Anode porous transmission layer for electrolyzed water as well as preparation method and application of anode porous transmission layer

Abstract

The invention relates to an anode porous transmission layer for water electrolysis and a preparation method and application thereof. The preparation method comprises the following steps: providing a nickel substrate; cleaning the nickel substrate, drying and collecting; taking nickel salt, ferric salt, boric acid and ammonium chloride, and adding pure water to prepare electroplating liquid; hydrochloric acid is dropwise added into the electroplating solution, and the pH value is adjusted; a two-electrode electrolytic bath system is adopted, the dried nickel substrate is immersed in the electroplating liquid with the adjusted pH value for electroplating, and the modified anode porous transmission layer is obtained through aftertreatment. The broccoli-shaped structure containing nickel and iron elementary substances and alloy is formed on the surface of the modified substrate, so that the conductivity, the electrochemical stability and the interface transmission efficiency are remarkably improved, the catalyst loading is more uniform and firmer, reactant transmission and bubble escape are smooth, the contact resistance is reduced, and the service life is prolonged. The anode PTL material shows excellent electrocatalytic oxygen evolution performance in alkaline or anion exchange membrane water electrolysis hydrogen production, the hydrogen production energy consumption and cost are effectively reduced, and the technical problems of an existing anode PTL material and a modification method are solved.

Description

Technical Field

[0001] This invention relates to the field of hydrogen production by water electrolysis, and more specifically to a porous anode transport layer for water electrolysis, its preparation method, and its application. Background Technology

[0002] Hydrogen energy, as a clean and renewable secondary energy source, has become a core energy carrier for achieving the goal of "carbon neutrality." Water electrolysis technology is the core pathway for the large-scale production of "green hydrogen." Among them, anion exchange membrane water electrolysis (AEMWE) technology integrates the advantages of traditional alkaline water electrolysis and proton exchange membrane water electrolysis. It uses a solid anion exchange membrane as the core separation component and operates in an alkaline environment. It is not only compatible with non-precious metal catalysts but also allows the use of low-cost engineering materials. It is widely recognized as a green hydrogen production technology with great industrialization prospects.

[0003] In anion exchange membrane electrolyzers, the membrane electrode assembly (MEA) is the core component determining electrolysis efficiency and stability. The porous transport layer (PTL) of the anode, as a key component of the MEA, undertakes three core functions: first, to achieve efficient current conduction between the anode catalyst layer and the bipolar plates; second, to precisely transport the reactant water to the active sites of the catalyst; and third, to promptly remove oxygen byproducts generated during electrolysis, preventing increased mass transfer resistance due to gas retention. However, the current industrialization of AEM water electrolysis technology is limited by the performance bottleneck of the anode PTL, which faces the dual challenges of insufficient material stability and low interfacial transport efficiency, severely restricting the long-term operating life and energy conversion efficiency of the electrolyzer.

[0004] Existing AEM water electrolysis anode PTL technology is largely derived from proton exchange membrane (PEM) water electrolyzers. PEM water electrolyzers operate in a highly acidic, high-potential environment, typically using titanium-based materials (such as titanium fiber felt or sintered titanium porous plates) as the PTL because their surface can form a dense and stable passivated oxide layer, resisting corrosion from the acidic environment. However, directly applying titanium-based PTLs to AEM electrolyzer anodes presents significant compatibility issues: the high potential of the AEM anode (typically >1.6V vs. RHE) and the strong oxidizing environment of nascent oxygen cause the oxide layer on the titanium material surface to continuously thicken, gradually transforming into a poorly conductive insulating layer. This results in a sharp increase in the battery's ohmic resistance, rapid degradation of electrolysis performance, and a severe shortening of equipment lifespan. Furthermore, the high cost of titanium contradicts the core objective of AEM technology—"low-cost hydrogen production"—limiting its large-scale application.

[0005] To address the shortcomings of titanium-based materials, the industry has proposed nickel-based and carbon-based materials as alternatives. Nickel-based materials such as nickel foam, nickel felt, and nickel mesh have become mainstream candidates for AEM anode PTLs due to their excellent conductivity, alkali resistance, and moderate cost. Carbon-based materials such as carbon paper and carbon felt have also attracted attention due to their low cost and high porosity. However, both types of materials still have significant performance limitations: nickel-based materials are prone to oxidation and even corrosion under long-term high-potential conditions at the anode, leading to increased contact resistance, damage to the porous structure, and consequently, a decline in electrolytic performance. While carbon-based materials offer excellent conductivity and low cost, they are susceptible to electrochemical corrosion (carbon oxidation reaction) in the strong oxidizing environment of the anode, causing the porous structure to collapse and ultimately leading to rapid failure of the electrolytic cell.

[0006] To improve the stability and transport performance of anode PTLs, various surface modification schemes have been proposed in existing technologies, among which physical vapor deposition (PVD) and chemical vapor deposition (CVD) are commonly used methods. For example, CN119465076B discloses a technology for modifying titanium fiber felt based on chemical vapor deposition, aiming to solve the problem of uneven platinum coating on the titanium-based diffusion layer of traditional PEM electrolytic cells. However, this type of vapor deposition technology has inherent defects: firstly, it requires harsh process conditions such as high temperature and high vacuum, resulting in large equipment investment and high operating energy consumption; secondly, the process is complex, making it difficult to accurately control the coating thickness and composition uniformity; thirdly, for PTL substrates with complex three-dimensional pore structures such as nickel foam and nickel felt, the precursor for vapor deposition is difficult to penetrate to the deep pores, resulting in uneven coating coverage, weak adhesion between the substrate and the coating, and the inability to achieve uniform modification of the entire surface, ultimately limiting its application in large-scale production.

[0007] Therefore, developing a modification technology that can be implemented under mild conditions and is suitable for low-cost nickel-based substrates (such as nickel foam, nickel felt, and nickel mesh) to achieve precise control of the surface composition and microstructure of PTLs through a simple process, while simultaneously improving their surface conductivity, electrochemical stability, and interfacial transport efficiency, is key to overcoming the bottlenecks in AEM water electrolysis technology. Electrodeposition technology, as a solution-phase processing technique, has advantages such as simple equipment, convenient operation, low cost, and easy scalability. Furthermore, by adjusting electrical parameters such as current density and electroplating time, the thickness, composition, and morphology of the deposited layer can be precisely controlled, making it particularly suitable for the uniform modification of the entire surface of complex three-dimensional structure substrates. This provides a highly promising technical path for solving the aforementioned technical challenges. Based on this, developing an efficient and low-cost modification method for anolyte porous transport layer electrodeposition is of great significance for promoting the industrialization of anion exchange membrane water electrolysis hydrogen production technology. Summary of the Invention

[0008] To address the problems of poor stability and low interfacial transport efficiency of AEM water electrolysis anode PTL materials, as well as the harsh conditions and complex processes of existing modification methods, this invention aims to provide a porous transport layer for water electrolysis anodes, its preparation method, and its application.

[0009] The method for preparing a porous anolyte transport layer for water electrolysis according to the present invention includes the following steps: S1, providing a nickel substrate; S2, cleaning the nickel substrate, drying and collecting it; S3, taking nickel salt, iron salt, boric acid and ammonium chloride, adding pure water to prepare an electroplating solution, wherein the molar ratio of the nickel salt and iron salt is 1:0.1~1:2; S4, adding hydrochloric acid dropwise to the electroplating solution to adjust the pH value; S5, using a two-electrode electrolytic cell system, immersing the dried nickel substrate in the pH-adjusted electroplating solution for electroplating, and obtaining the modified porous anolyte transport layer after post-treatment.

[0010] In a preferred embodiment, the nickel substrate is at least one of nickel mesh, nickel felt, and nickel foam.

[0011] In a preferred embodiment, in step S3, the nickel salt is at least one of nickel chloride hexahydrate and nickel sulfate hexahydrate; the iron salt is at least one of ferrous chloride tetrahydrate and ferrous sulfate heptahydrate.

[0012] In a preferred embodiment, in step S3, when preparing the electroplating solution, nickel salt, iron salt, boric acid and ammonium chloride are placed in a container, pure water is added, and the mixture is stirred at room temperature until completely dissolved, and the container is sealed during the stirring process.

[0013] In a preferred embodiment, in step S4, the adjusted pH value is 1~2, and the pH value is continuously stirred and dynamically monitored during the adjustment process.

[0014] In a preferred embodiment, in step S5, in the two-electrode electrolytic cell system, the working electrode is a dried nickel substrate held by a platinum electrode clamp, and the counter electrode is a platinum sheet or platinum mesh.

[0015] In a preferred embodiment, in step S5, the current density of electroplating is 0.1~1.5A·cm-2, and the electroplating is carried out at room temperature.

[0016] The porous anode transport layer according to the present invention is prepared by the above-described preparation method.

[0017] In a preferred embodiment, the surface of the porous anode transport layer has a cauliflower-like structure, and elemental nickel, elemental iron, and nickel-iron alloy are grown on the surface.

[0018] According to the present invention, the above-described porous anode transport layer is used in alkaline water electrolysis for hydrogen production or anion exchange membrane water electrolysis for hydrogen production, wherein the porous anode transport layer is formed as an anode electrode.

[0019] The modification method for electrodeposition of the anolyte porous transport layer of this invention involves electrodepositing a commercially available, low-cost nickel-based substrate at room temperature and under mild conditions. This eliminates the need for high-temperature, high-vacuum, or strong acid / alkali environments, offering advantages such as low energy consumption, simple process, convenient operation, and easy scalability. Furthermore, some solvents can be recycled, making it more environmentally friendly. By precisely controlling the ratio of nickel and iron salts and the electroplating electrical parameters, a cauliflower-like structure containing elemental nickel, elemental iron, and nickel-iron alloys can be uniformly grown on the surface of the nickel-based substrate. This significantly improves the surface roughness and pore richness of the substrate, optimizing its hydrophilic and hydrophobic properties. Simultaneously enhancing its surface conductivity, electrochemical stability, and interfacial transport efficiency, this not only provides ample contact space for subsequent catalyst coating, ensuring more uniform catalyst loading and stronger bonding, but also facilitates reactant transport and bubble escape, effectively reducing contact resistance. Ultimately, the modified anode porous transport layer exhibits excellent electrocatalytic oxygen evolution performance when used as a substrate or electrode for oxygen evolution supported catalysts in alkaline water electrolysis or anion exchange membrane water electrolysis for hydrogen production. This significantly improves the operating efficiency of the electrolyzer, reduces hydrogen production energy consumption and costs, and successfully solves the technical challenges of insufficient stability, low interfacial transport efficiency, and harsh conditions and poor adaptability of existing anode PTL materials, providing key support for promoting the industrialization of anion exchange membrane water electrolysis for hydrogen production technology. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0021] Figure 1 The plating solution prepared in Example 1 of this invention uses nickel felt as a substrate, has a nickel-iron ratio of 1:1, and an electroplating current density of 1 A·cm. -2 Scanning electron microscope (SEM) image of the prepared modified PTL.

[0022] Figure 2 The plating solution prepared in Example 1 of this invention uses nickel felt as a substrate, has a nickel-iron ratio of 1:1, and an electroplating current density of 1 A·cm. -2 X-ray diffraction (XRD) pattern of the modified PTL.

[0023] Figure 3 The figure shows a comparison of the current-voltage curves of AEM electrolyzers assembled with the modified PTL sprayed catalyst, the modified PTL unsprayed catalyst, and the unmodified PTL sprayed catalyst prepared in Example 1 of this invention at 80°C.

[0024] Figure 4 Example 2 of this invention uses nickel foam as a substrate, an electroplating solution with a nickel-iron ratio of 1:1, and an electroplating current density of 1 A·cm. -2 Scanning electron microscope image of the prepared modified PTL.

[0025] Figure 5 Example 2 of this invention uses nickel foam as a substrate, an electroplating solution with a nickel-iron ratio of 1:1, and an electroplating current density of 1 A·cm. -2 XRD patterns of modified PTL were prepared. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The method for preparing an anode porous transport layer according to a first aspect of the present invention first includes providing a nickel substrate. In a preferred embodiment, the nickel substrate is a commercially available nickel substrate. In another preferred embodiment, the nickel substrate is at least one of nickel mesh, nickel felt, and nickel foam.

[0028] The method for preparing an anolyte porous transport layer (or a modification method by electrodeposition) according to the first aspect of the present invention further includes cleaning and drying a nickel substrate. In a preferred embodiment, the solvents used for cleaning are acetone, 3M hydrochloric acid, anhydrous ethanol, and pure water. In a preferred embodiment, cleaning is performed sequentially with acetone, 3M hydrochloric acid, and pure water. In a preferred embodiment, the substrate is sonicated in acetone for 20 minutes, rinsed three times each with ethanol and pure water; sonicated in 3M hydrochloric acid for 20 minutes, rinsed three times each with ethanol and pure water; and sonicated in pure water for 20 minutes before drying. In a preferred embodiment, cleaning is performed at room temperature (15~25°C). In a preferred embodiment, the oven temperature is 60°C, and the drying time is approximately 30 minutes, taking care to avoid excessive drying time that could lead to secondary oxidation.

[0029] According to the method for preparing the porous anodic transport layer provided by the first aspect of the present invention, the next step includes preparing an electroplating solution by taking nickel salt, iron salt, boric acid, and ammonium chloride. In a preferred embodiment, the nickel salt includes at least one of nickel chloride hexahydrate and nickel sulfate hexahydrate, and the iron salt is at least one of ferrous chloride tetrahydrate and ferrous sulfate heptahydrate. In a preferred embodiment, the molar ratio of the nickel salt and iron salt is 1:0.1 to 1:2 (e.g., 1:0.1, 1:0.3, 1:0.6, 1:1, 1:1.5, or 1:2). In a preferred embodiment, the nickel salt, iron salt, boric acid, and ammonium chloride are placed in a beaker and stirred with a rotor at room temperature until completely dissolved to obtain the electroplating solution. In a preferred embodiment, the solution is a green or blue-green transparent solution. In a preferred embodiment, the beaker is sealed with plastic wrap during the stirring and dissolving process; if the solution is not sealed with plastic wrap during stirring and dissolving, oxygen from the air will enter the solution, causing the ferrous ions in the solution to be prematurely oxidized to ferric ions. In a preferred embodiment, the amount of boric acid is 0.5 to 2 times the total molar amount of nickel and iron salts, and the amount of ammonium chloride is 2 to 5 times the total molar amount of nickel and iron salts, used to adjust the surface pH during the electroplating process and improve the conductivity of the electroplating solution.

[0030] According to the method for preparing the porous anodic transport layer provided by the first aspect of the present invention, the next step includes adjusting the pH by adding hydrochloric acid dropwise to the electroplating solution. In a preferred embodiment, the pH of the solution is dynamically tested using a pH meter, and the hydrochloric acid is added dropwise while continuous stirring is performed. In a preferred embodiment, the concentration of the hydrochloric acid added dropwise is 3M, and stirring is continued until the pH is between 1 and 2. In a preferred embodiment, the pH adjustment is performed at room temperature.

[0031] The method for preparing the porous anodic transport layer according to the first aspect of the present invention includes, in the final step, employing a two-electrode electrolytic cell system, immersing a dried nickel substrate in a pH-adjusted electroplating solution for electroplating, followed by post-treatment to obtain the modified porous anodic transport layer. In a preferred embodiment, a platinum electrode clamp is used to hold the dried nickel substrate as the working electrode, and a platinum sheet is used as the counter electrode. In a preferred embodiment, the dried nickel substrate is cut into 4cm pieces. 2 ~100cm 2 The size is determined using platinum electrode clips. In a preferred embodiment, the electroplating current density is 0.1 A·cm. -2 ~1.5A·cm -2 (For example, 0.1 A·cm) -2 0.5A·cm -2 1A·cm -2 1.5A·cm -2 or 2A·cm -2The electroplating time is 200-500 seconds. In a preferred embodiment, electroplating is performed at room temperature. In a preferred embodiment, the post-treatment includes rinsing with pure water, ultrasonication for 1-3 minutes, and drying in an oven. The dried product is the modified anodic porous transport layer. In a preferred embodiment, the post-treatment layer is dried in an oven at a temperature of 60°C.

[0032] Thus, the method for preparing an anode porous transport layer according to the first aspect of the present invention modifies a nickel substrate that can serve as an anode porous transport layer through one-step electroplating. This involves preparing nickel salt and iron salt electroplating solutions with different proportions to electroplat the nickel substrate, while simultaneously changing the magnitude of the electroplating current to electroplat the nickel substrate. The entire method is carried out at room temperature, has the characteristics of low energy consumption and low cost, and is simple to operate and easy to scale up.

[0033] According to a second aspect of the present invention, an electrodeposited modified porous anolyte transport layer is obtained by the above-described electrodeposition preparation method. In a preferred embodiment, the surface of the porous anolyte transport layer has a cauliflower-like structure and is formed by growing elemental nickel, iron, and a nickel-iron alloy on the substrate surface by electroplating.

[0034] According to a third aspect of the present invention, the above-described porous anode transport layer is provided for use in anion exchange membrane electrolysis (AEMWE) for hydrogen production, wherein the porous anode transport layer is formed as an anode electrode. In a preferred embodiment, the porous anode transport layer serves as a substrate for a supported catalyst for anolyte oxygen evolution. In a preferred embodiment, the anode electrode is prepared by coating the porous anode transport layer with nickel-iron bimetallic hydroxides (NiFe LDHs). In a preferred embodiment, the loading of NiFe LDHs is 2.5 mg / cm³. 2 In a preferred embodiment, in the AEMWE system, 1.0 mol / L KOH is used as the electrolyte, and 40% commercial Pt / Ru is sprayed onto carbon paper as the cathode. Commercial PiperION is also used. ® The A40 membrane is an anion exchange membrane. In a preferred embodiment, the AEMWE system operates at a temperature of 70–100°C. In another preferred embodiment, the operating temperature is 80°C, and the modified anode porous transport layer exhibits good performance.

[0035] Example 1

[0036] Commercially available 0.25mm thick nickel felt was selected as the raw material and cut into 20mm×20mm dimensions.

[0037] The cut nickel felt was ultrasonically cleaned in acetone for 20 minutes to remove surface oil. Then it was rinsed repeatedly three times with anhydrous ethanol and pure water to remove residual acetone. The rinsed nickel felt was ultrasonically cleaned in 3M hydrochloric acid for 20 minutes to remove the surface oxide layer. It was then rinsed repeatedly three times with anhydrous ethanol and pure water to remove residual hydrochloric acid. The nickel felt was ultrasonically cleaned in pure water for 20 minutes to further purify the surface. The cleaned nickel felt was placed in an oven at 60°C and dried before being collected.

[0038] Take 6.575g of nickel sulfate hexahydrate, 6.95g of ferric sulfate heptahydrate, 6.19g of boric acid, and 26.75g of ammonium chloride, and place them together in a beaker. Add an appropriate amount of pure water, and seal the beaker with plastic wrap to prevent the ferrous ions in the solution from being exposed to air and oxidized. Place the beaker at room temperature and stir with a rotor until all the raw materials are completely dissolved, obtaining a 250mL green transparent electroplating solution, in which Ni... 2+ with Fe 2+ The molar ratio is 1:1.

[0039] Add 3M hydrochloric acid dropwise to the electroplating solution to adjust the pH to 1.6.

[0040] A two-electrode electrolytic cell system was used, with dried nickel felt as the working electrode (clamped with platinum electrode clips) and a 20mm × 20mm platinum sheet as the counter electrode. Both electrodes were immersed in the pH-adjusted electroplating solution; the electroplating current density was set to 1 A∙cm⁻¹. -2 Electroplating time is 240s, and electrodeposition is carried out at room temperature. After electroplating, the nickel felt is removed, and the surface residual electroplating solution is rinsed with a large amount of pure water. Then, it is ultrasonically cleaned for 1~3 minutes and placed in a 60℃ oven to dry, thus obtaining the modified anodic porous transport layer.

[0041] The microstructure of the modified anode porous transport layer prepared in this embodiment was observed using scanning electron microscopy. Figure 1 As shown, after electrodeposition modification, the nickel felt surface is no longer the original smooth fibrous structure, but forms a uniformly distributed "cauliflower-like" microstructure. This structure is composed of a large number of nanoscale particles (e.g., particles with a diameter of 50-200 nm), with abundant porosity (e.g., porosity of 60%-80%) and good connectivity. This cauliflower-like structure can significantly increase the specific surface area of ​​the porous transport layer of the anode, providing sufficient attachment sites for subsequent catalyst loading on the one hand, and optimizing the interfacial pore structure on the other hand, facilitating the transport of reactant water and the removal of product oxygen, thus laying a structural foundation for improving electrocatalytic performance.

[0042] The modified anolyte porous transport layer prepared in this embodiment was subjected to structural testing using X-ray diffraction. Figure 2As shown, in addition to the characteristic diffraction peaks of elemental nickel (Ni) (corresponding to the crystal structure of the nickel substrate), obvious characteristic diffraction peaks of nickel-iron alloy (Ni-Fe alloy) also appeared. The diffraction peaks were of high intensity and sharp shape, indicating that the electrodeposition method of the present invention successfully grew a nickel-iron alloy with good crystallinity on the surface of the nickel felt substrate. At the same time, no obvious iron oxide diffraction peaks were detected, proving that the sealing treatment with plastic wrap during the preparation of the electroplating solution effectively avoided the premature oxidation of ferrous ions, ensuring the smooth formation of the nickel-iron alloy and verifying the effectiveness of the modification method.

[0043] Using the modified anolyte porous transport layer prepared in this embodiment as a substrate, at a concentration of 2.5 mg / cm³... 2 The catalyst, NiFe bimetallic hydroxide (NiFe LDHs), was sprayed onto its surface to form the anode electrode; two control samples were also set up.

[0044] Control sample 1: Original nickel felt that has not undergone electrodeposition modification, also at 2.5 mg / cm³ 2 Loading and spraying NiFe LDHs catalyst;

[0045] Control sample 2: Modified anode porous transport layer prepared in this example (without NiFe LDHs catalyst spraying).

[0046] An anion exchange membrane electrolysis (AEMWE) test system was established: 1.0 mol / L KOH solution was used as the electrolyte, and a commercial Pt / Ru 40% catalyst was sprayed onto carbon paper as the cathode. A commercial PiperION membrane was used as the cathode. ® Using an A40 membrane as the anion exchange membrane, the above-mentioned anolyte and two sets of control samples were assembled into an electrolytic cell. The electrocatalytic oxygen evolution performance was tested at 80°C, and the results were as follows: Figure 3 The current-voltage curves shown in the figure correspond to the following three curves: the "modified PTL and NiFeLDHs catalyst" prepared in this embodiment (the present invention), the modified PTL without catalyst (control sample 2), and the "unmodified original nickel felt and NiFeLDHs catalyst" (control sample 1). The current density of the present invention is significantly higher than that of control sample 1 and control sample 2, reaching 3.02 A / cm² at a voltage of 2V. -2 This indicates that the modified porous anode transport layer, after loading the catalyst, exhibits excellent electrocatalytic oxygen evolution performance.

[0047] The comparative experimental results fully demonstrate that the cauliflower-like structure and nickel-iron alloy components formed on the nickel substrate surface by electrodeposition modification can effectively optimize the contact interface between the catalyst and the substrate, increase the catalyst loading, and improve the mass transfer efficiency, thereby significantly improving the electrocatalytic oxygen evolution performance of the anode and providing a high-performance porous anode transport layer material for anion exchange membrane water electrolysis hydrogen production technology.

[0048] Example 2

[0049] Commercially available 1.5mm thick nickel foam was selected as the raw material and cut into 30mm×30mm dimensions.

[0050] The cut nickel foam was washed sequentially with acetone, 3M hydrochloric acid and pure water. The washed nickel foam was then placed in an oven and dried at 60°C. After drying, it was collected.

[0051] Take 13.15g of nickel sulfate hexahydrate, 13.9g of ferric sulfate heptahydrate, 12.375g of boric acid, and 53.5g of ammonium chloride. Add an appropriate amount of pure water. Seal the beaker with plastic wrap to prevent the ferrous ions in the solution from being exposed to air and oxidized. Place the beaker at room temperature and stir with a rotor until all the raw materials are completely dissolved, obtaining 500mL of a blue-green transparent electroplating solution, in which Ni... 2+ with Fe 2+ The molar ratio is 1:1.

[0052] Add 3M hydrochloric acid dropwise to the electroplating solution to adjust the pH to 1.5.

[0053] A two-electrode system was used, with the working electrode being a modified nickel foam (platinum electrode clip) and the counter electrode being a 30mm × 30mm platinum sheet; both electrodes were immersed in the electroplating solution, and the electroplating current density was set to 1 A·cm. -2 The electroplating time is 300s; after electroplating, the surface of the foamed nickel is rinsed with a large amount of pure water, ultrasonically cleaned for 1~3min, and then dried in a 60℃ oven to obtain the modified anodic porous transport layer.

[0054] The microstructure of the modified anode porous transport layer prepared in this embodiment was observed using scanning electron microscopy. Figure 4 As shown, after electrodeposition modification, the nickel foam substrate also exhibits a uniform and dense cauliflower-like microstructure on its surface, consistent with the modified morphology of the nickel felt substrate in Example 1. This result demonstrates that the electrodeposition modification method of this invention has good adaptability to different types of nickel substrates, achieving uniform modification, and the resulting cauliflower-like structure is not significantly affected by the original morphology of the substrate, further proving the versatility and stability of this modification method.

[0055] The modified anolyte porous transport layer prepared in this embodiment was subjected to structural testing using X-ray diffraction. Figure 5 As shown in the figure, the characteristic diffraction peaks of elemental nickel (Ni) and nickel-iron alloy (Ni-Fe alloy) are clearly presented. The peaks are sharp and free of impurities, indicating that nickel-iron alloys were successfully grown on different types of nickel substrates with high product purity. Combined with the XRD results of Example 1, it can be seen that the electrodeposition modification method of the present invention can stably generate nickel-iron alloys regardless of whether the substrate is nickel felt or nickel foam, verifying the reliability of the modification method.

[0056] Example 3

[0057] Commercially available 1.0 mm thick nickel mesh was selected as the raw material and cut into 100 mm × 100 mm dimensions.

[0058] The cut nickel mesh was cleaned in sequence with acetone, 3M hydrochloric acid and pure water. The cleaned nickel mesh was then placed in an oven and the oven temperature was set to 60℃. After drying, it was taken out and collected.

[0059] Take 63.1g of nickel sulfate hexahydrate, 44.5g of ferric sulfate heptahydrate, 49.5g of boric acid, and 214.0g of ammonium chloride. Add an appropriate amount of pure water. Seal the beaker with plastic wrap to prevent the ferrous ions in the solution from being exposed to air and oxidized. Place the beaker at room temperature and stir with a rotor until all the raw materials are completely dissolved, obtaining a green and transparent 2000mL electroplating solution, in which Ni... 2+ with Fe 2+ The molar ratio is 1:0.6.

[0060] Add 3M hydrochloric acid dropwise to the electroplating solution to adjust the pH to 1.6.

[0061] A two-electrode system was used, with the working electrode being a clamped nickel mesh (platinum electrode clamp) and the counter electrode being a 100mm × 100mm platinum mesh electrode; both electrodes were immersed in the electroplating solution, and the electroplating current density was set to 1.2 A·cm. -2 The electroplating time is 400s; after electroplating, the surface is rinsed with a large amount of pure water, ultrasonically cleaned for 1~3min, and dried in a 60℃ oven to obtain the modified anodic porous transport layer.

[0062] In summary, the electrodeposition modification method of this invention uses commercially available nickel-based porous transport layers (such as nickel mesh, nickel foam, or nickel fiber felt) as a substrate. Electrodeposition is employed to grow elemental nickel particles, elemental iron particles, and elemental nickel-iron alloy particles on their surface (this alloy phase can be confirmed by the obvious nickel-iron alloy peaks in the XRD pattern). The modification process of this invention is carried out entirely at room temperature, without the need for heating or solvothermal processes, and does not require operation in strong acid or strong alkali environments, exhibiting significant low energy consumption advantages while meeting the technical requirements of a mild process. Electrodeposition technology itself, as a solution-based processing technology, is not only simple in equipment and low in cost, and easy to scale up for production, but also allows for precise control of the thickness, composition, and morphology of the deposited layer by adjusting electrical parameters such as the electroplating current. This enables deep and uniform modification of low-cost nickel-based substrates, effectively solving the problem that traditional modification methods are difficult to adapt to complex three-dimensional substrate structures.

[0063] The porous transport substrate modified using the electrodeposition method of this invention exhibits significantly improved surface roughness, richer pore structure, and optimized surface hydrophilic / hydrophobic properties. Simultaneously, it enhances surface conductivity, electrochemical stability, and interfacial transport performance. These structural and performance optimizations provide ample contact space for subsequent catalyst coating, resulting in more uniform coating and significantly strengthening the bond between the catalyst and the porous transport layer. Furthermore, the optimized interfacial pores provide smooth pathways for reactant transport and bubble escape, while reducing contact resistance. Ultimately, this leads to improved performance of the anion exchange membrane electrolyzer and reduced hydrogen production energy consumption.

[0064] From a preparation process perspective, this method is simple to operate: first, a specific cleaning process removes the oxide layer and impurities from the surface of a commercial nickel substrate, laying the foundation for subsequent uniform electrodeposition; then, an electroplating solution containing different proportions of nickel salts and iron salts is prepared, and a sealing treatment is used to prevent premature oxidation of ferrous ions; finally, a two-electrode system is used to electrodeposit on the cleaned nickel substrate, and after electroplating, the modified product is obtained after cleaning, ultrasonication, and drying. The entire preparation process uses readily available and simple raw materials, and some solvents can be reused, combining environmental friendliness with the advantages of scalable preparation.

[0065] Ultimately, the modified nickel substrate obtained by this invention can be directly used as the anode porous transport layer material or electrode in anion exchange membrane water electrolysis for hydrogen production. Its surface is more hydrophilic due to electrochemical action and has a highly active nickel-iron alloy grown on it. After loading a catalyst, it exhibits excellent electrocatalytic oxygen evolution performance, providing key support for promoting the development of AEM water electrolysis technology.

[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made in accordance with the claims and description of this invention fall within the protection scope of the claims. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A method for preparing a porous anode transport layer for water electrolysis, characterized in that, The preparation method includes the following steps: S1 provides a nickel substrate; S2, After cleaning the nickel substrate, dry and collect it; S3, take nickel salt, iron salt, boric acid and ammonium chloride, add pure water to prepare an electroplating solution, wherein the molar ratio of nickel salt to iron salt is 1:0.1~1:2; S4, add hydrochloric acid dropwise to the electroplating solution to adjust the pH value; S5 employs a two-electrode electrolytic cell system, immersing the dried nickel substrate in a pH-adjusted electroplating solution for electroplating, and then performing post-treatment to obtain a modified anodic porous transport layer.

2. The preparation method according to claim 1, characterized in that, The nickel substrate is at least one of nickel mesh, nickel felt, and nickel foam.

3. The preparation method according to claim 1, characterized in that, In step S3, the nickel salt is at least one of nickel chloride hexahydrate and nickel sulfate hexahydrate; the iron salt is at least one of ferrous chloride tetrahydrate and ferrous sulfate heptahydrate.

4. The preparation method according to claim 1, characterized in that, In step S3, when preparing the electroplating solution, nickel salt, iron salt, boric acid and ammonium chloride are placed in a container, pure water is added, and the mixture is stirred at room temperature until completely dissolved. During the stirring process, the container is sealed.

5. The preparation method according to claim 1, characterized in that, In step S4, the adjusted pH value is 1~2, and the pH value is continuously stirred and dynamically monitored during the adjustment process.

6. The preparation method according to claim 1, characterized in that, In step S5, in the two-electrode electrolytic cell system, the working electrode is a dried nickel substrate held by a platinum electrode clamp, and the counter electrode is a platinum sheet or platinum mesh.

7. The preparation method according to claim 1, characterized in that, In step S5, the electroplating current density is 0.1~1.5 A·cm. -2 Furthermore, the electroplating is carried out at room temperature.

8. An anode porous transport layer, characterized in that, It is prepared by any one of the preparation methods according to claims 1-7.

9. The anode porous transport layer according to claim 8, characterized in that, The surface of the porous anode transport layer has a cauliflower-like structure, and elemental nickel, elemental iron, and nickel-iron alloy are grown on the surface.

10. The application of the porous anode transport layer according to claim 8 or 9 in alkaline water electrolysis for hydrogen production or anion exchange membrane water electrolysis for hydrogen production, characterized in that, The porous transport layer of the anode is formed as the anode electrode.

Images