst layer (121).

[0080] In one embodiment, the first catalyst layer (121) may include a layered metal phosphide hybrid catalyst according to the embodiment of the present invention described above, and the first gas diffusion layer (122) may be a gas diffusion layer applied to a known water electrolysis device, without limitation.

[0081] The second electrode layer (130) may include a second catalyst layer (131) disposed to face the first catalyst layer (121) with the ion exchange membrane (110) interposed therebetween, and a second gas diffusion layer (132) disposed on the outer side of the second catalyst layer (131). As the second catalyst layer (131) and the second gas diffusion layer (132), a catalyst layer and a gas diffusion layer applied to an oxygen generation electrode of a known water electrolysis device may be applied without limitation.

[0082]

[0083] Hereinafter, specific embodiments of the present invention will be described in detail. However, the following examples are merely some embodiments of the present invention, and the scope of the present invention is not limited to the following examples.

[0084]

[0085] [Examples 1 to 4]

[0086] Preparation of Ni-Fe-LDH

[0087] A precursor solution of 40 mL of Ni(NO3)2·6H2O, Fe(NO3)3·9H2O, and RuCl3·xH2O mixed in the ratios shown in Table 1 and a 1 M NaOH solution of 50 mL were prepared. Next, a reaction solution in which NaNO3 (13.2 mmol) was dissolved in a mixture of 70 mL of distilled water and 30 mL of formamide solution was placed in a round flask and placed in silicone oil at 80°C. Next, the NaOH aqueous solution and the precursor aqueous solution were added dropwise to the reaction solution and mixed, and then stirred while adjusting the pH to 8 to form a solid reactant. Subsequently, a solid reactant was obtained through centrifugation, and the obtained solid reactant was washed with an excess of distilled water and then freeze-dried to prepare Ni-Fe-LDH.

[0088] Decarbonate water was used as a solvent throughout the entire Ni-Fe-LDH synthesis process.

[0089] Ni(NO3)2·6H2O[mmol]Fe(NO3)3·9H2O[mmol]RuCl3·xH2O[mmol]Example 1-1(Ni2Fe-LDH)6.63.30Example 2-1(Ni2Fe 0.8 Ru 0.2 -LDH)6.62.640.66Example 3-1(Ni2Fe 0.7 Ru 0.3 -LDH)6.62.310.99Example 4-1(Ni2Fe 0.6 Ru 0.4 -LDH)6.61.981.32

[0090]

[0091] Manufacturing of metal-phosphide hybrids

[0092] The layered metal hydroxide prepared above and the precursor material of phosphorus (P), NaH2PO2·xH2O, were placed in an alumina boat at a distance from each other. At this time, the weight ratio of the layered metal hydroxide and the NaH2PO2·xH2O was set to 1:10. Subsequently, heat treatment was performed at 250°C for 3 hours while flowing a hydrogen / argon (H2 / Ar=5 / 95) mixed gas. At this time, the heating rate was set to 2°C per minute.

[0093] After the ignition reaction was completed, the mixture was cooled to room temperature to obtain a metal phosphide hybrid. Hereinafter, the obtained metal phosphides are named RNFP0-250 (Example 1-2), RNFP2-250 (Example 2-2), RNFP3-250 (Example 3-2), and RNFP4-250 (Example 4-2), respectively, according to the Ru ratio.

[0094]

[0095] [Experimental Example 1]

[0096] Figure 3 is XRD data of layered metal double layer hydroxide nanosheets of Examples 1-1 to 4-1.

[0097] Referring to FIG. 3, the layered metal double-layer hydroxide nanosheets of Examples 1-1 to 4-1 were synthesized with different molar ratios of Fe:Ru, but the Ni2Fe-LDH form was maintained. However, as the molar ratio of Ru increased, the size of the peaks decreased, and from this, it can be inferred that Ru was well substituted within the lattice.

[0098]

[0099] Figure 4 is FE-SEM element mapping data of the layered metal double layer hydroxide nanosheet of Example 3-1.

[0100] Referring to Figure 4, each of the elements Ni, Fe, O, and Ru is a layered metal double layer hydroxide nanosheet (Ni2Fe) of Example 3-1. 0.7 Ru 0.3-LDH) was found to be uniformly distributed, and from this it can be seen that Ru was well substituted within the lattice.

[0101]

[0102] Figure 5 is XRD data of metal phosphide hybrid nanosheets according to Examples 1-2 to 4-2.

[0103] Referring to Figure 5, the formation of a Ni2P phase was confirmed as a result of the ignition reaction at 250°C for LDH synthesized with different Fe:Ru molar ratios, while no phosphide iron phase was observed. This is because iron ions enter the Ni2P lattice to form a solid solution. In addition, no peak of the Ru metal phase was observed, confirming that Ru does not exist in a metallic phase.

[0104]

[0105] Figure 6 is an FE-SEM image of metal phosphide hybrid nanosheets according to Examples 1-2 to 4-2.

[0106] Referring to Figure 6, it was found that even when NiFeRu-LDH was subjected to a ignition reaction, the nanosheet structure of several tens of nm in size was well maintained.

[0107]

[0108] Figure 7 shows XRD data of metal phosphide hybrids manufactured by subjecting the layered metal double-layer hydroxide nanosheet of Example 3-1 to a phosphide reaction at 250°C, 300°C, and 350°C.

[0109] Referring to Figure 7, when the layered metal double-layer hydroxide nanosheet was subjected to a ignition reaction at 250°C, only the Ni2P phase appeared, but when the ignition reaction was performed at higher temperatures of 300°C and 350°C, it was confirmed that various phases, such as Ni5P4, NiP, and Fe2P, appeared mixed together with the Ni2P phase.

[0110]

[0111] Figure 8 is a STEM image of the layered metal double-layer hydroxide nanosheet of Example 3-1 and the metal phosphide hybrid of Example 3-2 prepared therefrom.

[0112] Referring to Fig. 8, Ru is a heavier material than Ni, Fe, and P, and has a darker color than the surroundings when observed with STEM. In the layered metal double-layer hydroxide nanosheet of Example 3-1, a part with a darker color than the surroundings was not specifically observed because Ru existed within the lattice, but in the metal phosphide hybrid of Example 3-2, a part of Ru with a darker color was observed. Meanwhile, in light of the fact that no Ru metal peak was found in Fig. 5, it is judged that the part of Ru with a darker color corresponds to Ru eluted to the surface of the metal phosphide nanosheet in a monatomic state during the phosphizing reaction.

[0113]

[0114] Figure 9 is STEM element mapping data of the metal phosphide hybrid nanosheet of Example 3-2.

[0115] Referring to Figure 9, it can be seen that Ni, Fe, P, and Ru are evenly distributed in the metal phosphide hybrid nanosheet (RNFP3-250), and from this, it can be seen that the single-atom Ru is uniformly and well fixed to the metal phosphide nanosheet.

[0116]

[0117] Figure 10 is STEM data after FIB treatment of the metal phosphide hybrid nanosheet of Example 3-2.

[0118] Referring to Figure 10, it can be confirmed that all Ru present in a substituted state within the lattice in LDH is eluted after the ignition reaction and does not remain within the metal ignition lattice.

[0119]

[0120] Figure 11 shows XPS data of Example 3-1 and the layered metal double layer hydroxide nanosheet and the metal phosphide hybrid nanosheet of Example 3-2.

[0121] Referring to Figure 11, it was found that Ni and Fe formed bonds with P after the ignition reaction of LDH at 250°C, and from this, it can be seen that not only Ni-P phosphide but also Fe-P phosphide can be produced by the ignition reaction.

[0122]

[0123] Table 2 shows the ICP-OES results of the metal phosphide hybrid nanosheet of Example 3-2.

[0124] MaterialNi (%)Fe (%)Ru (%)RNFP3-25067.9423.998.07

[0125] Referring to Table 2, it was found that the mixing ratio of Ni, Fe, and Ru in the precursor solution for LDH synthesis was maintained in the metal phosphide (RNFP3-250) after the phosphide reaction, and from this, it can be seen that the amount of Ru eluted into the metal phosphide hybrid nanosheet can be controlled by controlling the ratio of Ru mixed in the precursor solution for LDH synthesis.

[0126]

[0127] [Experimental Example 2]

[0128] 7 mg of the synthesized metal-phosphide hybrid nanosheets and 3 mg of conductive carbon (Vulcan-XC72R) were added to a mixed solution of 4 mL of distilled water and 1 mL of isopropanol, and 40 μL of a 5 wt% Nafion solution was added and dispersed by ultrasonication. 10 μL of the dispersed solution was applied to a Glassy Carbon (GC) Rotating Disk Electrode (RDE) electrode (Company: ALS) to prepare a working electrode, which was then mounted on an RRDE-3A Rotating Ring Disk Electrode Apparatus (Company: ALS) to test its catalytic activity for the hydrogen evolution reaction. At this time, a SCE electrode was used as the reference electrode, a Pt wire was used as the counter electrode, and the measurement was performed at a scan rate of 5 mV / s in a 0.5 M H2SO4 solution.

[0129]

[0130] Figure 12 is a graph measuring the electrochemical performance of the metal phosphide hybrid nanosheet catalysts of Examples 1-2 to 4-2.

[0131] Referring to Fig. 12, (a) the hydrogen evolution reaction activity data and (b) the overvoltage data, the measurement results show that the RNFP3-250 material has a higher current value and a lower overvoltage than the RNFP0-250, RNFP2-250, and RNFP4-250 materials, and from this, it can be seen that the hydrogen evolution reaction catalytic performance is improved by the optimized Fe:Ru ratio and the induction reaction temperature conditions. Specifically, when the molar ratio of Ru to the total molar number of Fe and Ru is about 25 to 35% and the induction reaction in a reducing gas atmosphere is performed at about 250 to 350°C, a metal phosphide hybrid nanosheet catalyst with improved hydrogen evolution reaction catalytic performance can be manufactured.

[0132]

[0133] Although the present invention has been described above with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

Claims

1. A first step of manufacturing a layered metal double-layer hydroxide nanosheet structure represented by the following chemical formula 1; and A method for producing a layered metal phosphide hybrid catalyst, comprising: a second step of converting the layered metal double-layer hydroxide nanosheet structure into a layered metal phosphide hybrid nanosheet structure by heat-treating the metal double-layer hydroxide nanosheet structure and a phosphorus (P)-containing precursor material in a reducing atmosphere; [Chemical Formula 1] [M 1 2M 2 1-x Ru x (OH)2][A n- ] x / n· mH2O In the above chemical formula 1, M 1 is a first transition metal cation with an oxidation state of +2, and M 2 is a second transition metal cation having an oxidation state of +3, A is an interlayer anion having an oxidation state of -n, x is a real number greater than 0 and less than 1, n is an integer greater than or equal to 1 and less than or equal to 5, and m is a positive real number.

2. In paragraph 1, The first transition metal cation is Ca 2+ , Mg 2+ , Zn 2+ , Ni 2+ , Mn 2+ , Co 2+ , Fe 2+ and Cu 2+ Contains at least one selected from the group consisting of, The second transition metal cation is Fe 3+ , Al 3+ , Cr 3+ , Mn 3+ , Ga 3+ , Co 3+ and Ni 3+ Contains one or more selected from the group consisting of: The above interlayer anion is OH - , NO3 - , PO4 3- , HPO4 2- and H2PO4 - A method for producing a layered metal phosphide hybrid catalyst, characterized in that it comprises at least one selected from the group consisting of:

3. In paragraph 1, The above first step is, M in aqueous solvent 1 Contains first metal salt, M 2 A step of preparing a mixed solution by dissolving a second metal salt and a ruthenium (Ru) salt; and A method for producing a layered metal phosphide hybrid catalyst, characterized by comprising the step of adding the mixed solution and an alkaline aqueous solution to an aqueous solution containing the interlayer anion and stirring in an inert gas atmosphere to produce the layered metal double-layer hydroxide nanosheet structure.

4. In paragraph 3, A method for producing a layered metal phosphide hybrid catalyst, characterized in that the second step comprises a step of placing the layered metal double-layer hydroxide nanosheet structure and the phosphorus (P)-containing precursor in a heat treatment vessel and then performing a heat treatment while injecting a reducing gas.

5. In paragraph 4, A method for producing a layered metal phosphide hybrid catalyst, characterized in that in the above chemical formula 1, x is 0.2 or more and 0.4 or less.

6. In paragraph 4, A method for producing a layered metal phosphide hybrid catalyst, characterized in that the phosphorus (P)-containing precursor comprises sodium hypophosphate (NaH2PO2·xH2O).

7. In paragraph 4, A method for producing a layered metal phosphide hybrid catalyst, characterized in that the above heat treatment is performed at a temperature of about 250 to 350°C.

8. In paragraph 7, The above layered metal phosphide hybrid nanosheet structure is M 1 a P, M 2 b P and M 1 m M 2 n A method for producing a layered metal phosphide hybrid catalyst, characterized in that it comprises a nanosheet formed of one or more phosphides selected from the group consisting of P.

9. Nanosheets formed from metal phosphides; and A layered metal phosphide hybrid catalyst comprising ruthenium dispersed in a monoatomic state on the surface of the nanosheet.

10. In paragraph 9, A layered metal phosphide hybrid catalyst, characterized in that the layered metal phosphide hybrid catalyst is manufactured according to any one of claims 1 to 8.

11. In paragraph 9, The metal phosphide comprises at least one selected from a phosphide of the first transition metal, a phosphide of the second transition metal, and a phosphide comprising the first and second transition metals, The first transition metal includes at least one selected from the group consisting of Ca, Mg, Zn, Ni, Mn, Co, Fe, and Cu, A layered metal phosphide hybrid catalyst, characterized in that the second transition metal comprises at least one selected from the group consisting of Fe, Al, Cr, Mn, Ga, Co, and Ni.

12. In paragraph 11, A layered metal phosphide hybrid catalyst, characterized in that the mole ratio of the ruthenium salt to the total moles of the ruthenium and the second transition metal is 20% or more and 40% or less.

13. In paragraph 11, A layered metal phosphide hybrid catalyst, characterized in that the nanosheets have a size of 20 to 600 nm.

14. In a water electrolysis device including an ion exchange membrane and a first electrode and a second electrode facing each other with the ion exchange membrane in between, A water electrolysis device, characterized in that the first electrode where the hydrogen evolution reaction (HER) occurs comprises a layered metal phosphide hybrid catalyst selected from any one of claims 9 to 13.

15. In paragraph 14, The first electrode includes a first catalyst layer disposed adjacent to the ion exchange membrane and a first gas diffusion layer disposed on the outside of the first catalyst layer, A water electrolysis device, characterized in that the first catalyst layer comprises the layered metal phosphide hybrid catalyst.

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