Preparation method and application of bimetallic phosphide coupled layered double hydroxide electrocatalyst

Abstract

The present invention belongs to the technical field of hydrogen production catalysts by electrolysis of water, and more specifically relates to a preparation method and application of a bimetallic phosphide coupled layered double hydroxide electrocatalyst. The present invention uses a nickel source, an iron source, ammonium fluoride, and urea as reactants, and forms a nickel-iron layered double hydroxide nanocatalyst precursor on a conductive substrate through a hydrothermal reaction. The nickel-iron layered double hydroxide nanocatalyst precursor is then subjected to a phosphating treatment by electrodeposition to obtain a bimetallic phosphide coupled layered double hydroxide electrocatalyst. Under the test conditions of a 1 M potassium hydroxide solution, the current density in the linear sweep voltammetry curve of the catalyst is 10 mA cm ‑2 The overpotential required for the reaction is 89 mV. The catalyst has high stability, a simple and energy-saving preparation process, is suitable for industrial applications, and can be used for large-scale water electrolysis to produce hydrogen.

Description

Technical Field

[0001] The present invention belongs to the technical field of water electrolysis hydrogen production catalysts, and more specifically relates to a preparation method and application of a bimetallic phosphide coupled layered double hydroxide electrocatalyst. Background Art

[0002] As a green and clean energy source, hydrogen is considered to have broad development potential due to its high energy density and low pollution emissions. To address the high pollution and unsustainability issues of traditional hydrogen production technologies (such as steam reforming of CH4 and hydrogen production from industrial by-product gases), water electrolysis has emerged. In recent years, the development of various efficient and stable catalysts is crucial to minimize the low conversion efficiency and additional supply costs caused by overcoming the high energy barrier in alkaline water electrolysis hydrogen production. Currently, the precious metal Pt remains the most advanced catalyst, but its scarcity and high price clearly cannot meet the needs of large-scale hydrogen production. Therefore, people are committed to exploring non-precious metal-based electrocatalysts for the hydrogen evolution reaction (HER).

[0003] Transition metal phosphide (TMP) catalysts, due to their inherent catalytic activity and strong covalent bonds between PO and TMPs, help accelerate the oxidation of metal species and improve the long-term stability of the catalyst. Furthermore, TMPs have excellent surface wettability, which facilitates contact between the catalyst and the electrolyte, resulting in performance comparable to that of platinum catalysts. In recent years, nickel-iron layered double hydroxides (NiFe-LDHs) have been extensively studied due to their strong electronegativity. After surface modification, some materials have demonstrated excellent hydrogen evolution performance. However, most double hydroxides still suffer from drawbacks such as poor electronic conductivity and limited active sites. Therefore, the search for simple, highly active, and stable non-precious metal catalysts is urgent. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method and application of a bimetallic phosphide coupled layered double hydroxide electrocatalyst, by preparing a self-supporting NiCoP / NiFe-LDH catalyst to solve the problems existing in the above-mentioned prior art and realize the preparation of a catalyst with high catalytic activity and good stability.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention is to provide a method for preparing a bimetallic phosphide coupled layered double hydroxide electrocatalyst, comprising the following steps:

[0007] A nickel-iron layered double hydroxide nanocatalyst precursor (NiFe-LDH precursor) is formed on a conductive substrate through a hydrothermal reaction using a first nickel source, an iron source, ammonium fluoride and urea as reactants;

[0008] The nickel-iron layered double hydroxide nanocatalyst precursor is phosphated by an electrodeposition method to obtain a bimetallic phosphide coupled layered double hydroxide electrocatalyst (NiCoP / NiFe-LDH heterostructure catalyst).

[0009] The present invention performs phosphating treatment on the nickel-iron layered double hydroxide nanocatalyst precursor by an electrodeposition method, thereby avoiding the release of harmful gases such as PH3.

[0010] Furthermore, the molar ratio of the first nickel source, the iron source, ammonium fluoride and urea is (0.5-5):(0.5-10):(0.5-10):(0.5-10).

[0011] Optionally, the molar ratio of the first nickel source, iron source, ammonium fluoride and urea is 2.5:1.5:6:8.

[0012] Furthermore, the first nickel source includes at least one of nickel chloride hexahydrate, nickel nitrate hexahydrate and nickel sulfate hexahydrate.

[0013] Optionally, the first nickel source is nickel chloride hexahydrate.

[0014] Furthermore, the iron source includes at least one of ferric nitrate nonahydrate, ferric chloride hexahydrate and ferric sulfate nonahydrate.

[0015] Optionally, the iron source is ferric nitrate nonahydrate.

[0016] Furthermore, the temperature of the hydrothermal reaction is 90-120° C., and the time is 8-20 h.

[0017] Optionally, the temperature of the hydrothermal reaction is 120° C. and the time is 12 h.

[0018] The solvent in the hydrothermal treatment is deionized water, which is simple to prepare and green and environmentally friendly. The NiFe-LDH precursor structure obtained after the hydrothermal reaction is a nanoflower-like structure.

[0019] Furthermore, the parameters of the electrodeposition method include: voltage -2~-4 V, time 100-3600 s.

[0020] Optionally, the parameters of the electrodeposition method include: voltage of -4 V and time of 1800 s.

[0021] Furthermore, the electrolyte used in the electrodeposition method is a mixed aqueous solution of potassium chloride, a cobalt source, a second nickel source and a phosphorus source.

[0022] Electrodeposition treatment based on electrolyte can introduce other doping ions and improve the catalyst by regulating parameters such as deposition voltage, time, and solution concentration to meet the electrode requirements of different practical application scenarios.

[0023] Optionally, the molar ratio of the second nickel source, the cobalt source, the phosphorus source, potassium chloride and water in the mixed aqueous solution is (0.001-0.01):(0.001-0.01):(0.01-0.1):(0.009-0.09):(3-4).

[0024] Preferably, the molar ratio of the second nickel source, the cobalt source, the phosphorus source, potassium chloride and water in the mixed aqueous solution is 0.002:0.002:0.02:0.009:(3-4).

[0025] Optionally, the second nickel source includes at least one of nickel chloride hexahydrate, nickel nitrate hexahydrate and nickel sulfate hexahydrate.

[0026] Optionally, the cobalt source includes at least one of cobalt nitrate hexahydrate, cobalt chloride hexahydrate and cobalt sulfate heptahydrate.

[0027] Optionally, the phosphorus source includes sodium hypophosphite monohydrate and / or sodium dihydrogen phosphate dihydrate.

[0028] The present invention grows a target compound (nickel-iron layered double hydroxide) on the surface of a conductive substrate through a hydrothermal reaction, and then constructs a NiCoP / NiFe-LDH heterostructure catalyst by an electrodeposition method; potassium chloride is also added to the electrolyte used in the electrodeposition method of the present invention. By introducing chloride ions into the electrodeposition solution of the electrodeposition method, not only can the corrosion resistance of the electrode be improved, but also the pH value can be adjusted and the conductivity of the solution can be increased, thereby optimizing the electrodeposition process; a constant voltage method is used for electrodeposition, and when a negative voltage is applied, the deposition and phosphating processes proceed simultaneously, and Ni 2+ 、Co 2+ and H2PO2 - Gain electrons and reduce to Ni 0 、Co 0 and P atoms, while Ni 0 、Co 0 Phosphorylation occurs between the precursor and the in-situ generated P atoms to form bimetallic phosphides. Electrodeposition alters the surface structure of the precursor, forming compact, smooth particles based on the nanoflowers. This increases the specific surface area, shortens the electron mass transfer distance, improves conductivity, and further enhances catalytic efficiency. The doping of target elements Ni, Co, and P optimizes the electronic structure of the NiFe-LDH, enhancing the electrochemical activity and durability of the catalyst.

[0029] The second technical solution of the present invention is to provide a bimetallic phosphide coupled layered double hydroxide electrocatalyst, wherein the bimetallic phosphide coupled layered double hydroxide electrocatalyst is prepared by the above-mentioned preparation method.

[0030] The third technical solution of this scheme: provides an application of the above-mentioned bimetallic phosphide coupled layered double hydroxide electrocatalyst in hydrogen evolution in alkaline water electrolysis.

[0031] The present invention discloses the following technical effects:

[0032] The hydrothermal-electrodeposition method of the present invention synthesized the NiCoP / NiFe-LDH heterostructure catalyst directly grown on the surface of the conductive substrate. The current density of the linear sweep voltammetry curve of the catalyst under the test condition of 1 M potassium hydroxide solution was 10 mA cm -2 The overpotential required for the reaction is 89 mV. The catalyst has high stability, a simple and energy-saving preparation process, is suitable for industrial applications, and can be used for large-scale water electrolysis to produce hydrogen.

[0033] The present invention improves the durability of the catalyst by reducing high-valent metal substances to low-valent metals at the reduction potential of electrodeposition. Non-metallic elements are introduced into metal Ni and Co to form a NiCoP / NiFe-LDH heterostructure, exposing more catalytic active sites and reducing hydrogen adsorption energy. Due to the synergistic effect between the two metals, Ni promotes the Volmer reaction and Co promotes the generation and release of H2, thereby regulating the surface charge state, optimizing the adsorption of reactants / intermediates / products, and improving the catalytic activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0035] Figure 1 These are SEM images of the NiFe-LDH precursor in Example 1 at different magnifications, where (a) is a low magnification and (b) is a high magnification.

[0036] Figure 2 SEM images of the NiCoP / NiFe-LDH heterostructure catalyst at different magnifications, where (a) is low magnification and (b) is high magnification.

[0037] Figure 3 Linear sweep voltammograms of NiCoP / NiFe-LDH / NF, Co2P / NiFe-LDH / NF, Ni2P / NiFe-LDH / NF, Pt / C, nickel foam (NF), and NiFe-LDH.

[0038] Figure 4Linear sweep voltammograms of NiCo / NF, NiCoP / NF, NiCoP / NiFe-LDH / NF-1200s, NiCoP / NiFe-LDH / NF-2400s, NiCoP / NiFe-LDH / NF, NiFe-LDH-2, NiFe-LDH-2.5 and NiFe-LDH-3.

[0039] Figure 5 This is the current-time response curve of the NiCoP / NiFe-LDH heterostructure catalyst. DETAILED DESCRIPTION

[0040] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0041] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0042] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0043] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0044] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0045] The raw materials and reagents used in the specific embodiments of the present invention are all commercially available products, and the reagents are all analytically pure and do not require any treatment before use.

[0046] In some specific embodiments, a method for preparing a bimetallic phosphide coupled layered double hydroxide electrocatalyst (NiCoP / NiFe-LDH heterostructure catalyst) is provided, comprising:

[0047] The NiFe-LDH precursor was prepared by a hydrothermal synthesis method: the iron source and nickel source were dissolved in deionized water and stirred until completely dissolved. Ammonium fluoride and urea were then added and stirred until a light green solution was formed. The prepared light green solution was transferred to the liner of a 100 mL reactor. The pretreated conductive substrate was then placed vertically in the liner for a hydrothermal reaction to obtain the NiFe-LDH precursor grown on the conductive substrate.

[0048] The NiCoP / NiFe-LDH heterostructure catalyst was synthesized by electrodeposition: the NiFe-LDH precursor grown on a conductive substrate was used as the working electrode, the graphite rod was used as the counter electrode, and an aqueous solution containing a nickel source, a cobalt source, a phosphorus source and potassium chloride was used as the electrolyte. The constant potential method was used to carry out electrodeposition (room temperature) at an applied voltage of -2~-4 V for 100~3600 s, thereby growing NiCoP directly on the surface of the precursor. The catalyst was then repeatedly washed with ethanol and water three times to obtain the NiCoP / NiFe-LDH heterostructure catalyst.

[0049] In the specific embodiment of the present invention, nickel foam is used as an exemplary conductive substrate for specific description, but nickel foam is not used as a further limitation of the present invention. The processing process of nickel foam is as follows:

[0050] When using nickel foam as a substrate, cut the nickel foam into pieces of 4-8 square centimeters in size, first soak it in concentrated hydrochloric acid for 10-30 minutes to remove the surface oxide film and dirt; then ultrasonically soak it in water and anhydrous ethanol for 10-30 minutes in sequence until the pH is neutral; finally, place it in a vacuum drying oven to dry.

[0051] The NIFe-LDH precursor is hydrothermally synthesized, and the nickel on the surface of the nickel foam will be partially etched into Ni 2+ , Ni 2+ and Fe 3+ A coprecipitation reaction occurs to form NiFe-LDH. In order to accurately synthesize the NiCo bimetallic phosphide of the present invention, it is necessary to continue to add a nickel source to ensure the successful preparation of the catalyst.

[0052] It should be pointed out that the matters not described in detail in the present invention are conventional operating means in this field and are not the focus of the present invention.

[0053] Example 1

[0054] The preparation steps of the bimetallic phosphide coupled layered double hydroxide electrocatalyst (NiCoP / NiFe-LDH heterostructure catalyst) include:

[0055] S1. Preparation of NiFe-LDH precursor:

[0056] Weigh 0.606 g of Fe(NO3)3·9H2O and dissolve it in 70 mL of deionized water. Stir until completely dissolved. Then add 0.594 g of NiCl2·6H2O and continue stirring for 15 min (the molar ratio of Fe(NO3)3·9H2O to NiCl2·6H2O is 1.5:2.5). Then add 0.222 g of NH4F and 0.480 g of CO(NH2)2 and stir until the solution turns light green.

[0057] The light green mixed solution was transferred to a 100 mL hydrothermal reactor. The nickel foam (conductive substrate layer) with the oxide film removed was placed vertically in the mixed solution and subjected to a hydrothermal reaction at 120°C for 12 h. The sample was then cooled to room temperature and removed. It was washed three times with anhydrous ethanol and water and dried in a vacuum drying oven at 80°C for 3 h to obtain a NiFe double hydroxide nanocatalyst precursor grown on a conductive substrate (NiFe-LDH precursor), which was denoted as NiFe-LDH.

[0058] S2. Preparation of NiCoP / NiFe-LDH heterostructure catalyst:

[0059] Dissolve 2 mmol NiCl2·6H2O, 2 mmol Co(NO3)2·6H2O, 20 mmol NaH2PO2·H2O, and 9 mmol KCl in 60 mL of deionized water, stir well, and use as the electrolyte;

[0060] The NiFe-LDH precursor obtained in step S1 was used as the working electrode, and the graphite rod was used as the counter electrode to form a two-electrode system. The constant potential method was used to apply an external voltage of -4 V at room temperature. Electrodeposition was performed in the above electrolyte for 1800 s to grow NiCoP on the surface of the NiFe-LDH precursor. The precursor was then washed repeatedly with water and ethanol three times and dried in a vacuum drying oven at 60 °C for 8 h to obtain a NiCoP / NiFe-LDH heterostructure catalyst, which was recorded as NiCoP / NiFe-LDH / NF.

[0061] Example 2

[0062] Compared with Example 1, the difference is that the electrodeposition preparation is carried out in the above electrolyte for 1200 s, and the final product is NiCoP / NiFe-LDH / NF electrocatalyst, which is recorded as NiCoP / NiFe-LDH / NF-1200s.

[0063] Example 3

[0064] Compared with Example 1, the difference is that the electrodeposition preparation is carried out in the above electrolyte for 2400 s, and the final product is NiCoP / NiFe-LDH / NF electrocatalyst, which is recorded as NiCoP / NiFe-LDH / NF-2400s.

[0065] Comparative Example 1

[0066] Compared with Example 1, the difference is that the electrolyte is prepared by dissolving 2 mmol NiCl2·6H2O, 20 mmol NaH2PO2·H2O and 9 mmol KCl in 60 mL deionized water, and the final product is Ni2P / NiFe-LDH electrocatalyst, which is recorded as Ni2P / NiFe-LDH / NF.

[0067] Comparative Example 2

[0068] Compared with Example 1, the difference is that the electrolyte is prepared by dissolving 2 mmol Co(NO3)2·6H2O, 20 mmol NaH2PO2·H2O and 9 mmol KCl in 60 mL deionized water, and the final product is Co2P / NiFe-LDH electrocatalyst, which is recorded as Co2P / NiFe-LDH / NF.

[0069] Comparative Example 3

[0070] Preparation of conventional Pt / C electrocatalyst:

[0071] 5 mg of 20% Pt / C, 720 μL of deionized water, 250 μL of ethanol and 30 μL of Nafion (5.0 wt %) were mixed and ultrasonicated for 30 min to obtain Pt / C catalyst electrode ink. 50 μL of Pt / C catalyst electrode ink was dropped on nickel foam (1 cm × 1 cm) and dried at room temperature to obtain Pt / C electrocatalyst, which was recorded as Pt / C.

[0072] Comparative Example 4

[0073] Compared with Example 1, the difference is that no NiFe-LDH precursor was prepared, and NiCoP was directly deposited on NF. The electrolyte was prepared by dissolving 2 mmol Co(NO3)2·6H2O, 20 mmol NaH2PO2·H2O and 9 mmol KCl in 60 mL of deionized water. The final product was NiCoP / NF electrocatalyst, which was recorded as NiCoP / NF.

[0074] Comparative Example 5

[0075] Compared with Example 1, the difference is that no NiFe-LDH precursor was prepared and no P element was introduced. NiCo was directly deposited on NF. The electrolyte was prepared by dissolving 2 mmol Co(NO3)2·6H2O and 9 mmol KCl in 60 mL of deionized water. The final product was NiCo / NF electrocatalyst, denoted as NiCo / NF.

[0076] Comparative Example 6

[0077] Compared with Example 1, the difference is that when preparing the NiFe-LDH precursor, the Ni source is changed to 2 mmol, 2.5 mmol, and 3 mmol, and the final products are NiFe-LDH-2, NiFe-LDH-2.5, and NiFe-LDH-3 electrocatalysts, which are recorded as NiFe-LDH-2, NiFe-LDH-2.5, and NiFe-LDH-3.

[0078] Test example

[0079] Figure 1 The SEM images of NiFe-LDH / NF at different magnifications are shown, with (a) at low magnification and (b) at high magnification. As can be seen from the images, NiFe-LDH is successfully grown on a smooth nickel skeleton, and the nanoflower-like structure of the NiFe-LDH precursor is also revealed.

[0080] Figure 2 The SEM images of NiCoP / NiFe-LDH / NF at different magnifications are shown, with (a) at low magnification and (b) at high magnification. As can be seen from the images, the nickel foam skeleton further develops dense, compact, and smooth particles, which possess more catalytically active sites.

[0081] NiCoP / NiFe-LDH / NF, NiCoP / NiFe-LDH / NF-1200s, Co2P / NiFe-LDH / NF, Ni2P / NiFe-LDH / NF, Pt / C, nickel foam (NF), NiFe-LDH-2.5, NiFe-LDH-2, NiFe-LDH-3, NiCoP / NF, NiCo / NF, NiCoP / NiFe-LDH / NF-2400s and NiFe-LDH were used as working electrodes, Hg / HgO was used as reference electrode, graphite rod was used as auxiliary electrode, and the electrolyte was 1 mol L -1 KOH solution with a scan rate of 5 mV s -1 , linear sweep voltammetry test was carried out on Chenhua electrochemical workstation (CHI760E), and the results are as follows Figure 3 and Figure 4 As shown.

[0082] Figure 3 Linear sweep voltammograms of NiCoP / NiFe-LDH / NF, Co2P / NiFe-LDH / NF, Ni2P / NiFe-LDH / NF, Pt / C, nickel foam (NF), and NiFe-LDH.

[0083] Figure 4 Linear sweep voltammograms of NiCo / NF, NiCoP / NF, NiCoP / NiFe-LDH / NF-1200s, NiCoP / NiFe-LDH / NF-2400s, NiCoP / NiFe-LDH / NF, NiFe-LDH-2, NiFe-LDH-2.5 and NiFe-LDH-3.

[0084] Depend on Figure 3-Figure 4 It can be seen that the synergistic effect between Ni and Co leads to the high -2 The overpotential under the conditions of 1 and 2 is significantly better than that of Comparative Examples 1 and 2, indicating that the bimetallic phosphide-coupled layered double hydroxide electrocatalyst prepared by the method of the present invention has a faster H2 release process and electron / proton transfer step, thereby accelerating the entire HER process.

[0085] The obtained NiCoP / NiFe-LDH / NF sample was subjected to 10 mA cm -2 The IT test was carried out at a potential of 1.5 to evaluate the long-term stability of the catalyst in alkaline solution. The results are shown in Figure 2. Figure 5 shown.

[0086] Figure 5Figure 2 shows the current-time response curve of NiCoP / NiFe-LDH / NF. As can be seen, the current density remains almost unchanged after 24 hours of continuous operation, indicating good stability.

[0087] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0088] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a bimetallic phosphide coupled layered double hydroxide electrocatalyst, characterized in that the steps include: A nickel-iron layered double hydroxide nanocatalyst precursor is formed on a conductive substrate through a hydrothermal reaction using a first nickel source, an iron source, ammonium fluoride and urea as reactants; Phosphating the nickel-iron layered double hydroxide nanocatalyst precursor by electrodeposition to obtain a bimetallic phosphide coupled layered double hydroxide electrocatalyst; The electrolyte used in the electrodeposition method is a mixed aqueous solution of potassium chloride, a cobalt source, a second nickel source and a phosphorus source; The parameters of the electrodeposition method include: voltage of -2 to -4 V and time of 100 to 3600 s.

2. The preparation method according to claim 1, wherein The molar ratio of the first nickel source, iron source, ammonium fluoride and urea is (0.5-5):(0.5-10):(0.5-10):(0.5-10); and / or the molar ratio of the second nickel source, cobalt source, phosphorus source, potassium chloride and water in the mixed aqueous solution is (0.001-0.01):(0.001-0.01):(0.01-0.1):(0.009-0.09):(3-4).

3. The preparation method according to claim 1, wherein The first nickel source includes at least one of nickel chloride hexahydrate, nickel nitrate hexahydrate and nickel sulfate hexahydrate; and / or the iron source includes at least one of ferric nitrate nonahydrate, ferric chloride hexahydrate and ferric sulfate nonahydrate.

4. The preparation method according to claim 1, wherein The temperature of the hydrothermal reaction is 90-120° C., and the time is 8-20 h.

5. The preparation method according to claim 1, wherein The second nickel source includes at least one of nickel chloride hexahydrate, nickel nitrate hexahydrate, and nickel sulfate hexahydrate.

6. The preparation method according to claim 1, wherein The cobalt source includes at least one of cobalt nitrate hexahydrate, cobalt chloride hexahydrate, and cobalt sulfate heptahydrate.

7. The preparation method according to claim 1, wherein The phosphorus source includes sodium hypophosphite monohydrate and / or sodium dihydrogen phosphate dihydrate.

8. A bimetallic phosphide coupled layered double hydroxide electrocatalyst, characterized in that: The bimetallic phosphide coupled layered double hydroxide electrocatalyst is prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the bimetallic phosphide coupled layered double hydroxide electrocatalyst according to claim 8 in hydrogen evolution by alkaline water electrolysis.

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