Preparation method and application of bifunctional medium-entropy alloy catalyst for brine electrolysis hydrogen production

Abstract

The invention discloses a preparation method and application of a bifunctional medium-entropy alloy catalyst for brine electrolysis hydrogen production. Belongs to the field of nano material preparation. The preparation method of the medium-entropy alloy catalyst comprises the following steps: by taking a copper foil as a carrier, electroplating different precursor metal salts to quickly synthesize a nano-flower-shaped quaternary medium-entropy alloy nano material FeCoNiRu / Cu with a self-supporting structure; various metals are beneficial to the synergistic effect among atoms, and the nano three-dimensional spherical flower-shaped porous structure is beneficial to rapid mass transfer and release of hydrogen and oxygen; the preparation process of the medium-entropy alloy catalyst is simple, the electrolyte can be recycled, and the prepared sample shows excellent electro-catalysis water decomposition hydrogen production performance in a saline solution; the composite material has excellent electro-catalysis oxygen evolution performance and full water splitting performance and super-long stability under high current density; compared with traditional electrodes with foamed nickel, carbon paper, carbon cloth and the like as carriers, the electrode has excellent application and popularization prospects in seawater electrolysis or high-salinity brine electrolysis.

Description

Technical Field

[0001] The present invention relates to the fields of nanomaterial preparation and green hydrogen energy, and particularly relates to a preparation method and application of a bifunctional medium-entropy alloy catalyst for hydrogen production by electrolyzing salt water. Background Art

[0002] Currently, the methods for hydrogen production mainly include fossil energy reforming, biomass pyrolysis, microbial fermentation, industrial by-product gas, electrolysis of water, etc. Among them, hydrogen production by electrolysis of water is to convert intermittent energy (solar energy, tidal energy, wind energy, etc.) into electrical energy, and then produce hydrogen by electrolyzing water. This method is one of the current mainstream low-carbon hydrogen production routes. The disadvantages of this method mainly include: First, alkaline fresh water is used as the electrolyte. Fresh water only accounts for 2.5-3% of the global water resources, while alkaline water such as seawater and salt lake water accounts for about 97.47%, resulting in high electrolyte costs; Second, currently, noble metal IrO2 is used for the anodic oxygen evolution reaction in electrocatalytic overall water splitting, and noble metal Pt / C is used for the cathodic hydrogen evolution reaction, and the catalyst stability is poor, resulting in a further increase in the cost of electrolyzing water; Third, due to the different electrocatalysts used for anodic oxygen evolution and cathodic hydrogen evolution, the preparation process of the electrolytic cell is complicated. Therefore, there is an urgent need to develop a bifunctional low-cost catalyst that can be used for both hydrogen evolution and oxygen evolution reactions for the electrolysis of alkaline salt water, so as to utilize seawater and salt lake water for hydrogen production by electrolysis.

[0003] A medium-entropy alloy is an alloy system with 3-10 elements. It is a new type of material proposed in recent years, and its entropy value is between that of high-entropy alloys and low-entropy alloys. Medium-entropy alloys not only have relatively high stability, but also have an entropy value between high entropy and low entropy. The atomic arrangement is relatively disordered compared to low-entropy alloys, but more ordered than high-entropy alloys. Therefore, the degree of atomic order and disorder can be effectively adjusted by adjusting the atomic content. Moreover, the synergistic effect between multiple metals can effectively synergistically improve the performance. However, there are still certain problems in the use of medium-entropy alloys for hydrogen production from alkaline high-salt water: First, the preparation conditions are cumbersome, which is not conducive to industrial production; Second, medium-entropy alloys generally only exhibit single functionality, and there are reports that medium-entropy alloys are commonly used for the electrolysis of alkaline salt water. In view of this, it is of great significance to develop a simple and fast bifunctional medium-entropy alloy electrocatalyst for hydrogen production from alkaline salt water. Summary of the Invention

[0004] The object of the present invention is to overcome the shortcomings of the prior art, and provides a preparation method and application of a bifunctional medium-entropy alloy catalyst for hydrogen production by electrolyzing brine; belonging to the field of preparation of nanomaterials and green hydrogen energy; the preparation method of the medium-entropy alloy catalyst is as follows: using a copper foil as a carrier, and rapidly synthesizing a self-supporting quaternary medium-entropy alloy nanomaterial FeCoNiRu / Cu with a nano-flower-like structure by electroplating different precursor metal salts. A variety of metals are beneficial to the synergistic effect between atoms, and the nano three-dimensional spherical flower-like porous structure is beneficial to rapid mass transfer and the release of hydrogen and oxygen; the preparation process of the medium-entropy alloy catalyst is simple, and the electrolyte can be recycled. The prepared sample exhibits excellent electrocatalytic water splitting hydrogen production performance in a brine solution; it has excellent electrocatalytic oxygen evolution performance and overall water splitting performance, and the prepared sample has ultra-long stability at a large current density; compared with traditional electrodes such as nickel foam, carbon paper, and carbon cloth, it has excellent application and promotion prospects.

[0005] To achieve the above technical effects, the following technical solutions are adopted:

[0006] A preparation method of a bifunctional medium-entropy alloy catalyst for hydrogen production by electrolyzing brine, comprising the following steps:

[0007] Step S1: Preparation of electroplating solution

[0008] Dissolve the required nickel salt, ferrous salt, cobalt salt, ruthenium salt, and ammonium salt in deionized water, and then ultrasonically dissolve all the salt compounds to obtain an electroplating solution;

[0009] Step S2: Preparation of medium-entropy alloy catalyst by electroplating

[0010] Cut the copper foil into the required shape, then wash it. The washed copper foil is used as the cathode, and the carbon rod is used as the anode. In an electrolytic cell filled with the electroplating solution obtained in step S1, adjust the voltage for electroplating. After obtaining the FeCoNiRu / Cu electrode material, wash and dry it to obtain the final electrode material, which is the bifunctional medium-entropy alloy catalyst for hydrogen production by electrolyzing brine.

[0011] Further, in step S1, the nickel salt is nickel chloride hexahydrate, nickel sulfate hexahydrate, nickel nitrate hexahydrate, and the concentration of the nickel salt is 0.25 - 0.35 mol / L; in step S1, the ferrous salt is ferrous sulfate heptahydrate, ferrous chloride tetrahydrate, and the concentration of the ferrous salt is 0.1 - 0.2 mol / L; in step S1, the cobalt salt is cobalt chloride hexahydrate, cobalt nitrate hexahydrate, cobalt sulfate hexahydrate, and the concentration of the cobalt salt is 0.15 - 0.25 mol / L; in step S1, the ruthenium salt is ruthenium chloride, and the concentration of the ruthenium salt is 0.025 - 0.035 mol / L; in step S1, the ammonium salt is ammonium chloride, ammonium nitrate, ammonium sulfate, and the concentration of the ammonium salt is 5.6 - 6.0 mol / L.

[0012] Further, the ultrasonic time in step S1 is 10 - 30 min.

[0013] Further, the size of the copper foil in step S2 is 1.5 - 4.0 cm * 1 - 2 cm * 0.2 - 0.8 mm.

[0014] Further, before use, the copper foil in step S2 is cleaned 1 - 3 times successively with 95% ethanol, acetone, and deionized water by ultrasonic waves.

[0015] Further, electroplating is carried out using a DC regulated voltage in step S2, and the voltage range for electroplating is 10 - 20 V, and the electroplating time is 20 - 60 s.

[0016] Further, the diameter of the carbon rod in step S2 is 4 - 8 mm.

[0017] Further, it is washed with deionized water in step S2, and the drying time is 40 - 120 min, and the drying temperature is 40 - 80 °C.

[0018] A bifunctional medium-entropy alloy catalyst for hydrogen production by saline water electrolysis is prepared by using any one of the above preparation methods.

[0019] The above bifunctional medium-entropy alloy catalyst for hydrogen production by saline water electrolysis can be used in the electrolysis of high-salinity water for hydrogen production.

[0020] Currently, the cost of fresh water resources in water electrolysis is high, the catalysts are expensive and have single functionality, and the preparation of medium-entropy alloys is cumbersome; for the bifunctional medium-entropy alloy catalyst for hydrogen production by saline water electrolysis prepared in the present invention, the medium-entropy alloy composed of multiple components in the catalyst is beneficial to the synergistic effect between atoms, and the three-dimensional spherical porous structure is beneficial to rapid mass transfer and the release of hydrogen and oxygen; in the present invention, copper as the catalyst substrate is a self-supporting structure, and compared with traditional electrodes such as nickel foam, carbon paper, and carbon cloth, it shows low values, better and more stable performance.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1. The preparation process of the present invention is simple and fast, the product has good stability, and the electroplating solution can be recycled more than five times;

[0023] 2. The electrode material obtained in the present invention has excellent electrocatalytic water decomposition performance for hydrogen production in alkaline high-salinity water; it has excellent electrocatalytic oxygen evolution performance and overall water splitting performance, and the prepared sample has ultra-long stability at high current density and can continuously work for at least 136 hours without performance degradation in alkaline high-salinity water;

[0024] 3. The present invention synthesizes a self - supported quaternary medium - entropy alloy nanomaterial FeCoNiRu / Cu with a nano - flower - like structure through a simple electroplating method by electroplating different precursor metal salts. The presence of multiple metals facilitates the synergistic effect between atoms, and the nano - three - dimensional spherical flower - like porous structure is conducive to rapid mass transfer and the release of hydrogen and oxygen. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. The drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0026] Figure 1 Schematic diagram of the process for preparing the medium - entropy alloy electrocatalyst in the embodiment of the present invention;

[0027] Figure 2 Scanning electron microscope image of the medium - entropy alloy electrocatalyst prepared in Example 1 of the present invention;

[0028] Figure 3 XRD pattern of the medium - entropy alloy electrocatalyst prepared in Example 1 of the present invention;

[0029] Figure 4 LSV curve of the medium - entropy alloy catalyst prepared in Example 1 of the present invention and the comparison with IrO2 / CP;

[0030] Figure 5 Tafel slope graph of the medium - entropy alloy catalyst prepared in Example 1 of the present invention and the comparison with IrO2 / CP;

[0031] Figure 6 Electrochemical impedance diagram of the medium - entropy alloy catalyst prepared in Example 1 of the present invention and the comparison with IrO2 / CP;

[0032] Figure 7 Electrochemical active surface area diagram of the medium - entropy alloy catalyst prepared in Example 1 of the present invention and the comparison with IrO2 / CP;

[0033] Figure 8 LSV curve of the medium - entropy alloy catalyst prepared in Example 1 of the present invention and IrO2 / CP for hydrogen production by electrolyzing brine;

[0034] Figure 9 For the medium - entropy alloy catalyst prepared in Example 1 of the present invention, IrO2 / CP and Pt / C / CP at 50 mA cm -2 CP test graph at this point. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0037] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations and / or combinations thereof.

[0038] According to Figure 1 As shown in the process schematic diagram of preparing a bifunctional medium-entropy alloy catalyst for hydrogen production by electrolyzing saline water, the preparation of the bifunctional medium-entropy alloy catalyst in the embodiment is completed.

[0039] Example 1:

[0040] (1) Preparation of electroplating solution: 0.25 mol / L nickel chloride hexahydrate, 0.1 mol / L ferrous sulfate heptahydrate, 0.15 mol / L cobalt chloride hexahydrate, 0.025 mol / L ruthenium chloride, and 5.6 mol / L ammonium chloride were dissolved in 40 mL of deionized water, and then ultrasonicated for 10 min to completely dissolve the salt compounds.

[0041] (2) Cut the copper foil into a rectangle of 1.5 * 1 * 0.2 cm, and then ultrasonicate it for 3 minutes successively with 5 mL of 95% ethanol, 5 mL of acetone, and 5 mL of deionized water. Repeat the above steps twice. The obtained copper foil was used as the cathode, and a carbon rod with a diameter of 4 mm was used as the anode. In an electrolytic cell containing 40 mL of the above electroplating solution, under a DC regulated voltage of 10 V, after electroplating for 30 s, the FeCoNiRu / Cu electrode material was washed with deionized water and then dried in a blast drying oven at 40 °C for 40 min to obtain the final electrode material A.

[0042] Example 2:

[0043] (1) Preparation of electroplating solution: 0.35 mol / L nickel chloride hexahydrate, 0.2 mol / L ferrous sulfate heptahydrate, 0.25 mol / L cobalt chloride hexahydrate, 0.035 mol / L ruthenium chloride, and 6 mol / L ammonium chloride were dissolved in 40 mL of deionized water, and then ultrasonicated for 10 min to completely dissolve the salt compounds.

[0044] (2) The copper foil was cut into a rectangle of 4 * 2 * 0.8 cm, and then ultrasonically treated for 3 minutes successively with 10 mL of 95% ethanol, 10 mL of acetone, and 10 mL of deionized water. The above steps were repeated twice. The obtained copper foil was used as the cathode, and a carbon rod with a diameter of 8 mm was used as the anode. In an electrolytic cell containing 40 mL of the above electroplating solution, a DC regulated voltage of 20 V was applied for electroplating for 60 s. After washing with deionized water, the FeCoNiRu / Cu electrode material was dried in a blast drying oven at 80 °C for 60 min to obtain the final electrode material B.

[0045] For the electrode material obtained in Example 1, that is, the bifunctional medium-entropy alloy catalyst A for hydrogen production by saline electrolysis, an electrolytic alkaline brine test evaluation was carried out:

[0046] Preparation of alkaline brine electrolyte: 300 mL of deionized water was measured with a measuring cylinder, and 28.0 g of potassium hydroxide was weighed. While stirring with a glass rod, potassium hydroxide was dissolved in deionized water, and then transferred to a 1 L volumetric flask. Then, in the same way, 28.1 g of potassium hydroxide was dissolved in 300 mL of deionized water, and then transferred to the above 1 L volumetric flask. Deionized water was added to make up to 1 L to obtain a 1 M KOH solution; 5.0 g of sodium chloride was weighed with a balance and placed in a beaker, and then the above-prepared 1 M KOH solution was added to 100 g to obtain an alkaline brine solution.

[0047] Figure 2 It is the scanning electron microscope image of the medium-entropy alloy electrocatalyst prepared in Example 1. Since this preparation method is simple and fast, and it is a self-supporting electrode material, it can avoid the loss of the electrode, resulting in the activity and stability of the electrocatalyst. The synergistic effect between different atoms in the medium-entropy alloy improves the activity of the electrocatalyst. As Figure 2 shown, FeCoNiRu / Cu is a spherical porous structure, which is conducive to rapid mass transfer and the release of hydrogen and oxygen, thus showing excellent activity and stability for hydrogen production by electrolyzing alkaline brine.

[0048] Figure 3 It is the XRD pattern of the medium-entropy alloy electrocatalyst prepared in Example 1. It can be seen from the XRD pattern that the main components of the prepared medium-entropy alloy are FeNi3, Co, and Fe2O3. Among them, FeNi3 is the main active component, and the presence of Co and Fe2O3 synergistically regulates the electronic structure of Fe and Ni; optimizing the performance of electrocatalytic water decomposition.

[0049] Figure 4 LSV curves of the medium-entropy alloy catalyst prepared in Example 1 and the IrO2 / CP control. Using the prepared electrode material as the working electrode, a Hg / HgO electrode as the reference electrode, and a carbon rod with a diameter of 6 mm as the counter electrode, the electrocatalytic oxygen evolution activity of the material was measured by linear sweep voltammetry (LSV) with a scan rate of 5 mV s -1 , without 95% iR correction. The current density of FeCoNiRu / Cu reached 10 mA cm -2 and 50 mA cm -2 with overpotentials of 230 mV and 326 mV, respectively, while the current density of IrO2 / CP reached 10 mA cm -2 and 50 mA cm -2 with overpotentials of 289 mV and 370 mV, respectively.

[0050] Preparation method of the IrO2 / CP control catalyst: Weigh 5 mg of iridium oxide and put it into 4850 μL of 5 w% nafion solution, and ultrasonicate for 30 min to form an ink-like catalyst, then evenly spread 100 μL on the hydrophilic carbon cloth.

[0051] Figure 5 Tafel slope plots of the medium-entropy alloy catalyst prepared in Example 1 and the IrO2 / CP control. The Tafel slope reflects the kinetics of the electrocatalytic oxygen evolution reaction. As Figure 5 shown, the Tafel slope of FeCoNiRu / Cu is 68.42 mV dec -1 , and the Tafel slope of IrO2 / CP is -1 114.13, indicating that FeCoNiRu / Cu has excellent electrocatalytic oxygen evolution reaction kinetics.

[0052] Figure 6 Electrochemical impedance plots of the medium-entropy alloy catalyst prepared in Example 1 and the IrO2 / CP control. The impedance spectrum is an important parameter for evaluating the ease of electron transfer during the electrocatalytic process. Many information can be obtained from the electrochemical impedance spectrum, such as the electrode / solution resistance and some surface information of the electrode. As Figure 6 shown, the semicircle of the prepared catalyst is much smaller than that of the IrO2 / CP catalyst, indicating that the electron transfer rate at the interface is extremely rapid, which is very beneficial for the electrocatalytic oxygen evolution.

[0053] Figure 7 Electrochemical active surface area plots of the medium-entropy alloy catalyst prepared in Example 1 and the IrO2 / CP control. As Figure 7As shown, the electrochemically active surface area of FeCoNiRu / Cu is about 9 times that of IrO2 / CP. This indicates that the prepared FeCoNiRu / Cu has a relatively large electrochemically surface area, and a larger electrochemically surface area is beneficial to the improvement of the intrinsic activity of the electrocatalyst.

[0054] Figure 8 The LSV curve diagram of the hydrogen production by electrolyzing brine using the medium-entropy alloy catalyst prepared in Example 1 and IrO2 / CP. A two-electrode system was adopted, with FeCoNiRu / Cu as the cathode and anode respectively, and hydrogen production by electrolysis was carried out in the above electrolyte. The LSV curve measured by the same method is as Figure 8 shown. The Pt / C electrode was prepared by a method similar to that for preparing the iridium oxide electrode. Using IrO2 and Pt / C electrodes as the anode and cathode respectively, the LSV of hydrogen production by electrolyzing alkaline brine was measured. As Figure 8 shown, it can be seen that at 50 mA cm -2 , only a potential of 1.85 V is required, which is much lower than that of the IrO2 / CP and Pt / C / CP electrode pairs, indicating that the prepared electrocatalyst has very excellent electrocatalytic activity for hydrogen production from alkaline brine. The preparation method of Pt / C / CP is similar to that of IrO2 / CP, and only IrO2 needs to be replaced with Pt / C.

[0055] Figure 9 The CP test diagram of the medium-entropy alloy catalyst prepared in Example 1, IrO2 / CP and Pt / C / CP at 50 mA cm -2 . The stability of the catalyst at a certain current density is another important index for measuring the practical application of the electrocatalyst. Therefore, the chronopotentiometry method was used to evaluate

[0056] the stability of the FeCoNiRu / Cu∥FeCoNiRu / Cu and IrO2 / CP∥Pt / C / CP electrode pairs at 50 mA cm -2 . As Figure 9 shown, the prepared FeCoNiRu / Cu∥FeCoNiRu / Cu has no performance decay in at least 136 h, while IrO2 / CP∥Pt / C / CP can only maintain stability for a few hours. This is mainly because during the test, the catalyst is easily detached due to being directly coated on the carbon cloth. Therefore, the catalytic performance of the FeCoNiRu / Cu prepared in the present invention is greatly improved. This shows that the self-supporting electrocatalyst prepared by the electroplating method has very excellent stability and is expected to be used for hydrogen production by electrolyzing high-salinity seawater or salt lake water.

[0057] Comparative Example 1:

[0058] Other preparation methods were the same as in Example 1, except that ruthenium chloride in Example 1 was removed, or ruthenium chloride and nickel chloride hexahydrate were removed, or nickel chloride and ferrous sulfate heptahydrate were removed, or ruthenium chloride or cobalt chloride hexahydrate were removed, or ferrous sulfate heptahydrate and ruthenium chloride were removed, or nickel nitrate hexahydrate and cobalt nitrate hexahydrate were removed, or ferrous sulfate heptahydrate and cobalt nitrate hexahydrate were removed to prepare FeCoNi / Cu, FeCo / Cu, CoRu / Cu, NiFe / Ru, CoNi / Cu, FeRu / Cu, CoRu / Cu; their overpotentials at 10 mA cm -2 were 270 mV, 287 mV, 268 mV, 245 mV, 261 mV, 305 mV, 278 mV respectively at this point, which were significantly greater than 230 mV of this Example 1.

[0059] Comparative Example 2:

[0060] Other preparation methods were the same as in Example 1, except that ruthenium chloride in Example 1 was replaced with manganese chloride tetrahydrate or aluminum chloride to prepare FeCoNiMn / Cu or FeCoNiAl / Cu; their overpotentials at 10 mA cm -2 were 350 mV and 404 mV respectively at this point. They were significantly greater than 230 mV of this Example 1.

[0061] Comparative Example 3:

[0062] Other preparation methods were the same as in Example 1, except that sodium molybdate dihydrate or sodium tungstate dihydrate was added to Example 1 to prepare FeCoNiRuMo / Cu or FeCoNiRuW / Cu, and their overpotentials at 10 mA cm -2 were 326 mV and 367 mV respectively at this point. They were significantly greater than 230 mV of this Example 1.

[0063] Comparative Example 4:

[0064] The other preparation methods are the same as those in Example 1, except that the composition of the electroplating solution in Example 1: 0.35 mol / L nickel chloride hexahydrate, 0.2 mol / L ferrous sulfate heptahydrate, 0.25 mol / L cobalt chloride hexahydrate, 0.035 mol / L ruthenium chloride, and 6 mol / L ammonium chloride dissolved in 40 mL of deionized water is replaced with: 0.35 mol / L nickel chloride hexahydrate, 0.2 mol / L ferrous sulfate heptahydrate, 0.25 mol / L cobalt chloride hexahydrate, 6 mol / L ruthenium chloride, and 0.035 mol / L ammonium chloride dissolved in 40 mL of deionized water or replaced with: 0.35 mol / L nickel chloride hexahydrate, 6 mol / L ferrous sulfate heptahydrate, 0.25 mol / L cobalt chloride hexahydrate, 0.035 mol / L ruthenium chloride, and 0.2 mol / L ammonium chloride dissolved in 40 mL of deionized water. Materials are prepared respectively; the overpotentials of the obtained FeCoNiRu / Cu at 10 mA cm -2 are 306 mV and 347 mV respectively. This is significantly greater than 230 mV in Example 1 of the present invention.

[0065] In summary, the present invention discloses a preparation method and application of a bifunctional medium-entropy alloy catalyst for hydrogen production by saline water electrolysis; belonging to the fields of nanomaterial preparation and green hydrogen energy; the preparation method of this medium-entropy alloy catalyst is: using a copper foil as a carrier, and rapidly synthesizing a self-supporting structure quaternary medium-entropy alloy nanomaterial FeCoNiRu / Cu with a nano-flower shape by electroplating different precursor metal salts. A variety of metals are beneficial to the synergistic effect between atoms, and the nano three-dimensional spherical flower-shaped porous structure is beneficial to rapid mass transfer and the release of hydrogen and oxygen; the preparation process of this medium-entropy alloy catalyst is simple, and the electrolyte can be recycled. The prepared samples show excellent electrocatalytic water splitting hydrogen production performance in saline solutions; they have excellent electrocatalytic oxygen evolution performance and overall water splitting performance, and the prepared samples have extremely long stability at high current densities; compared with traditional electrodes such as nickel foam, carbon paper, and carbon cloth, they have excellent application and promotion prospects.

[0066] At this point, those skilled in the art recognize that although the embodiments of the present invention have been shown and described in detail herein, still, many other variations or modifications that conform to the principles of the present invention can be directly determined or derived from the content disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all these other variations or modifications.

Claims

1. A preparation method of a bifunctional medium-entropy alloy catalyst for hydrogen production by electrolyzing salt water, characterized in that, The preparation method includes the following steps: Step S1: Preparation of electroplating solution Dissolve the required nickel salt, ferrous salt, cobalt salt, ruthenium salt, and ammonium salt in deionized water, and then perform ultrasonic treatment to completely dissolve the salt compounds to obtain an electroplating solution; Step S2: Electroplating to prepare a medium-entropy alloy catalyst Cut the copper foil into the required shape, then wash it. The obtained copper foil after washing is used as the cathode, and the carbon rod is used as the anode. In an electrolytic cell filled with the electroplating solution obtained in Step S1, adjust the voltage for electroplating. After obtaining the FeCoNiRu / Cu electrode material, wash and dry it to obtain the final electrode material, which is a bifunctional medium-entropy alloy catalyst for hydrogen production by saline water electrolysis.

2. The preparation method of the bifunctional medium-entropy alloy catalyst for hydrogen production by electrolyzing salt water as described in claim 1, characterized in that, In Step S1, the nickel salt is nickel chloride hexahydrate, nickel sulfate hexahydrate, or nickel nitrate hexahydrate, and the concentration of the nickel salt is 0.25 - 0.35 mol / L; in Step S1, the ferrous salt is ferrous sulfate heptahydrate or ferrous chloride tetrahydrate, and the concentration of the ferrous salt is 0.1 - 0.2 mol / L; in Step S1, the cobalt salt is cobalt chloride hexahydrate, cobalt nitrate hexahydrate, or cobalt sulfate hexahydrate, and the concentration of the cobalt salt is 0.15 - 0.25 mol / L; in Step S1, the ruthenium salt is ruthenium chloride, and the concentration of the ruthenium salt is 0.025 - 0.035 mol / L; in Step S1, the ammonium salt is ammonium chloride, ammonium nitrate, or ammonium sulfate, and the concentration of the ammonium salt is 5.6 - 6.0 mol / L.

3. The preparation method of a bifunctional medium-entropy alloy catalyst for hydrogen production by electrolyzing salt water as described in claim 1, characterized in that, In Step S1, the ultrasonic time is 10 - 30 min.

4. The preparation method of a bifunctional medium-entropy alloy catalyst for hydrogen production by electrolyzing salt water as described in claim 1, characterized in that, In Step S2, the size of the copper foil is 1.5 - 4.0 cm * 1 - 2 cm * 0.2 - 0.8 mm.

5. The preparation method of a bifunctional medium-entropy alloy catalyst for hydrogen production by electrolyzing salt water as described in claim 1, characterized in that, Before use in Step S2, the copper foil is washed 1 - 3 times with 95% ethanol, acetone, and deionized water in sequence by ultrasonic wave.

6. The preparation method of a bifunctional medium-entropy alloy catalyst for hydrogen production by electrolyzing salt water as described in claim 1, characterized in that, In Step S2, electroplating is performed using a DC regulated voltage, and the voltage range for electroplating is 10 - 20 V, and the electroplating time is 20 - 60 s.

7. The preparation method of the bifunctional medium-entropy alloy catalyst for hydrogen production by saline electrolysis according to claim 1, characterized in that, In Step S2, the diameter of the carbon rod is 4 - 8 mm.

8. The preparation method of a bifunctional medium-entropy alloy catalyst for hydrogen production by electrolyzing salt water as described in claim 1, characterized in that, In Step S2, it is washed with deionized water, and the drying time is 40 - 120 min, and the drying temperature is 40 - 80 °C.

9. A bifunctional medium-entropy alloy catalyst for hydrogen production by electrolyzing salt water, characterized in that, Prepared by using the preparation method according to any one of claims 1 - 8.

10. The application method of a bifunctional medium-entropy alloy catalyst for hydrogen production by electrolyzing salt water as described in claim 9, characterized in that, Application of the bifunctional medium-entropy alloy catalyst for hydrogen production by saline water electrolysis in hydrogen production by electrolysis of high-salinity water.

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