Alkaline water electrolysis electrode as well as preparation method and application thereof

Abstract

The invention discloses an alkaline water electrolysis electrode. The alkaline water electrolysis electrode structurally comprises a substrate, and a metal composite oxide layer and a noble metal catalyst layer which are sequentially coated on the substrate. The mass ratio of nickel to tantalum to platinum in the metal composite oxide layer is (6.5-8.5): (1.5-2.5): (1.5-2.5), and the loading capacity of platinum is 0.25-2 g / m; and the loading amount of noble metal in the noble metal catalyst layer is 6-16 g / m. Aiming at the problems of cathode oxidation, corrosion and activity attenuation caused by reverse current under starting, stopping and fault working conditions of the alkaline electrolytic cell, a double-layer structure with a specific component proportion is designed, an oxygen evolution reaction is preferentially triggered by utilizing a noble metal catalyst layer to perform current shunting, and a stable chemical barrier is formed by virtue of a metal composite oxide layer; and the electrode is suitable for the field of hydrogen production by alkaline water electrolysis.

Description

Technical Field

[0001] This invention belongs to the field of alkaline water electrolysis hydrogen production technology, specifically relating to an alkaline water electrolysis electrode, its preparation method, and its application. Background Technology

[0002] Alkaline water electrolysis is one of the most mature and widely used hydrogen production technologies. The hydrogen evolution reaction primarily occurs at the cathode, which typically uses metallic nickel or nickel mesh as the substrate due to its low cost and catalytic activity towards the hydrogen evolution reaction. When the electrolyzer shuts down, experiences a power outage, or a system malfunction, the potential difference between the cathode and anode can lead to a reverse current. In this case, the original cathode will briefly function as the anode.

[0003] When the nickel cathode is reversed to become the anode, an oxygen evolution reaction occurs on its surface. Under alkaline conditions, nickel is rapidly oxidized, transforming from the metallic state Ni(0) to... Furthermore, it is oxidized into unstable high-valence oxides. This process is accompanied by huge volume changes and structural stress, resulting in loss of active area and corrosion and pulverization of the matrix. Specifically, the original nickel catalyst surface is covered by insulating or poorly conductive oxides, resulting in a permanent decrease in hydrogen evolution activity; repeated oxidation-reduction cycles cause the nickel matrix to be continuously corroded and pulverized, reducing mechanical strength and ultimately leading to the destruction of the electrode structure.

[0004] Therefore, there is an urgent need for an alkaline water electrolysis electrode to alleviate or solve the above-mentioned technical problems. Summary of the Invention

[0005] In order to solve the technical problem that the alkaline electrolyzer is deactivated by reverse current and the electrode structure is damaged due to reverse current during start-up and shutdown, thus affecting the operational stability, the present invention provides an alkaline water electrolysis electrode, including a substrate and a metal composite oxide layer and a noble metal catalyst layer sequentially coated on the substrate. The metal composite oxide layer is a nickel-tantalum composite oxide layer containing platinum, with the mass ratio of nickel, tantalum, and platinum being (6.5-8.5):(1.5-2.5):(1.5-2.5). The platinum loading in the alkaline water electrolysis electrode is 0.25-2 g / m³. 2 The loading of the noble metal in the alkaline water electrolysis electrode is 6-16 g / m³. 2 .

[0006] This invention provides an alkaline water electrolysis electrode. Addressing the problems of cathode oxidation, corrosion, and activity decay caused by reverse current during start-up, shutdown, and fault conditions of alkaline electrolyzers, it innovatively designs a double-layer structure (metal composite oxide layer + noble metal catalyst layer), achieving a significant improvement in anti-reverse polarity. Specific technical effects are as follows: Excellent anti-reverse polarity (in this invention, anti-reverse polarity mainly emphasizes the operational stability of the alkaline water electrolysis electrode under reverse polarity potential): Highly efficient current diversion and protection of the noble metal catalyst layer. When the electrode switches from cathode to anode due to reverse current, platinum and / or ruthenium in the outer noble metal catalyst layer, acting as highly efficient oxygen evolution reaction (OER) catalysts, preferentially trigger the OER, directing most of the anodic current to the catalyst layer surface. This process significantly reduces the direct impact of the current on the underlying metal composite oxide layer and the nickel substrate, avoiding excessive oxidation of nickel at the anodic potential (such as the formation of...). (and high-valence oxides), thereby suppressing volume expansion, structural stress concentration and active area loss caused by oxidation, ensuring stable operation of the electrode under start-up and shutdown conditions.

[0007] The metal composite oxide layer acts as a stabilizing barrier. This layer is composed of nickel, tantalum, and platinum in a specific mass ratio (6.5-8.5:1.5-2.5:1.5-2.5). The introduction of the composite metal oxide imparts chemical stability to the electrode at the anodic potential; simultaneously, tantalum oxide (such as...) It exhibits extremely high corrosion resistance at anodic potential, is not easily oxidized or dissolved, and can effectively block the electrolyte from... This prevents corrosive media from penetrating into the nickel matrix. The synergistic effect effectively forms a chemical barrier, protecting the electrode structure and further ensuring the electrode's operational stability.

[0008] Furthermore, the substrate is made of nickel; the noble metals in the noble metal catalyst layer include ruthenium and / or platinum.

[0009] Furthermore, the platinum loading in the alkaline water electrolysis electrode is 0.25-1.5 g / m³. 2 The loading of the noble metal in the alkaline water electrolysis electrode is 6-14 g / m³. 2 .

[0010] This invention provides a method for preparing an alkaline water electrolysis electrode as described in any one of the above claims, comprising the following steps: S1. A nickel source, a tantalum source, and a platinum source are mixed in a solvent to prepare a first precursor slurry, wherein the mass ratio of nickel, tantalum, and platinum in the first precursor slurry is (6.5-8.5):(1.5-2.5):(1.5-2.5). S2. The first precursor slurry is coated onto the surface of the substrate and subjected to a first sintering treatment to obtain a first electrode containing the metal composite oxide layer; S3. Prepare a second precursor slurry containing precious metals; S4. The second precursor slurry is coated onto the surface of the metal composite oxide layer electrode, and after a second sintering treatment, an alkaline hydrolysis electrode containing the noble metal catalyst layer is obtained.

[0011] This invention provides a method for preparing an alkaline water electrolysis electrode. Through precise process design and coordinated steps, a bilayer functional structure is efficiently constructed, synergistically enhancing the anti-reverse polarity capability. The technical effects are as follows: This method employs a stepwise coating and sintering process to sequentially form a metal composite oxide layer and a noble metal catalyst layer on a substrate. In steps S1-S2, the mass ratio of nickel, tantalum, and platinum is controlled (6.5-8.5:1.5-2.5:1.5-2.5), resulting in strong chemical bonds between the oxides in the composite oxide layer and the substrate. Simultaneously, the tantalum oxide is not easily oxidized and dissolved, effectively blocking the presence of catalytic oxides in the electrolyte. This prevents corrosive media from penetrating into the nickel matrix. The synergistic effect effectively forms a chemical barrier, protecting the electrode structure and ensuring operational stability during start-up and shutdown.

[0012] Steps S3-S4 involve coating the second precursor slurry and performing a second sintering process to form a uniform and dense noble metal catalytic layer on the surface of the composite oxide layer. Its highly efficient oxygen evolution reaction catalytic activity can quickly divert the anodic current, inhibit the oxidation of the nickel substrate, and further ensure the stable operation of the electrode under start-up and shutdown conditions.

[0013] Furthermore, the nickel source includes nickel chloride, the tantalum source includes tantalum pentachloride, the platinum source includes chloroplatinic acid and / or platinum acetylacetonate, and the source of the noble metal includes ruthenium trichloride and / or chloroplatinic acid.

[0014] Furthermore, before coating the first precursor slurry onto the substrate surface, the substrate is pretreated, the pretreatment including sandblasting and surface roughening in sequence.

[0015] Furthermore, the temperature of the first sintering treatment is 400-500℃ and the duration is 10-30 min; the temperature of the second sintering treatment is 400-500℃ and the duration is 10-30 min.

[0016] Furthermore, the mass concentration of nickel in the first precursor slurry is 4%-8%, and the mass concentration of precious metals in the second precursor slurry is 2%-5%.

[0017] Furthermore, if the platinum loading in the metal composite oxide layer is less than 0.25 g / m, repeat step S2 until the platinum loading in the metal composite oxide layer is 0.25-2 g / m. 2 ; If the loading of the noble metal in the noble metal catalyst layer is less than 6 g / m³, repeat step S4 until the loading of the noble metal in the noble metal catalyst layer is 6-16 g / m³. 2 .

[0018] This invention provides an application of the alkaline water electrolysis electrode as described in any one of the above claims or the alkaline water electrolysis electrode prepared by any one of the above claims in alkaline water electrolysis for hydrogen production.

[0019] The alkaline water electrolysis electrode and its preparation method provided by this invention exhibit significant technical advantages in alkaline water electrolysis for hydrogen production: the double-layer structure (metal composite oxide layer + noble metal catalyst layer) synergistically enhances the anti-reverse polarity capability, effectively suppresses cathode oxidation corrosion under start-up, shutdown and abnormal operating conditions, and ensures long-term stable operation of the electrolyzer. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. 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.

[0021] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0022] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of the invention, may be implemented using any prior art methods, devices, and materials similar to or equivalent to the methods, devices, and materials in the embodiments of the present invention.

[0023] The present invention provides an alkaline water electrolysis electrode, comprising a substrate and a metal composite oxide layer and a noble metal catalyst layer sequentially coated on the substrate; the metal composite oxide layer is a nickel-tantalum composite oxide layer containing platinum, wherein the mass ratio of nickel, tantalum and platinum is (6.5-8.5):(1.5-2.5):(1.5-2.5).

[0024] In this invention, the platinum loading in the metal composite oxide layer can be 0.25-2 g / m³. 2 The loading of the noble metal in the noble metal catalyst layer can be 6-16 g / m³. 2 In some embodiments, the platinum loading in the metal composite oxide layer can be 0.25-1.5 g / m³. 2The loading of the noble metal in the noble metal catalyst layer can be 6-14 g / m³. 2 .

[0025] In some more specific embodiments, the platinum loading in the metal composite oxide layer can be 0.25-1.25 g / m³. 2 Or 0.25-1.0 g / m 2 Or 0.3-1.25g / m 2 Or 0.4-1.25g / m 2 Or 0.3-1.0 g / m 2 Or 0.4-1.0 g / m 2 Or 0.25-0.8g / m 2 Or 0.3-0.8g / m 2 Or 0.4-0.8g / m 2 Or 0.25-0.7g / m 2 Or 0.25-0.6g / m 2 .

[0026] In some more specific embodiments, the loading of the noble metal in the noble metal catalyst layer can be 6-12 g / m³. 2 Or 6-11g / m 2 Or 6-10g / m 2 Or 7-12g / m 2 Or 7-11g / m 2 Or 8-12g / m 2 .

[0027] In this invention, the substrate is made of nickel; in some embodiments, the substrate may be a nickel mesh.

[0028] In this invention, the noble metal species of the noble metal catalyst layer may include ruthenium and / or platinum.

[0029] This invention provides a method for preparing an alkaline water electrolysis electrode as described in any one of the above claims, comprising the following steps: S1. A nickel source, a tantalum source, and a platinum source are mixed in a solvent to prepare a first precursor slurry, wherein the mass ratio of nickel, tantalum, and platinum in the first precursor slurry is (6.5-8.5):(1.5-2.5):(1.5-2.5).

[0030] In this invention, the nickel source includes nickel chloride, the tantalum source includes tantalum pentachloride, and the platinum source may include chloroplatinic acid and / or platinum acetylacetonate.

[0031] In some embodiments, the mass concentration of nickel in the first precursor slurry can be 4%-8%. Based on this, the mass concentrations of tantalum and platinum in the first precursor slurry can be adaptively adjusted according to the required mass ratio of nickel, tantalum, and platinum.

[0032] In some embodiments, the solvent may be an organic solvent; for example, the solvent may be anhydrous ethanol and / or isopropanol.

[0033] S2. The first precursor slurry is coated onto the substrate surface and subjected to a first sintering treatment to obtain a first electrode containing the metal composite oxide layer.

[0034] In this invention, the substrate is made of nickel; in some embodiments, the substrate may be a nickel mesh.

[0035] In this invention, the substrate can be pretreated before the first precursor slurry is coated onto the substrate surface. The pretreatment includes sandblasting and surface roughening treatment performed sequentially.

[0036] In some embodiments, pretreatment may include sandblasting, cleaning, roughening, and cleaning and drying processes performed sequentially.

[0037] In some embodiments, the cleaning process may include ultrasonically cleaning the object to be treated sequentially in sodium hydroxide and ethanol to remove surface oil.

[0038] Roughening treatment may include immersing the material to be treated in an acid to remove the oxide layer and roughen the surface. For example, the acid may include dilute hydrochloric acid and / or dilute sulfuric acid.

[0039] In some specific embodiments, the pretreatment may include the following steps: First, the substrate is sandblasted to enhance its surface roughness and improve the adhesion of subsequent coatings. Then, the sandblasted substrate is sequentially placed in a sodium hydroxide solution and ethanol, and ultrasonic cleaning is performed to efficiently remove oil and other impurities adhering to the substrate surface using the cavitation effect of ultrasound. Next, the substrate is immersed in a dilute hydrochloric acid or dilute sulfuric acid solution to remove the oxide layer on the substrate surface through the chemical reaction between the acid and the metal oxide, while simultaneously roughening the surface and increasing its surface activity. Finally, the substrate is thoroughly rinsed with deionized water to ensure no residual acid remains on the surface, and then dried for later use.

[0040] In this invention, the coating method can be brushing, spraying or dipping, so as to uniformly apply the first precursor slurry to the substrate surface.

[0041] In this invention, the temperature of the first sintering treatment can be 400-500℃, and the duration can be 10-30 minutes. In some embodiments, the temperature of the first sintering treatment can be 400-480℃, 420-500℃, 420-480℃, 430-480℃, or 420-470℃.

[0042] In some embodiments, the first sintering process can be performed in an air or oxygen atmosphere.

[0043] In this invention, step S2 can be repeated until the platinum loading in the alkaline water electrolysis electrode is 0.25-2 g / m³. 2 .

[0044] S3. Prepare a second precursor slurry containing precious metals.

[0045] In this invention, the source of the noble metal may include ruthenium trichloride and / or chloroplatinic acid.

[0046] In some embodiments, the mass concentration of noble metals in the second precursor slurry can be 2%-5%.

[0047] S4. The second precursor slurry is coated onto the surface of the metal composite oxide layer electrode, and after a second sintering treatment, an alkaline water electrolysis electrode containing the noble metal catalyst layer is obtained.

[0048] In this invention, the coating method can be brushing, spraying or dipping, so as to uniformly apply the second precursor slurry to the substrate surface.

[0049] In this invention, the temperature of the second sintering treatment can be 400-500℃, and the duration can be 10-30 min. In some embodiments, the temperature of the second sintering treatment can be 400-480℃, 420-500℃, 420-480℃, 430-480℃, or 420-470℃.

[0050] In some embodiments, the second sintering process can be carried out in an air or oxygen atmosphere.

[0051] In this invention, step S4 can be repeated until the loading of the noble metal in the alkaline water electrolysis electrode is 6-16 g / m³. 2 .

[0052] It should be emphasized that in the alkaline water electrolysis electrode preparation method provided by this invention, steps S1 to S4 do not necessarily have to be performed in a predetermined order. In actual operation, each step can be adapted according to the specific process conditions, equipment status, raw material characteristics, and other actual conditions. For example, in certain specific situations, step S3 can be performed first to prepare the second precursor slurry containing noble metals, and then step S1 can be carried out to mix the nickel source, tantalum source, and platinum source in a solvent to prepare the first precursor slurry, etc., as long as it can be ensured that the alkaline water electrolysis electrode finally prepared meets the performance requirements and technical indicators of this invention.

[0053] The alkaline water electrolysis electrode preparation method provided by this invention utilizes the complementary dual protection mechanisms of chemical and physical barriers to ensure the operational stability of the electrode under start-up and shutdown conditions.

[0054] Chemical barrier construction. In steps S1-S2, by strictly controlling the mass ratio of nickel, tantalum, and platinum (6.5-8.5:1.5-2.5:1.5-2.5), the composite oxide in the composite oxide layer forms a strong chemical bond with the substrate, while simultaneously endowing it with unique corrosion resistance properties. For example, tantalum oxide has extremely high chemical inertness and is not easily oxidized and dissolved in an alkaline electrolytic environment. The strong chemical bond and corrosion resistance work together to construct a dense chemical barrier on the surface of the nickel substrate.

[0055] Physical barrier enhancement. The sandblasting pretreatment process plays a crucial role in the preparation of the composite metal oxide layer. Sandblasting the nickel mesh substrate creates a uniform micro-rough structure on its surface, thereby forming a strong mechanical bond with the composite oxide layer. Furthermore, the synergistic effect of tantalum, nickel, and platinum further enhances interfacial adhesion: the introduction of tantalum optimizes the crystal structure of the oxide layer, improving its compatibility with the nickel substrate; nickel, as the main component of the substrate, provides stable structural support; and platinum, through partial embedding in the oxide layer, forms chemical anchoring points. This synergistic effect of strong mechanical bonding and optimized interfacial adhesion effectively prevents the catalytic layer from peeling off during repeated oxidation-reduction cycles, constructing a second reliable physical barrier for the nickel substrate.

[0056] On the other hand, this invention utilizes the high-efficiency current shunting driven by the noble metal catalyst layer to further ensure the operational stability of the electrode under start-up and shutdown conditions. Steps S3-S4 focus on the construction of the noble metal catalyst layer. Through precise coating of the second precursor slurry and a second sintering treatment, a uniform and dense noble metal catalyst layer (such as platinum) is formed on the surface of the composite oxide layer. This catalyst layer has extremely high oxygen evolution reaction (OER) catalytic activity, which can quickly shunt the anolyte current and guide most of the current to the surface of the catalyst layer for oxygen evolution reaction, thereby effectively inhibiting the oxidation process of the nickel substrate and avoiding volume expansion, structural stress concentration and loss of active area caused by oxidation, thus ensuring the stable operation of the electrode under start-up and shutdown conditions.

[0057] In summary, this invention, through a dual protection mechanism of chemical and physical barriers and a system design of a noble metal catalytic layer, ensures the operational stability of the electrode under start-up and shutdown conditions, significantly improves its anti-reverse polarity capability, and provides key technical support for the industrial application of alkaline water electrolysis hydrogen production technology.

[0058] This invention provides an application of the alkaline water electrolysis electrode as described in any one of the above claims or the alkaline water electrolysis electrode prepared by any one of the above claims in alkaline water electrolysis for hydrogen production.

[0059] To facilitate a further understanding of the present invention by those skilled in the art, the following examples are provided: Example 1 Preparation of alkaline water electrolysis electrodes: S1. Dissolve the nickel source, tantalum source, and platinum source in anhydrous ethanol at a mass ratio of nickel:tantalum:platinum of 8:1.5:1.5, and mix thoroughly to form a uniform and stable first precursor slurry; the mass concentration of nickel in the first precursor slurry is 4%; wherein, the nickel source is nickel chloride, the tantalum source is tantalum pentachloride, and the platinum source is chloroplatinic acid.

[0060] S2. The base slurry is evenly applied to the pretreated nickel mesh substrate using a brush coating method. Subsequently, it is sintered at 500°C for 30 minutes in air and then naturally cooled to room temperature to obtain a first electrode containing a metal composite oxide layer. The platinum loading in the metal composite oxide layer is 0.5 g / m². 2 .

[0061] The substrate pretreatment includes the following steps: first, the nickel mesh is sandblasted with white corundum, then ultrasonically cleaned in 30% sodium hydroxide and anhydrous ethanol to remove surface oil, then soaked in dilute hydrochloric acid or dilute sulfuric acid to remove the oxide layer and roughen the surface, and finally rinsed with deionized water and dried for later use.

[0062] S3. Prepare a second precursor slurry containing ruthenium trichloride; the mass concentration of the noble metal (ruthenium) in the second precursor slurry is 3%.

[0063] S4. The second precursor slurry is loaded onto the sintered first electrode surface by brushing, and then sintered at 500°C for 30 minutes in an air or oxygen atmosphere to form an alkaline hydrolysis electrode containing a noble metal catalyst layer. The loading of ruthenium in the noble metal catalyst layer is 8 g / m³. 2 .

[0064] Application of alkaline water electrolysis electrodes in alkaline water electrolysis for hydrogen production: When simulating the start-up and shutdown conditions of actual alkaline water electrolysis hydrogen production, a back electromotive force (which can be understood as a situation similar to the reverse electrode action, i.e., the electrical state, such as the direction of current, changes in the opposite or different manner compared to normal hydrogen production) may occur. To evaluate the performance of the alkaline water electrolysis electrode prepared in this embodiment under such complex operating conditions, the following tests were conducted: Test conditions: Electrolyte was 30% NaOH solution, electrolyte temperature was 80℃; forward -4.8A for 10 min, reverse 0.2A for 10 min; test duration was 12 h; anode was nickel mesh, cathode was the alkaline water electrolysis electrode prepared in this embodiment, test area was 2 cm². 2 .

[0065] Test results: Voltage attenuation is 40 / mV.

[0066] Example 2 Preparation of alkaline water electrolysis electrodes: S1. Dissolve the nickel source, tantalum source, and platinum source in anhydrous ethanol at a mass ratio of nickel:tantalum:platinum of 8.5:1.5:1.5, and mix thoroughly to form a uniform and stable first precursor slurry; the mass concentration of nickel in the first precursor slurry is 5%; wherein the nickel source is nickel chloride, the tantalum source is tantalum pentachloride, and the platinum source is chloroplatinic acid.

[0067] S2. The base slurry is evenly applied to the pretreated nickel mesh substrate using a brush coating method. Subsequently, it is sintered at 500°C for 30 minutes in air and then naturally cooled to room temperature to obtain a first electrode containing a metal composite oxide layer. The platinum loading in the metal composite oxide layer is 1.25 g / m². 2 .

[0068] The substrate pretreatment includes the following steps: first, the nickel mesh is sandblasted with white corundum, then ultrasonically cleaned in 30% sodium hydroxide and anhydrous ethanol to remove surface oil, then soaked in dilute hydrochloric acid or dilute sulfuric acid to remove the oxide layer and roughen the surface, and finally rinsed with deionized water and dried for later use.

[0069] S3. Prepare a second precursor slurry containing ruthenium trichloride; the mass concentration of the precious metal (ruthenium) in the second precursor slurry is 2%.

[0070] S4. The second precursor slurry is loaded onto the sintered first electrode surface by brushing, and then sintered at 500°C for 30 minutes in an air or oxygen atmosphere to form an alkaline hydrolysis electrode containing a noble metal catalyst layer. The loading of ruthenium in the noble metal catalyst layer is 8 g / m³. 2 .

[0071] Application of alkaline water electrolysis electrodes in alkaline water electrolysis for hydrogen production: Test conditions: Electrolyte was 30% NaOH solution, electrolyte temperature was 80℃, forward voltage -4.8A for 10 min, reverse voltage 0.2A for 10 min. The anode was a nickel mesh, and the cathode was the alkaline water electrolysis electrode prepared in this embodiment, with a test area of ​​2 cm². 2 .

[0072] Test results: Voltage attenuation is 45 mV.

[0073] Comparative Example 1 Preparation of alkaline water electrolysis electrodes: Compared to Example 1, this comparative example retains all other conditions except for steps S1 and S2, resulting in an alkaline water electrolysis electrode consisting only of a substrate and a noble metal catalyst layer.

[0074] The substrate pretreatment includes the following steps: first, the nickel mesh is sandblasted with white corundum, then ultrasonically cleaned in 30% sodium hydroxide and anhydrous ethanol to remove surface oil, then soaked in dilute hydrochloric acid or dilute sulfuric acid to remove the oxide layer and roughen the surface, and finally rinsed with deionized water and dried for later use.

[0075] S3. Prepare a second precursor slurry containing ruthenium trichloride; the mass concentration of the noble metal (ruthenium) in the second precursor slurry is 3%.

[0076] S4. The second precursor slurry is loaded onto the pretreated substrate surface by brushing, and then sintered at 500°C for 30 minutes in an air or oxygen atmosphere to form an alkaline hydrolysis electrode containing a noble metal catalyst layer. The ruthenium loading in the noble metal catalyst layer is 8 g / m³. 2 .

[0077] Application of alkaline water electrolysis electrodes in alkaline water electrolysis for hydrogen production: Test conditions: Electrolyte was 30% NaOH solution, electrolyte temperature was 80℃; forward voltage -4.8A for 10 min, reverse voltage 0.2A for 10 min; test duration was 12 h; anode was nickel mesh, cathode was the alkaline water electrolysis electrode prepared in this comparative example, test area was 2 cm². 2 .

[0078] Test results: The voltage decay was 100 / mV, indicating that the alkaline water electrolysis electrode prepared in this comparative example was significantly less stable than that in Example 1.

[0079] Comparative Example 2 Compared to Example 1, all other conditions remained unchanged in this comparative example, except that the mass ratio of nickel, tantalum and platinum in the metal composite oxide layer was adjusted to 10:0.5:0.5.

[0080] Preparation of alkaline water electrolysis electrodes: S1. Dissolve nickel, tantalum and platinum in anhydrous ethanol at a mass ratio of 10:0.5:0.5 and mix thoroughly to form a uniform and stable first precursor slurry; the mass concentration of nickel in the first precursor slurry is 4%.

[0081] S2. The base slurry is evenly applied to the pretreated nickel mesh substrate using a brush coating method. Subsequently, it is sintered at 500°C for 30 minutes in air and then naturally cooled to room temperature to obtain a first electrode containing a metal composite oxide layer. The platinum loading in the metal composite oxide layer is 0.5 g / m². 2 .

[0082] The substrate pretreatment includes the following steps: first, the nickel mesh is sandblasted with white corundum, then ultrasonically cleaned in 30% sodium hydroxide and anhydrous ethanol to remove surface oil, then soaked in dilute hydrochloric acid or dilute sulfuric acid to remove the oxide layer and roughen the surface, and finally rinsed with deionized water and dried for later use.

[0083] S3. Prepare a second precursor slurry containing ruthenium trichloride; the mass concentration of the noble metal in the second precursor slurry is 3%.

[0084] S4. The second precursor slurry is loaded onto the sintered first electrode surface by brushing, and then sintered at 500°C for 30 minutes in an air or oxygen atmosphere to form an alkaline hydrolysis electrode containing a noble metal catalyst layer. The loading of ruthenium in the noble metal catalyst layer is 8 g / m³. 2 .

[0085] Application of alkaline water electrolysis electrodes in alkaline water electrolysis for hydrogen production: Test conditions: Electrolyte was 30% NaOH solution, electrolyte temperature was 80℃; forward voltage -4.8A for 10 min, reverse voltage 0.2A for 10 min; test duration was 12 h; anode was nickel mesh, cathode was the alkaline water electrolysis electrode prepared in this comparative example, test area was 2 cm². 2 .

[0086] Test results: Voltage attenuation is 80 / mV.

[0087] Comparative Example 3 Compared to Example 1, all other conditions remained unchanged in this comparative example, except that the mass ratio of nickel:tantalum:platinum was adjusted to 5:2.5:2.5.

[0088] Preparation of alkaline water electrolysis electrodes: S1. Dissolve nickel, tantalum, and platinum in anhydrous ethanol at a mass ratio of 5:2.5:2.5 and mix thoroughly to form a uniform and stable first precursor slurry; the mass concentration of nickel in the first precursor slurry is 4%; wherein the nickel source is nickel chloride, the tantalum source is tantalum pentachloride, and the platinum source is chloroplatinic acid.

[0089] S2. The base slurry is evenly applied to the pretreated nickel mesh substrate using a brush coating method. Subsequently, it is sintered at 500°C for 30 minutes in air and then naturally cooled to room temperature to obtain a first electrode containing a metal composite oxide layer. The platinum loading in the metal composite oxide layer is 0.5 g / m². 2 .

[0090] The substrate pretreatment includes the following steps: first, the nickel mesh is sandblasted with white corundum, then ultrasonically cleaned in 30% sodium hydroxide and anhydrous ethanol to remove surface oil, then soaked in dilute hydrochloric acid or dilute sulfuric acid to remove the oxide layer and roughen the surface, and finally rinsed with deionized water and dried for later use.

[0091] S3. Prepare a second precursor slurry containing ruthenium trichloride; the mass concentration of the noble metal in the second precursor slurry is 3%.

[0092] S4. The second precursor slurry is loaded onto the sintered first electrode surface by brushing, and then sintered at 500°C for 30 minutes in an air or oxygen atmosphere to form an alkaline hydrolysis electrode containing a noble metal catalyst layer. The loading of ruthenium in the noble metal catalyst layer is 8 g / m³. 2 .

[0093] Application of alkaline water electrolysis electrodes in alkaline water electrolysis for hydrogen production: Test conditions: Electrolyte was 30% NaOH solution, electrolyte temperature was 80℃; forward voltage -4.8A for 10 min, reverse voltage 0.2A for 10 min; test duration was 12 h; anode was nickel mesh, cathode was the alkaline water electrolysis electrode prepared in this comparative example, test area was 2 cm². 2 .

[0094] Test results: Voltage attenuation is 100 / mV.

[0095] Comparative Example 4 Compared to Example 1, this comparative example retains all other conditions except for steps S3 and S4, generating an alkaline water electrolysis electrode consisting only of a substrate and a composite metal oxide layer.

[0096] Preparation of alkaline water electrolysis electrodes: S1. Dissolve nickel, tantalum, and platinum in anhydrous ethanol at a mass ratio of 8:1.5:1.5 and mix thoroughly to form a uniform and stable first precursor slurry; the mass concentration of nickel in the first precursor slurry is 4%; wherein the nickel source is nickel chloride, the tantalum source is tantalum pentachloride, and the platinum source is chloroplatinic acid.

[0097] S2. The base slurry is evenly applied to the pretreated nickel mesh substrate using a brush coating method. Subsequently, it is sintered at 500°C for 30 minutes in air and then naturally cooled to room temperature to obtain a first electrode containing a metal composite oxide layer. The platinum loading in the metal composite oxide layer is 0.5 g / m². 2 .

[0098] The substrate pretreatment includes the following steps: first, the nickel mesh is sandblasted with white corundum, then ultrasonically cleaned in 30% sodium hydroxide and anhydrous ethanol to remove surface oil, then soaked in dilute hydrochloric acid or dilute sulfuric acid to remove the oxide layer and roughen the surface, and finally rinsed with deionized water and dried for later use.

[0099] Application of alkaline water electrolysis electrodes in alkaline water electrolysis for hydrogen production: Test conditions: Electrolyte was 30% NaOH solution, electrolyte temperature was 80℃; forward voltage -4.8A for 10 min, reverse voltage 0.2A for 10 min; test duration was 12 h; anode was nickel mesh, cathode was the alkaline water electrolysis electrode prepared in this comparative example, test area was 2 cm². 2 .

[0100] Test results: Voltage attenuation is 90 / mV.

[0101] The above technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. An alkaline water electrolysis electrode, characterized in that, It includes a substrate and a metal composite oxide layer and a noble metal catalyst layer sequentially coated on the substrate; The mass ratio of nickel, tantalum, and platinum in the metal composite oxide layer is (6.5-8.5):(1.5-2.5):(1.5-2.5). The platinum loading in the metal composite oxide layer is 0.25-2 g / m². 2 The loading of the noble metal in the noble metal catalyst layer is 6-16 g / m³. 2 .

2. The alkaline water electrolysis electrode according to claim 1, characterized in that, The substrate is made of nickel; the noble metals in the noble metal catalyst layer include ruthenium and / or platinum.

3. The alkaline water electrolysis electrode according to claim 2, characterized in that, The platinum loading in the metal composite oxide layer is 0.25-1.5 g / m³. 2 The loading of the noble metal in the noble metal catalyst layer is 6-14 g / m³. 2 .

4. A method for preparing the alkaline water electrolysis electrode according to any one of claims 1-3, characterized in that, Including the following steps: S1. A nickel source, a tantalum source, and a platinum source are mixed in a solvent to prepare a first precursor slurry, wherein the mass ratio of nickel, tantalum, and platinum in the first precursor slurry is (6.5-8.5):(1.5-2.5):(1.5-2.5). S2. The first precursor slurry is coated onto the surface of the substrate and subjected to a first sintering treatment to obtain a first electrode containing the metal composite oxide layer; S3. Prepare a second precursor slurry containing precious metals; S4. The second precursor slurry is coated onto the surface of the metal composite oxide layer electrode, and after a second sintering treatment, an alkaline hydrolysis electrode containing the noble metal catalyst layer is obtained.

5. The method for preparing the alkaline water electrolysis electrode according to claim 4, characterized in that, The nickel source includes nickel chloride, the tantalum source includes tantalum pentachloride, the platinum source includes chloroplatinic acid and / or platinum acetylacetonate, and the source of the noble metal includes ruthenium trichloride and / or chloroplatinic acid.

6. The method for preparing the alkaline water electrolysis electrode according to claim 4, characterized in that, Before coating the first precursor slurry onto the substrate surface, the substrate is pretreated, the pretreatment including sandblasting and surface roughening in sequence.

7. The method for preparing the alkaline water electrolysis electrode according to claim 4, characterized in that, The temperature of the first sintering treatment is 400-500℃ and the duration is 10-30 min; the temperature of the second sintering treatment is 400-500℃ and the duration is 10-30 min.

8. The method for preparing the alkaline water electrolysis electrode according to claim 4, characterized in that, The mass concentration of nickel in the first precursor slurry is 4%-8%, and the mass concentration of precious metals in the second precursor slurry is 2%-5%.

9. The method for preparing the alkaline water electrolysis electrode according to claim 4, characterized in that, If the platinum loading in the metal composite oxide layer is less than 0.25 g / m, repeat step S2 until the platinum loading in the metal composite oxide layer is 0.25-2 g / m. 2 ; If the loading of the noble metal in the noble metal catalyst layer is less than 6 g / m³, repeat step S4 until the loading of the noble metal in the noble metal catalyst layer is 6-16 g / m³. 2 .

10. The application of an alkaline water electrolysis electrode as described in any one of claims 1-3 or an alkaline water electrolysis electrode prepared by the preparation method described in any one of claims 4-9 in alkaline water electrolysis for hydrogen production.