A supported electrocatalyst based on redox-active ligand-modified metal nanomaterials and its preparation method.

Abstract

This invention belongs to the field of new materials technology, and more specifically relates to a supported electrocatalyst of redox-active ligand-modified metal nanomaterials and its preparation method. The supported electrocatalyst provided by this invention comprises a conductive support with a high specific surface area, and metal nanomaterials modified and stabilized by redox-active ligands supported on the conductive support. The preparation method involves dissolving the redox-active ligands in water at 0-5°C, then adding an aqueous solution of the metal nanomaterial precursor, and stirring to obtain a mixed solution. A reducing agent solution is then added dropwise to the mixed solution, followed by the addition of the conductive support. The resulting solid product is purified and dried to obtain the electrocatalyst. This supported electrocatalyst exhibits strong hydrogen evolution performance in water electrolysis and has excellent potential for electrocatalytic applications.

Description

Technical Field

[0001] This invention belongs to the field of new materials technology, and more specifically relates to a supported electrocatalyst of metal nanomaterials modified with redox active ligands and its preparation method. Background Technology

[0002] Hydrogen energy is widely available, low-carbon and pollution-free. In particular, it has an overwhelming advantage over other energy storage technologies such as pumped hydro storage, compressed air storage and chemical energy storage in long-term, large-scale energy storage. It can be coupled with renewable energy sources (such as solar, wind, hydro, geothermal and tidal energy) to achieve peak shaving and valley filling of unstable power in time and space and stable grid-connected power generation.

[0003] Among various technologies, water electrolysis for hydrogen production coupled with renewable energy power generation to produce hydrogen (green hydrogen) for energy storage stands out due to its advantages such as abundant sources, high hydrogen purity (99.999%), and zero carbon emissions, making centralized hydrogen production and storage a possibility. However, proton exchange membrane electrolyzers and alkaline water electrolyzers, which have the highest technological maturity, often use large amounts of precious metals such as platinum and iridium as electrode materials and catalysts. Under this premise, reducing the amount of precious metals used and developing nanomaterials with extremely high precious metal activity is of profound significance for the inflection point of the rise of hydrogen energy.

[0004] While platinum's own hydrogen adsorption energy is near zero, the development of stable and reliable platinum catalysts with high activity and low noble metal loading remains a significant challenge. Currently, the difficulty in improving the quality and activity of platinum-based and other noble metal catalytic materials ultimately stems from two aspects:

[0005] Firstly, for materials with low precious metal loadings, it is difficult to provide satisfactory catalytic performance, and secondly, the tendency of precious metals to agglomerate often leads to poor stability. Industry often overcomes these two problems by increasing the precious metal loading; however, high precious metal loadings significantly increase costs.

[0006] Secondly, the highly active platinum sites deplete the H+ of the inner electrical layer in a short time. + This makes H near the electrode interface + The transfer medium consists of H3O + The hydrogen is converted to H2O, which leads to a higher activation energy barrier for proton dissociation. At high current hydrogen evolution overpotentials, polarization caused by mass transfer issues almost dominates.

[0007] Polyoxometalates (POMs), as polynuclear metal oxide molecular clusters, possess well-defined structures. In particular, the flexible tunability of their elements and structures leads to rich variations in their electronic structure, acidity, and other properties. POMs are also excellent proton and electron storage and transfer media, especially due to their inherent co-proton and electron transfer (CPET). Furthermore, their high negative charge, numerous coordinated oxygen atoms, and mostly nanoscale dimensions create immense potential for applications in nanomaterials. How to combine these ligands with metal nanoparticles to enhance the performance of electrocatalytic materials has become a pressing challenge for those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to provide a supported electrocatalyst for redox-active ligand-modified metal nanomaterials and its preparation method. This invention utilizes redox-active ligands and, through strong mutual coupling, modifies and stabilizes metal nanomaterials to obtain redox-active ligand-modified metal nanomaterials. These nanomaterials are then dispersed and loaded onto a high specific surface area conductive support, enabling them to serve as high-performance electrocatalytic materials, thereby solving the problems existing in the prior art.

[0009] To achieve the above objectives, the present invention provides the following solution:

[0010] One of the technical solutions of the present invention is to provide a supported electrocatalyst of a metal nanomaterial modified with redox active ligands, wherein the supported electrocatalyst comprises a conductive support with a high specific surface area and a metal nanomaterial modified with redox active ligands loaded on the conductive support.

[0011] Furthermore, the conductive carrier includes carbon nanotubes, nitrogen-doped graphene, carbon paper, carbon cloth, or metal foam.

[0012] The carbon nanotubes, nitrogen-doped graphene, carbon paper, carbon cloth, or foam metal conductive carriers used in this invention all have high specific surface areas.

[0013] Furthermore, the metal nanomaterials include Pt, non-Pt metals, alloys, or non-metallic compounds of metals.

[0014] Furthermore, the morphology of the metal nanomaterial is nanoparticles, nanorods, or nanowires.

[0015] Furthermore, the redox-active ligands include polyoxometalates, non-polyoxometalates, sulfides, carbides, nitrides, phosphides, arsenides, antimonides, or borides.

[0016] Optionally, the redox active ligand is a polyoxometalate.

[0017] Preferably, the polyoxometalate includes classic Keggin-type polyacids or vacancy-type Keggin-structured polyacids.

[0018] The second technical solution of this invention provides a method for preparing a supported electrocatalyst of the above-mentioned redox-active ligand-modified metal nanomaterials, comprising the following steps:

[0019] The redox-active ligand was dissolved in water at 0-5℃ to obtain a ligand solution;

[0020] An aqueous solution of a metal nanomaterial precursor was added to the ligand solution and stirred to obtain a mixed solution.

[0021] A reducing agent solution is added dropwise to a mixed solution, followed by the addition of a conductive support. The resulting solid product is then purified and dried to obtain the supported electrocatalyst.

[0022] The concentration of the aqueous solution of the metal nanomaterial precursor is 0.01–0.5 M;

[0023] The concentration of the reducing agent solution is 0.01–0.1 M.

[0024] Furthermore, the concentration of the redox-active ligand in the ligand solution is 0.1–1 μmol / mL.

[0025] Furthermore, the molar ratio of the redox active ligand to the metal nanomaterial precursor in the aqueous solution is 1 to 5.

[0026] Furthermore, the molar ratio of the metal nanomaterial precursor in the aqueous solution to the reducing agent in the reducing agent solution is 1:10.

[0027] Furthermore, the metal nanomaterial precursor in the aqueous solution of the metal nanomaterial precursor includes H2PtCl6, K2PtCl6, or RuCl3.

[0028] Furthermore, the reducing agent in the reducing agent solution includes hydrazine hydrate or NaBH4.

[0029] Furthermore, the ratio of the redox active ligand to the conductive carrier is 5-100 μmol: 100 mg.

[0030] Furthermore, the purification step includes: dispersing the solid product in water, stirring and filtering, and then washing with water at least once.

[0031] Furthermore, the drying process is vacuum drying.

[0032] Based on the present invention, a low-temperature water bath (0-5℃ water) environment is used to inhibit the decomposition and isomerization of unstable redox active ligands. The instantaneous reduction of sodium borohydride avoids the decomposition, destruction or isomerization transformation that may be caused by long-term and violent effects of light, heat, electricity, etc. on redox active ligands.

[0033] Based on the problems of easy aggregation, poor binding force and poor hydrophilicity of metal nanoparticles, this invention uses a high specific surface area carrier to inhibit the aggregation of metal nanoparticles, stabilize their dispersion, and increase the active specific surface area. Meanwhile, during the formation of metal particles in redox-active ligand-modified metal nanomaterials, the high negative charge of the redox-active ligands enables the dispersion and aggregation of metal particles, thereby controlling the size of metal nanoparticles, obtaining different quantum effects, and achieving stable high metal quality activity. Redox-active ligands enable the formation of a high negative charge shell on the surface of metal particles, which greatly inhibits the aggregation of ultrafine metal particles under storage, catalysis, and harsh conditions. Redox-active ligands in the electron-depleted oxidation state exhibit extremely strong proton capillary ability and are close to the nanoscale in size, enabling them to extend across the platinum-electrolyte double layer to rapidly capture protons. Redox-active ligands are a superior proton-electron co-transfer medium, capable of coupling electrons and protons, and realizing the storage and relay of large amounts of activated hydrogen. As an oxide, redox-active ligands create a smooth path for the overflow of activated hydrogen and can utilize their multiple vacancies and highly electronegative oxygen atoms to regulate the electronic structure of platinum nanoparticles, achieving optimal adsorption energies for reactants and intermediates such as hydrogen.

[0034] The third technical solution of the present invention provides an application of the above-mentioned redox-active ligand-modified metal nanomaterial supported electrocatalyst as an electrode modification material in the preparation of electrocatalytic reaction electrodes.

[0035] Furthermore, the electrocatalytic reaction includes water electrolysis to produce hydrogen.

[0036] The fourth technical solution of the present invention provides an electrode for producing hydrogen by electrolysis of water, wherein the active component of the electrode includes a supported electrocatalyst of metal nanomaterials modified with the above-mentioned redox active ligands.

[0037] Fifth technical solution of the present invention: A method for producing hydrogen by electrolysis of water is provided, wherein the above-mentioned electrode is used as the working electrode.

[0038] The present invention discloses the following technical effects:

[0039] The supported electrocatalysts of redox-active ligand-modified metal nanomaterials prepared in this invention exhibit strong water electrolysis and hydrogen evolution performance and good electrocatalytic application potential. The beneficial effects are illustrated using polyoxometalates as an example:

[0040] Polyoxometalates, as ligands with unique redox properties distinct from traditional ligands such as thiols, were successfully used to modify the surface of metal nanoparticles with highly negatively charged and multi-vacant ligands, which were then loaded onto a conductive support. During the nanoreactor-pumped reductive synthesis process, the highly negatively charged polyoxometalate ligands significantly refined and stabilized the metal nanoparticles. In the negative potential hydrogen evolution process of the nanoreactor-pumped process, the high negative charge and proton-electron co-transfer ability of the polyoxometalates exhibited a proton-rich microenvironment, strong proton-electron coupling transfer mass transfer kinetics, and high platinum mass activity for hydrogen evolution was achieved by regulating the adsorption energy of platinum nanoparticles through multi-oxygen vacancies.

[0041] The material prepared by the method of this invention can achieve an electrocatalytic hydrogen evolution initiation overpotential close to 0 mV with extremely low metal loading, reaching a world-leading level of 79.90 A·mg for platinum. Pt -1 (η=100mV) Extremely high mass activity and superior electron conversion frequency 80.77H2·s -1 It exhibits extremely strong high-current mass transfer capability, with the Tafel slope exceeding 23.39 mV·dec -1 It shows great application potential for other types of inorganic and organic catalysis and is a pioneer in the development of other types of polyacid and metal nanoparticle nanocatalysts. Attached Figure Description

[0042] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0043] Figure 1 This is a schematic diagram of platinum nanoparticles modified with highly negatively charged, multi-vacancy Keggin-type polyacid (SiW9) and loaded onto carbon nanotubes (SiW9@Pt NPs / CNT).

[0044] Figure 2 This is a transmission electron microscope (TEM) image of SiW9@Pt NPs / CNTs.

[0045] Figure 3 Images of SiW9@Pt NPs / CNTs with spherical aberration correction from high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and elemental mapping EDS surface scans are shown, where a and b are HAADF-STEM images and c is an EDS image.

[0046] Figure 4 For SiW9, SiW 12 SiW 12 Infrared spectra of @Pt NPs and SiW9@Pt NPs.

[0047] Figure 5 Linear sweep voltammetry (LSV) curves for hydrogen evolution by water electrolysis at different electrodes.

[0048] Figure 6 Stability curves of Pt NPs@SiW9 / CNT (SiW9@Pt NPs / CNT) and Pt NPs / CNT modified electrodes during hydrogen evolution in water electrolysis. Detailed Implementation

[0049] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0050] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0051] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0052] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0053] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0054] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0055] In the specific embodiments of the present invention, the room temperature and ambient temperature are both 20-30℃.

[0056] The raw materials and reagents used in the specific embodiments of this invention are all commercially available products.

[0057] It should be noted that the polyoxometalates involved in the specific embodiments of the present invention can be commercially available or self-made without affecting the realization of the technical effect.

[0058] The following is an exemplary self-preparation procedure for a missing Keggin-structured polyacid:

[0059] Polyacid ligand Na 10 (α-SiW9O 34 Synthesis of α-KSiW9 (abbreviated as SiW9, a polyacid with a missing Keggin structure):

[0060] Sodium tungstate hydrate Na2WO4·2H2O (55 mmol) and sodium metasilicate Na2SiO3 (50 mmol) were dissolved in 200 mL of hot water (80-100 °C) and placed in a 1.2 L beaker with a magnetic stir bar to obtain a mixed solution.

[0061] Add 13 mL of 6M hydrochloric acid (HCl) dropwise to the above mixture, stir for 30 min, boil and concentrate to 30 mL, remove unreacted silica by filtration to obtain the concentrated solution.

[0062] In a separate beaker, dissolve 5g of anhydrous sodium carbonate in 15mL of water. Slowly add the anhydrous sodium carbonate solution to the concentrate and stir gently. The precipitate slowly forms. After 1 hour, filter to obtain the solid. Then stir with 100mL of 4M NaCl solution, filter again, and wash with two 10mL portions of ethanol and 10mL of diethyl ether in sequence. Dry under vacuum to obtain SiW9. Yield: ~110g (85%).

[0063] The following is an exemplary self-preparation procedure for a classic Keggin-type polyacid:

[0064] Polyacid ligand Na4(α-SiW) 12 O 40 (abbreviated as SiW) 12 Synthesis of classic Keggin-type polyacids:

[0065] Sodium silicate (Na2SiO3) (1.16526 g, 50 mmol) was dissolved in 10 mL of distilled water at room temperature while being magnetically stirred to form solution A;

[0066] In another 100 mL beaker, sodium tungstate dihydrate (Na2WO4·2H2O) (18.23291 g, 55 mmol) was dissolved in 30 mL of boiling distilled water and stirred magnetically to prepare solution B.

[0067] Subsequently, under vigorous stirring, 16.5 mL of 4M hydrochloric acid (HCl) solution was added dropwise over 5 minutes to boiling solution B to promote the dissolution of tungstic acid precipitate. Next, solution A was added, followed immediately by 5 mL of 4M HCl. The pH was then adjusted to approximately 5-6. The resulting mixture was incubated at approximately 100°C for 1 hour. Then, 5 mL of 1M sodium tungstate dihydrate (Na₂WO₄·2H₂O, equivalent to 5 mmol) was added, followed immediately by 8 mL of concentrated HCl. The reaction solution was cooled to room temperature and filtered. After filtration, the pH was adjusted to approximately 2 using 1M NaOH aqueous solution. Finally, approximately 50 g of solid sodium chloride (NaCl) was added to the mixture. After removing any potential potassium salts by filtration, the mixture was dried in air to obtain the target SiW. 12 product.

[0068] Example 1

[0069] The preparation steps of supported catalysts made from polyoxometalate-modified metal nanomaterials include:

[0070] SiW9 (25 μmol) was dissolved in 55 mL of water in an ice bath (~3℃), and then 150 μL of 0.1 M K2PtCl6 aqueous solution (containing 15 μmol Pt) was added. After stirring the solution for 60 min, freshly prepared 0.03 M NaBH4 (5 mL, 150 μmol) ice-water solution was added dropwise over 10 min. Immediately after adding NaBH4, 100 mg of high specific surface area conductive support carbon nanotubes (CNT) was added. The mixture was stirred for 20 min, and solid-liquid separation was performed to obtain the crude catalyst.

[0071] The crude catalyst (100 mg) was dispersed in water (50 mL), stirred for 10 min, then filtered, and washed with 50 mL of water to obtain the target material. The obtained material was then vacuum dried (60 °C) to obtain the supported catalyst, denoted as SiW9@PtNPs / CNT.

[0072] Figure 1 This is a schematic diagram of platinum nanoparticles modified with highly negatively charged, multi-vacancy Keggin-type polyacid (SiW9) and loaded onto carbon nanotubes (SiW9@Pt NPs / CNT).

[0073] Figure 2 The image shows a transmission electron microscope (TEM) image of SiW9@Pt NPs / CNTs. As can be seen from the image, the synthesized SiW9@Pt NPs have a size of 2 nm and are uniformly distributed on the surface of multi-walled carbon nanotubes.

[0074] Figure 3The images show aberration-corrected high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) image and elemental mapping EDS surface scan of SiW9@Pt NPs / CNTs, where a and b are HAADF-STEM images and c is an EDS image. The figures show polyacid modification on the surface of the platinum nanoparticles.

[0075] Example 2

[0076] The preparation steps of supported catalysts made from polyoxometalate-modified metal nanomaterials include:

[0077] SiW 12 Dissolve 25 μmol of the solution in 55 mL of water in an ice bath (~3℃), then add 150 μL of 0.1 M K2PtCl6 aqueous solution (15 μmol). After stirring the solution for 60 min, add 5 mL of freshly prepared 0.03 M NaBH4 (containing 150 μmol of Pt) ice-water solution dropwise over 10 min. Immediately after adding NaBH4, add 100 mg of high specific surface area conductive support carbon nanotubes (CNTs). Stir for 20 min, and then separate the solid and liquid phases to obtain the crude catalyst.

[0078] The crude catalyst (100 mg) was dispersed in water (50 mL) and stirred for 10 min. The mixture was then filtered and washed with 50 mL of water to obtain the target material. The obtained material was then vacuum dried (60 °C) to obtain the supported catalyst, denoted as SiW. 12 @Pt NPs / CNT.

[0079] Figure 4 For SiW9, SiW 12 SiW 12 Infrared spectra of @Pt NPs and SiW9@Pt NPs. SiW9@Pt NPs and SiW 12 @PtNPs are SiW9@Pt NPs and SiW2 loaded on a support, prepared in Examples 1 and 2. 12 @Pt NPs. As shown in the figure, the characteristic peaks are located at 985, 940 (sh), 930, 865, 848 (sh), 808, 712, 552, 530, 490 (sh), 435, 373, and 335 nm.

[0080] Comparative Example 1

[0081] The preparation steps of supported catalysts made of metal nanomaterials include:

[0082] 0.1 M K2PtCl6 aqueous solution (150 μL, containing 15 μmol Pt) was mixed with 55 mL of ice bath (~3℃) water. After stirring the solution for 60 min, freshly prepared 0.03 M NaBH4 (5 mL, 150 μmol) ice water solution was added dropwise over 10 min. Immediately after adding NaBH4, high specific surface area conductive support carbon nanotubes (CNTs) (100 mg) were added. The mixture was stirred for 20 min, and solid-liquid separation was performed to obtain the crude catalyst.

[0083] The crude catalyst was dispersed in water (50 mL), stirred for 10 min, then filtered, and washed with 50 mL of water to obtain the target material. The obtained material was then vacuum dried (60 °C) to obtain the supported catalyst, denoted as Pt NPs / CNT.

[0084] Comparative Example 2

[0085] 0.1 M K2PtCl6 aqueous solution (150 μL, containing 15 μmol of Pt) was mixed with sodium tungstate [Na2WO4] (abbreviated as WO3). x A 25 μmol, 55 mL aqueous solution was mixed in an ice-water bath (0–3 °C). After stirring the solution for 60 min, a freshly prepared 0.03 M NaBH4 (5 mL, 150 μmol) ice-water solution was added dropwise over 10 min. Immediately after adding NaBH4, 100 mg of carbon nanotubes (CNTs) was added. The mixture was stirred for 20 min, and the solid and liquid were separated to obtain the crude catalyst.

[0086] The crude catalyst was dispersed in water (50 mL), stirred for 10 min, then filtered, and washed with 50 mL of water to obtain the target material. The obtained material was then vacuum dried (60 °C) to obtain the supported catalyst, denoted as Pt NPs@WO. x / CNT.

[0087] Test case

[0088] Weigh 5 mg of catalyst powder, add isopropanol (900 μL) and Nafion membrane solution (100 μL), sonicate to form a uniform dispersion, and then coat it onto the electrode to be modified. The electrode to be modified can be carbon paper, glassy carbon electrode or membrane electrode, etc. The following is a further explanation using glassy carbon electrode.

[0089] The above dispersion was coated onto a glassy carbon electrode at a coating amount of 100 μL / cm². 2 After drying, the working electrode is obtained.

[0090] The electrocatalytic hydrogen evolution performance of the above working electrode was characterized by the following tests:

[0091] Electrochemical tests were conducted using a Shanghai Chenhua electrochemical workstation (CHI770E) in a three-electrode system with a reversible hydrogen electrode as the reference electrode, a carbon rod as the counter electrode, the electrode prepared above as the working electrode, and 0.5 mol / L H2SO4 solution as the electrolyte solution.

[0092] Figure 5 Linear sweep voltammetry (LSV) curves for hydrogen evolution during water electrolysis using different electrodes are shown in the figure. In the figure, Commercial20%Pt / C represents a commercially available platinum-carbon modified glassy carbon electrode, Pt NPs / CNT represents the glassy carbon electrode modified with the material from Comparative Example 1, and Pt NPs@WO x / CNT represents the glassy carbon electrode modified with the material in Comparative Example 2, Pt NPs@SiW12 / CNT(SiW 12 @Pt NPs / CNT) is the glassy carbon electrode modified with the material in Example 2, and Pt NPs@SiW9 / CNT (SiW9@Pt NPs / CNT) is the glassy carbon electrode modified with the material in Example 1.

[0093] As can be seen from the figure, Pt NPs@SiW9 / CNT (SiW9@Pt NPs / CNT) achieved an electrocatalytic hydrogen evolution initiation overpotential close to 0 mV with extremely low metal loading.

[0094] Figure 6 The figure shows the stability curves of Pt NPs@SiW9 / CNT (SiW9@Pt NPs / CNT) and Pt NPs / CNT modified electrodes during hydrogen evolution in water electrolysis. As can be seen from the figure, at approximately 100 mA·cm⁻¹, the stability of the electrodes is relatively stable. -2 At a current density of [value missing], the Pt NPs@SiW9 / CNT catalyst can operate for 100 hours without significant degradation, exhibiting excellent electrochemical hydrogen evolution stability, far exceeding that of the Pt NPs / CNT catalyst.

[0095] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0096] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those 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 invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a supported electrocatalyst of a metal nanomaterial modified with redox active ligands, characterized in that the step... include: The redox-active ligand was dissolved in water at 0-5℃ to obtain a ligand solution; An aqueous solution of a metal nanomaterial precursor was added to the ligand solution and stirred to obtain a mixed solution. A reducing agent solution is added dropwise to a mixed solution, followed by the addition of a conductive support. The resulting solid product is then purified and dried to obtain the supported electrocatalyst. The concentration of the aqueous solution of the metal nanomaterial precursor is 0.01~0.5 M; The concentration of the reducing agent solution is 0.01~0.1 M; The conductive carrier includes carbon nanotubes, nitrogen-doped graphene, carbon paper, carbon cloth, or foamed metal. The metallic nanomaterial is Pt; The morphology of the metal nanomaterial is nanoparticles, nanorods, or nanowires. The redox active ligand is a polyoxometalate.

2. The preparation method according to claim 1, characterized in that, The concentration of the redox-active ligand in the ligand solution is 0.1~1 μmol / mL; and / or, the molar ratio of the redox-active ligand to the metal nanomaterial precursor in the aqueous solution of the metal nanomaterial precursor is 1~5.

3. The preparation method according to claim 1, characterized in that, The molar ratio of the metal nanomaterial precursor in the aqueous solution to the reducing agent in the reducing agent solution is 1:10; and / or, the metal nanomaterial precursor in the aqueous solution includes H2PtCl6 or K2PtCl6.

4. The preparation method according to claim 1, characterized in that, The reducing agent in the reducing agent solution includes hydrazine hydrate or NaBH4; and / or, the ratio of the redox active ligand to the conductive carrier is 5-100 μmol:100 mg.

5. The preparation method according to claim 1, characterized in that, The purification steps include: dispersing the solid product in water, stirring and filtering, and washing with water at least once; and / or, the drying is vacuum drying.

6. A supported electrocatalyst of a metal nanomaterial modified with a redox-active ligand, characterized in that, The supported electrocatalyst of the redox-active ligand-modified metal nanomaterial is prepared by the preparation method described in any one of claims 1-5.

7. The application of a supported electrocatalyst of redox-active ligand-modified metal nanomaterials as described in claim 6 as an electrode modification material in the preparation of electrocatalytic reaction electrodes, characterized in that, The electrocatalytic reaction electrode is used for the hydrogen production reaction by water electrolysis.

8. An electrode for producing hydrogen by electrolysis of water, characterized in that, The active component of the electrode includes the supported electrocatalyst of the metal nanomaterial modified with redox active ligands as described in claim 6.

9. A method for producing hydrogen by electrolysis of water, characterized in that, The method uses the electrode described in claim 8 as the working electrode.

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