Alkaline electrolytic medium, double-active-site phosphide catalyst, preparation method and application

Abstract

The invention discloses an alkaline electrolytic medium, a double-active-site phosphide catalyst, a preparation method and application, and belongs to the field of water electrolysis hydrogen production. The double-active-site phosphide catalyst comprises a phosphide-based material of which the chemical formula is R-MPx, wherein R is an oxyphilic component, and is a monometal or multi-metal doped hydroxide or oxide in Fe, Co, Ni, Cu, La, Cr, Mn, Ti, V, Ce, Re and Y; mPx is single-metal phosphide or multi-metal phosphide, and M is transition metal or precious metal. In the preparation method, when R in R-MPx is metal doping, a one-step electrodeposition method is used; when R in R-MPx is a metal hydroxide or oxide, a two-step electrodeposition method is used; according to the scheme, the preparation cost of the water electrolysis hydrogen production catalyst can be effectively reduced, and commercialized application of the water electrolysis hydrogen production technology is better facilitated.

Description

Technical Field

[0001] This invention relates to the field of hydrogen production by water electrolysis, and particularly to an alkaline electrolysis medium and a dual-active-site phosphide catalyst, its preparation method, and its uses. Background Technology

[0002] With the rapid depletion of fossil fuels and increasingly severe environmental problems, the development of renewable and clean energy is urgently needed. Hydrogen (H2) combustion produces only water and does not cause environmental pollution or contribute to the greenhouse effect, making it an ideal renewable and clean energy source and a potential substitute for fossil fuels. Electrolysis of water is a highly promising method for hydrogen production, offering advantages such as rapid production rates, sustainable production of large quantities of high-purity H2, simple processing, and environmental friendliness. Currently, one of the biggest challenges in water electrolysis for hydrogen production is its high overpotential, which reduces energy conversion efficiency, leading to high energy consumption and excessively high H2 production costs. This makes it uneconomical, hindering large-scale promotion and preventing the formation of an industrial advantage. Highly active catalysts can effectively reduce the overpotential, thereby lowering energy consumption and saving on hydrogen production costs.

[0003] The electrolysis of water is typically carried out in acidic or alkaline media. Although acidic media can provide abundant H+... + While acidic water electrolysis is beneficial for hydrogen evolution, the oxidizing effect of the anolyte potential and its acidic corrosiveness limit the range of available catalysts, primarily consisting of precious metals such as Pt, Ru, and Ir. The high cost of precious metals significantly hinders the commercial application of acidic water electrolysis for hydrogen production. Conversely, alkaline water electrolysis offers greater advantages, with a wider range of available catalysts, including inexpensive non-precious metals such as Fe, Co, Ni, and Mo. Alkaline water electrolysis for hydrogen production can be divided into alkaline electrolyzer-based and anion exchange membrane electrolyzer-based methods. In recent years, numerous researchers have conducted extensive studies on non-precious metal alkaline water electrolysis catalysts. However, the performance of these catalysts still falls short of commercial application requirements, and further improvements are needed. Therefore, developing inexpensive and abundant non-precious metal highly active catalysts is of great significance for the development of alkaline water electrolysis for hydrogen production technology and the use of renewable clean hydrogen energy.

[0004] Specifically, the overall reactions of the acidic and basic hydrogen evolution reactions are shown in Table 1, and their reaction mechanisms are as follows: Figure 8 As shown.

[0005] Both acidic and basic hydrogen evolution reactions first proceed through the Volmer step to generate the intermediate MH (M being the active site), then proceed through the Tafel or Heyrovsky step to generate H2, simultaneously releasing the active site M. Clearly, the rate of MH formation directly affects the rate of H2 formation. Therefore, the reaction rate of the Volmer step directly influences the rate of H2 formation. Due to the high concentration of H2 in acidic electrolytes... + The active site M readily interacts with H. + The intermediate MH is formed through a proton reduction reaction, making the Volmer step more likely to occur in acidic electrolytes, resulting in a faster hydrogen evolution reaction rate. However, in alkaline electrolytes, due to the H+... + The concentration is very low, so it can only originate from the water dissociation reaction, and then combine with the active site M through a proton reduction reaction to form the intermediate MH. Compared with the acidic hydrogen evolution reaction, the basic hydrogen evolution reaction has an additional water dissociation step in the Volmer step. Therefore, the reaction rate of the water dissociation reaction can affect the reaction rate of the Volmer step, and thus affect the hydrogen evolution activity of the catalyst. Summary of the Invention

[0006] The purpose of this invention is to propose a dual-active-site phosphide catalyst for alkaline electrolysis media. The phosphide catalyst prepared by the simple electrodeposition synthesis method can be used for hydrogen evolution reaction in alkaline water electrolysis. It does not require heating equipment and the synthesis process does not produce toxic gases or harmful substances. It is easy to achieve large-scale mass production and effectively reduces the cost of preparing hydrogen production catalysts for water electrolysis.

[0007] To achieve this objective, the present invention adopts the following technical solution: A dual-active-site phosphide catalyst for alkaline electrolysis media, comprising the chemical formula R-MP x Phosphate-based materials; Wherein, R is the oxyphilic component, which is a dopant, hydroxide, or oxide of a single or multiple metal from Fe, Co, Ni, Cu, La, Cr, Mn, Ti, V, Ce, Re, and Y; MP x It is a single-metal phosphide or a multi-metal phosphide, where M is a transition metal or a noble metal.

[0008] Optimally, the transition metal is at least one selected from Mn, Fe, Co, Ni, Cu, Mo, and W; the noble metal is at least one selected from Fe, Co, Ni, Cu, La, Cr, Mn, Ti, V, Ce, Re, and Y. The monometallic phosphide is at least one of Ni2P, Ni5P4, CoP, Co2P, FeP, Fe2P, MnP, Mn2P, Cu3P, MoP, W2P, Ru2P, Rh2P, Pd2P, OsP2, Ir2P, Au2P3, AgP2, and PtP2. The polymetallic phosphide is at least one of NiCoP, FeNi2P, Mn3NiP2, CoMnP, Ni2P / CoP, Ni2P / Co2P, Ni2P / Fe2P, Ni2P / FeP, NiFeP, CoFeP, Ni2P / MnP, Co2P / MnP, CoP / MnP, CoP / Ni2P / FeP, Ru2P / Ni2P, Ir2P / CoP, and Pd2P / NiCoP.

[0009] Optimally, the phosphide-based material is NiCoP or MnO. x / NiCoP, CeO x / NiCoP or Ni(OH)2 / NiCoP.

[0010] A method for preparing a dual-active-site phosphide catalyst, used to prepare the above-mentioned dual-active-site phosphide catalyst for an alkaline electrolysis medium, R-MP. x When R represents metal doping, a one-step electrodeposition method is used; The one-step electrodeposition method includes the following steps: (1) Phosphate MP x The metal M, the metal salt of the oxyphilic component R, sodium hypophosphite, and sodium salt are completely dissolved in deionized water to form an electrolyte. The molar ratio between metal M and oxyphilic component R is 5–15. The molar amount of sodium hypophosphite is 1.5–3 times the sum of M and R. The molar amount of sodium salt is 0.5–2 times the molar amount of sodium hypophosphite. (2) At room temperature and normal pressure, a three-electrode system is used to carry out the electrodeposition reaction. The three-electrode system includes a working electrode, a counter electrode and a reference electrode. The working electrode is a conductive support. The electrodeposition reaction is carried out under constant voltage. After the electrodeposition is completed, the conductive support is washed and dried with deionized water to obtain a dual-active-site phosphide catalyst.

[0011] Optimally, in step (1), the metal salt of metal M, the metal salt of oxyphilic component R, and the sodium salt are selected as chloride, nitrate, acetate, sulfate, or hydrates of the above four, respectively.

[0012] A method for preparing a dual-active-site phosphide catalyst, used to prepare the above-mentioned dual-active-site phosphide catalyst for an alkaline electrolysis medium, R-MP. x When R is a hydroxide or oxide of a metal, a two-step electrodeposition method is used; The two-step electrodeposition method includes the following steps: (1) The metal salt of metal M, sodium hypophosphite and sodium salt are completely dissolved in deionized water as electrolyte 1; at room temperature and normal pressure, a three-electrode system is used to carry out the electrodeposition reaction, the three-electrode system includes: working electrode, counter electrode and reference electrode; the electrodeposition reaction is carried out using electrolyte 1 at constant voltage to obtain a single-component phosphide catalyst with dual active sites. The molar amount of sodium hypophosphite is 1.5 to 3 times that of M; the molar amount of sodium salt is 0.5 to 2 times that of sodium hypophosphite; and a conductive carrier is selected as the working electrode. (2) The metal salt of the oxyphilic component R and sodium nitrate are completely dissolved in deionized water at a molar ratio of 1:(1-4) to form electrolyte 2. The conductive support is washed and dried with deionized water. In a three-electrode system, the dual-active-site single-component phosphide catalyst supported on the conductive support in step (1) is used as the working electrode. Electrodeposition reaction is carried out in electrolyte 2 under constant voltage. The conductive support is washed and dried with deionized water to obtain the dual-active-site dual-component phosphide catalyst.

[0013] Optimally, in step (1), when the metal salt of the oxyphilic component R is an oxide, the metal salt of metal M, the metal salt of the oxyphilic component R, and the sodium salt are selected as chlorides, nitrates, acetates, sulfates, or hydrates of the above four; when the metal salt of the oxyphilic component R is a hydroxide, the metal salt of R is a nitrate, and the metal salt of metal M and the sodium salt are selected as chlorides, nitrates, acetates, sulfates, or hydrates of the above four.

[0014] An alkaline electrolytic medium for producing hydrogen by electrolysis of water, wherein a catalyst is added, the catalyst being a dual-active-site phosphide catalyst of the aforementioned alkaline electrolytic medium, or prepared by the aforementioned method for preparing a dual-active-site phosphide catalyst.

[0015] The use of a catalyst in alkaline water electrolysis for hydrogen production, wherein the catalyst is a dual-active-site phosphide catalyst of an alkaline electrolysis medium as described above, or is prepared by the preparation method of a dual-active-site phosphide catalyst as described above.

[0016] An application of a catalyst in the preparation of an alkaline electrolytic medium for hydrogen production by water electrolysis, wherein the catalyst is a dual-active-site phosphide catalyst of the above-mentioned alkaline electrolytic medium, or is prepared by the above-mentioned method for preparing a dual-active-site phosphide catalyst.

[0017] Compared with the prior art, one of the above technical solutions has the following beneficial effects: This solution provides a dual-active-site phosphide catalyst for alkaline electrolysis media. The phosphide catalyst prepared by the simple electrodeposition synthesis method can be used for hydrogen evolution reaction in alkaline water electrolysis. It does not require heating equipment and the synthesis process does not produce toxic gases or harmful substances. It is easy to achieve large-scale mass production, effectively reducing the cost of preparing hydrogen production catalysts for water electrolysis and further facilitating the commercial application of water electrolysis hydrogen production technology. Attached Figure Description

[0018] Figure 1 NiCoP and MnO prepared in Examples 1-4 x / NiCoP, CeO x X-ray diffraction patterns of / NiCoP and Ni(OH)2 / NiCoP catalysts; Figure 2 Scanning electron microscope image and elemental mapping diagram of the NiCoP catalyst prepared in Example 1; Figure 3 MnO prepared in Example 2 x Scanning electron microscope image of the NiCoP catalyst and its elemental mapping diagram; Figure 4 CeO prepared in Example 3 x Scanning electron microscope image of the NiCoP catalyst and its elemental mapping diagram; Figure 5 Scanning electron microscope image and elemental mapping diagram of the Ni(OH)2 / NiCoP catalyst prepared in Example 4; Figure 6 NiCoP and MnO from Examples 1-4 x / NiCoP, CeO x Alkaline water electrolysis hydrogen evolution activity test diagrams for / NiCoP and Ni(OH)2 / NiCoP catalysts; Figure 7 NiCoP and MnO from Examples 1-4 x / NiCoP, CeO x Stability test results of hydrogen evolution in alkaline water electrolysis for NiCoP and Ni(OH)2 / NiCoP catalysts; Figure 8 These are the elementary reactions of hydrogen evolution in acidic (black arrow) and alkaline (red arrow) electrolytes. The green arrows correspond to the Volmer-Tafel mechanism of hydrogen evolution, while the black arrows correspond to the Volmer-Heyrovsky mechanism. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0020] To facilitate understanding of the present invention, a more comprehensive description is provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with techniques or conditions described in the literature in the art or according to product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0021] A dual-active-site phosphide catalyst for alkaline electrolysis media, comprising the chemical formula R-MP x Phosphate-based materials; Wherein, R is the oxyphilic component, which is a dopant, hydroxide, or oxide of a single or multiple metal from Fe, Co, Ni, Cu, La, Cr, Mn, Ti, V, Ce, Re, and Y; MP x It is a single-metal phosphide or a multi-metal phosphide, where M is a transition metal or a noble metal.

[0022] This solution provides a dual-active-site phosphide catalyst for alkaline electrolysis media. The phosphide catalyst prepared by the simple electrodeposition synthesis method can be used for hydrogen evolution reaction in alkaline water electrolysis. It does not require heating equipment and the synthesis process does not produce toxic gases or harmful substances. It is easy to achieve large-scale mass production, effectively reducing the cost of preparing hydrogen production catalysts for water electrolysis and further facilitating the commercial application of water electrolysis hydrogen production technology.

[0023] The strategy for dual-active-site phosphide catalysts lies in preparing phosphide catalysts using a simple electrodeposition synthesis method for hydrogen evolution reaction in alkaline media water electrolysis. In the alkaline media water electrolysis hydrogen evolution reaction, the reaction intermediate MH (where M is the active site) must first be generated, and MH can only originate from the water dissociation reaction (H₂O + M + e⁻). − → MH + OH −Therefore, the water dissociation reaction rate affects the hydrogen evolution reaction rate in alkaline water electrolysis. Accelerating the water dissociation reaction through an oxygen-loving component (with suitable OH adsorption energy) promotes the release of H protons, increases the formation rate of the MH intermediate, and significantly improves the alkaline water electrolysis hydrogen evolution reaction rate of the catalyst. This electrodeposition synthesis method is simple and efficient, requires no heating equipment, and does not produce toxic gases or harmful substances during the synthesis process. It is easily achievable for large-scale production, effectively reducing the cost of preparing hydrogen production catalysts for water electrolysis.

[0024] The catalyst material in this invention is a phosphide-based material—R-MP x It contains phosphide MP x And the oxyphilic component R.

[0025] Metal M includes transition metals such as Mn, Fe, Co, Ni, Cu, Mo, and W, as well as noble metals such as Ru, Rh, Pd, Os, Ir, Ag, Pt, and Au.

[0026] R is a dopant or hydroxide or oxide of a single metal or polymetallic such as Fe, Co, Ni, Cu, La, Cr, Mn, Ti, V, Ce, Re, and Y.

[0027] The phosphides in this catalyst include monometallic or polymetallic phosphides; it should be specified that MP... x This is a general term for metal phosphides, where x in the formula represents the undefined number of phosphorus atoms. The actual number of M atoms is determined by pairing the metal valence with the number of phosphorus atoms. Examples include single-metal phosphides such as Ni2P, Ni5P4, CoP, Co2P, FeP, Fe2P, MnP, Mn2P, Cu3P, MoP, W2P, Ru2P, Rh2P, Pd2P, OsP2, Ir2P, Au2P3, AgP2, and PtP2, and / or N... Multimetallic phosphides including iCoP, FeNi2P, Mn3NiP2, CoMnP, Ni2P / CoP, Ni2P / Co2P, Ni2P / Fe2P, Ni2P / FeP, NiFeP, CoFeP, Ni2P / MnP, CoP / MnP, CoP / Ni2P / FeP, Ru2P / Ni2P, Ir2P / CoP, Pd2P / NiCoP, etc.

[0028] The oxyphilic component R in this catalyst includes single or multimetallic dopants, hydroxides, or oxides of Fe, Co, Ni, Cu, La, Cr, Mn, Ti, V, Ce, Re, and Y, such as Ni(OH)2, Co(OH)2, Fe(OH)3, Cu(OH)2, La(OH)3, Cr(OH)3, and Ni. x Co 1-x (OH)2, Ni x Fe1-x (OH)2, Ni x Mn 1-x (OH)2, Ni x La 1-x (OH)2, Ni x Ce 1-x (OH)2, Co x La 1-x (OH)2, Co x Fe 1-x (OH)2, MnO2, V2O3, CeO2, TiO2, Mn x Fe 1-x O2, Mn x Ce 1-x O2, Ce x V 1-x O2, Ce x Ti 1-x O2, etc.

[0029] Optimally, the transition metal is at least one selected from Mn, Fe, Co, Ni, Cu, Mo, and W; the noble metal is at least one selected from Fe, Co, Ni, Cu, La, Cr, Mn, Ti, V, Ce, Re, and Y. The monometallic phosphide is at least one of Ni2P, Ni5P4, CoP, Co2P, FeP, Fe2P, MnP, Mn2P, Cu3P, MoP, W2P, Ru2P, Rh2P, Pd2P, OsP2, Ir2P, Au2P3, AgP2, and PtP2. The polymetallic phosphide is at least one of NiCoP, FeNi2P, Mn3NiP2, CoMnP, Ni2P / CoP, Ni2P / Co2P, Ni2P / Fe2P, Ni2P / FeP, NiFeP, CoFeP, Ni2P / MnP, Co2P / MnP, CoP / MnP, CoP / Ni2P / FeP, Ru2P / Ni2P, Ir2P / CoP, and Pd2P / NiCoP.

[0030] Optimally, the phosphide-based material is NiCoP or MnO. x / NiCoP, CeO x / NiCoP or Ni(OH)2 / NiCoP.

[0031] A method for preparing a dual-active-site phosphide catalyst, used to prepare the above-mentioned dual-active-site phosphide catalyst for an alkaline electrolysis medium, R-MP. x When R represents metal doping, a one-step electrodeposition method is used; The one-step electrodeposition method includes the following steps: (1) Phosphate MP x The metal M, the metal salt of the oxyphilic component R, sodium hypophosphite, and sodium salt are completely dissolved in deionized water to form an electrolyte. The molar ratio between metal M and oxyphilic component R is 5–15. The molar amount of sodium hypophosphite is 1.5–3 times the sum of M and R. The molar amount of sodium salt is 0.5–2 times the molar amount of sodium hypophosphite. (2) At room temperature and normal pressure, a three-electrode system is used to carry out the electrodeposition reaction. The three-electrode system includes a working electrode, a counter electrode and a reference electrode. The working electrode is a conductive support. The electrodeposition reaction is carried out under constant voltage. After the electrodeposition is completed, the conductive support is washed and dried with deionized water to obtain a dual-active-site phosphide catalyst.

[0032] A one-step electrodeposition method was used to prepare dual-active-site-doped phosphide catalysts. The preparation process of the phosphide-based materials was very simple, and the reaction formula was as follows: Where n is 2 or 3, this preparation method does not require heating equipment and the synthesis process does not produce toxic gases or harmful substances, making it easy to achieve large-scale mass production and effectively reducing the cost of preparing hydrogen production catalysts by water electrolysis.

[0033] Optimally, in step (1), the metal salt of metal M, the metal salt of oxyphilic component R, and the sodium salt are selected as chloride, nitrate, acetate, sulfate, or hydrates of the above four, respectively.

[0034] The chemical formula of this scheme is R-MP x The phosphide-based materials prepared by this method allow for the selection of a wide range of catalysts, including inexpensive non-precious metals such as Fe, Co, Ni, and Mo, where both the metal salt of metal M and the metal salt of the oxyphilic component R can be chlorides, nitrates, acetates, sulfates, or hydrates of the above four. The resulting dual-active-site phosphide catalyst exhibits superior catalytic activity compared to pure phosphide catalysts in alkaline water electrolysis for hydrogen evolution. The addition of the oxyphilic component R effectively enhances the catalyst's alkaline hydrogen evolution activity, demonstrating excellent alkaline water electrolysis hydrogen evolution activity and stability.

[0035] In step (2) above, the conductive carrier is nickel foam, copper foam, carbon cloth, carbon paper, ITO conductive glass or FTO conductive glass.

[0036] A method for preparing a dual-active-site phosphide catalyst, used to prepare the above-mentioned dual-active-site phosphide catalyst for an alkaline electrolysis medium, R-MP. x When R is a hydroxide or oxide of a metal, a two-step electrodeposition method is used; The two-step electrodeposition method includes the following steps: (1) The metal salt of metal M, sodium hypophosphite and sodium salt are completely dissolved in deionized water as electrolyte 1; at room temperature and normal pressure, a three-electrode system is used to carry out the electrodeposition reaction, the three-electrode system includes: working electrode, counter electrode and reference electrode; the electrodeposition reaction is carried out using electrolyte 1 at constant voltage to obtain a single-component phosphide catalyst with dual active sites. The molar amount of sodium hypophosphite is 1.5 to 3 times that of M; the molar amount of sodium salt is 0.5 to 2 times that of sodium hypophosphite; and a conductive carrier is selected as the working electrode. (2) The metal salt of the oxyphilic component R and sodium nitrate are completely dissolved in deionized water at a molar ratio of 1:(1-4) to form electrolyte 2. The conductive support is washed and dried with deionized water. In a three-electrode system, the dual-active-site single-component phosphide catalyst supported on the conductive support in step (1) is used as the working electrode. Electrodeposition reaction is carried out in electrolyte 2 under constant voltage. The conductive support is washed and dried with deionized water to obtain the dual-active-site dual-component phosphide catalyst.

[0037] A two-step electrodeposition method was used to prepare a two-component phosphide catalyst with coupled hydroxide or oxide sites, as shown in the following reaction formula: ; Hydroxide-coupled phosphide catalyst: ; Oxide-coupled phosphide catalysts: ; The dual-active-site phosphide catalyst prepared by this method exhibits superior catalytic activity compared to pure phosphide catalysts in alkaline water electrolysis hydrogen evolution reaction. The addition of the oxyphilic R component effectively improves the alkaline hydrogen evolution activity of the catalyst, demonstrating excellent alkaline water electrolysis hydrogen evolution activity and stability.

[0038] Optimally, in step (1), when the metal salt of the oxyphilic component R is an oxide, the metal salt of metal M, the metal salt of the oxyphilic component R, and the sodium salt are selected as chlorides, nitrates, acetates, sulfates, or hydrates of the above four; when the metal salt of the oxyphilic component R is a hydroxide, the metal salt of R is a nitrate, and the metal salt of metal M and the sodium salt are selected as chlorides, nitrates, acetates, sulfates, or hydrates of the above four.

[0039] In step (2) above, the conductive carrier is nickel foam, copper foam, carbon cloth, carbon paper, ITO conductive glass or FTO conductive glass.

[0040] An alkaline electrolytic medium for producing hydrogen by electrolysis of water, wherein a catalyst is added, the catalyst being a dual-active-site phosphide catalyst of the aforementioned alkaline electrolytic medium, or prepared by the aforementioned method for preparing a dual-active-site phosphide catalyst.

[0041] The purpose of this invention is to provide a dual-activity strategy for preparing phosphide catalysts for hydrogen evolution reaction in alkaline medium water electrolysis using a simple electrodeposition synthesis method. In the alkaline medium water electrolysis hydrogen evolution reaction, the reaction intermediate MH (M being the active site) must first be generated, and MH can only originate from the water dissociation reaction (H₂O + M + e⁻). − → MH + OH − Therefore, the rate of water dissociation reaction affects the rate of hydrogen evolution in alkaline water electrolysis. This scheme accelerates the water dissociation reaction by using an oxyphilic component (with suitable OH adsorption energy), thereby promoting the release of H protons, increasing the formation rate of MH intermediates, and significantly improving the rate of hydrogen evolution in alkaline water electrolysis of the catalyst. This electrodeposition synthesis method is simple and efficient, requires no heating equipment, and does not produce toxic gases or harmful substances during the synthesis process. It is easy to achieve large-scale production, effectively reducing the cost of preparing hydrogen production catalysts for water electrolysis and contributing to the commercial application of water electrolysis hydrogen production technology.

[0042] The use of a catalyst in alkaline water electrolysis for hydrogen production, wherein the catalyst is a dual-active-site phosphide catalyst of an alkaline electrolysis medium as described above, or is prepared by the preparation method of a dual-active-site phosphide catalyst as described above.

[0043] An application of a catalyst in the preparation of an alkaline electrolytic medium for hydrogen production by water electrolysis, wherein the catalyst is a dual-active-site phosphide catalyst of the above-mentioned alkaline electrolytic medium, or is prepared by the above-mentioned method for preparing a dual-active-site phosphide catalyst.

[0044] Example 1: NiCoP catalyst was prepared using a one-step electrodeposition method: First, 0.71 g NiCl₂·6H₂O, 0.71 g CoCl₂•6H₂O, 2.67 g NaH₂PO₂, and 0.58 g NaCl were weighed and added to 50 mL of deionized water. The mixture was then stirred for 10 minutes to ensure complete dissolution. This solution was used as the electrolyte. A three-electrode system was used to electrodeposit the catalyst onto the surface of nickel foam, with nickel foam as the working electrode, a carbon rod as the counter electrode, and a saturated silver chloride electrode as the reference electrode. The electrodeposition reaction was carried out at a constant voltage of -1.2 V (relative to the saturated silver chloride electrode) for 500 seconds. After electrodeposition, the nickel foam support was washed with deionized water and dried for 12 hours to obtain the NiCoP catalyst. X-ray diffraction, scanning electron microscopy, and elemental analysis confirmed the catalyst's properties. Figure 1 and Figure 2 As shown.

[0045] Example 2, Preparation of MnO x / NiCoP catalyst uses a two-step electrodeposition method: The first step, electrodeposition, was used to prepare NiCoP material, following the same process as in Example 1. In the second step, 0.845 g of MnSO4 and 1.7 g of NaNO3 were completely dissolved in 50 mL of deionized water to form electrolyte 2. A three-electrode system was used for electrodeposition, with the nickel foam-supported NiCoP as the working electrode, a carbon rod as the counter electrode, and a saturated calomel electrode as the reference electrode. The electrodeposition reaction was carried out at a constant voltage of -0.5 V (relative to the saturated calomel electrode) for 5 seconds. After electrodeposition, the nickel foam support was washed with deionized water and dried for 12 hours to obtain MnO. x The NiCoP catalyst was confirmed by X-ray diffraction, scanning electron microscopy, and elemental analysis, as follows: Figure 1 and Figure 3 As shown.

[0046] Example 3, Preparation of CeO x The NiCoP catalyst uses a two-step electrodeposition method: The first step, electrodeposition, was used to prepare NiCoP material, following the same process as in Example 1. In the second step, 2.171 g of Ce(NO3)3·6H2O and 0.425 g of NaNO3 were completely dissolved in 50 mL of deionized water to form electrolyte 3. A three-electrode system was used for electrodeposition, with the nickel foam-supported NiCoP as the working electrode, a carbon rod as the counter electrode, and a saturated calomel electrode as the reference electrode. The electrodeposition reaction was carried out at a constant voltage of -0.5 V (relative to the saturated calomel electrode) for 5 seconds. After electrodeposition, the nickel foam support was washed with deionized water and dried for 12 hours to obtain CeO2. x The NiCoP catalyst was confirmed by X-ray diffraction, scanning electron microscopy, and elemental analysis, as follows: Figure 1 and Figure 4 As shown.

[0047] Example 4: Preparation of Ni(OH)2 / NiCoP catalyst using a two-step electrodeposition method: The first step, electrodeposition, was used to prepare NiCoP material, following the same process as in Example 1. In the second step, 1.46 g of Ni(NO3)2·6H2O and 0.425 g of NaNO3 were completely dissolved in 50 mL of deionized water to form electrolyte 4. A three-electrode system was used for electrodeposition, with nickel foam-supported NiCoP as the working electrode, a carbon rod as the counter electrode, and a saturated calomel electrode as the reference electrode. The electrodeposition reaction was carried out at a constant voltage of -0.5 V (relative to the saturated calomel electrode) for 10 seconds. After electrodeposition, the nickel foam support was washed with deionized water and dried for 12 hours to obtain the Ni(OH)2 / NiCoP catalyst. X-ray diffraction, scanning electron microscopy, and elemental analysis confirmed the catalyst's properties. Figure 1 and Figure 5 As shown.

[0048] The alkaline water electrolysis hydrogen evolution activity of the catalysts in Examples 1-4 above was studied, as follows: Using a 1 mol / L KOH solution as the electrolyte, the hydrogen evolution reaction activity was tested using a three-electrode system. The catalyst, supported on nickel foam, served as the working electrode, a carbon rod as the counter electrode, and a saturated silver chloride electrode as the reference electrode. Reaction conditions: Polarization curves were obtained using linear sweep voltammetry at a scan rate of 5 mV / s. The test results are shown below. Figure 6 As shown; the EIS impedance test plot was obtained at an overpotential of 150 mV; stability was evaluated using multi-current step curves and chronovoltammetry, such as... Figure 6 and Figure 7 .

[0049] illustrate: 1. By Figure 1 It can be seen that the NiCoP and MnO prepared in Examples 1-4 respectively x / NiCoP, CeO x The figure shows diffraction peaks for NiCoP and Ni(OH)2 / NiCoP, with only metallic Ni appearing in the image, indicating that NiCoP and MnO prepared by this electrodeposition method... x / NiCoP, CeO x Both / NiCoP and Ni(OH)2 / NiCoP catalysts have nanocrystalline or amorphous structures.

[0050] 2. By Figure 2 As can be seen from the (ac) scanning electron microscope image and (dg) elemental mapping diagram of the NiCoP catalyst, the scanning electron microscope image shows that the NiCoP catalyst prepared by electrodeposition method presents spherical particles of varying sizes aggregated on the nickel foam surface; the elemental mapping diagram confirms the presence of Ni, Co and P elements, indicating the successful preparation of the NiCoP catalyst of Example 1.

[0051] 3. Figure 3 It can be seen that MnO x The (ac) scanning electron microscope (SEM) image and (di) elemental mapping diagram of the NiCoP catalyst show the MnO electrodeposited on the surface of the spherical NiCoP catalyst. x The components exhibit a nanoflower structure; the elemental mapping diagram confirms the presence of Ni, Co, P, Mn, and O elements, indicating the presence of MnO in Example 2. x Successful preparation of / NiCoP catalyst.

[0052] 4. Figure 4 It can be seen that CeO x The (ac) scanning electron microscope (SEM) image and (di) elemental mapping diagram of the NiCoP catalyst show CeO electrodeposited on the surface of the spherical NiCoP catalyst. x The components also exhibit a nanoflower structure, but unlike MnO... x The components exhibit different nanoflower structures, with smaller twisted nanosheet sizes; elemental mapping diagrams confirm the presence of Ni, Co, P, Ce, and O elements, indicating the presence of CeO in Example 3. x Successful preparation of / NiCoP catalyst.

[0053] 5. Figure 5 The scanning electron microscope (SEM) images and elemental mapping diagrams of the Ni(OH)₂ / NiCoP catalyst (AD) show that the Ni(OH)₂ component electrodeposited on the surface of the spherical NiCoP catalyst also exhibits a nanoflower structure, but it differs from MnO. x and CeO x The nanoflower structures of the components are all different, unlike CeO. x The components are closer together, and the twisted nanosheets are smaller in size, appearing to exist as a thin layer on the surface of the spherical NiCoP component; the elemental mapping diagram confirms the presence of Ni, Co, P and O elements, indicating the successful preparation of the Ni(OH)2 / NiCoP catalyst.

[0054] 6. NiCoP, MnO x / NiCoP, CeO x Alkaline water electrolysis hydrogen evolution activity test results for / NiCoP and Ni(OH)2 / NiCoP catalysts, including (a) the LSV plot, (b) the corresponding Tafel plot and (c) the EIS impedance plot: The LSV plot in (a) shows NiCoP and MnO x / NiCoP, CeO x / NiCoP and Ni(OH)2 / NiCoP catalysts exhibited excellent alkaline water electrolysis hydrogen evolution activity, achieving industrial-grade 1000 mAcm⁻¹ activity. -2 The catalysts required overpotentials of 260 mV, 205 mV, 180 mV, and 150 mV, respectively, and their activities all exceeded those of commercial 20% Pt / C catalysts, demonstrating significant application potential and indicating the effectiveness of MnO coupling. x CeO x The Ni(OH)2 component can provide the catalyst with alkaline water electrolysis hydrogen evolution activity.

[0055] (b) Tafel plot shows NiCoP, MnO x / NiCoP, CeO x The Tafel slopes of the NiCoP and Ni(OH)2 / NiCoP catalysts were 97.8 mVdec. -1 70.2 mVdec -1 64.2 mVdec -1 and 55.1 mVdec -1 This indicates that the NiCoP catalyst follows the Volmer-Heyrovsky mechanism, where the Volmer step (M + H₂O + e⁻) is involved. - → MH + OH - The reaction that is the rate-determining step in the basic hydrogen evolution reaction (H₂O + M + e⁻) is the hydrolysis reaction (H₂O + M + e⁻). − → MH + OH − This step plays a decisive role. Coupling MnO x CeO x MnO with Ni(OH)2 component x / NiCoP, CeO x / NiCoP and Ni(OH)2 / NiCoP catalysts follow the Volmer-Heyrovsky mechanism, where the Heyrovsky step (MH + H2O + e) - → M + H2 + OH - This is the rate-determining step in the basic hydrogen evolution reaction. Because MnO x CeO x The synergistic effect of the Ni(OH)₂ component promotes the water dissociation reaction, accelerates the rate of MH formation in the Volmer step, alters the rate-determining step, and accelerates the rate of alkaline hydrogen evolution reaction. Furthermore, compared to MnO… x and CeO xThe Ni(OH)2 component may have the best adsorption energy for OH, which can better promote the water dissociation reaction. Therefore, the Ni(OH)2 / NiCoP catalyst has the best alkaline hydrogen evolution reaction kinetics.

[0056] (c) EIS impedance plots of the four catalysts, R ct The smaller the radius, the higher the charge transfer efficiency on the electrode surface and the better the reaction kinetics. All four catalysts can promote the rate of alkaline hydrogen evolution reaction; among them, the Ni(OH)₂ / NiCoP catalyst has the smallest radius, i.e., the charge transfer resistance. R ct This indicates that the Ni(OH)2 / NiCoP catalyst has the best charge transfer capability and the best effect on promoting the alkaline hydrogen evolution reaction rate.

[0057] 7. Figure 7 The graph shows the alkaline water electrolysis hydrogen evolution stability test results for the Ni(OH)2 / NiCoP catalyst, including (a) multi-current density step stability (200-1000 mAcm). -2 (a) and (b) Timing voltage analysis (industrial grade 500 mA cm⁻¹) -2 Figure a shows the various high current densities (200-1000 mA / cm²) of the Ni(OH)₂ / NiCoP catalyst in the alkaline water electrolysis hydrogen evolution reaction. -2 The catalyst remains stable under various conditions, demonstrating excellent mechanical and chemical stability. Figure b shows that the Ni(OH)2 / NiCoP catalyst can maintain stability at industrial-grade 500 mAcm⁻¹. -2 It operated stably for about 100 hours under alkaline water electrolysis hydrogen evolution current density, demonstrating very good stability and indicating great potential for industrial applications.

[0058] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A dual-active-site phosphide catalyst for alkaline electrolysis media, characterized in that, Including chemical formula R-MP x Phosphate-based materials; Wherein, R is the oxyphilic component, which is a dopant, hydroxide, or oxide of a single or multiple metal from Fe, Co, Ni, Cu, La, Cr, Mn, Ti, V, Ce, Re, and Y; MP x It is a single-metal phosphide or a multi-metal phosphide, where M is a transition metal or a noble metal.

2. The dual-active-site phosphide catalyst for alkaline electrolysis media according to claim 1, characterized in that, The transition metal is at least one of Mn, Fe, Co, Ni, Cu, Mo, and W; the noble metal is at least one of Fe, Co, Ni, Cu, La, Cr, Mn, Ti, V, Ce, Re, and Y. The monometallic phosphide is at least one of Ni2P, Ni5P4, CoP, Co2P, FeP, Fe2P, MnP, Mn2P, Cu3P, MoP, W2P, Ru2P, Rh2P, Pd2P, OsP2, Ir2P, Au2P3, AgP2, and PtP2. The polymetallic phosphide is at least one of NiCoP, FeNi2P, Mn3NiP2, CoMnP, Ni2P / CoP, Ni2P / Co2P, Ni2P / Fe2P, Ni2P / FeP, NiFeP, CoFeP, Ni2P / MnP, Co2P / MnP, CoP / MnP, CoP / Ni2P / FeP, Ru2P / Ni2P, Ir2P / CoP, and Pd2P / NiCoP.

3. The dual-active-site phosphide catalyst for alkaline electrolysis media according to claim 1, characterized in that, The phosphide-based material is NiCoP or MnO. x / NiCoP, CeO x / NiCoP or Ni(OH)2 / NiCoP.

4. A method for preparing a dual-active-site phosphide catalyst, used to prepare a dual-active-site phosphide catalyst for an alkaline electrolysis medium as described in any one of claims 1-3, characterized in that, R-MP x When R represents metal doping, a one-step electrodeposition method is used; The one-step electrodeposition method includes the following steps: (1) Phosphate MP x The metal M, the metal salt of the oxyphilic component R, sodium hypophosphite, and sodium salt are completely dissolved in deionized water to form an electrolyte. The molar ratio between metal M and oxyphilic component R is 5–15. The molar amount of sodium hypophosphite is 1.5–3 times the sum of M and R. The molar amount of sodium salt is 0.5–2 times the molar amount of sodium hypophosphite. (2) At room temperature and normal pressure, a three-electrode system is used to carry out the electrodeposition reaction. The three-electrode system includes a working electrode, a counter electrode and a reference electrode. The working electrode is a conductive support. The electrodeposition reaction is carried out under constant voltage. After the electrodeposition is completed, the conductive support is washed and dried with deionized water to obtain a dual-active-site phosphide catalyst.

5. The method for preparing a dual-active-site phosphide catalyst according to claim 4, characterized in that, In step (1), the metal salt of metal M, the metal salt of oxyphilic component R, and the sodium salt are selected as chloride, nitrate, acetate, sulfate, or hydrates of the above four, respectively.

6. A method for preparing a dual-active-site phosphide catalyst, used to prepare a dual-active-site phosphide catalyst for an alkaline electrolysis medium as described in any one of claims 1-3, characterized in that, R-MP x When R is a hydroxide or oxide of a metal, a two-step electrodeposition method is used; The two-step electrodeposition method includes the following steps: (1) The metal salt of metal M, sodium hypophosphite and sodium salt are completely dissolved in deionized water as electrolyte 1; at room temperature and normal pressure, a three-electrode system is used to carry out the electrodeposition reaction, the three-electrode system includes: working electrode, counter electrode and reference electrode; the electrodeposition reaction is carried out using electrolyte 1 at constant voltage to obtain a single-component phosphide catalyst with dual active sites. The molar amount of sodium hypophosphite is 1.5 to 3 times that of M; the molar amount of sodium salt is 0.5 to 2 times that of sodium hypophosphite; and a conductive carrier is selected as the working electrode. (2) The metal salt of the oxyphilic component R and sodium nitrate are completely dissolved in deionized water at a molar ratio of 1:(1-4) to form electrolyte 2. The conductive support is washed and dried with deionized water. In a three-electrode system, the dual-active-site single-component phosphide catalyst supported on the conductive support in step (1) is used as the working electrode. Electrodeposition reaction is carried out in electrolyte 2 under constant voltage. The conductive support is washed and dried with deionized water to obtain the dual-active-site dual-component phosphide catalyst.

7. The method for preparing a dual-active-site phosphide catalyst according to claim 6, characterized in that, In step (1), when the metal salt of the oxyphilic component R is an oxide, the metal salt of metal M, the metal salt of the oxyphilic component R, and the sodium salt are selected as chlorides, nitrates, acetates, sulfates, or hydrates of the above four; when the metal salt of the oxyphilic component R is a hydroxide, the metal salt of R is a nitrate, and the metal salt of metal M and the sodium salt are selected as chlorides, nitrates, acetates, sulfates, or hydrates of the above four.

8. An alkaline electrolytic medium for producing hydrogen by electrolysis of water, characterized in that, A catalyst is added, wherein the catalyst is a dual-active-site phosphide catalyst for alkaline electrolysis medium as described in any one of claims 1-3, or is prepared by the preparation method of a dual-active-site phosphide catalyst as described in any one of claims 4-7.

9. The use of a catalyst in alkaline water electrolysis for hydrogen production, characterized in that, The catalyst is a dual-active-site phosphide catalyst for alkaline electrolysis medium as described in any one of claims 1-3, or is prepared by the preparation method of a dual-active-site phosphide catalyst as described in any one of claims 4-7.

10. The application of a catalyst in the preparation of an alkaline electrolytic medium for hydrogen production by water electrolysis, characterized in that, The catalyst is a dual-active-site phosphide catalyst for alkaline electrolysis medium as described in any one of claims 1-3, or is prepared by the preparation method of a dual-active-site phosphide catalyst as described in any one of claims 4-7.

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