Electrode for electrolysis and manufacturing method therefor

Abstract

The present invention relates to an electrode for electrolysis having a catalyst layer including a layered double hydroxide containing nickel, iron, and yttrium, which is easy to manufacture and has excellent electrochemical activity and durability under seawater conditions.

Description

Electrode for electrolysis and method for manufacturing the same

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0032733, filed March 7, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a novel electrolytic electrode and a method for manufacturing the same, which can be manufactured economically by applying a layered double hydroxide containing nickel, iron and yttrium to a catalyst layer, has excellent electrolytic performance and, in particular, has excellent durability in a seawater environment.

[0005] Various types of energy sources are being studied as alternatives to fossil fuels, and a representative example is hydrogen, which has a high energy density without emitting harmful byproducts.

[0006] The most commonly studied and practiced method for producing hydrogen is electrolysis. When water is electrolyzed, oxygen is produced at the oxidation electrode and hydrogen at the reduction electrode. Water is one of the most abundant substances on Earth, making it readily available as a raw material.

[0007] There are two methods for producing hydrogen through electrolysis: seawater electrolysis and freshwater electrolysis. Freshwater electrolysis, however, presents disadvantages, such as the difficulty in obtaining raw materials due to the lower availability of freshwater compared to seawater. Furthermore, the cost of producing freshwater itself also incurs costs, making the hydrogen production process less economical. Seawater electrolysis, on the other hand, offers the advantages of readily available seawater and its natural electrolyte content, allowing for efficient production of hydrogen and oxygen.

[0008] However, seawater has a disadvantage in that ions of components such as sodium, calcium, and magnesium dissolved in it can form complexes, corroding the electrolysis electrode and causing a chlorine generation reaction, which is a side reaction. In particular, the chlorine generation reaction is a reaction that competes with the oxygen generation reaction. It is known that the oxygen generation reaction is superior to the chlorine generation reaction when the pH exceeds 7.5 and the operating conditions are within an overvoltage of 480 mV under the condition of a 0.5 M NaCl aqueous solution concentration. Therefore, in order to efficiently electrolyze seawater, it is essential to use an electrode that can maintain the overvoltage within 480 mV and at the same time maintain a stable state so that the electrode itself does not corrode.

[0009] In relation to this, many studies have been conducted to apply NiFe-based layered double hydroxide (LDH) to the electrode for electrolysis of seawater, taking into account its inherent high activity and synergistic effect. However, it is generally unstable under seawater conditions, and the synthesis itself requires excessively long time when using conventionally known methods such as hydrothermal synthesis and sol-gel method.

[0010] Furthermore, in order to solve the problem that chlorine generation reaction is accompanied as a side reaction when applying layered double hydroxide to water electrolysis, there are prior technologies that form a separate layer capable of blocking chloride ions on the electrode surface, or introduce a metal component such as cobalt into layered double hydroxide to improve the performance and durability of the electrode. However, the former has the problem of a complicated manufacturing process, and the latter still has the problem of not providing a sufficient level of durability.

[0011]

[0012] Prior art literature

[0013] (Patent Document 1) KR 10-2022-0111791 A

[0014] (Patent Document 2) KR 10-2022-0031516 A

[0015]

[0016] The purpose of the present invention is to provide a novel electrolytic electrode and a method for manufacturing the same, which is easy to manufacture, has excellent activity in the electrolytic reaction of water, particularly seawater, and can exhibit sufficient durability even in a seawater environment.

[0017] In order to solve the above-mentioned problem, the present invention provides an electrode for electrolysis and a method for manufacturing the same.

[0018] More specifically, (1) the present invention provides an electrolytic electrode comprising a conductive substrate and a catalyst layer formed on the substrate, wherein the catalyst layer comprises a layered double hydroxide comprising nickel, iron and yttrium.

[0019] (2) The present invention provides an electrolytic electrode according to (1), wherein the conductive substrate has a network-shaped skeletal structure.

[0020] (3) The present invention provides an electrode for electrolysis, wherein the conductive substrate comprises at least one selected from the group consisting of nickel, nickel-iron alloy, titanium, graphene, carbon paper, and carbon film in the above (1) or (2).

[0021] (4) The present invention provides an electrolytic electrode in which the molar ratio between nickel and iron included in the catalyst layer is 10:1 to 1:1 in any one of (1) to (3).

[0022] (5) The present invention provides an electrolytic electrode in which the molar ratio between nickel and yttrium included in the catalyst layer is 50:1 to 10:1 in any one of the above (1) to (4).

[0023] (6) The present invention provides an electrolytic electrode according to any one of the above (1) to (5), wherein the catalyst layer has a nanosheet structure.

[0024] (7) The present invention provides a method for manufacturing an electrode for electrolysis according to any one of (1) to (6), including a step (S1) of pretreating a conductive substrate, a step (S2) of forming a catalyst layer on the conductive substrate by stirring the conductive substrate while immersing the conductive substrate in a precursor solution containing a nickel precursor, an iron precursor, and an yttrium precursor, and a step (S3) of washing and drying the conductive substrate on which the catalyst layer is formed.

[0025] (8) The present invention provides a method for manufacturing an electrode for electrolysis, wherein the step S2 is performed under a temperature condition of 50°C or higher and 100°C or lower in the above (7).

[0026] The electrolytic electrode of the present invention can be manufactured through a relatively simple process and can exhibit excellent electrolytic performance and durability even under seawater conditions.

[0027] Figure 1 shows a photograph after manufacturing an electrode for electrolysis according to Example 1 of the present invention.

[0028] Figure 2 shows an SEM image and EDS mapping photograph of an electrolysis electrode according to Example 1 of the present invention.

[0029] Figure 3 shows an XPS analysis graph of an electrolytic electrode according to Example 1 of the present invention.

[0030] Figure 4 shows an LSV graph of the oxygen evolution reaction of Example 1, Comparative Example 1, and an iridium oxide catalyst of the present invention.

[0031] Figure 5 is a graph comparing the Tafel plots for the electrolysis electrodes of Example 1 and Comparative Example 1.

[0032] Figure 6 is a graph comparing the resistance (EIS) and electrochemical surface area (ECSA) of Example 1 and Comparative Example 1.

[0033] Figure 7 is a graph showing the oxygen generation reaction activity of the electrolysis electrode of Example 1 under freshwater and seawater conditions.

[0034] Figure 8 shows a chronopotentiometry graph of a 100-hour stability experiment in seawater conditions of Example 1.

[0035] Figure 9 shows the results of analyzing the electrode surface of Example 1 using an SEM image after undergoing a stability test in seawater.

[0036] Figure 10 is a graph showing the results of XPS analysis comparison before and after the stability test in seawater of Example 1.

[0037] Hereinafter, the present invention will be described in more detail.

[0038] Terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0039]

[0040] Electrode for electrolysis

[0041] The present invention provides an electrolytic electrode comprising a conductive substrate and a catalyst layer formed on the substrate, wherein the catalyst layer comprises a layered double hydroxide comprising nickel, iron, and yttrium.

[0042]

[0043] conductive substrate

[0044] The electrolytic electrode provided by the present invention has a structure consisting of 1) a substrate and 2) a catalyst layer. The substrate serves to provide a structure capable of supporting a catalyst layer exhibiting substantial catalytic activity, and may be a porous substrate. When the substrate is porous, the contact area with water, a reactant during the electrolysis process, can be maximized.

[0045]

[0046] More specifically, the conductive substrate may have a network-shaped skeletal structure. The conductive substrate may include at least one selected from the group consisting of nickel, a nickel-iron alloy, titanium, graphene, carbon paper, and a carbon film, and may be in the form of a foam or felt thereof. The components listed above can provide sufficient strength to the electrode while also providing sufficient electrical conductivity, and thus are particularly suitable for use as a substrate for an electrolysis electrode. In particular, when nickel or an alloy containing nickel is used as the conductive substrate, the adhesion between the nickel component included in the catalyst layer and the nickel component of the substrate can be further enhanced.

[0047]

[0048] catalyst layer

[0049] The catalyst layer of the electrolytic electrode of the present invention comprises a layered double hydroxide comprising nickel, iron, and yttrium. The catalyst layer may be formed on the conductive substrate described above, and being formed on the conductive substrate means that the catalyst layer is formed on the surface of the conductive substrate.

[0050]

[0051] The above catalyst layer provides activity for the electrolysis reaction of water, and in particular, by including a layered double hydroxide containing nickel, iron and yttrium, it can provide sufficiently high catalytic activity without being easily corroded even in a seawater environment.

[0052] In particular, yttrium included in the above layered double hydroxide is the most common element among rare earth elements, and has the advantage of being relatively low in price. In terms of performance, it can exhibit a level equivalent to or higher than cobalt, which is conventionally used with nickel and iron, and in terms of durability in a seawater environment, it can achieve a superior effect compared to cobalt.

[0053]

[0054] The molar ratio between nickel and iron contained in the catalyst layer may be 10:1 to 1:1, and preferably 8:1 to 2:1. If the molar ratio between nickel and iron is not appropriate, the catalytic activity for the oxygen evolution reaction may be reduced.

[0055] The molar ratio between nickel and yttrium included in the catalyst layer may be 50:1 to 10:1, and preferably 40:1 to 15:1. If yttrium is included in less than this amount, the improvement effect due to the inclusion of yttrium may be minimal, and if yttrium is included in more than this amount, the excessively included yttrium may reduce the activity for the oxygen evolution reaction.

[0056]

[0057] Meanwhile, the catalyst layer may have a nanosheet structure. More specifically, the catalyst layer may have a nanosheet structure of a layered double hydroxide in which the plane direction is oriented perpendicular to the plane direction of the substrate to which the nanosheets are in contact. Through such a structure, the contact area of ​​the layered double hydroxide can be maximized.

[0058]

[0059] The electrolytic electrode of the present invention may be used in an oxygen evolution reaction. That is, the electrolytic electrode of the present invention may be an electrolytic anode. The oxygen evolution reaction involves more electrons than the hydrogen evolution reaction, resulting in a complex reaction process and a slower reaction rate, thus requiring a higher overvoltage than the hydrogen evolution reaction. However, the electrolytic electrode of the present invention can maintain a low overvoltage required for the oxygen evolution reaction.

[0060]

[0061] The electrolytic electrode of the present invention may be used for the electrolysis of seawater. Electrolysis in seawater conditions poses greater risk of electrode corrosion than in freshwater conditions. However, the electrolytic electrode of the present invention maintains excellent durability even under seawater conditions by applying a layered double hydroxide comprising nickel, iron, and yttrium.

[0062]

[0063] Method for manufacturing an electrode for electrolysis

[0064] The present invention provides a method for manufacturing an electrode for electrolysis as described above.

[0065]

[0066] More specifically, the present invention provides a method for manufacturing an electrode for electrolysis, comprising a step (S1) of pretreating a conductive substrate, a step (S2) of forming a catalyst layer on a conductive substrate by immersing the metal substrate in a precursor solution containing a nickel precursor, an iron precursor, and an yttrium precursor and stirring the substrate, and a step (S3) of washing and drying the conductive substrate on which the catalyst layer is formed.

[0067]

[0068] The conductive substrate used in the method for manufacturing the electrolytic electrode of the present invention is as described above.

[0069] The pretreatment in step S1 is performed for the purpose of cleaning the surface of the conductive substrate. More specifically, the pretreatment may be performed by immersing the conductive substrate in one or more solutions selected from the group consisting of an acidic solution, an alcoholic solution, and water, and then ultrasonically treating the conductive substrate.

[0070] Meanwhile, the pretreatment may be performed multiple times using different solutions. Specifically, the pretreatment may be performed through a series of steps, including pretreatment using an acidic solution, pretreatment using an alcoholic solution, and finally pretreatment in water. For example, the acidic solution may be a hydrochloric acid solution, and the alcoholic solution may be an ethanol solution.

[0071] By pretreating in this manner, impurities present on the surface of the conductive substrate can be minimized. After completing the pretreating process, a drying process may be performed to remove any water or solvent remaining on the surface of the conductive substrate. The drying process may be performed at a temperature of 40 to 80°C for a sufficient period of time, specifically, 3 hours or more, to sufficiently remove any remaining components.

[0072]

[0073] After pretreating the conductive substrate through the above process, a catalyst layer can be formed on the surface of the conductive substrate by immersing it in a precursor solution.

[0074]

[0075] The above precursor solution may include precursors of nickel, iron, and yttrium included in the layered double hydroxide. More specifically, the nickel precursor may include at least one selected from the group consisting of nickel nitrate, nickel chloride, nickel sulfate, nickel acetate, and hydrates thereof; the iron precursor may include at least one selected from the group consisting of iron nitrate, iron chloride, iron sulfate, iron acetate, and hydrates thereof; and the yttrium precursor may include at least one selected from the group consisting of yttrium chloride, yttrium nitrate, yttrium acetate, and hydrates thereof. The above-listed types of precursors may be suitable for forming the layered double hydroxide while being easily soluble in water.

[0076]

[0077] By immersing a conductive substrate in the precursor solution and then stirring it, a layered double hydroxide can be formed by mutual oxidation-reduction of the components of the conductive substrate and the metal ions of the precursor. This process can also be called an electrode corrosion method, and the electrode corrosion method has the advantage of being able to form a layered double hydroxide more simply than the existing hydrothermal synthesis method or sol-gel method. Furthermore, through this process, a layered double hydroxide can be directly attached and formed on the surface of a conductive substrate, and by using this method, when the layered double hydroxide is manufactured in a powder form and applied to an electrode, the use of a binder required for contact between the powder and the substrate can be minimized or omitted.

[0078]

[0079] The above electrode corrosion process may be performed under a temperature condition of 50°C or higher and 100°C or lower, and preferably under a temperature condition of 50°C or higher, 60°C or higher, or 65°C or higher, and 100°C or lower, 90°C or lower, or 80°C or lower. If the temperature in this process is too low or high, the reaction between the substrate and the precursor may not proceed smoothly.

[0080]

[0081] After the formation of the catalyst layer through the above electrode corrosion method is completed, a washing and drying step may be performed. Washing in this step is intended to remove unreacted metal precursor components, and may be performed using alcohol or water in which the precursor can be dissolved.

[0082] Drying in this step, like drying in the previous pretreatment step, is to remove any remaining alcohol or water used in the washing process, and can be performed at 40 to 80°C for a sufficient time, specifically, 3 hours or more.

[0083]

[0084] Hereinafter, the present invention will be described in more detail with examples and experimental examples to specifically explain the present invention. However, the present invention is not limited to these examples and experimental examples. The examples according to the present invention can be modified in various different forms, and the scope of the present invention should not be construed as being limited to the examples described below. The examples of the present invention are provided to more completely explain the present invention to those of average skill in the art.

[0085]

[0086] ingredient

[0087] Nickel foam (NF), a conductive substrate, 1 X 2cm 2After cutting to size, the nickel foam was pretreated by immersing it in 0.1 M hydrochloric acid aqueous solution, ethanol, and distilled water in that order, followed by ultrasonic treatment for 15 minutes each. Afterwards, it was dried overnight at 60°C to produce a pretreated nickel foam.

[0088]

[0089] Example 1

[0090] 0.559 g of nickel nitrate hexahydrate (Ni(NO3)2·6H2O), a nickel precursor, 0.194 g of iron nitrate nonahydrate (Fe(NO3)3·9H2O), a iron precursor, and 0.029 g of yttrium chloride hexahydrate (YCl3·6H2O), a yttrium precursor, were added to 50 ml of distilled water and stirred for about 5 minutes. Then, a beaker was placed in a heating mantle, and the nickel foam of the above material was immersed in the beaker containing the precursor solution and stirred at 70°C for 5 hours. A coating layer including a layered double hydroxide containing nickel, iron, and yttrium was formed on the surface of the nickel foam, and the nickel foam with the coating layer formed thereon was taken out, washed with ethanol and distilled water, placed on a tray, and dried overnight at 60°C to obtain an electrolysis electrode.

[0091]

[0092] Comparative Example 1

[0093] An electrolytic electrode having a catalyst layer comprising a layered double hydroxide containing only nickel and iron was obtained by performing the same procedure as in Example 1 except that the yttrium precursor was not used.

[0094]

[0095] Comparative Example 2

[0096] In Example 1, an electrolytic electrode having a catalyst layer comprising a layered double hydroxide comprising nickel, iron, and cobalt was obtained by using a cobalt precursor of the same molar ratio instead of the yttrium precursor.

[0097]

[0098] The components of the layered double hydroxide in the catalyst layer manufactured in the above examples and comparative examples and the molar ratios therebetween are summarized in Table 1 below.

[0099]

[0100] Components of layered double hydroxides and their molar ratiosExample 1Ni:Fe:Y = 4:1:0.2Comparative Example 1Ni:Fe = 4:1Comparative Example 2Ni:Fe:Co = 4:1:0.2

[0101]

[0102] Experimental Example 1. Characteristics of the manufactured electrolytic electrode

[0103] The content of each element in the catalyst layer of the electrolytic electrode manufactured in Example 1 was confirmed using EDS mapping. The results are summarized in Table 2 below.

[0104] Atomic %NiFeYO Example 117.078.880.2573.80

[0105]

[0106] Referring to the results in Table 2 above, it can be seen that the nickel component of the layered double hydroxide included in the coating layer reacts with the nickel foam as a substrate, and thus the nickel content in the surface layer is low, whereas iron and yttrium are synthesized on the nickel foam substrate, and therefore are more exposed to the surface layer, and thus the content is high.

[0107]

[0108] In addition, an actual photograph of the electrolytic electrode manufactured through the above Example 1 is shown in Fig. 1, and an FE-SEM image of the electrode surface is shown in Fig. 2. It can be confirmed through Fig. 1 that the layered double hydroxide was well formed on the surface of the nickel foam through the electrode corrosion method. In addition, Fig. 2 a and b show high-magnification SEM analysis images, and it can be confirmed that the layered double hydroxide was uniformly grown in a nanosheet structure. c is a low-magnification SEM analysis image, and d shows the element mapping analysis using EDS described above, through which it can be seen that Ni, Fe, Y, and O included in the layered double hydroxide are uniformly distributed.

[0109]

[0110] Finally, XPS analysis was performed on the electrolytic electrode manufactured in Example 1, and the results are shown in Fig. 3. Through Fig. 3, it can be confirmed that Ni, Fe, Y, and O, which are the constituent elements of the double layered hydroxide, exist. In addition, more specifically, Ni 2p 2 / 3 In Ni 2+ and Ni 3+ exists at 855 eV and 856.39 eV, and Fe 2p 2 / 3 In Fe 2+ and Fe 3+ It can be confirmed that Y 2p exists at 710.4 eV and 712.78 eV. 2 / 3 It can be confirmed that it exists with a binding energy of 157.27 eV. In the spectrum of O 1s, hydroxyl group (O OH ), oxygen (O L ), chemically adsorbed water (O H ) can be confirmed to exist. Through these XPS analysis results, it can be confirmed that Ni, Fe, Y, and O have a layered double hydroxide structure, and that all components are evenly doped.

[0111]

[0112] Experimental Example 2. Electrochemical Activity Evaluation

[0113] To measure the activity of the electrolytic electrodes of Example 1 and Comparative Example 1 for the oxygen evolution reaction, a three-electrode experiment was performed. A silver-silver chloride electrode (vs. Ag / AgCl) was used as the reference electrode, and a platinum (Pt) electrode was used as the counter electrode. Linear sweep voltammetry (LSV) was measured by a potentiostat (Metrohm Autolab VIONIC) in aqueous solutions of 1 M KOH freshwater and 1 M + 0.5 M NaCl seawater.

[0114] FIG. 4 is a graph showing the oxygen evolution reaction LSV of the electrolytic electrodes of Example 1 and Comparative Example 1 and the iridium oxide catalyst as a control, FIG. 5 is a graph comparing the Tafel plots for the electrolytic electrodes of Example 1 and Comparative Example 1, and FIG. 6 is a graph comparing the resistance (EIS) and electrochemical surface area (ECSA) of Example 1 and Comparative Example 1. FIG. 7 is a graph showing the oxygen evolution reaction activity of the electrolytic electrode of Example 1 under freshwater and seawater conditions. In addition, the oxygen evolution reaction overvoltages of Example 1 and Comparative Example 1 are shown in Table 3 below.

[0115] OER overvoltage (@100mA / cm) 2 )OER overvoltage (@200mA / cm) 2 ) Comparative Example 1344372 Example 1273296

[0116]

[0117] From the results in Table 3 above, it can be seen that the electrolytic electrode of the present invention exhibits a lower overvoltage compared to the case where a double-layered hydroxide containing only Ni and Fe is used. That is, by further including yttrium in the double-layered hydroxide, the overvoltage required for performing the oxygen evolution reaction can be lowered, which means that the electrolytic process can be performed at a lower voltage when using the electrolytic electrode of the present invention.

[0118] In addition, it can be confirmed through FIG. 4 that the activity of the electrolytic electrode according to Example 1 is the best, and from the fact that the Tafel slope of Example 1 confirmed in FIG. 5 is 102 mV / dec, while the Tafel slope of Comparative Example 1 is 134 mV / dec, it can be confirmed that electrons move faster in the layered double hydroxide containing yttrium, resulting in excellent electrochemical activity.

[0119] In addition, through the values ​​of resistance and electrochemically active area confirmed in Fig. 6, it can be confirmed that the electrode of Example 1, which applied a layered double hydroxide containing yttrium, has a lower resistance value and a higher electrochemically active area, and thus has superior electrochemical performance compared to Comparative Example 1.

[0120] Finally, it can be confirmed from FIG. 7 that the electrolysis electrode according to Example 1 of the present invention exhibits excellent activity in both seawater and freshwater.

[0121]

[0122] Experimental Example 3. Stability Test in Seawater

[0123] Seawater stability evaluation was performed on the electrolytic electrodes of Example 1 and Comparative Example 2. Specifically, the same seawater conditions and 100 mA / cm 2 A 100-hour stability experiment chronopotentiometry was performed under current density conditions, and the results are shown in Fig. 8 and Table 4 below (in the meantime, no separate iR correction was performed on the data for this experiment).

[0124] Comparative Example 2 Example 1 After 1100 hours, the potential increased by 0.030 V and 0.020 V.

[0125]

[0126] Referring to FIG. 8, it can be seen that there is no significant difference in the voltage value for maintaining 100 mA / cm2 even after 100 hours between the electrolytic electrode according to Example 1 of the present invention containing yttrium and the electrolytic electrode according to Comparative Example 2 of the present invention containing cobalt. From this, it can be confirmed that both the electrolytic electrodes of Comparative Example 2 and Example 1 exhibit excellent stability under seawater conditions.

[0127] In addition, through Table 4 showing the increase potential after 100 hours, it can be confirmed that the increase potential of Example 1 is lower than that of Comparative Example 2, and through this, it can be confirmed that the electrolytic electrode of Example 1 containing yttrium has a smaller increase in voltage value than the electrolytic electrode of Comparative Example 2, and thus has better durability under seawater conditions.

[0128]

[0129] Experimental Example 4. Evaluation of electrode characteristics after electrochemical activity evaluation

[0130] After evaluating the electrochemical activity, the maintenance of the electrode properties was confirmed through SEM images and XPS analysis.

[0131] Figure 9 shows the results of SEM image analysis of the electrode surface of Example 1 after undergoing the stability test in seawater described above. Figures 9 (a) and (b) show images at high magnification, and the results of Figure 9 show that the sheet form of the double-layered hydroxide is stably maintained even when the oxygen evolution reaction is performed for 100 hours under seawater conditions. This means that the electrolysis electrode of the present invention maintains excellent durability even under the harsh environmental conditions of seawater.

[0132] Figure 10 shows the XPS analysis results before and after stability testing in seawater. Similar XPS analysis results were observed after the seawater stability test, confirming that the yttrium-containing layered double hydroxide stably maintains its properties even in seawater.

Claims

1. Conductive substrate; and A catalyst layer formed on the above substrate; An electrolytic electrode, wherein the catalyst layer comprises a layered double hydroxide comprising nickel, iron and yttrium.

2. In paragraph 1, An electrode for electrolysis, wherein the conductive substrate has a network-shaped skeletal structure.

3. In paragraph 1, An electrode for electrolysis, wherein the conductive substrate comprises at least one selected from the group consisting of nickel, nickel-iron alloy, titanium, graphene, carbon paper, and carbon film.

4. In paragraph 1, An electrolysis electrode having a molar ratio between nickel and iron contained in the catalyst layer of 10:1 to 1:

1.

5. In paragraph 1, An electrolytic electrode having a molar ratio between nickel and yttrium included in the catalyst layer of 50:1 to 10:

1.

6. In paragraph 1, An electrolytic electrode wherein the catalyst layer has a nanosheet structure.

7. Step of preprocessing the conductive substrate (S1); Step (S2) of forming a catalyst layer on a conductive substrate by stirring the conductive substrate while immersing it in a precursor solution containing a nickel precursor, an iron precursor, and an yttrium precursor; and A method for manufacturing an electrode for electrolysis according to claim 1, comprising a step (S3) of washing and drying a conductive substrate on which a catalyst layer is formed.

8. In paragraph 7, A method for manufacturing an electrode for electrolysis, wherein the above step S2 is performed under temperature conditions of 50°C or higher and 100°C or lower.

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