Chiral metal oxide-based water electrolysis electrode, method for manufacturing same, and water electrolysis device comprising same

Abstract

Provided are a chiral metal oxide-based water electrolysis electrode, a method for manufacturing same, and a water electrolysis device comprising same. The chiral metal oxide-based water electrolysis electrode includes an L-type or D-type chiral metal oxide disposed on a substrate, and the chiral metal oxide may have chirality-induced spin selectivity. Therefore, when the chiral metal oxide-based water electrolysis electrode is used in a water electrolysis electrode and a water electrolysis device including same, spin polarization can be controlled without an additional external magnetic field, and the efficiency of the electrode and the device can be improved.

Description

Chiral metal oxide-based water electrolysis electrode, method for manufacturing the same, and water electrolysis device including the same

[0001] The present invention relates to a water electrolysis electrode, and more specifically, to a chiral metal oxide-based water electrolysis electrode, a method for manufacturing the same, and a water electrolysis device including the same.

[0002] As hydrogen gains prominence as an alternative energy source to address environmental issues such as global warming, the demand for green hydrogen technology is rapidly increasing. Currently, one technology available for practical application is the production of green hydrogen using water electrolysis. Metal oxide-based electrodes are being developed as catalysts for use in this water electrolysis method.

[0003] Metal oxides are very stable even under extreme conditions such as high temperature, strong acids, and strong bases, and in particular, oxygen vacancies in metal oxides can improve the electrical conductivity of the material and facilitate the adsorption and conversion of water, thereby exhibiting high efficiency in oxygen and hydrogen production.

[0004] However, due to the characteristics of oxygen having a triplet state spin structure, when randomly arranged hydroxyl radicals are generated during the water electrolysis reaction, hydrogen peroxide is produced as a reaction byproduct along with oxygen and hydrogen, which leads to a problem of reduced selectivity for the material and decreased water electrolysis efficiency.

[0005] Chiral molecules (or chiral structures) can control spin without an external magnetic field due to the phenomenon where spins in one direction selectively pass through when electrons pass, caused by the interaction between the charge and the chiral molecule.

[0006] Accordingly, the present invention aims to provide a chiral metal oxide-based water electrolysis electrode that can suppress the generation of hydrogen peroxide, a reaction byproduct of the water electrolysis electrode, and improve the efficiency of the electrode by utilizing chirality, a method for manufacturing the same, and a water electrolysis device including the same.

[0007] In addition, the present invention aims to provide a chiral metal oxide-based water electrolysis electrode capable of effectively controlling electrode thickness, a method for manufacturing the same, and a water electrolysis device including the same.

[0008] The technical problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below.

[0009] To achieve the above objective, one aspect of the present invention provides a chiral metal oxide-based water electrolysis electrode disposed on a substrate and comprising an L-type or D-type chiral metal oxide, wherein the chiral metal oxide is represented by the following chemical formula 1.

[0010] [Chemical Formula 1]

[0011] M 1 M 2 O x

[0012] In the above chemical formula 1, the M 1 and the above M 2 is composed of two different metallic elements, and the above M 1 is any one selected from Co, Ni, and Mn, and said M 2 is the above M 1 It is a metal atom having an atomic radius that is greater than 0% and less than 15% of the difference from the atomic radius of, and x is an integer from 1 to 10.

[0013] The above M 2It may be any one metal atom selected from Co, Mn, Ni, Li, Mg, Al, Sc, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, As, Se, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Sn, Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Bi, Po, At, U, Np, and Pu.

[0014] The above chiral metal oxide is CoMnO x , CoNiO x , NiCoO x , and NiMnO x It may include any one selected from among them.

[0015] The above chiral metal oxide is Co 1-y Mn y It is Ox, and the above y can be 0.01 to 0.8.

[0016] The above electrode can exhibit circular dichroism at 200 nm to 1000 nm.

[0017] The above electrode may further include a single-atom catalyst deposited on the chiral metal oxide.

[0018] The above-mentioned single-atom catalyst may include one or more selected from ruthenium (Ru), iridium (Ir), platinum (Pt), silver (Ag), copper (Cu), and iron (Fe).

[0019] The above chiral metal oxide is Ir-Co 1-y Mn y O x And, the above y may be 0.1 to 0.15.

[0020] Another aspect of the present invention provides a method for manufacturing a chiral metal oxide-based water electrolysis electrode comprising the steps of mixing a metal oxide precursor, a chiral organic material, and an alkalizing agent to form a mixed solution, and electrodepositing the mixed solution onto a substrate to form an L-type or D-type chiral metal oxide, wherein the chiral metal oxide is represented by the following chemical formula 1.

[0021] [Chemical Formula 1]

[0022] M 1 M 2 O x

[0023] In the above chemical formula 1, the M 1 and the above M 2 is composed of two different metallic elements, and the above M 1 is any one selected from Co, Ni, and Mn, and said M 2 is the above M 1 It is a metal atom having an atomic radius that is greater than 0% and less than 15% of the difference from the atomic radius of, and x is an integer from 1 to 10.

[0024] The above M 2 It may be any one metal atom selected from Co, Mn, Ni, Li, Mg, Al, Sc, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, As, Se, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Sn, Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Bi, Po, At, U, Np, and Pu.

[0025] The above chiral metal oxide may be one in which the chiral organic material transfers chiral properties to the metal oxide to exhibit chirality.

[0026] The above electrodeposition may be anodic electrodeposition.

[0027] The above metal oxide precursor may include at least two of cobalt (Co), nickel (Ni), and manganese (Mn).

[0028] The above chiral metal oxide is Co 1-y Mn y O x And, the above y can be 0.01 to 0.8.

[0029] The chiral organic material may be L-type tartaric acid or D-type tartaric acid.

[0030] The above alkalizing agents are sodium carbonate (Na2CO3), potassium carbonate (K2CO3), sodium bicarbonate (NaHCO3), and sodium phosphate (Na5P3O2). 10 It may include one or more selected from sodium pyrophosphate (Na4P2O7), disodium phosphate (K2HPO4), disodium phosphate (Na2HPO4), sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), trisodium citrate (C6Na3H5O7) and sodium metaphosphate (NaPO3)6).

[0031] After the step of forming the L-type or D-type chiral metal oxide, the method may further include the step of electrodepositing a monatomic catalyst on the chiral metal oxide.

[0032] The above-mentioned single-atom catalyst may include one or more selected from ruthenium (Ru), iridium (Ir), platinum (Pt), silver (Ag), copper (Cu), and iron (Fe).

[0033] Another aspect of the present invention provides a water electrolysis device comprising the water electrolysis electrode described above.

[0034] The chiral metal oxide-based water electrolysis electrode and the water electrolysis device including the same according to the present invention can control the direction of spins passing through according to the spin direction by forming an ionic complex by adding a chiral organic material to an ionic electrolyte in which a metal is dissolved and depositing it on a substrate by an electrolysis method to form a metal oxide having a chiral structure.

[0035] By controlling the direction of such spins, the water electrolysis efficiency of the water electrolysis electrode and the device including it can be increased, and the generation of hydrogen peroxide during the water electrolysis reaction can be suppressed, thereby enabling the production of high-purity gas.

[0036] In addition, the method for manufacturing a chiral metal oxide-based water electrolysis electrode of the present invention forms a metal oxide using an electrode deposition method, thereby enabling uniform deposition regardless of the electrode size and allowing for easy control of the electrode thickness, which can be achieved by making it possible to manufacture large-area electrodes.

[0037] In addition, the characteristics of the manufactured chiral metal oxide-based water electrolysis electrode can be formed more uniformly.

[0038] The technical effects of the present invention are not limited to those mentioned above, and other unmentioned technical effects will be clearly understood by those skilled in the art from the description below.

[0039] FIG. 1 is a flowchart illustrating a method for manufacturing a chiral metal oxide-based water electrolysis electrode according to one embodiment of the present invention.

[0040] FIGS. 2(a) and FIGS. 2(b) show the L- / D-CoO of Preparation Example 1-1 of the present invention. x and L- / D-MnO of Preparation Example 1-11 x This is an image of a metal oxide thin film on an electrode.

[0041] FIG. 3 shows the L-Co of Preparation Examples 1-2 to 1-10 of the present invention. 1-y Mn y O x (y = 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.4, 0.6, and 0.8) This is an image showing the metal oxide thin film of the electrode.

[0042] FIGS. 4(a) to 4(c) are images showing the analysis results of the contact angles of the electrodes of Preparation Example 1-1 (Co 100%), Preparation Example 1-4 (Co 90% + Mn 10%), and Preparation Example 1-11 (Mn 100%) of the present invention.

[0043] Figure 5 is an image showing the thin film shapes of the electrodes of Preparation Examples 1-1 to 1-11 of the present invention and the control group (nickel foam) observed using a scanning electron microscope (SEM).

[0044] FIG. 6(a) is a graph showing the analysis of the electrodes of Preparation Examples 1-1 to 1-11 of the present invention using linear sweep voltammetry (LSV), and FIG. 6(b) is a graph showing the correlation between the contact angle and the overpotential required for the oxygen evolution reaction (OER) according to the ratio of manganese dopant (Mn dopant) of the electrodes of Preparation Examples 1-1 to 1-11 of the present invention.

[0045] FIGS. 7(a) to 7(c) show the L- / D-CoO of Preparation Example 1-1 of the present invention. x Electrode, L- / D-Co of Preparation Example 1-4 0.9 Mn 0.1 O x Electrode and L- / D-MnO of Preparation Example 11 x This is a graph showing the ultraviolet-visible (UV-Vis) spectrophotometric measurement data of the electrode.

[0046] FIG. 8 is Preparation Example 1-1 of the present invention (L- / D-CoO x ) Electrode and Preparation Example 1-4 (L- / D-Co 0.9 Mn 0.1 O x This is a graph comparing the g-factors of the electrodes.

[0047] FIG. 9 is a graph showing the ratio of cobalt ions to manganese ions according to the manganese doping content of the electrodes of Preparation Example 1-3 (Mn 5), Preparation Example 1-4 (Mn 10), Preparation Example 1-5 (Mn 15), Preparation Example 1-6 (Mn 20), and Preparation Example 1-7 (Mn 25) of the present invention.

[0048] FIG. 10(a) is a schematic diagram of a measurement method using a magnetic conductive probe atomic force microscopy (mCP-AFM) according to an embodiment of the present invention, and FIG. 10(b) and FIG. 10(c) are of the L- / D-CoO of Preparation Example 1-1 of the present invention. x and L- / D-Co of Preparation Examples 1-4 0.9 Mn 0.1 O x This is a graph showing the chiral-induced spin selectivity of the electrode.

[0049] FIGS. 11(a) and FIGS. 11(b) show the L- / D-CoO of Preparation Example 1-12 of the present invention. x Electrode, Meso-CoO of Comparative Examples 1-3 x Electrode, L- / D-Co of Preparation Example 1-13 0.9 Mn 0.1 O x Electrode and Meso-Co of Comparative Examples 1-4 0.9 Mn 0.1 O x This is a graph showing the results of analyzing the extent of hydrogen peroxide generation via UV-Vis depending on the presence or absence of spin after the oxygen evolution reaction (OER) at the electrode.

[0050] FIGS. 12(a) to 12(c) show the electrodes (L-NiO) of Preparation Examples 1-14 to 1-20 of the present invention. x , L-Ni 0.9 Mn 0.1 O x , L-Ni 0.8 Mn 0.2 O x , L-Ni 0.9 Co 0.1 O x , L-Ni 0.8 Co 0.2 O x , L-Co 0.9 Ni 0.1 O x , L-Co 0.8 Ni 0.2 O x This is a graph showing the result of analyzing ) using linear scanning potential (LSV).

[0051] FIG. 13 is the L-IrO of Preparation Example 1-21 of the present invention. x and D-IrO x This is an image showing the metal oxide thin film of the electrode.

[0052] FIG. 14(a) is an image showing nickel foam according to one embodiment of the present invention, FIG. 14(b) is L-IrO of Preparation Example 1-22 of the present invention x and D-IrO x This is an image showing the electrode.

[0053] FIG. 15 is the L-IrO of Preparation Example 1-22 of the present invention. x and D-IrO x This is a graph showing the results of analyzing the electrode and control group (nickel foam) using linear scanning potentiometry (LSV).

[0054] Figure 16 is a graph showing the electrode of Manufacturing Example 2-1 of the present invention analyzed by linear scanning potential (LSV).

[0055] FIG. 17(a) shows the thin film shape of Preparation Example 2-7 of the present invention, and FIG. 17(b) is a graph showing the electrodes of Preparation Example 1-4, Preparation Example 1-5, Preparation Example 2-7, Preparation Example 2-8, and the control group (nickel foam) of the present invention analyzed by linear scanning potential (LSV).

[0056] Hereinafter, embodiments according to the present invention will be described in detail with reference to the attached drawings.

[0057] While the present invention allows for various modifications and variations, specific embodiments are illustrated in the drawings and will be described in detail below. However, it is not intended to limit the invention to the particular forms disclosed, but rather the invention includes all modifications, equivalents, and substitutions consistent with the spirit of the invention as defined by the claims.

[0058] When an element such as a layer, region, or substrate is referred to as existing "on" another component, it can be understood that this exists directly on the other element, or that an intermediate element may exist between them.

[0059] Although terms such as first, second, etc., may be used to describe various elements, components, regions, layers, and / or regions, it will be understood that these elements, components, regions, layers, and / or regions should not be limited by these terms.

[0060]

[0061] Chiral metal oxide-based water electrolysis electrode

[0062] One aspect of the present invention may provide a water electrolysis electrode based on a chiral metal oxide. The water electrolysis electrode may comprise a substrate and an L-type or D-type chiral metal oxide disposed on the substrate.

[0063] The above L-type or D-type chiral metal oxide may be formed directly on the substrate and may not be accompanied by a separate conductive additive or binder. The above L-type or D-type chiral metal oxide may be disposed on the surface of the substrate and / or on the surface of the internal structure of the substrate.

[0064] The above substrate may be made of various materials applicable as a substrate for a water electrolysis electrode. Specifically, for example, the substrate may be made of indium tin oxide (ITO), nickel (Ni), titanium (Ti), copper (Cu), gold (Au), or stainless steel (SUS), but is not limited thereto. In one embodiment, the substrate may be a foam-type current collector having a porous structure with a large specific surface area and an easy mass transfer pathway for reactants and products. In this embodiment, indium tin oxide (ITO) and nickel foam (Ni foam) were used as the substrate.

[0065] The above L-type or D-type chiral metal oxide may include chiral metal oxide nanoparticles (NP). According to an embodiment, the above L-type or D-type chiral metal oxide may be arranged on a substrate in a zero-dimensional, one-dimensional, or two-dimensional structure. Specifically, the above L-type or D-type chiral metal oxide may be provided on the substrate in the form of a thin film having a two-dimensional structure. In this case, the chiral metal oxide thin film may have a thickness of 1 nm to 1 μm.

[0066] The above L-type or D-type chiral metal oxide may exhibit chirality, and such chirality may be formed by transferring chiral properties to the metal oxide from an L-type or D-type chiral organic compound added during the manufacturing process. Chirality refers to asymmetry distinguishable from the mirror image of an object, and may exhibit molecular structures that cannot overlap each other in the mirror image. The above L-type or D-type chiral metal oxide may refer to enantiomers of the metal oxide, that is, L- and D-type isomers.

[0067] The above L-type or D-type chiral metal oxide is chiral and can have the characteristics of a spin filter, which is a chiral-induced spin-selectivity effect (CISS effect) that allows specific spins to pass through in the chiral direction and restricts spins in the opposite direction. Accordingly, the chiral metal oxide-based water electrolysis electrode of the present invention can suppress hydrogen peroxide, a reaction byproduct formed during the water electrolysis electrode reaction, and can increase the efficiency of oxygen and hydrogen generation.

[0068] The above L-type or D-type chiral metal oxide can be represented by the following chemical formula 1.

[0069] [Chemical Formula 1]

[0070] M 1 M 2 O x

[0071] In the above chemical formula 1, the M 1 and the above M 2 is composed of two different metallic elements, and the above M 1 is any one selected from Co, Ni, and Mn, and said M 2 is the above M 1 It is a metal atom having an atomic radius that is greater than 0% and less than 15% of the difference from the atomic radius of, and x is an integer from 1 to 10.

[0072] More specifically, metals with d-orbitals can have five d-orbital structures consisting of dz2, dx2-y2, dxy, dxz, and dyz. According to crystal field theory, when six ligands attempt to bind to the octahedral structure of the central metal, the energy levels of the dz and dx2-y2 orbitals can rise due to the interaction between the ligand electrons and the d-orbitals, which are the two relatively higher energy levels of the d-orbitals, known as equally degenerated (eg It is referred to as ). In addition, the dxy, dxz, and dyz orbitals can have relatively lower energy levels as the d orbitals bind slightly offset from the direction in which the ligand binds; this is called the triply degenerated (t2g) d orbital, which refers to the three relatively low energy levels of the d orbital. The difference between these two energy levels is the crystal field splitting energy (Δ o It is called ). As such, depending on the crystal field splitting energy between the metal and the ligand, and the oxidation state of the metal, a relatively high energy e g and t, which has relatively low energy 2g Spin comes into existence in it.

[0073] In this case, ligands that induce a strong field have a lower coupling energy, so according to Hund's rule, they have a relatively smaller number of unpaired electrons and can form low-spin complexes. Additionally, ligands that induce a weak field have a higher coupling energy, so they have a larger number of unpaired electrons and do not satisfy Hund's rule, and e having a higher energy level g Electrons can be placed there. In metal oxides, oxygen is a ligand that forms a relatively weak field, with small crystal field splitting energy (△ o The role of having ) to have a low-spin or high-spin state can be influenced by the oxidation state of the metal.

[0074] In addition, for electron transfer to occur more easily by increasing the overlap between oxygen (O) 2p orbitals and metal orbitals in the oxygen evolution reaction (OER) of a water electrolysis electrode, e g t compared to a high-spin state where spin exists in (anti-bonding) 2g A low-spin state with spin can increase overlap with the oxygen (O) 2p orbital.

[0075] Accordingly, the present invention comprises the above-mentioned L-type or D-type chiral metal oxide to increase the oxygen evolution reaction (OER) by increasing overlap with the oxygen (O) 2p orbital through spin control. That is, M represented by the above-mentioned chemical formula 1 1 M 2 O x M of the above L-type or D-type chiral metal oxide 1 as cobalt (Co), nickel (Ni), It can be composed of any one metal atom selected from manganese (Mn). These may be metal atoms that exist in a low-spin state according to theoretical values ​​among metal atoms having d4-7 orbitals.

[0076] In addition, to enhance chirality, the present invention doped the L-type or D-type chiral metal oxide with metal atoms capable of further increasing lattice distortion. That is, M represented by Chemical Formula 1. 1 M 2 O x M of the above L-type or D-type chiral metal oxide 2 As mentioned above M 1 It can be doped with a metal element different from and. At this time, the above M 2 is the above M 1 It is possible to constitute metal atoms having an atomic radius that is greater than 0% and less than 15% of the difference from the atomic radius of. That is, the above M 1 The atomic radius of and the above M 2 The difference in the atomic radius of may be greater than 0% and less than 15%. The above M 1 M having an atomic radius within the range described above 2 The chiral lattice distortion of the L-type or D-type chiral metal oxide can be further increased by doping.

[0077] Specifically, for example, the above M 2may be any one metal atom selected from Co, Mn, Ni, Li, Mg, Al, Sc, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, As, Se, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Sn, Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Bi, Po, At, U, Np, and Pu. For this, reference may be made to the experimental examples described below.

[0078] In one embodiment, the M 1 When this is Co, Co 2+ The atomic radius of is 79 pm, and Co 3+ The atomic radius of can be 68.5 pm. Accordingly, the above M 2 It can be composed of metal atoms having an atomic radius of 58.23 pm or more and 90.85 pm or less.

[0079] Specifically, for example, the above L-type or D-type chiral metal oxide is CoMnO x , CoNiO x , NiCoO x , and NiMnO x It may include any one selected from among. More specifically, the L-type or D-type chiral metal oxide is Co 1-y Mn y O x And, the above y may be 0.01 to 0.8. Preferably, the L-type or D-type chiral metal oxide is Co 0.9 Mn 0.1 O x It could be.

[0080] The above chiral metal oxide-based water electrolysis electrode may further include a single-atom catalyst deposited on the L-type or D-type chiral metal oxide. The single-atom catalyst may be a single-atom catalyst used in water electrolysis electrodes. Specifically, for example, the above-mentioned single-atom catalyst may be one or more selected from transition metals, alkaline earth metals, and rare earth metals, and the above-mentioned single-atom catalyst may be one or more selected from Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Rb, Sr, Y, Zn, Ga, Ge, As, Se, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Bi, Th, Pa, U, Pu, and Am, but is not limited thereto. More specifically, the above-mentioned single-atom catalyst may use one or more selected from ruthenium (Ru), iridium (Ir), platinum (Pt), silver (Ag), copper (Cu), and iron (Fe). Preferably, the above-mentioned single-atom catalyst may be iridium (Ir).

[0081] The above chiral metal oxide-based water electrolysis electrode can exhibit circular dichroism in the range of 200 nm to 1000 nm. Circular polarization is light with a polarization state that possesses chirality and has a polarization form different from linear polarization, which is commonly known. The fact that the chiral metal oxide-based water electrolysis electrode of the present invention exhibits circular dichroism can be seen as a result of chirality being effectively transferred to the metal oxide by the chiral organic material during the manufacturing process. Furthermore, as the chirality of the above chiral metal oxide-based water electrolysis electrode is enhanced, it may exhibit circular dichroism over a relatively wide wavelength range.

[0082] As described above, the chiral metal oxide-based water electrolysis electrode of the present invention possesses chiral-induced spin selectivity, allowing for the control of spin polarization without the need for an additional external magnetic field. Furthermore, the chiral metal oxide-based water electrolysis electrode of the present invention can synthesize various chiral metal oxide structures with novel structures exhibiting high activity by utilizing various types of chiral organic materials and metal ions.

[0083]

[0084] Method for manufacturing a chiral metal oxide-based water electrolysis electrode

[0085] Another aspect of the present invention may provide a method for manufacturing a chiral metal oxide-based water electrolysis electrode. This may be a method for manufacturing the chiral metal oxide-based water electrolysis electrode described above.

[0086] FIG. 1 is a flowchart illustrating a method for manufacturing a chiral metal oxide-based water electrolysis electrode according to one embodiment of the present invention.

[0087] Referring to FIG. 1, the method for manufacturing a chiral metal oxide-based water electrolysis electrode may include the step of forming a mixed solution by mixing a metal oxide precursor, a chiral organic material, and an alkalizing agent (S100), and the step of forming an L-type or D-type chiral metal oxide by electrodepositing the mixed solution on a substrate (S200).

[0088] Specifically, the chiral metal oxide can be represented by the following chemical formula 1.

[0089] [Chemical Formula 1]

[0090] M 1 M 2 O x

[0091] In the above chemical formula 1, the M 1 and the above M 2 is composed of two different metallic elements, and the above M 1is any one selected from Co, Ni, and Mn, and said M 2 is the above M 1 It is a metal atom having an atomic radius that is greater than 0% and less than 15% of the difference from the atomic radius of, wherein x is an integer from 1 to 10. Specifically, M 2 It may be any one metal atom selected from Co, Mn, Ni, Li, Mg, Al, Sc, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, As, Se, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Sn, Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Bi, Po, At, U, Np, and Pu.

[0092] First, a mixed solution can be formed by mixing a metal oxide precursor, a chiral organic material, and an alkalizing agent in S100. Specifically, the step of preparing the mixed solution may include a process of preparing a solution containing the alkalizing agent, a process of mixing the metal ion and the alkalizing agent into the solution, and a process of mixing the chiral organic material into the solution.

[0093] The metal oxide precursor may be a precursor comprising one or more of transition metals, alkaline earth metals, and rare earth metals. Specifically, the metal oxide precursor may comprise one or more metals selected from Co, Mn, Ni, Li, Mg, Al, Sc, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, As, Se, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Sn, Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Bi, Po, At, U, Np, and Pu. More specifically, the metal oxide precursor may comprise at least two of cobalt (Co), nickel (Ni), and manganese (Mn). That is, the chiral metal oxide is CoMnO x, CoNiO x , NiCoO x , and NiMnO x It may include any one selected from among. Preferably, the chiral metal oxide is Co 1-y Mn y O x And, the above y may be 0.01 to 0.8. More preferably, the chiral metal oxide is Co 0.9 Mn 0.1 O x It could be.

[0094] The above chiral organic material may be a chiral ligand that transfers chirality to the metal oxide produced by forming an ionic complex with the above metal oxide precursor, and may be an organic material having chirality. The above chiral organic material may be an L-type chiral organic material and a D-type chiral organic material, respectively, depending on the sample. The above L-type chiral organic material and D-type chiral organic material may refer to enantiomers of the chiral organic material, that is, L- and D-type isomers.

[0095] That is, the above L-type or D-type chiral metal oxide may be formed as a chiral metal oxide through the transfer of chiral properties via the formation of a complex between a chiral organic and a metal ion constituting the metal oxide. In other words, a chiral organic having L-type or D-type chirality acts as a chiral ligand and binds to the surface of the metal oxide nanoparticle, causing its structural symmetry to collapse and the crystal structure to become distorted. Consequently, the metal oxide nanoparticle may align in a specific direction, and a transfer of chiral properties may occur.

[0096] Specifically, for example, the above chiral organic material is tartaric acid, amino acid, sugar, phenylalanine, valine, cysteine, glutamate, serine, threonine, leucine, isoleucine, tyrosine, tryptophan, proline, methionine, asparagine, glutamine, glutathione, aspartic acid, glutamic acid, arginine, lysine, histidine, ornithine, glyceraldehyde, glucose, Alanine, Ribose, Fructose, Erythrose, Threose, Arabinose, Xylose, Lyxose, Talose, Galactose, Gulose, Allose, Altrose, Idose, Mannose, Methylbenzylamine (C6H5CH(CH3)NH2), 2-amino-3-methylbutane (C5H 13 N), ethylbenzylamine (C6H5CH(C2H5)NH2), 3,3-dimethyl-2-butylamine (((CH3)3C)CH(NH2)CH3), 1-cyclohexylethylamine (C6H 11 CH(CH3)NH2), 1-(1-naphthyl)ethylamine(C 10 H7CH(CH3)NH2), sec-butylamine(CH3CH2CH(NH2)CH3), 1-(2-naphthyl)ethylamine(C 12 H 13N), fluoromethylbenzylamine (FC6H4CH(CH3)NH2), chloromethylbenzylamine (ClC6H4CH(CH3)NH2), bromomethylbenzylamine (BrC6H4CH(CH3)NH2), iodomethylbenzylamine (IC6H4CH(CH3)NH2), 1,2,3,4-tetrahydro-3-isoquinolinecarboxylic acid (C 10 H 11 NO2), 3-cyclohexene-1-carboxylic acid (C7H 10 O2), 3-amino-1-quadrubutyloxycarbonyl-piperidine(C 10 H2ON2O2), 1,2,3,4-tetrahydro-1-naphthylamine((C 10 H 11 )NH2), 1-aminoindene(C9H 11 N), 1-amino-2-(methoxymethyl)pyrrolidine(C6H 14 N2O), 1-cyclopropylethylamine (C5H 11 N), bornylamine (C 10 H 19 N), 1-(m-tolyl)etheneamine (C9H 13 N), (S)-1,4-benzodioxane-2-carboxylic acid (C9H8O4), 1-methoxy-2-propylamine (CH3OCH2CH(CH3)NH2), (S)-1,2,3,4-tetrahydro-1-naphthoic acid (C 12 H 14 O2), 1-methyl-3-phenylpropylamine(C6H5CH2CH2CH(NH2)CH3), (R)-(-)-1,2,3,4-tetrahydro-1-naphthylamine((C 10 H 11 )NH2), 1-amino-2-propanol(CH3CH(OH)CH2NH2), (R)-(+)-1,2-dithiolan-3-pentanoic acid(C8H 14 O2S2), (S)-1-Boc-4-oxopiperidine-2-carboxylic acid(C 11 H 17 NO5), β-methylphenylamine (C6H5CH(CH3)CH2NH2), 2-methylpiperidine (C6H 13 N), 3-quinuclideinol (C7H 13 NO) and 3-aminopiperidine (C5H 12It may include one or more selected from N2).

[0097] More specifically, the chiral organic material may be L-type tartaric acid or D-type tartaric acid. When using tartaric acid (or a tartaric acid derivative) as the chiral organic material, L-type and D-type may be used separately or in combination; however, in the present invention, it may be preferable to use them separately without mixing them. This may be because the optical purity value when the L-type tartaric acid and the D-type tartaric acid are used in combination may be lower than when the L-type tartaric acid and the D-type tartaric acid are used separately.

[0098] The above alkalizing agents are sodium carbonate (Na2CO3), potassium carbonate (K2CO3), sodium bicarbonate (NaHCO3), and sodium phosphate (Na5P3O2). 10 It may include one or more selected from sodium pyrophosphate (Na4P2O7), disodium phosphate (K2HPO4), disodium phosphate (Na2HPO4), sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), trisodium citrate (C6Na3H5O7), and sodium metaphosphate (NaPO3)6). In this embodiment, sodium carbonate (Na2CO3) was used as the alkalizing agent.

[0099] The step of forming the chiral metal oxide described above can be performed using an electrodeposition method. Conventional methods for fabricating chiral metal oxide electrodes include hydrothermal synthesis and self-assembly monolayer methods. Hydrothermal synthesis has limitations, such as a very limited surface area due to the use of specialized synthesis equipment, the necessity of high temperature and high pressure conditions, and very long synthesis times. Additionally, the self-assembly monolayer method may be limited in its application due to the very long synthesis time and limitations in controlling electrode thickness. Other methods for electrode deposition include chemical vapor deposition and physical vapor deposition, but these require expensive deposition equipment, and fabricating chiral metal oxide electrodes using these technologies may be somewhat difficult.

[0100] To address this, the present invention provides a method for synthesizing a chiral metal oxide electrode that can utilize various metal ions by electrodeposition (electrochemical deposition) at room temperature, without the need for expensive deposition equipment or complex processes as in conventional deposition methods. In other words, by forming a chiral metal oxide-based water electrolysis electrode using the electrodeposition method, the use of chiral organic materials and metal ions can be facilitated.

[0101] Accordingly, the present invention can provide a chiral metal oxide-based water electrolysis electrode with a uniform thickness on any conductor regardless of the shape of the substrate. In addition, by introducing one or more materials, it is possible to control the characteristics of the electrode, and since uniform deposition is possible regardless of the electrode size, it is very easy to scale up to a large area and exhibit uniform characteristics. Furthermore, since deposition is performed while maintaining the shape of the electrode structure, deposition can be performed without deformation.

[0102] The chiral metal oxide can be formed with a thickness of 1 nm to 1 µm. When configured within the above-described range, it can be easily used as a water electrolysis electrode, and the effect of chirality can be increased through an appropriate thickness.

[0103] After the step of forming the L-type or D-type chiral metal oxide, the method may further include the step of depositing a single-atom catalyst on the chiral metal oxide. That is, a single-atom catalyst can be deposited on the metal oxide formed on the substrate using an electrodeposition method. For a description of the single-atom catalyst, refer to the previously described content. In one embodiment, the content of the single-atom catalyst may be 1 wt% to 10 wt%. Within the above-described range, the intrinsic characteristics of the electrode can be effectively realized while maintaining chirality when depositing the single-atom catalyst.

[0104]

[0105] Water electrolysis device including a chiral metal oxide-based water electrolysis electrode

[0106] Another aspect of the present invention may provide a water electrolysis device. The water electrolysis device may be a water electrolysis device comprising the chiral metal oxide-based water electrolysis electrode described above.

[0107] Specifically, the above-described water electrolysis device may include a water electrolysis electrode according to the present invention as an anode. Such a water electrolysis device may be an alkaline water electrolysis device. Depending on the embodiment, the above-described water electrolysis device may further include various configurations in addition to the anode, and is not particularly limited.

[0108] The above-described water electrolysis device can effectively improve the performance of the device by being equipped with the above-described chiral metal oxide-based water electrolysis electrode.

[0109] Hereinafter, preferred experimental examples are presented to aid in understanding the present invention. However, the following experimental examples are intended only to aid in understanding the present invention, and the present invention is not limited by the following experimental examples.

[0110]

[0111] Preparation Examples 1-1 to 1-11: Chiral cobalt-manganese oxide-based water electrolysis electrodes

[0112] The total amount of cobalt chloride hexahydrate (CoCl2-6H2O) and manganese chloride (MnCl2) was set to 0.16 mmol, and the addition ratio of cobalt chloride hexahydrate (CoCl2-6H2O) and manganese chloride (MnCl2) was adjusted so that the mixing ratio of cobalt and manganese was as shown in Table 1 below. After adding this mixture to 40 ml of ultrapure water, it was stirred for 10 minutes.

[0113] 1.6 mmol of L- and D-type tartaric acid (L- / D-tartaric acid) were each added to the above mixed solution and dissolved, then 4 mmol of sodium carbonate (Na2CO3) was added and stirred for 10 minutes. At this time, L- and D- represent chiral oxides.

[0114] With the clear solution prepared, a washed indium tin oxide (ITO) substrate is connected to the working electrode of a three-electrode system, a platinum (Pt) electrode is connected to the counter electrode, and a silver chloride (Ag / AgCl) electrode is connected to the reference electrode to achieve a constant current of 0.1 mA·cm² -2 Water electrolysis electrodes were prepared by performing electrochemical deposition for 30 minutes, in which an L-type chiral metal oxide thin film and a D-type chiral metal oxide thin film were formed, respectively.

[0115] Classification Cobalt Manganese Preparation Example 1-11000 Preparation Example 1-2991 Preparation Example 1-3955 Preparation Example 1-49010 Preparation Example 1-58515 Preparation Example 1-68020 Preparation Example 1-77525 Preparation Example 1-86040 Preparation Example 1-94060 Preparation Example 1-102080 Preparation Example 1-110100

[0116] Comparative Examples 1-1 and 1-2: Nickel-manganese oxide-based water electrolysis electrodes

[0117] A water electrolysis electrode having a meso-type metal oxide thin film was prepared by performing the same procedure as in Preparation Examples 1-1 and 1-4 above, except that a meso-type tartaric acid (L- / D- / Meso-tartaric acid) was used. Meso- refers to an oxide without chiral properties.

[0118]

[0119] FIGS. 2(a) and FIGS. 2(b) show the L- / D-CoO of Preparation Example 1-1 of the present invention. x and L- / D-MnO of Preparation Example 1-11 x This is an image showing the metal oxide thin film of the electrode.

[0120] Referring to FIGS. 2(a) and FIGS. 2(b), the L- / D-CoO of Preparation Example 1-1 x and L- / D-MnO of Preparation Example 1-11 x Through the electrode photographs, it can be confirmed that the colors of cobalt oxide and manganese oxide are brown.

[0121] FIG. 3 shows the L-Co of Preparation Examples 1-2 to 1-10 of the present invention. 1-y Mn y O x (y = 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.4, 0.6 and 0.8) This is an image showing the metal oxide thin film of the electrode.

[0122] Referring to FIG. 3, the L-Co of Preparation Examples 1-2 to 1-10 1-y Mn y O x (y = 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.4, 0.6 and 0.8) Through the electrode photographs, it can be seen that as the manganese doping content in the cobalt increases, a change to a dark brown color occurs.

[0123] FIGS. 4(a) to 4(c) are images showing the results of contact angle analysis for the electrodes of Preparation Example 1-1 (Co 100%), Preparation Example 1-4 (Co 90% + Mn 10%), and Preparation Example 1-11 (Mn 100%) of the present invention. Specifically, the moment a drop of water was dropped onto the chiral metal oxide thin film of the electrodes of Preparation Example 1-1, Preparation Example 1-4, and Preparation Example 1-11 was photographed, and the contact angle was measured. The scale bar is 1 μm. The average angle, left angle, right angle, drop volume, and temperature of the contact angle are shown together in the figure.

[0124] Figures 4(a) to 4(c) show the extent to which surface roughness affects hydrophilicity according to the cobalt-manganese content. Specifically, it can be seen that the electrode of Preparation Example 1-1 (Co 100%) in Figure 4(a) and the electrode of Preparation Example 1-11 (Mn 100%) in Figure 4(c) exhibit very low contact angles due to their strong hydrophilicity and ability to adsorb water well. On the other hand, in the electrode of Preparation Example 1-4 (Co 90% + Mn 10%) in Figure 4(b), when cobalt and manganese are mixed, it can be seen that the contact angle becomes very high while relatively low hydrophilicity is exhibited due to the difference in surface roughness. Additionally, it can be seen that a uniform surface is formed in the electrode of Preparation Example 1-4 (Co 90% + Mn 10%) in Figure 4(b) as 10 to 20% of manganese is doped into the cobalt.

[0125] Figure 5 is a scanning electron microscope (SEM) image showing the thin film shapes of the electrodes of Preparation Examples 1-1 to 1-11 of the present invention and the control group (nickel foam).

[0126] Referring to FIG. 5, it can be seen that the surface roughness differs as the amount of manganese gradually increases, as in Preparation Examples 1-2 to 10, compared to the 100% cobalt of Preparation Example 1-1. Additionally, it can be seen that a rough surface appears when the manganese content is low, as in the electrodes of Preparation Example 1-2 and Preparation Example 1-3, but a uniform surface is exhibited when the manganese doping content is 10 to 20%, as in the electrodes of Preparation Examples 1-4 to 1-6. Furthermore, it can be seen that as the manganese content increases further, as in Preparation Examples 1-7 to 1-11, spherical particles are formed, resulting in an uneven electrode surface.

[0127] In metal oxides, the diffusion rate varies depending on the bond strength of metal-oxygen (metal-O), and the higher the bond strength, the lower the diffusion rate may be. The bond energy of manganese-oxygen (Mn-O) is 402 kJ / mol, while the bond energy of cobalt-oxygen (Co-O) is 368 kJ / mol, indicating that the bond energy of manganese-oxygen is higher. As mobility decreases due to manganese doping, the degree of particle aggregation caused by collisions is reduced, allowing for the formation of a uniform thin film of small particles. Consequently, roughness can be reduced up to a certain level depending on the manganese doping content.

[0128] FIG. 6(a) is a graph showing the electrodes of Preparation Examples 1-1 to 1-11 of the present invention analyzed by linear scanning potential (LSV), and FIG. 6(b) is a graph showing the correlation between the contact angle and the overpotential required for the oxygen evolution reaction (OER) according to the manganese dopant (Mn dopant) ratio of the electrodes of Preparation Examples 1-1 to 1-11 of the present invention.

[0129] FIG. 6(a) shows the electrodes of Preparation Examples 1-1 to 1-11 at a length of 1 cm 2After cutting the electrode into an area and placing it in a 1M KOH solution, the working electrode was connected, the platinum electrode was connected to the counter electrode, and the silver chloride electrode (Ag / AgCl) was connected to the reference electrode. A portion of the electrodes was immersed in 40ml of a 1M KOH solution, and the measurement range was set from 1.2V to 2.0V (V Vs. RHE) in linear scanning potential (LSV) mode and measurements were taken.

[0130] Specifically, OH radicals, which are intermediate products of the oxygen evolution reaction (OER), are slow reactions that determine the reaction rate and are relatively hydrophobic, repelling water from the surroundings and reducing the total charge required for the reaction. However, if the surface is partially made hydrophobic, this process is omitted, and a state is created where OH radicals can be generated immediately, allowing for a rapid reaction and lowering the overpotential. Accordingly, the efficiency of the electrode can be confirmed by comparing the current density at the same voltage in the results measured by the linear scanning potential (LSV) method, which is data measuring current density according to voltage as shown in Fig. 6(a).

[0131] Referring to FIG. 6(a), the electrode of Preparation Example 1-4 (L-Co) in which 10% manganese is doped into cobalt 0.9 Mn 0.1 O x It can be seen that it exhibits the lowest overpotential in ). In addition, Preparation Example 1-7 (L-Co 0.75 Mn 0.25 O x ) and, Preparation Example 1-8 (L-Co 0.6 Mn 0.4 O x ) and, Preparation Example 1-10 (L-Co 0.2 Mn 0.8 O x ) is Preparation Example 1-6 (L-Co 0.8 Mn 0.2 O x It appeared as a value similar to ).

[0132] Figure 6(b) shows the relationship between the contact angle and the overpotential, and it can be seen that when the manganese doping ratio in Preparation Example 1-4 is 10%, the highest contact angle and the lowest overpotential are observed. As shown in Equation (1) below, as manganese is doped into a hydrophilic surface, the surface roughness decreases, and the surface becomes hydrophobic. When the manganese doping ratio is 1 to 5%, the surface roughness is non-uniform, so the contact angle increases slightly, whereas when it is 10%, the surface is very uniform, so the roughness decreases and the contact angle is formed highest, and from 10% or more, the roughness increases due to the formation of large particles, so the contact angle may decrease again.

[0133] … … Equation (1)

[0134] In the above equation (1), θ real : Actual observed contact angle, θ ideal : It is the contact angle measured on a physically smooth surface.

[0135] Since the surface of Preparation Example 1-4 in FIG. 5 described above is uniform, it can be considered that the roughness has decreased. In addition, it is determined that the contact angle has increased due to the decrease in hydrophilicity. When hydrophilicity decreases, OH during the oxygen evolution reaction (OER) - During the reaction from ions to ·OH radicals, the ·OH radicals are relatively hydrophobic, so the overpotential can be reduced through the effect of lowering the reaction energy.

[0136] FIGS. 7(a) to 7(c) show the L- / D-CoO of Preparation Example 1-1 of the present invention. x Electrode, L- / D-Co of Preparation Example 1-4 0.9 Mn 0.1 O x Electrode and L- / D-MnO of Preparation Example 11 xThis is a graph showing the ultraviolet-visible (UV-Vis) spectrophotometric measurement data of the electrodes. After placing the electrodes in a circular dichroism instrument, measurements were taken after setting the measurement range to 300 to 500 nm. Chiral characteristics were measured by irradiating two different lights, left circular polarization and right circular polarization, and determining the CD based on the difference in absorption for one of the lights.

[0137] In the left graphs of Figures 7(a) to 7(c), when aligned in one direction, a skewed graph can be observed.

[0138] The right graphs of Figures 7(a) to 7(c) are typical absorption wavelengths, and the thickness of the thin film can be determined according to the degree of absorption.

[0139] … … Equation (2)

[0140] According to the CD values ​​of FIGS. 7(a) to 7(c) and the g-factor calculation formula of Equation (2), the L-CoO of Preparation Example 1-1 x The g-factor is 8.95 x 10⁻⁶ -5 and, D-CoO x The g-factor is 6.79 x 10⁻⁶ -5 is. In addition, the L-Co of Preparation Examples 1-4 0.9 Mn 0.1 O x The g-factor of is 1.29 x 10⁻⁶ -4 is, and D-Co 0.9 Mn 0.1 O x The g-factor of is 1.47 x 10 -4 am.

[0141] FIG. 8 is Preparation Example 1-1 of the present invention (L- / D-CoO x ) Electrode and Preparation Example 1-4 (L- / D-Co 0.9 Mn 0.1 O x This is a graph showing the g-factor of the electrodes compared.

[0142] Referring to FIG. 8, the atomic radius of manganese is 161 pm, and the atomic radius of cobalt is 152 pm, so the atomic radius of manganese is larger. Accordingly, the distortion of the electrode of Preparation Example 1-4 increased as manganese was doped into cobalt. The electrode of Preparation Example 1-1 (CoO x The electrode of Preparation Example 1-4 (Co) is better than ) 1-y Mn y O x The increase in the distortion of ) can be confirmed through the g-factor. As such, spin selectivity and oxygen evolution reaction (OER) efficiency can be increased through the enhancement of chirality by manganese.

[0143] FIG. 9 is a graph showing the ratio of cobalt ions to manganese ions according to the manganese doping content of the electrodes of Preparation Example 1-3 (Mn 5), Preparation Example 1-4 (Mn 10), Preparation Example 1-5 (Mn 15), Preparation Example 1-6 (Mn 20), and Preparation Example 1-7 (Mn 25) of the present invention.

[0144] Referring to Fig. 9, manganese is Mn 2+ , Mn 3+ , and Mn 4+ It is a representative material of the Jahn-Teller effect, which twists the structure of substances with various oxidation states. Among them, Mn 3+ is (t 2g 3 e g 1 The orbital of ), Mn 4+ is (t 2g 3 e g 0 It has an orbital of ) so Mn 3+ Distortion increases due to the antibonding of ions, and Mn 4+ ...can reduce distortion. When the manganese doping ratio in the electrode of Preparation Example 1-4 of the present invention is 10%, as the electron withdrawing effect increases, Co on the XPS analysis results of Fig. 9 3+ / Co 2+ The ratio of is high, and Mn 4+ / Mn 3+ Since the ratio of decreases, Mn 3+ It can be seen that the distortion increases with the increase in ions. This is consistent with the g-factor results of Figure 7 described above, and through this, the oxygen evolution reaction (OER) efficiency can also be increased.

[0145] FIG. 10(a) is a schematic diagram of a measurement method using a magnetic conductive probe atomic force microscopy (mCP-AFM) according to an embodiment of the present invention, and FIG. 10(b) and FIG. 10(c) are of the L- / D-CoO of Preparation Example 1-1 of the present invention. x and L- / D-Co of Preparation Examples 1-4 0.9 Mn 0.1 O x This is a graph showing the chiral-induced spin selectivity of the electrode.

[0146] As shown in Fig. 10(a), electrical characteristics were analyzed using a magnetic conductive probe atomic force microscope (mCP-AFM). Depending on the chiral direction, a centripetal force acts on the Lorentz force, causing electrons to rotate in a specific direction and forming a magnetic field. Accordingly, when electrons with an up or down spin pass through, only those electrons that match the magnetic field in one direction formed by the chirals pass through, while electrons with the opposite spin are prevented from passing through, thus acting as a spin filter.

[0147] In FIG. 10(a), the Co-Cr tip is a tip capable of exhibiting magnetism, and the tip is magnetized according to the N or S pole of a permanent magnet. When this tip is brought into contact with a chiral thin film and current flows, if electrons transmitted through the magnetized tip flow in a direction consistent with the chiral direction, the signal is amplified, and if the opposite is true, the signal is weakened. Accordingly, the electrodes of Preparation Example 1-1 and Preparation Example 1-4 of the present invention were positioned in the center of the scanning probe microscope in the left image of FIG. 10, and currents from -5V to 5V were measured using the magnetized ferromagnetic tip.

[0148] Referring to the measurement result in Fig. 10(b), it can be seen that the trends of the current flow in L- and D- are opposite when up and when down, which confirms the chiral characteristics as a phenomenon where the signal is amplified or weakened depending on the N or S pole. The same measurement result can be confirmed when manganese is doped in Fig. 10(c).

[0149]

[0150] Preparation Examples 1-12 and 1-13: Chiral metal oxide-based water electrolysis electrodes deposited on nickel foam

[0151] Water electrolysis electrodes were prepared by performing the same procedure as in Preparation Examples 1-1 and 1-4 above, except that nickel foam (Ni foam) was used as the substrate, thereby forming L-type chiral metal oxide thin films and D-type chiral metal oxide thin films, respectively.

[0152] Comparative Examples 1-3 and 1-4: Metal oxide-based water electrolysis electrodes deposited on nickel foam

[0153] A water electrolysis electrode having a meso-type metal oxide thin film formed thereon was prepared by performing the same procedure as Comparative Examples 1-1 and 1-2 above, except that nickel foam (Ni foam) was used as the substrate.

[0154] FIGS. 11(a) and FIGS. 11(b) show the L- / D-CoO of Preparation Example 1-12 of the present invention. xElectrode, Meso-CoO of Comparative Examples 1-3 x Electrode, L- / D-Co of Preparation Example 1-13 0.9 Mn 0.1 O x Electrode and Meso-Co of Comparative Examples 1-4 0.9 Mn 0.1 O x This graph shows the results of analyzing the extent of hydrogen peroxide generation via UV-Vis depending on the presence or absence of spin after the oxygen evolution reaction (OER) at the electrode. Through this, the results of hydrogen peroxide generation according to reaction time in cobalt and cobalt-manganese oxides can be confirmed.

[0155] Specifically, for analysis, the L- / D-CoO of Preparation Example 1-12 x Electrode, Meso-CoO of Comparative Examples 1-3 x Electrode, L- / D-Co of Preparation Example 1-13 0.9 Mn 0.1 O x Electrode and Meso-Co of Comparative Examples 1-4 0.9 Mn 0.1 O x The electrode was connected to the working electrode, the platinum electrode to the counter electrode, and the silver chloride electrode to the reference electrode. These were immersed in 40 ml of 0.1 M Na2SO4 solution, and 1 ml of the reaction solution was extracted at 30-minute intervals. The solution was then mixed with a 0.1% w / v aqueous solution of ortho-tolidine (o-tolidine) in a 5:1 ratio and analyzed using a UV-Vis spectrophotometer. When reacted with the electrode in a 0.1 M Na2SO4 electrolyte, hydrogen peroxide is generated; upon mixing with the o-tolidine indicator (0.1% w / v in 1 M HCl), the solution turns yellow, and the absorbance of hydrogen peroxide can be confirmed by measuring the absorbance of the solution.

[0156] Referring to FIGS. 11(a) and FIGS. 11(b), the L- / D-CoO of Preparation Example 1-12 x Electrode and L- / D-Co of Preparation Example 1-13 0.9 Mn 0.1 O xIn cases where chiral properties are present, such as with electrodes, almost no hydrogen peroxide is generated, whereas Comparative Examples 1-3 and Meso-CoO x Electrode or Meso-Co of Comparative Examples 1-4 0.9 Mn 0.1 O x In cases where chiral properties are absent, such as with electrodes, the presence or absence of chiral properties can be confirmed through the generation of hydrogen peroxide.

[0157]

[0158] Preparation Examples 1-14 to 1-16: Chiral nickel-manganese oxide-based water electrolysis electrodes

[0159] The total amount of nickel chloride hexahydrate (NiCl2-6H2O) and manganese chloride (MnCl2) was 0.16 mmol, and the addition ratio of nickel chloride hexahydrate (NiCl2-6H2O) and manganese chloride (MnCl2) was adjusted so that the mixing ratio of nickel and manganese was as shown in Table 2 below. After adding this to 40 ml of ultrapure water, the mixture was stirred for 10 minutes.

[0160] 1.6 mmol of L-type and D-type tartaric acid were added to the above mixed solution and dissolved, then 4 mmol of sodium carbonate (Na2CO3) was added and stirred for 10 minutes.

[0161] With a clear solution prepared, connect the washed indium tin oxide substrate to the working electrode of the three-electrode system, connect a platinum electrode to the counter electrode, and connect a silver chloride (Ag / AgCl) electrode to the reference electrode to a constant current of 0.1 mA·cm² -2 Water electrolysis electrodes were prepared by performing electrochemical deposition for 30 minutes, in which an L-type chiral metal oxide thin film and a D-type chiral metal oxide thin film were formed, respectively.

[0162] Classification Nickel Manganese Preparation Example 1-14 1000 Preparation Example 1-15 9010 Preparation Example 1-16 8020

[0163]

[0164] Preparation Examples 1-17 to 1-20: Chiral nickel-cobalt oxide-based water electrolysis electrodes

[0165] Nickel chloride hexahydrate (NiCl2-6H2O) and cobalt chloride hexahydrate (CoCl 2- To ensure the total amount of 6H2O is 0.16 mmol, and to ensure the mixing ratio of nickel and cobalt is as shown in Table 3 below, nickel chloride hexahydrate (NiCl2-6H2O) and cobalt chloride hexahydrate (CoCl2-6H2O) are prepared. 2- The addition ratio of 6H2O was adjusted and added to 40 ml of ultrapure water, then stirred for 10 minutes.

[0166] 1.6 mmol of L-type and D-type tartaric acid were added to the above mixed solution and dissolved, respectively, then 4 mmol of sodium carbonate (Na2CO3) was added and stirred for 10 minutes.

[0167] With the clear solution prepared, connect the washed indium tin oxide substrate to the working electrode of the three-electrode system, connect a platinum (Pt) electrode to the counter electrode, and connect a silver chloride (Ag / AgCl) electrode to the reference electrode for a constant current of 0.1 mA·cm² -2 Water electrolysis electrodes were prepared by performing electrochemical deposition for 30 minutes, in which an L-type chiral metal oxide thin film and a D-type chiral metal oxide thin film were formed, respectively.

[0168]

[0169] Classification Nickel Cobalt Manufacturing Example 1-17 90 10 Manufacturing Example 1-18 80 20 Manufacturing Example 1-19 20 80 Manufacturing Example 1-20 10 90

[0170] FIGS. 12(a) to 12(c) show the L-NiO of Preparation Examples 1-14 to 1-20 of the present invention. x , L-Ni 0.9 Mn 0.1 O x , L-Ni 0.8 Mn 0.2 O x , L-Ni 0.9 Co 0.1 O x , L-Ni 0.8 Co 0.2 O x , L-Co 0.9 Ni0.1 O x , and L-Co 0.8 Ni 0.2 O x This is a graph showing the results of analyzing the electrodes using linear scanning potentiometry (LSV). For the analysis, the electrodes of Preparation Examples 1-14 to 1-20 of the present invention were 1 cm 2 After cutting the electrodes into an area and placing them in a 1M KOH solution, the working electrode was connected, the platinum electrode was connected to the counter electrode, and the silver chloride electrode (Ag / AgCl) was connected to the reference electrode. A portion of the electrodes was immersed in 40ml of a 1M KOH solution, and the measurement range was set from 1.2V to 2.0V (vs. RHE) in linear scanning potentiometry (LSV) mode and measurements were taken.

[0171] As shown in FIGS. 12(a) to 12(c), chiral metal oxide thin films can be easily deposited by doping with heterogeneous elements, and through this, differences in electrode efficiency according to doping content can be confirmed.

[0172] Specifically, as a result of measuring the oxygen evolution reaction (OER) of electrodes doped with 10% and 20% manganese relative to chiral nickel oxide in Fig. 12(a), the current density measured at 1.8 V was 130.84 mA cm⁻¹. -2 At 131.8 mA cm -2 and 147.27 mA cm -2 It was improved, and as the overvoltage decreased from 338 mV to 290 mV and 287 mV, it can be confirmed that the efficiency has increased further.

[0173] In Fig. 12(b), the oxygen evolution reaction (OER) of electrodes doped with 10% and 20% cobalt relative to chiral nickel oxide was measured, and the current density measured at 1.8 V was 130.84 mA cm⁻¹. -2 At 161.87 mA cm -2 and 191.94 mA cm -2It was improved, and as the overvoltage decreased from 338 mV to 334 mV and 332 mV, it can be confirmed that the efficiency has increased further.

[0174] In Fig. 12(c), the oxygen evolution reaction (OER) of electrodes doped with 80% and 90% cobalt relative to chiral nickel oxide was measured, and the current density measured at 1.8 V was 130.84 mA cm⁻¹. -2 At 210.02 mA cm -2 and 201.43 mA cm -2 It was improved, and as the overvoltage decreased from 338 mV to 297 mV and 302 mV, it can be confirmed that the efficiency has increased further.

[0175]

[0176] Preparation Example 1-21: Chiral iridium oxide-based water electrolysis electrode

[0177] A solution prepared by dissolving 1.6 mmol of L-, D-, and Meso-form tartaric acids and 32 mmol of sodium carbonate (Na2CO3) in 0.16 mmol of iridium chloride trihydrate (IrCl3-3H2O) in 40 ml of distilled water was applied to indium tin oxide (ITO) at 1.0 mA·cm -2 An iridium oxide water electrolysis electrode was prepared by performing electrodeposition for 30 minutes.

[0178] FIG. 13 is the L-IrO of Preparation Example 1-21 of the present invention. x and D-IrO x This is an image of the metal oxide thin film of the electrode.

[0179] Referring to Fig. 13, L-IrO using iridium metal x It was electrodeposited, and it can be confirmed that the color is indigo, which is the color of iridium oxide.

[0180]

[0181] Preparation Example 1-22: Chiral iridium oxide-based water electrolysis electrode

[0182] A solution prepared by dissolving 1.6 mmol of L-, D-, and Meso-form tartaric acids and 32 mmol of sodium carbonate (Na2CO3) in 0.16 mmol of iridium chloride trihydrate (IrCl3-3H2O) in 40 ml of distilled water at 1.0 mA·cm² on nickel foam (Ni foam). -2 An iridium oxide water electrolysis electrode was prepared by performing electrodeposition for 30 minutes.

[0183] FIG. 14(a) is a nickel foam image, FIG. 14(b) is the L-IrO of Preparation Example 1-22 of the present invention. x and D-IrO x This is an image showing the electrode.

[0184] Figure 14(a) shows a nickel foam electrode used for oxygen evolution (OER), and as shown in Figure 14(b), it can be seen that chiral iridium oxide is well deposited on the nickel foam electrode.

[0185] FIG. 15 is the L-IrO of Preparation Example 1-22 of the present invention. x and D-IrO x This is a graph showing the results of analyzing the electrode and control group (nickel foam) using linear scanning potentiometry (LSV). The electrode of Preparation Example 1-22 is 1 cm 2 After cutting the electrodes into an area and placing them in a 1M KOH solution, the working electrode was connected, the platinum electrode was connected to the counter electrode, and the silver chloride electrode (Ag / AgCl) was connected to the reference electrode. A portion of the electrodes was immersed in 40ml of a 1M KOH solution, and measurements were taken using linear scanning potentiometry (LSV) mode with the measurement range set from 1.2V to 2.0V (vs. RHE).

[0186] Referring to FIG. 15, the current density measured at 1.8 V for the electrode of Preparation Example 1-22 with deposited chiral L- and D-iridium oxide and the nickel foam control without deposited chiral iridium oxide is 27.47 mA cm⁻¹. -2 L-iridium oxide at 352.88 mA cm⁻¹ -2 and D-iridium oxide 303.36 mA cm -2It was improved, and it can be confirmed that the efficiency increased further as the overvoltage decreased from 484 mV to 142 mV for L-iridium oxide and 181 mV for D-iridium oxide.

[0187]

[0188] Preparation Example 2-1: Chiral metal oxide-based water electrolysis electrode equipped with Ir monatomic catalyst

[0189] A solution of 100 µM iridium chloride trihydrate (IrCl3-3H2O) dissolved in a 1 M aqueous potassium hydroxide (KOH) solution was used with the L- / D-CoO prepared in Preparation Example 1-1 above. x A water electrolysis electrode was prepared by performing 10 cycles of electrochemical deposition in -0.4V to 0.1V (vs. Standard hydrogen electrode, SHE) cyclic voltammetry mode on the water electrolysis electrode to form an L-type chiral metal oxide thin film and a D-type chiral metal oxide thin film equipped with an Ir single-atom catalyst, respectively.

[0190] Preparation Example 2-2: Chiral metal oxide-based water electrolysis electrode equipped with Ru monatomic catalyst

[0191] Water electrolysis electrodes were prepared by performing the same procedure as in Preparation Example 2-1 above, except that ruthenium chloride trihydrate (RuCl3-3H2O) was used instead of iridium chloride trihydrate (IrCl3-3H2O), thereby forming L-type chiral metal oxide thin films and D-type chiral metal oxide thin films equipped with Ru monatom catalysts.

[0192] Preparation Example 2-3: Chiral metal oxide-based water electrolysis electrode equipped with Pt monatomic catalyst

[0193] Water electrolysis electrodes were prepared by performing the same procedure as in Preparation Example 2-1 above, except that platinum chloride (PtCl2) was used instead of iridium chloride trihydrate (IrCl3-3H2O), thereby forming L-type chiral metal oxide thin films and D-type chiral metal oxide thin films equipped with a Pt monatomic catalyst.

[0194] Preparation Example 2-4: Chiral metal oxide-based water electrolysis electrode equipped with Ag single-atom catalyst

[0195] Water electrolysis electrodes were prepared by performing the same procedure as in Preparation Example 2-1 above, except that silver chloride (AgCl) was used instead of iridium chloride trihydrate (IrCl3-3H2O), and L-type chiral metal oxide thin films and D-type chiral metal oxide thin films equipped with an Ag single-atom catalyst were formed, respectively.

[0196] Preparation Example 2-5: Chiral metal oxide-based water electrolysis electrode equipped with a Cu single-atom catalyst

[0197] In the above Preparation Example 2-1, copper chloride dihydrate (CuCl₂) instead of iridium chloride trihydrate (IrCl₃-3H₂O) 2- Water electrolysis electrodes were prepared by performing the same procedure except that 2H2O) was used, in which an L-type chiral metal oxide thin film and a D-type chiral metal oxide thin film equipped with a Cu single-atom catalyst were formed, respectively.

[0198] Preparation Example 2-6: Chiral metal oxide-based water electrolysis electrode equipped with Fe monatomic catalyst

[0199] Water electrolysis electrodes were prepared by performing the same procedure as in Preparation Example 2-1 above, except that iron chloride hexahydrate (FeCl3-6H2O) was used instead of iridium chloride trihydrate (IrCl3-3H2O), thereby forming L-type chiral metal oxide thin films and D-type chiral metal oxide thin films equipped with Fe monoatom catalysts.

[0200]

[0201] FIG. 16 is a graph showing the electrode of Preparation Example 2-1 of the present invention analyzed by linear scanning potential (LSV). Specifically, the electrode of Preparation Example 2-1 is 1 cm 2After cutting the electrodes into an area and placing them in a 1M KOH solution, the working electrode was connected, the platinum electrode was connected to the counter electrode, and the silver chloride electrode (Ag / AgCl) was connected to the reference electrode. A portion of the electrodes was immersed in 40ml of a 1M KOH solution, and measurements were taken using linear scanning potential (LSV) mode with the measurement range set from 1.2V to 2.0V (vs. RHE).

[0202] L-CoO through Fig. 16 x It can be confirmed that single-atom catalysts or heterogeneous or multi-atom catalysts can be easily deposited by additionally electrodepositing iridium (Ir) after deposition. Furthermore, as shown in Fig. 16, the oxygen evolution reaction (OER) of the electrode deposited with an iridium single-atom catalyst compared to chiral cobalt oxide was measured, and the current density measured at 1.8 V was 178.04 -2 At 221.54 mA cm -2 It was improved, and as the overvoltage decreased from 350 mV to 287 mV, it can be confirmed that the efficiency has increased further.

[0203]

[0204] Preparation Example 2-7: Chiral metal oxide-based water electrolysis electrode equipped with Ir monatomic catalyst

[0205] In the above Preparation Example 2-1, the L-Co of Preparation Example 1-4, not Preparation Example 1-1. 0.9 Mn 0.1 O x A water electrolysis electrode was prepared by performing the same procedure except for using Ir single-atom catalyst, thereby forming an L-type chiral metal oxide thin film.

[0206] Preparation Example 2-8: Chiral metal oxide-based water electrolysis electrode equipped with Ir monatomic catalyst

[0207] In the above Preparation Example 2-1, the L-Co of Preparation Example 1-5, not Preparation Example 1-1. 0.85 Mn 0.15 O xA water electrolysis electrode was prepared by performing the same procedure except for using Ir single-atom catalyst, thereby forming an L-type chiral metal oxide thin film.

[0208] FIG. 17(a) shows the thin film shape of Preparation Example 2-7 of the present invention, and FIG. 17(b) is a graph showing the linear scanning potentiometry (LSV) analysis of the electrodes of Preparation Examples 1-4, 1-5, 2-7, 2-8, and the control group (nickel foam) of the present invention. Specifically, the electrodes of Preparation Examples 1-4, 1-5, 2-7, 2-8, and the control group (nickel foam) are 1 cm 2 After cutting the area to a specific size and placing it in a 1M KOH solution, it was connected to the working electrode, the platinum electrode was connected to the counter electrode, and the silver chloride electrode (Ag / AgCl) was connected to the reference electrode. It was then immersed in 40ml of a 1M KOH solution, and the measurement range was set from 1.2V to 2.0V (vs. RHE) in linear scanning potential (LSV) mode.

[0209] Referring to FIG. 17(b), in Preparation Examples 2-7 and 2-8, Ir is L-Co 1-y Mn y O x By forming an L-type chiral metal oxide thin film equipped with an Ir single-atom catalyst by electrodeposition at (y = 0.1 and 0.15), it can be seen that the efficiency of the electrode increased further, as the overpotential decreased from 310 mV to 249 mV at y = 0.1 and from 309 mV to 263 mV at y = 0.15.

[0210] Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the above embodiments, and various modifications and changes are possible by those skilled in the art within the technical spirit and scope of the present invention.

Claims

1. Disposed on a substrate and comprising an L-type or D-type chiral metal oxide, The above chiral metal oxide is a chiral metal oxide-based water electrolysis electrode represented by the following chemical formula 1. [Chemical Formula 1] M 1 M 2 O x In the above chemical formula 1, The above M 1 and the above M 2 It is composed of two different metallic elements, and The above M 1 It is any one selected from Co, Ni, and Mn, and The above M 2 is the above M 1 It is a metal atom having an atomic radius that is greater than 0% and less than 15% of the difference from the atomic radius of, and The above x is an integer from 1 to 10.

2. In Paragraph 1, The above M 2 A chiral metal oxide-based water electrolysis electrode, wherein is any one metal atom selected from Co, Mn, Ni, Li, Mg, Al, Sc, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, As, Se, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Sn, Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Bi, Po, At, U, Np, and Pu.

3. In Paragraph 1, A chiral metal oxide-based water electrolysis electrode comprising any one selected from CoMnOx, CoNiOx, NiCoOx, and NiMnOx.

4. In Paragraph 3, The above chiral metal oxide is Co 1-y Mn y It is Ox, and A chiral metal oxide-based water electrolysis electrode in which y is 0.01 to 0.

8.

5. In Paragraph 4, The above chiral metal oxide is Co 0.9 Mn 0.1 Ox-based chiral metal oxide-based water electrolysis electrode.

6. In Paragraph 1, The above electrode is a chiral metal oxide-based water electrolysis electrode that exhibits circular dichroism at 200 nm to 1000 nm.

7. In Paragraph 1, The above electrode is a chiral metal oxide-based water electrolysis electrode further comprising a single-atom catalyst deposited on the chiral metal oxide.

8. In Paragraph 7, The above-mentioned single-atom catalyst comprises one or more selected from ruthenium (Ru), iridium (Ir), platinum (Pt), silver (Ag), copper (Cu), and iron (Fe), forming a chiral metal oxide-based water electrolysis electrode.

9. In Paragraph 8, The above chiral metal oxide is Ir-Co 1-y Mn y It is Ox, and A chiral metal oxide-based water electrolysis electrode in which y is 0.1 to 0.

15.

10. A step of forming a mixed solution by mixing a metal oxide precursor, a chiral organic material, and an alkalizing agent; and The method includes the step of forming an L-type or D-type chiral metal oxide by electrodepositing the above-mentioned mixed solution onto a substrate; A method for manufacturing a chiral metal oxide-based water electrolysis electrode, wherein the chiral metal oxide is represented by the following chemical formula 1. [Chemical Formula 1] M 1 M 2 O x In the above chemical formula 1, The above M 1 and the above M 2 It is composed of two different metallic elements, and The above M 1 It is any one selected from Co, Ni, and Mn, and The above M 2 is the above M 1 It is a metal atom having an atomic radius that is greater than 0% and less than 15% of the difference from the atomic radius of, and The above x is an integer from 1 to 10.

11. In Paragraph 10, A method for manufacturing a chiral metal oxide-based water electrolysis electrode, wherein the chiral metal oxide is a chiral metal oxide that exhibits chirality by transferring chiral properties to the metal oxide through the chiral organic material.

12. In Paragraph 10, A method for manufacturing a chiral metal oxide-based water electrolysis electrode, wherein the above-mentioned electrodeposition is anodic electrodeposition.

13. In Paragraph 10, The above M 2 A method for manufacturing a chiral metal oxide-based water electrolysis electrode, wherein the metal atom is any one metal atom selected from Co, Mn, Ni, Li, Mg, Al, Sc, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, As, Se, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Sn, Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Bi, Po, At, U, Np, and Pu.

14. In Paragraph 10, A method for manufacturing a chiral metal oxide-based water electrolysis electrode, wherein the metal oxide precursor comprises at least two of cobalt (Co), nickel (Ni), and manganese (Mn).

15. In Paragraph 14, The above chiral metal oxide is Co 1-y Mn y It is Ox, and A method for manufacturing a chiral metal oxide-based water electrolysis electrode, wherein y is 0.01 to 0.

8.

16. In Paragraph 10, A method for manufacturing a chiral metal oxide-based water electrolysis electrode, wherein the chiral organic material is L-type tartaric acid or D-type tartaric acid.

17. In Paragraph 10, The above alkalizing agents are sodium carbonate (Na2CO3), potassium carbonate (K2CO3), sodium bicarbonate (NaHCO3), and sodium phosphate (Na5P3O2). 10 A method for manufacturing a chiral metal oxide-based water electrolysis electrode comprising one or more selected from sodium pyrophosphate (Na4P2O7), disodium phosphate (K2HPO4), disodium phosphate (Na2HPO4), sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), trisodium citrate (C6Na3H5O7), and sodium metaphosphate (NaPO3)6).

18. In Paragraph 10, After the step of forming the above L-type or D-type chiral metal oxide, A method for manufacturing a chiral metal oxide-based water electrolysis electrode, further comprising the step of electrodepositing a single-atom catalyst on the chiral metal oxide.

19. In Paragraph 18, A method for manufacturing a chiral metal oxide-based water electrolysis electrode, wherein the above-mentioned single-atom catalyst comprises one or more selected from ruthenium (Ru), iridium (Ir), platinum (Pt), silver (Ag), copper (Cu), and iron (Fe).

20. A water electrolysis device comprising a water electrolysis electrode according to any one of claims 1 to 9.

Images