Design method of natural seawater electrolysis efficient catalyst based on stainless steel, catalyst and application of catalyst

Abstract

The invention relates to a design method of a stainless steel-based natural seawater electrolysis high-efficiency catalyst, a catalyst and application thereof, and the design method comprises the following steps: taking a stainless steel mesh as a carrier, and placing the carrier in a high-concentration alkaline solution; the stainless steel surface is subjected to oxidation treatment by applying long-time oxidation voltage to form an amorphous nickel-iron mixed oxide layer, the stainless steel with the oxidation layer formed on the surface is further soaked in a solution containing metal M salt, and nanoclusters loaded with the M salt of the stainless steel oxidation layer are formed through pulse electrodeposition; and the loading capacity and the cluster size of the nanocluster are regulated and controlled by changing the deposition current and the pulse frequency of pulse electrodeposition. Compared with the prior art, excellent seawater electrolysis anode catalysis corrosion resistance is achieved through commercial stainless steel surface modification treatment and precious metal nanocluster loading, and the stainless steel material subjected to modification treatment achieves long-term stable operation under the real seawater electrolysis industrial current density working condition.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen production by electrolysis of water, and more particularly to a design method of an efficient catalyst for electrolysis of natural seawater based on stainless steel, the catalyst and its application. Background Art

[0002] In recent years, fossil fuels have been gradually depleted, and their massive consumption has caused increasingly serious environmental pollution and global warming problems. The development of clean and renewable green energy is of great significance for a country to build a modern energy system and achieve the goals of "carbon peak" and "carbon neutrality". Hydrogen production by electrolysis of water is not only safe, efficient, and green, but also has a relatively high purity of hydrogen production, which has more advantages compared with hydrogen production from fossil fuels.

[0003] Existing electrolysis technologies, such as alkaline electrolyzers and proton exchange membrane (PEM) electrolyzers, require the use of high-purity water; however, seawater, as an abundant resource, has become an ideal solution. Although seawater has great potential, its complex composition poses significant challenges to direct seawater electrolysis, especially the corrosiveness of "free chlorine" species (i.e., Cl 2 , HOCl, OCl - ) generated by the chloride oxidation reaction (COR).

[0004] Currently, the main strategies for suppressing COR can be roughly divided into three categories. First, by designing anode catalysts or establishing a protective layer to enhance the selectivity of the oxygen evolution reaction (OER), thereby improving corrosion resistance. Second, by controlling the microenvironment at the electrode interface to inhibit the generation of chlorine gas. Third, at the equipment level, explore methods for directly removing chloride ions or adopting an asymmetric feed configuration combined with bipolar membranes. Although significant efforts have been made in catalyst engineering, it is still difficult to work under actual seawater electrolysis conditions. Although the latter two methods can achieve direct seawater electrolysis, the complex electrolyzer structure leads to an increase in internal resistance and a decrease in current density. At the same time, considering the corrosion resistance of the equipment, the pore transport layer (PTL) and bipolar plate (BP) materials are usually made of relatively expensive titanium. On an equipment scale, this cost exceeds 30% of the total cost of the stack. Stainless steel is cheaper and easier to process than titanium, but it will corrode when polarized in an oxidative medium with a high overpotential. Therefore, developing a highly catalytic and selective coating to protect stainless steel substrates for direct seawater electrolysis is a very promising direction. Summary of the Invention

[0005] The object of the present invention is to overcome the defects existing in the above-mentioned prior art, and to provide a method for regulating and designing an efficient catalyst for natural seawater electrolysis based on cheap stainless steel, as well as the catalyst and its application. This material uses a stainless steel mesh as the substrate, and noble metal nanoclusters are loaded on the nickel-iron mixed oxide coupling layer through constant current oxidation and pulse electrodeposition. The mass fraction of the noble metal is only 0.03-0.05 w%, and long-term stable operation can be achieved under the working current density conditions of real seawater electrolysis industry.

[0006] The object of the present invention can be achieved through the following technical solutions:

[0007] The first aspect of the present invention provides a method for regulating and designing an efficient catalyst for natural seawater electrolysis based on cheap stainless steel, as well as the catalyst and its application, including the following steps:

[0008] Using a stainless steel mesh as the carrier, placing the carrier in an alkaline solution, oxidizing the surface of the stainless steel by applying an oxidation voltage to form an amorphous nickel-iron mixed oxide layer, and further impregnating the stainless steel with an oxidized surface layer into a solution containing metal M salt, forming nanoclusters of M salt loaded on the stainless steel oxide layer through pulse electrodeposition, and regulating the loading amount and cluster size of the nanoclusters by changing the deposition current and pulse number of the pulse electrodeposition, preparing a series of nickel-iron mixed oxide supported nanoclusters, and performing an electrocatalyst seawater oxygen evolution performance test to obtain the composite material with the best performance as the target catalyst product;

[0009] The metal M is selected from one of platinum, palladium, iridium, ruthenium, and gold.

[0010] Further preferably, the metal M is platinum.

[0011] Further, the nanoclusters are: nanodispersed clusters formed by stacking single atoms, and the clusters are composed of 3-4 platinum atoms.

[0012] Further, the stainless steel mesh is a 400-mesh 304 stainless steel mesh, and the size of the stainless steel mesh is 1.0×1.5 cm 2 。

[0013] Further, the preparation of the amorphous nickel-iron mixed oxide layer specifically includes the following steps:

[0014] Step 1, dissolving potassium hydroxide in pure water, stirring evenly to obtain a mixed solution. The concentration of potassium hydroxide in the mixed solution is 1.0 M, and the constant current oxidation parameters are set at 100-1000 mA. By setting multiple current densities for the preparation of the stainless steel oxide layer, the thickness of the nickel-iron mixed oxide layer can be regulated;

[0015] Step 2: Immerse the stainless-steel mesh in a 0.5 M sulfuric acid solution, wash it at room temperature for 30 minutes to remove surface oxides, then rinse it with deionized water until neutral, and dry it for later use. The ratio of the stainless-steel mesh to the mixed solution in Step 1 is 1 mg:5 mL.

[0016] Step 3: Fix the stainless-steel mesh with electrode clips and immerse it in the mixed solution. The exposed area of the stainless-steel mesh is 1 cm -2 , and form a nickel-iron mixed oxide layer by applying an oxidation current.

[0017] Furthermore, the platinum salt is one or a mixture of several of platinum chloride, chloroplatinic acid, and platinum(II) acetylacetonate.

[0018] Furthermore, the platinum nanoclusters account for 0.03 - 0.05 w% of the total weight of the stainless-steel mesh;

[0019] The immersion area of the stainless-steel mesh in the mixed solution is 1.0×1.0 cm 2 , and an inert gas needs to be introduced into the solution throughout the deposition process to remove dissolved oxygen.

[0020] Furthermore, the constant-current oxidation conditions are to apply 500 mA - 1000 mA for 20 hours.

[0021] The second aspect of the present invention provides a highly efficient catalyst for natural seawater electrolysis obtained by the above design method.

[0022] The third aspect of the present invention provides an application of the above highly efficient catalyst for natural seawater electrolysis in the process of seawater electrolysis for hydrogen production.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention obtains a platinum metal nanocluster-coupled nickel-iron mixed oxide layer through a two-step electrochemical method. First, the preparation process involved in the present invention is simple and very easy for the large-scale production of the catalyst; second, the stainless-steel mesh carrier has good electrical conductivity, and its mesh structure is conducive to mass transfer and diffusion; and through the coupling effect of platinum nanoclusters, the dissociation of water is promoted and chloride ions in the seawater environment are captured to improve the stability and selectivity of the catalyst, and the material operates stably for a long time under the conditions of real seawater feeding and industrial current density. Therefore, the platinum metal nanocluster-coupled nickel-iron mixed oxide layer prepared by the present invention shows very good catalytic activity and ultra-long stability in direct seawater electrolysis for hydrogen production, basically meeting the industrial requirements and having very good industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a process flow chart for the preparation of the catalyst in Examples 1, 2, 3 and the control example of the present invention.

[0026] Figure 2 XRD patterns of SS, SS-O, and SS-O-Pt in Example 1 of the present invention and the control example.

[0027] Figure 3 AC-TEM image and elemental distribution map of the SS-O-Pt catalyst in Example 2 of the present invention.

[0028] Figure 4 Synchrotron radiation XANES spectrum of the catalyst in Example 3 of the present invention.

[0029] Figure 5 Synchrotron radiation EXAFS spectrum of the catalyst in Example 1 of the present invention.

[0030] Figure 6 XPS graph of the catalyst in Example 1 of the present invention.

[0031] Figure 7 OER curves of the catalyst in Example 1 of the present invention in NaCl solutions with different KOH concentrations.

[0032] Figure 8 Tafel corrosion curves of the catalyst in Example 1 of the present invention in NaCl solutions with different KOH concentrations.

[0033] Figure 9 Trend graph of the in-situ electrochemical impedance spectrum of the catalyst in Example 1 of the present invention in NaCl solutions with different KOH concentrations.

[0034] Figure 10 Trend graph of the correlation between the Tafel slope and the solution pH of the catalyst in Example 2 of the present invention in NaCl solutions with different KOH concentrations.

[0035] Figure 11 Stability test graphs of the catalyst in Example 3 of the present invention in NaCl solutions with different KOH concentrations and natural seawater.

[0036] Figure 12 Device diagram for evaluating the electrolysis performance of SS-O-Pt in natural seawater in Example 1 of the present invention.

[0037] Figure 13 Stability test curve graph of the electrolysis performance of SS-O-Pt in natural seawater of the present invention. Detailed implementation manners

[0038] Overall, the present invention uses a stainless-steel mesh as a carrier. The carrier is placed in a high-concentration alkaline solution, and the surface of the stainless steel is oxidized by applying a long-term oxidation voltage to form an amorphous nickel-iron mixed oxide layer. Further, the stainless steel with an oxide layer formed on its surface is impregnated into a solution containing a metal platinum salt, and platinum nanoclusters are formed on the stainless-steel oxide layer by pulse electrodeposition. The loading amount and cluster size of the nanoclusters are regulated by changing the deposition current and the number of pulses of the pulse electrodeposition. The composition and content of this material are as follows: the percentage of platinum nanoclusters in the total weight of the stainless-steel mesh is 0.03 - 0.05 w%. Through the coupling effect of the platinum nanoclusters, the dissociation of water is promoted and chloride ions in the seawater environment are captured, improving the stability and selectivity of the catalyst. The material operates stably for a long time under the conditions of real seawater feeding and industrial current density operation.

[0039] The porous stainless-steel mesh carrier is 304 stainless steel with 400 meshes, and its size is cut to 1.0 × 1.5 cm. 2 。

[0040] The platinum salt is one or a mixture of several of platinum chloride, chloroplatinic acid, and platinum(II) acetylacetonate;

[0041] The design method of the above metal nanocluster-coupled nickel-iron mixed oxide layer includes the following steps:

[0042] Step 1: Dissolve potassium hydroxide in pure water and stir evenly to obtain a mixed solution. The concentration of potassium hydroxide in the mixed solution is 1.0 M. Set the constant-current oxidation parameters to 100 - 1000 mA, and set multiple current densities for the preparation of the stainless-steel oxide layer to achieve the regulation of the thickness of the nickel-iron mixed oxide layer.

[0043] Step 2: Immerse the stainless-steel mesh in a 0.5 M sulfuric acid solution, wash it at room temperature for 30 minutes to remove the surface oxide, then wash it with deionized water until it is neutral, and dry it for standby. The ratio of the stainless-steel mesh to the mixed solution in Step 1 is 1 mg:5 mL.

[0044] Step 3: Fix the stainless-steel mesh with an electrode clip and immerse it in the mixed solution. The exposed area of the stainless-steel mesh is 1 cm -2 , and a nickel-iron mixed oxide layer is formed by applying an oxidation current.

[0045] Further, the platinum salt is one or a mixture of several of platinum chloride, chloroplatinic acid, and platinum(II) acetylacetonate;

[0046] Further, the percentage of platinum nanoclusters in the total weight of the stainless-steel mesh is 0.03 - 0.05 w%;

[0047] The impregnation area of the stainless-steel mesh in the mixed solution is 1.0 × 1.0 cm 2, an inert gas needs to be introduced into the solution throughout the deposition process to remove dissolved oxygen.

[0048] Further, prepare a pulsed electrodeposition plating solution: dissolve platinum salt in pure water, and the dosage of platinum salt is 10 mg / 100 ml;

[0049] Further, fix the stainless steel mesh with an electrode clamp and immerse it in the series of mixed solutions prepared in Step 1. Perform pulsed electrodeposition for 200 cycles. Each cycle consists of -200 mA for 2 ms and 0 mA for 500 ms to load platinum nanoclusters by pulsed electrodeposition.

[0050] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Features such as preparation means, materials, structures, or composition ratios that are not clearly described in this technical solution are regarded as common technical features disclosed in the prior art.

[0051] Example 1

[0052] The preparation of a nickel-iron mixed oxide layer on the stainless steel surface is as follows:

[0053] Step 1: Dissolve potassium hydroxide in pure water and stir evenly to obtain a mixed solution. The concentration of potassium hydroxide in the mixed solution is 1.0 M. Set the constant current oxidation parameters at 100 - 1000 mA. By setting multiple current densities for the preparation of the stainless steel oxide layer, the thickness of the nickel-iron mixed oxide layer can be regulated;

[0054] Step 2: Immerse the stainless steel mesh in a 0.5 M sulfuric acid solution, wash it at room temperature for 30 minutes to remove the surface oxide, then wash it with deionized water until neutral, and dry it for standby. The ratio of the stainless steel mesh to the mixed solution in Step 1 is 1 mg:5 mL;

[0055] Step 3: Fix the stainless steel mesh with an electrode clamp and immerse it in the mixed solution. The exposed area of the stainless steel mesh is 1 cm -2 , and a nickel-iron mixed oxide layer is formed by applying an oxidation current.

[0056] Example 2

[0057] The preparation of a platinum nanocluster-coupled nickel-iron mixed oxide layer is as follows:

[0058] Step 1: Prepare a pulsed electrodeposition plating solution: dissolve platinum salt in pure water, and the dosage of platinum salt is 10 mg / 100 ml;

[0059] Step 2: Immerse the 304 stainless steel mesh in a 0.5 M sulfuric acid solution, wash it at room temperature for 30 minutes to remove the surface oxide, then wash it with deionized water until neutral, and dry it for standby;

[0060] Step 3: Fix the stainless steel mesh with electrode clips and immerse it in the series of mixed solutions prepared in Step 1. Perform pulsed electrodeposition for 200 cycles, with each cycle consisting of -200 mA for 2 ms and 0 mA for 500 ms, to load platinum nanoclusters by pulsed electrodeposition.

[0061] The percentage of the prepared platinum nanoclusters in the total weight of the stainless steel mesh is 0.03 - 0.05 w%.

[0062] Control Example 1

[0063] Preparation of nickel-iron mixed oxide layer without metal nanocluster loading

[0064] Step 1: Dissolve potassium hydroxide in pure water and stir evenly to obtain a mixed solution. The concentration of potassium hydroxide in the mixed solution is 1.0 M. Set the constant current oxidation parameters to 100 - 1000 mA, and adjust the thickness of the nickel-iron mixed oxide layer by setting multiple current densities for the preparation of the stainless steel oxide layer.

[0065] Step 2: Immerse the stainless steel mesh in a 0.5 M sulfuric acid solution, wash it at room temperature for 30 minutes to remove surface oxides, then wash it with deionized water until neutral, and dry it for standby. The ratio of the stainless steel mesh to the mixed solution in Step 1 is 1 mg:5 mL.

[0066] Step 3: Fix the stainless steel mesh with electrode clips and immerse it in the mixed solution. The exposed area of the stainless steel mesh is 1 cm -2 , and form a nickel-iron mixed oxide layer by applying an oxidation current.

[0067] Verification Example 1

[0068] Structural morphology characterization of platinum nanocluster-coupled nickel-iron mixed oxide layer (SS-O-Pt)

[0069] Perform X-ray diffraction analysis (XRD) on the above-prepared SS-O-Pt, SS-O, and other samples. The XRD patterns are as shown in Figure 2 . Compared with pure stainless steel (SS), obvious NiFe 2 O 4 , Fe(OH) 2 , and NiOOH formed by alkaline constant current oxidation of the elements contained in the stainless steel substrate itself appear in SS-O. The austenite diffraction peak corresponding to the stainless steel substrate shows no obvious change; after loading platinum nanoclusters, the characteristic peaks originally belonging to the mixed oxide layer disappear.

[0070] Perform aberration-corrected transmission electron microscopy analysis (AC-TEM) on the above-prepared SS-O-Pt, as shown in Figure 3 . Figure 3It can be observed that the platinum nanoclusters are basically composed of single platinum atoms, evenly dispersed on the amorphous nickel-iron mixed oxide substrate, and the elements Pt, Ni, Fe, and O are evenly distributed.

[0071] The as-prepared SS-O-Pt was subjected to synchrotron radiation X-ray absorption spectroscopy (XAS). As Figure 4 shown, the valence state of Pt in SS-O-Pt is slightly higher than that of elemental Pt and much lower than that of PtO 2 , indicating that Pt exists in the form of nanoclusters rather than single atoms in the system. Further analysis of the extended X-ray absorption fine structure (EXAFS) of Pt was carried out. As Figure 5 shown, the peak corresponding to the Pt-Pt scattering path in SS-O-Pt becomes significantly broader, proving the emergence of the Pt-O scattering path, which fully demonstrates that the Pt nanoclusters are tightly bound to the nickel-iron mixed oxide layer and there is an interaction.

[0072] The as-prepared SS-O-Pt was subjected to X-ray photoelectron spectroscopy (XPS) analysis. As Figure 6 shown, the Cr element originally on the surface of the stainless steel substrate basically disappears after oxidation and pulsed electrodeposition, while Ni, which was originally less present on the surface, appears in the oxidized state, and the valence state of Fe also shows a significant increase compared to the stainless steel originally containing divalent and zero-valent Fe. The XPS of Pt further proves that Pt mainly exists in the oxidized state.

[0073] Verification Example 2

[0074] Oxygen evolution experiment of seawater electrolysis by platinum nanocluster-coupled nickel-iron mixed oxide layer (SS-O-Pt)

[0075] The as-prepared SS-O-Pt, SS-O and other samples were used as anode electrode materials for electrolytic water hydrogen production, and electrochemical performance tests and evaluations were carried out.

[0076] All electrochemical performance tests were carried out using a three-electrode system. The as-prepared materials were the working electrodes, the carbon rod was the counter electrode, Hg / HgO (1.0 M KOH) was the reference electrode in alkaline aqueous solution (pH = 14), and Ag / AgCl (saturated KCl) was the reference electrode in neutral aqueous solution. Linear voltammetry scans were carried out at a scan rate of 5 mV s -1 . The relevant tests were completed using an Autolab workstation (Metrohm, Multi Autolan m204) from Metrohm Switzerland.

[0077] As Figure 7As shown, the oxygen evolution reaction performance of SS-O-Pt, SS-O and other samples was tested respectively in 0.6 M NaCl solutions with different KOH concentrations (1.0 M, 0.1 M, 0.0 M). In 0.6 M NaCl and 1.0 M KOH + 0.6 M NaCl, SS-O-Pt has the best performance, while in 0.1 M KOH + 0.6 M NaCl, the performance difference between SS-O-Pt and SS-O is not significant.

[0078] As Figure 8 shown, the Tafel corrosion curves of the samples in three solutions were further tested. In 0.6 M NaCl and 0.1 M KOH + 0.6 M NaCl solutions, SS-O-Pt exhibits the highest corrosion voltage and the lowest corrosion current, demonstrating its excellent corrosion resistance. While in 1.0 M KOH + 0.6 M NaCl solution, the relevant parameters of pure stainless steel are the best.

[0079] As Figure 9 shown, the in-situ electrochemical impedance spectra of SS-O-Pt, SS-O and SS were tested in three different solutions. The peaks corresponding to the SS-O-Pt phase diagram are all in the lower frequency range during the voltage increase process, which is characteristic of the oxygen evolution reaction. While obvious high-frequency region corrosion signals appear during the 0.6 M NaCl test for SS and SS-O, proving the excellent corrosion resistance of SS-O-Pt.

[0080] As Figure 10 shown, the Tafel slope of SS-O-Pt shows a lower kinetic slope in all three different solutions, proving its excellent selectivity and reaction activity.

[0081] As Figure 11 shown, the long-term stability of SS-O-Pt in a three-electrode system was tested. It can stably work at a current density of 1.0 A cm -2 for more than 100 hours in 1.0 M KOH + 0.6 M NaCl, and can stably work at a current density of 200 mA cm -2 for more than 100 hours in 0.1 M KOH + 0.6 M NaCl, and can stably work at a current density of 10 cm -2 for more than 100 hours in 0.6 M NaCl.

[0082] As Figure 12 shown, using SS-O-Pt and commercial Pt / C catalysts as the anode and cathode catalysts for direct seawater electrolysis, the electrode and 117 membrane (DuPont, thickness 183.2 microns) were pressed together by hot pressing to construct a membrane electrode, and a proton exchange membrane electrolyzer device (natural seawater feed) was assembled for overall water splitting experiments.

[0083] As Figure 13 shown, by controlling the flow rate of natural seawater with a peristaltic pump to be 60 milliliters per minute, at a working temperature of 60 °C, the device can stably operate at a large current of 2 A for more than 100 hours, showing the prospect of industrial application.

[0084] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and all improvements and modifications made by those skilled in the art without departing from the scope of the present invention as disclosed should be within the protection scope of the present invention.

Claims

1. A design method for a natural seawater electrolysis high-efficiency catalyst based on stainless steel, comprising the following steps: A stainless steel mesh is used as a carrier, the carrier is placed in an alkaline solution, and an oxidation voltage is applied to the surface of the stainless steel to perform oxidation treatment, thereby forming an amorphous nickel-iron mixed oxide layer, and the stainless steel with the oxide layer formed on the surface is further immersed in a solution containing a metal M salt, and nanoclusters of the M salt loaded with the stainless steel oxide layer are formed by pulse electrodeposition, and the loading amount and cluster size of the nanoclusters are regulated by changing the deposition current and pulse number of the pulse electrodeposition, so as to prepare a series of nickel-iron mixed oxide loaded nanoclusters, and perform an electrocatalyst seawater oxygen evolution performance test, and obtain a composite material with the best performance as a target catalyst product; The metal M is selected from platinum, palladium, iridium, ruthenium and gold.

2. The design method of a natural seawater electrolysis high-efficiency catalyst based on stainless steel according to claim 1 is characterized in that: The metal M is platinum.

3. The design method of a natural seawater electrolysis high-efficiency catalyst based on stainless steel according to claim 2 is characterized in that: The nano cluster is a nano-dispersed cluster formed by stacking single atoms, and the cluster is composed of 3-4 platinum atoms.

4. The design method of a stainless steel-based natural seawater electrolysis high-efficiency catalyst according to claim 1, characterized in that: The stainless steel mesh is a 400-mesh 304 stainless steel mesh, and the size of the stainless steel mesh is 1.0×1.5 cm 2 .

5. The design method of a natural seawater electrolysis high-efficiency catalyst based on stainless steel according to claim 2, characterized in that: The preparation of the amorphous nickel-iron mixed oxide layer specifically comprises the following steps: Step 1, dissolving potassium hydroxide in pure water and stirring evenly to obtain a mixed solution, wherein the potassium hydroxide concentration in the mixed solution is 1.0M, the constant current oxidation parameter is set to 100-1000mA, and multiple current densities are set for stainless steel oxide layer preparation to achieve regulation of the thickness of the nickel-iron mixed oxide layer; Step 2, immersing the stainless steel mesh in a 0.5M sulfuric acid solution, washing at room temperature for 30 minutes to remove surface oxides, then washing with deionized water until neutral, and drying for later use, wherein the ratio of the stainless steel mesh to the mixed solution in step 1 is 1 mg:5 mL; Step 3: Fix the stainless steel mesh with an electrode clamp and immerse it in the mixed solution. The exposed area of ​​the stainless steel mesh is 1 cm -2 , a nickel-iron mixed oxide layer is formed by applying an oxidation current.

6. The design method of a natural seawater electrolysis high-efficiency catalyst based on stainless steel according to claim 1 is characterized in that: The metal M salt is a platinum salt, and the platinum salt is one or a mixture of platinum chloride, chloroplatinic acid, and acetylacetonate platinum (II).

7. The design method of a natural seawater electrolysis high-efficiency catalyst based on stainless steel according to claim 6, characterized in that: The generated platinum nanoclusters accounted for 0.03-0.05w% of the total weight of the stainless steel mesh; The immersion area of ​​the stainless steel mesh in the mixed solution is 1.0×1.0 cm 2 During the entire deposition process, inert gas needs to be introduced into the solution to remove dissolved oxygen.

8. The design method of a natural seawater electrolysis high-efficiency catalyst based on stainless steel according to claim 5, characterized in that: The constant current oxidation condition is to apply 500 mA to 1000 mA for 20 hours.

9. A natural seawater electrolysis high-efficiency catalyst obtained by the design method as described in any one of claims 1 to 8.

10. Use of the natural seawater electrolysis high-efficiency catalyst as claimed in claim 9 in a process of producing hydrogen by seawater electrolysis.

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