An interface strong binding of a multi-metal hydroxide catalyst electrode and a preparation method and application thereof

Abstract

This invention discloses a strongly interfacially bonded multimetal hydroxide catalyst electrode, its preparation method, and its application, belonging to the technical field of alkaline water electrolysis hydrogen production catalyst preparation. First, a metal substrate is pretreated. Then, using the metal substrate as the working electrode and a platinum sheet as the counter electrode, deposition is performed using a dual-potential step chronoamperometric method. After deposition, a multimetal hydroxide catalyst electrode is obtained. This invention utilizes the aforementioned strongly interfacially bonded multimetal hydroxide catalyst electrode, its preparation method, and its application. The resulting multimetal hydroxide catalyst electrode exhibits high uniformity and strong bonding with the substrate, and can operate stably under the high temperature, high alkalinity, and high current density conditions of industrial alkaline water electrolysis hydrogen production.

Description

Technical Field

[0001] This invention relates to the field of alkaline water electrolysis hydrogen production catalyst preparation technology, and in particular to a strongly interfacially bonded multimetal hydroxide catalyst electrode, its preparation method, and its application. Background Technology

[0002] Currently, among numerous energy storage solutions, hydrogen energy is considered a key secondary energy carrier due to its ultra-high energy density, zero carbon emissions, and long-term storage capabilities. Water electrolysis for hydrogen production is an important technological pathway for green hydrogen production, with alkaline water electrolysis (ALK) showing the greatest potential for large-scale industrial application due to its high single-cell capacity, long system lifespan, and low operation and maintenance costs.

[0003] Transition metal layered double hydroxides (LDHs), with their unique electronic structure and excellent intrinsic activity in the oxygen evolution reaction (OER), have become the most promising anode catalyst materials in the ALK (Alternating Current Kinematics) field. However, they require loading onto a conductive metal substrate to form the electrode. Traditional preparation processes have significant drawbacks: physical spraying methods result in weak interfacial bonding and easy catalyst peeling; hydrothermal synthesis is sensitive to reaction parameters, easily leading to uneven catalyst nucleation and agglomeration, and is difficult to scale up with poor batch reproducibility; negative potential deposition methods easily cause uneven catalyst growth, and the catalyst lacks a transition layer with the substrate, resulting in weak bonding. Consequently, the durability of traditional integrated LDH electrodes at industrial-grade current densities is far from satisfactory. Therefore, developing a method for preparing LDH catalyst electrodes that combines high activity, strong substrate bonding, and high stability is crucial for promoting the industrialization of ALK technology. Summary of the Invention

[0004] The purpose of this invention is to provide a polymetallic hydroxide catalyst electrode with strong interfacial bonding, its preparation method and application. The obtained polymetallic hydroxide catalyst electrode has high uniformity and strong bonding with the substrate, and can operate stably under the high temperature, high alkalinity and operating current density of industrial alkaline water electrolysis for hydrogen production.

[0005] To achieve the above objectives, the present invention provides a method for preparing a polymetallic hydroxide catalyst electrode with strong interfacial bonding, comprising the following steps: S1. Pre-treat the metal substrate; S2. Add deposition solution to the electrolytic cell, use a metal substrate as the working electrode and a platinum sheet as the counter electrode, and perform deposition using the dual-potential step chronoamperometry method. After deposition, a multi-metal hydroxide catalyst electrode is obtained.

[0006] Preferably, in S1, the metal substrate includes Ni-based metal, Fe-based metal, Cu-based metal, Cr-based metal, Ti-based metal, NiFe-based binary alloy, NiCu-based binary alloy, NiCr-based binary alloy, or multi-element alloy.

[0007] Preferably, in S1, the pretreatment method for the metal substrate includes acid washing, alkaline washing, physical polishing, or electrochemical reduction.

[0008] Preferably, in S1, the structure of the metal substrate includes sheet-like, mesh-like, or foam-like structures.

[0009] Preferably, the specific steps of the dual-potential step chronoamperometry in S2 are as follows: first, a positive potential is applied to the surface of the metal substrate for etching, and then the potential is instantaneously stepped to a negative potential for catalyst deposition.

[0010] Furthermore, the applied positive potential is 0.5~3V, the etching time is 30~300s, the applied negative potential is -0.4~-2V, and the catalyst deposition time is 60~3600s.

[0011] Preferably, in S2, the deposition solution includes any two or more of the following: solutions of nitrate, sulfate, chloride, acetate, and oxalate of Co and Mn ions, and solutions of nitrate, sulfate, chloride, and acetate of Ni, Fe, Zn, and Cr ions.

[0012] Furthermore, the concentration of metal ions in the sediment is 0.01~1 mol / L.

[0013] The present invention also provides a strongly bonded multimetal hydroxide catalyst electrode, which is prepared by the above-mentioned method for preparing a strongly bonded multimetal hydroxide catalyst electrode.

[0014] This invention also provides an application of a strongly bonded multimetal hydroxide catalyst electrode, which is used as an anode in alkaline water electrolysis for hydrogen production.

[0015] Therefore, the present invention, employing the above-mentioned interfacially strongly bonded multimetal hydroxide catalyst electrode, its preparation method, and its application, has the following beneficial effects: (1) The present invention uses a dual-potential step chronoamperometry method to etch the metal substrate before depositing the catalyst, which can increase the surface roughness of the substrate. The metal ions generated by the positive potential etching of the metal substrate are preferentially deposited, forming a transition layer between the LDH and the metal substrate. Therefore, the catalyst and the substrate have excellent bonding force.

[0016] (2) The present invention performs uniform etching on the metal substrate to form dense and uniform nanoscale etching pits, which increases hydrophilicity and increases the local supersaturation of the metal surface. According to formula (1), etching increases the surface roughness, which reduces the liquid contact angle, thereby reducing the critical radius of nucleation and greatly increasing the density of nucleation sites. The catalyst layer grows uniformly and densely, which is suitable for industrial-scale scale-up.

[0017] (1), in, The critical radius for nucleation. For solid-liquid interfacial tension, The difference in phase transition free energy per unit volume. It represents the contact angle.

[0018] (3) The electrode prepared by the present invention has a layered structure. As an anode, it can operate efficiently and stably under the high temperature, high alkali and high current conditions of industrial alkaline electrolysis cell. Compared with other LDH integrated electrode preparation processes, its stability is significantly improved.

[0019] (4) The LDH integrated electrode preparation method of the present invention has a simple process, low energy consumption, and is conducive to large-scale industrial application.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 This is a scanning electron microscope image of the NiFeLDH catalyst prepared on a nickel foam substrate using the dual-potential step chronoamperometry method in Example 1 of the present invention. Figure 2 The NiFe LDH catalysts obtained by different preparation methods in Example 1 and Comparative Example 1 of this invention were prepared in 6M sodium hydroxide solution at 80°C with a concentration of 1 A / cm³. -2 Stability curves for current density operation; Figure 3 NiFe LDH prepared by different methods in Example 1 and Comparative Example 1 of this invention were respectively subjected to a reaction in a 6M sodium hydroxide solution at 80°C at a flow rate of 1 A / cm. -2 Scanning electron microscope image after 20 hours of operation; Figure 4 NiFe LDH prepared by different methods in Example 1 and Comparative Example 1 of this invention were respectively subjected to a reaction in a 6M sodium hydroxide solution at 80°C at a flow rate of 1 A / cm. -2 Scanning electron microscope image of the electrode cross-section after 20 hours of operation; Figure 5 The NiFe LDH prepared in Example 1 of this invention was reacted in a 6M sodium hydroxide solution at 80°C at a rate of 1 A / cm. -2 EDS energy spectrum of the electrode cross section after 20 hours of operation; Figure 6 Scanning electron microscope images of the catalyst electrodes prepared in Comparative Examples 1-3 after stable operation under operating conditions until catalyst deactivation via negative potential deposition. Figure 7The scanning electron microscope image of the catalyst electrode prepared in Comparative Example 8-10 after the LDH catalyst synthesized by hydrothermal operation under the operating conditions until the catalyst deactivation. Figure 8 The image shows a scanning electron microscope image of LDH obtained by short-time negative potential deposition after etching using the dual-potential step chronoamperometry method in Example 8. Figure 9 The image shows a scanning electron microscope image of LDH obtained by short-time deposition using the negative potential deposition method in Comparative Example 15. Figure 10 Scanning electron microscope images of substrate etching after LDH was synthesized by hydrothermal synthesis with different precipitants in Comparative Examples 8 and 16, showing the substrate etching conditions after the synthesis of LDH by different precipitants in Comparative Examples 8 and 16. Figure 11 Scanning electron microscope images of LDH obtained by using an excessively low etching potential in Examples 9-11, using the dual-potential step chronoamperometry. Figure 12 Scanning electron microscope images of LDH obtained by using excessively high etching potential in Examples 16-18, using the dual-potential step chronoamperometry. Figure 13 Scanning electron microscope images of LDH obtained using the dual-potential step chronoamperometry method in Examples 23-25 ​​with excessively low deposition potential; Figure 14 Scanning electron microscope images of LDH obtained using the dual-potential step chronoamperometry method with excessively high deposition potential in Examples 30-32; Figure 15 Scanning electron microscope images of the nickel substrates after etching with different positive potentials in Examples 1 and 59-60; Figure 16 The scanning electron microscope image of LDH obtained by high-potential etching followed by short-time negative potential deposition using the dual-potential chronoamperometry method in Example 77 is shown. Figure 17 The scanning electron microscope images of NiFe LDH deposited on a nickel substrate using the dual-potential step chronoamperometry method with different negative potentials in Examples 78-80 are shown. Figure 18 Example 81 shows an integrated LDH electrode fabricated on an 8 cm diameter nickel mesh using a dual-potential step chronoamperometry method. Figure 19 Scanning electron microscope images of different locations in the integrated LDH electrode obtained by dual-potential step chronoamperometry in Example 81; Figure 20 The electrode prepared in Example 81 was used in an alkaline electrolytic cell; Figure 21 The stability curve of the electrode prepared in Example 81 in an alkaline electrolytic cell. Detailed Implementation

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0024] Example 1 This invention provides a method for preparing a multimetal hydroxide catalyst electrode with strong interfacial bonding, comprising the following steps: S1. Clean the nickel foam substrate sequentially with acetone, ethanol and deionized water, then ultrasonically clean it with 2M sulfuric acid solution for 10 min to remove surface oxides, and obtain the pretreated nickel foam substrate, which is then vacuum dried for later use. S2. Prepare a mixed solution of 0.15M nickel nitrate and 0.05M ferrous sulfate as the deposition solution, add it to the electrolytic cell, and adopt a three-electrode system. Use a pretreated nickel foam substrate as the working electrode, a platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode. Using the dual-potential step chronoamperometry, first apply a positive potential of 1.5V to the surface of the metal substrate to etch the nickel foam substrate for 100s, increasing the surface roughness and nucleation sites of the substrate, and at the same time increasing the local metal ion concentration. Then apply a negative potential of -0.7V to deposit the catalyst. The etched metal ions preferentially co-deposit with the cations in the deposition solution to form a transition layer between the catalyst and the substrate, increasing the interfacial bonding force. After 600s, the deposition is completed. Rinse the working electrode with deionized water and dry it to obtain the NiFe LDH catalyst electrode.

[0025] Example 2 This embodiment follows the same steps as Embodiment 1, except that in S2, a mixed solution of 0.15M nickel nitrate and 0.05M cobalt sulfate is prepared as the deposition solution to obtain the NiCo LDH catalyst electrode.

[0026] Example 3 This embodiment is the same as the steps in Embodiment 1, except that: in S2, a mixed solution of 0.15M nickel nitrate and 0.05M nickel sulfate is prepared as the deposition solution to obtain the Ni LDH catalyst electrode.

[0027] Example 4 This embodiment is the same as the steps in Embodiment 1, except that: in S2, a mixed solution of 0.15M nickel nitrate, 0.05M cobalt sulfate and 0.05M ferrous sulfate is prepared as a deposition solution to obtain the NiFeCo LDH catalyst electrode.

[0028] Example 5 This embodiment follows the same steps as Embodiment 1, except that in S2, a mixed solution of 0.15M nickel nitrate and 0.05M zinc nitrate is prepared as the deposition solution to obtain the NiZn LDH catalyst electrode.

[0029] Example 6 This embodiment has the same steps as Embodiment 1, except that: in S2, a mixed solution of 0.15M nickel nitrate and 0.05M manganese sulfate is prepared as a deposition solution to obtain the NiMn LDH catalyst electrode.

[0030] Example 7 This embodiment is the same as the steps in Embodiment 1, except that: in S2, a mixed solution of 0.15M nickel nitrate and 0.05M chromium nitrate is prepared as a deposition solution to obtain the NiCr LDH catalyst electrode.

[0031] Example 8 This embodiment has the same steps as Embodiment 1, except that the negative potential deposition time in S2 is 60s.

[0032] Example 9 This embodiment has the same steps as Embodiment 1, except that the positive potential applied in S2 is 1V.

[0033] Example 10 This embodiment has the same steps as Embodiment 2, except that the positive potential applied in S2 is 1V.

[0034] Example 11 This embodiment has the same steps as Embodiment 3, except that the positive potential applied in S2 is 1V.

[0035] Example 12 This embodiment has the same steps as embodiment 4, except that the positive potential applied in S2 is 1V.

[0036] Example 13 This embodiment has the same steps as embodiment 5, except that the positive potential applied in S2 is 1V.

[0037] Example 14 This embodiment has the same steps as Embodiment 6, except that the positive potential applied in S2 is 1V.

[0038] Example 15 This embodiment has the same steps as Embodiment 7, except that the positive potential applied in S2 is 1V.

[0039] Example 16 This embodiment has the same steps as Embodiment 1, except that the positive potential applied in S2 is 2V.

[0040] Example 17 This embodiment has the same steps as Embodiment 2, except that the positive potential applied in S2 is 2V.

[0041] Example 18 This embodiment has the same steps as Embodiment 3, except that the positive potential applied in S2 is 2V.

[0042] Example 19 This embodiment has the same steps as embodiment 4, except that the positive potential applied in S2 is 2V.

[0043] Example 20 This embodiment has the same steps as embodiment 5, except that the positive potential applied in S2 is 2V.

[0044] Example 21 This embodiment has the same steps as Embodiment 6, except that the positive potential applied in S2 is 2V.

[0045] Example 22 This embodiment has the same steps as Embodiment 7, except that the positive potential applied in S2 is 2V.

[0046] Example 23 This embodiment has the same steps as Embodiment 1, except that the negative potential applied in S2 is -1.6V.

[0047] Example 24 This embodiment has the same steps as Embodiment 2, except that the negative potential applied in S2 is -1.6V.

[0048] Example 25 This embodiment has the same steps as Embodiment 3, except that the negative potential applied in S2 is -1.6V.

[0049] Example 26 This embodiment has the same steps as Embodiment 4, except that the negative potential applied in S2 is -1.6V.

[0050] Example 27 This embodiment has the same steps as Embodiment 5, except that the negative potential applied in S2 is -1.6V.

[0051] Example 28 This embodiment is the same as the steps in embodiment 6, except that the negative potential applied in S2 is -1.6V.

[0052] Example 29 This embodiment has the same steps as Embodiment 7, except that the negative potential applied in S2 is -1.6V.

[0053] Example 30 This embodiment has the same steps as Embodiment 1, except that the negative potential applied in S2 is -0.4V.

[0054] Example 31 This embodiment has the same steps as Embodiment 2, except that the negative potential applied in S2 is -0.4V.

[0055] Example 32 This embodiment has the same steps as Embodiment 3, except that the negative potential applied in S2 is -0.4V.

[0056] Example 33 This embodiment has the same steps as Embodiment 4, except that the negative potential applied in S2 is -0.4V.

[0057] Example 34 This embodiment has the same steps as embodiment 5, except that the negative potential applied in S2 is -0.4V.

[0058] Example 35 This embodiment is the same as the steps in embodiment 6, except that the negative potential applied in S2 is -0.4V.

[0059] Example 36 This embodiment has the same steps as Embodiment 7, except that the negative potential applied in S2 is -0.4V.

[0060] Example 37 This embodiment has the same steps as Embodiment 1, except that: in S2, a mixed solution of 0.15M nickel nitrate and 0.01M ferrous sulfate is prepared as the deposition solution.

[0061] Example 38 This embodiment has the same steps as Embodiment 1, except that: in S2, a mixed solution of 0.15M nickel nitrate and 0.1M ferrous sulfate is prepared as the deposition solution.

[0062] Example 39 This embodiment has the same steps as Embodiment 1, except that: in S2, a mixed solution of 0.15M nickel nitrate and 0.2M ferrous sulfate is prepared as the deposition solution.

[0063] Example 40 This embodiment has the same steps as Embodiment 1, except that: in S2, a mixed solution of 0.15M nickel nitrate and 0.5M ferrous sulfate is prepared as the deposition solution.

[0064] Example 41 This embodiment has the same steps as Embodiment 2, except that: in S2, a mixed solution of 0.15M nickel nitrate and 0.01M cobalt sulfate is prepared as the deposition solution.

[0065] Example 42 This embodiment has the same steps as Embodiment 2, except that: in S2, a mixed solution of 0.15M nickel nitrate and 0.1M cobalt sulfate is prepared as the deposition solution.

[0066] Example 43 This embodiment has the same steps as Embodiment 2, except that: in S2, a mixed solution of 0.15M nickel nitrate and 0.2M cobalt sulfate is prepared as the deposition solution.

[0067] Example 44 This embodiment has the same steps as Embodiment 2, except that: in S2, a mixed solution of 0.15M nickel nitrate and 0.5M cobalt sulfate is prepared as the deposition solution.

[0068] Example 45 This embodiment is the same as the steps in embodiment 7, except that: in S2, a mixed solution of 0.15M nickel nitrate and 0.01M chromium nitrate is prepared as the deposition solution.

[0069] Example 46 This embodiment is the same as the steps in embodiment 7, except that: in S2, a mixed solution of 0.15M nickel nitrate and 0.1M chromium nitrate is prepared as the deposition solution.

[0070] Example 47 This embodiment is the same as the steps in embodiment 7, except that: in S2, a mixed solution of 0.15M nickel nitrate and 0.2M chromium nitrate is prepared as the deposition solution.

[0071] Example 48 This embodiment is the same as the steps in embodiment 7, except that: in S2, a mixed solution of 0.15M nickel nitrate and 0.5M chromium nitrate is prepared as the deposition solution.

[0072] Example 49 This embodiment has the same steps as Embodiment 1, except that: a copper foam substrate is used in S1, and the positive potential applied in S2 is 0.1V.

[0073] Example 50 This embodiment has the same steps as Embodiment 1, except that: a copper foam substrate is used in S1, and the positive potential applied in S2 is 0.2V.

[0074] Example 51 This embodiment has the same steps as Embodiment 1, except that: a copper foam substrate is used in S1, and the positive potential applied in S2 is 0.3V.

[0075] Example 52 This embodiment has the same steps as Embodiment 1, except that: a foamed iron substrate is used in S1, and the positive potential applied in S2 is 0.8V.

[0076] Example 53 This embodiment has the same steps as Embodiment 1, except that: a foamed iron substrate is used in S1, and the positive potential applied in S2 is 1.0V.

[0077] Example 54 This embodiment has the same steps as Embodiment 1, except that: a foamed iron substrate is used in S1, and a positive potential of 1.2V is applied in S2.

[0078] Example 55 This embodiment has the same steps as Embodiment 1, except that: a foamed chromium substrate is used in S1, and the positive potential applied in S2 is 1.2V.

[0079] Example 56 This embodiment has the same steps as Embodiment 1, except that: a foamed chromium substrate is used in S1, and a positive potential of 1.5V is applied in S2.

[0080] Example 57 This embodiment is the same as the steps in Embodiment 1, except that: a foamed chromium substrate is used in S1, and a positive potential of 1.7V is applied in S2.

[0081] Example 58 This embodiment has the same steps as Embodiment 1, except that the positive potential applied in S2 is 1.0V.

[0082] Example 59 This embodiment has the same steps as Embodiment 1, except that the positive potential applied in S2 is 1.2V.

[0083] Example 60 This embodiment has the same steps as Embodiment 1, except that the positive potential applied in S2 is 1.8V.

[0084] Example 61 This embodiment has the same steps as Embodiment 1, except that: a foamed titanium substrate is used in S1, and a positive potential of 1.5V is applied in S2.

[0085] Example 62 This embodiment has the same steps as Embodiment 1, except that: a foamed titanium substrate is used in S1, and a positive potential of 2.0V is applied in S2.

[0086] Example 63 This embodiment has the same steps as Embodiment 1, except that: a foamed titanium substrate is used in S1, and a positive potential of 2.5V is applied in S2.

[0087] Example 64 This embodiment has the same steps as Embodiment 1, except that: a foamed nickel-iron alloy substrate is used in S1, and the positive potential applied in S2 is 1.0V.

[0088] Example 65 This embodiment has the same steps as Embodiment 1, except that: a foamed nickel-iron alloy substrate is used in S1, and the positive potential applied in S2 is 1.6V.

[0089] Example 66 This embodiment has the same steps as Embodiment 1, except that: a foamed nickel-iron alloy substrate is used in S1, and the positive potential applied in S2 is 2.0V.

[0090] Example 67 This embodiment is the same as the steps in Embodiment 1, except that: a foamed nickel-chromium alloy substrate is used in S1, and the positive potential applied in S2 is 1.5V.

[0091] Example 68 This embodiment is the same as the steps in Embodiment 1, except that: a foamed nickel-chromium alloy substrate is used in S1, and the positive potential applied in S2 is 1.8V.

[0092] Example 69 This embodiment has the same steps as Embodiment 1, except that: a foamed nickel-chromium alloy substrate is used in S1, and the positive potential applied in S2 is 2.0V.

[0093] Example 70 This embodiment has the same steps as Embodiment 1, except that: a foamed nickel-copper alloy substrate is used in S1, and the positive potential applied in S2 is 0V.

[0094] Example 71 This embodiment has the same steps as Embodiment 1, except that: a foamed nickel-copper alloy substrate is used in S1, and the positive potential applied in S2 is 0.1V.

[0095] Example 72 This embodiment is the same as the steps in Embodiment 1, except that: a foamed nickel-copper alloy substrate is used in S1, and the positive potential applied in S2 is 0.2V.

[0096] Example 73 This embodiment has the same steps as Embodiment 1, except that: a foamed nickel-copper alloy substrate is used in S1, and the positive potential applied in S2 is 0.3V.

[0097] Example 74 This embodiment has the same steps as Embodiment 1, except that: a foam 316 stainless steel alloy substrate is used in S1, and a positive potential of 1.4V is applied in S2.

[0098] Example 75 This embodiment is the same as the steps in Embodiment 1, except that: a foam 316 stainless steel alloy substrate is used in S1, and a positive potential of 1.7V is applied in S2.

[0099] Example 76 This embodiment has the same steps as Embodiment 1, except that: a foam 316 stainless steel alloy substrate is used in S1, and the positive potential applied in S2 is 2.0V.

[0100] Example 77 This embodiment has the same steps as embodiment 8, except that the positive potential applied in S2 is 1.8V.

[0101] Example 78 This embodiment has the same steps as Embodiment 1, except that the negative potential applied in S2 is -0.6V.

[0102] Example 79 This embodiment has the same steps as Embodiment 1, except that the negative potential applied in S2 is -0.8V.

[0103] Example 80 This embodiment has the same steps as Embodiment 1, except that the negative potential applied in S2 is -1.0V.

[0104] Example 81 This embodiment has the same steps as Embodiment 1, except that a nickel mesh with a diameter of 8cm is used in S1.

[0105] Comparative Example 1 The steps in this comparative example are the same as those in Example 1, except that in S2, the dual-potential step chronoamperometry is changed to the negative potential deposition method, that is, the step of applying a positive potential is omitted.

[0106] Comparative Example 2 The steps in this comparative example are the same as those in Example 2, except that in S2, the dual-potential step chronoamperometry is changed to the negative potential deposition method, that is, the step of applying a positive potential is omitted.

[0107] Comparative Example 3 The steps in this comparative example are the same as those in Example 3, except that in S2, the dual-potential step chronoamperometry is changed to the negative potential deposition method, that is, the step of applying a positive potential is omitted.

[0108] Comparative Example 4 The steps in this comparative example are the same as those in Example 4, except that in S2, the dual-potential step chronoamperometry is changed to the negative potential deposition method, that is, the step of applying a positive potential is omitted.

[0109] Comparative Example 5 The steps in this comparative example are the same as those in Example 5, except that in S2, the dual-potential step chronoamperometry is changed to the negative potential deposition method, that is, the step of applying a positive potential is omitted.

[0110] Comparative Example 6 The steps in this comparative example are the same as those in Example 6, except that in S2, the dual-potential step chronoamperometry is changed to the negative potential deposition method, that is, the step of applying a positive potential is omitted.

[0111] Comparative Example 7 The steps in this comparative example are the same as those in Example 7, except that in S2, the dual-potential step chronoamperometry is changed to the negative potential deposition method, that is, the step of applying a positive potential is omitted.

[0112] Comparative Example 8 The steps of this comparative example are the same as those of Example 1, except that the hydrothermal synthesis method is used in S2. The specific steps are as follows: a mixed solution of 0.05 mM nickel nitrate and 0.05 mM ferrous sulfate is prepared as a precipitation solution, 600 mg of urea is added as a precipitant and placed in a reaction vessel, a pretreated foam substrate is added to completely immerse it, and the reaction is carried out at a constant temperature of 120°C for 8 hours in an oven. After cooling, it is rinsed clean with deionized water and dried to obtain the NiFe LDH catalyst electrode synthesized by hydrothermally in this comparative example.

[0113] Comparative Example 9 The steps in this comparative example are the same as those in Comparative Example 8, except that in S2, a mixed solution of 0.05 mM nickel nitrate and 0.05 mM cobalt sulfate is prepared as the deposition solution to obtain the NiCo LDH catalyst electrode synthesized hydrothermally in this comparative example.

[0114] Comparative Example 10 This comparative example follows the same steps as Comparative Example 8, except that in S2, a 0.1 mM nickel nitrate solution is prepared as the deposition solution to obtain the Ni LDH catalyst electrode synthesized hydrothermally in this comparative example.

[0115] Comparative Example 11 The steps in this comparative example are the same as those in Comparative Example 8, except that in S2, a mixed solution of 0.033 mM nickel nitrate, 0.033 mM cobalt sulfate and 0.033 mM ferrous sulfate was prepared as the deposition solution to obtain the NiFeCo LDH catalyst electrode synthesized by hydrothermal synthesis in this comparative example.

[0116] Comparative Example 12 The steps in this comparative example are the same as those in Comparative Example 8, except that in S2, a mixed solution of 0.08 mM nickel nitrate and 0.02 mM zinc nitrate is prepared as the deposition solution to obtain the NiZn LDH catalyst electrode synthesized by hydrothermal synthesis in this comparative example.

[0117] Comparative Example 13 The steps in this comparative example are the same as those in Comparative Example 8, except that in S2, a mixed solution of 0.05 mM nickel nitrate and 0.05 mM manganese sulfate is prepared as the deposition solution to obtain the NiMn LDH catalyst electrode synthesized hydrothermally in this comparative example.

[0118] Comparative Example 14 The steps in this comparative example are the same as those in Comparative Example 8, except that in S2, a mixed solution of 0.05 mM nickel nitrate and 0.05 mM chromium nitrate is prepared as the deposition solution to obtain the NiCr LDH catalyst electrode synthesized by hydrothermal synthesis in this comparative example.

[0119] Comparative Example 15 The steps in this comparative example are the same as those in Example 8, except that in S2, the dual-potential step chronoamperometry is changed to the negative potential deposition method, that is, the step of applying a positive potential is omitted.

[0120] Comparative Example 16 This comparative example follows the same steps as Comparative Example 8, except that the precipitant in S2 is 600 mg urea and 111 mg ammonium fluoride.

[0121] The NiFe LDH catalyst electrode prepared in Example 1 was characterized by scanning electron microscopy, and the results are as follows: Figure 1 As shown, from Figure 1 As can be seen, the catalyst is evenly distributed, has good bonding with the substrate, and shows no cracking.

[0122] Using 6M sodium hydroxide solution, under industrial alkaline water electrolysis conditions at 80°C, at a rate of 1 A / cm -2 The constant current stability of the NiFe LDH catalyst electrodes prepared in Example 1 and Comparative Example 1 was tested, and the results are as follows: Figure 2 As shown, from Figure 2 As can be seen from the results, under the same conditions, the NiFe LDH catalyst prepared by the dual-potential step chronoamperometry method has significantly improved electrode stability and higher activity compared with the negative potential deposition method. The experimental results are listed in Table 1.

[0123] Table 1. Performance of catalysts obtained by different electroplating methods

[0124] The NiFe LDH catalyst electrodes prepared in Example 1 and Comparative Example 1 were characterized by scanning electron microscopy in a 6M sodium hydroxide solution at 80 °C with a current of 1 A / cm. -2 The morphology after 20 hours of operation is as follows: Figure 3 As shown, where Figure 3 (a) is the NiFe LDH catalyst electrode prepared by the dual-potential step chronoamperometry method in Example 1, and (b) is the NiFe LDH catalyst electrode prepared by the negative potential deposition method in Comparative Example 1. Figure 3 As can be seen, after 20 hours of stability testing, the catalyst prepared in Example 1 remained firmly bonded to the substrate, while the catalyst obtained in Comparative Example 1 showed a large number of cracks.

[0125] The NiFe LDH catalyst electrodes prepared in Example 1 and Comparative Example 1 were characterized by scanning electron microscopy in a 6M sodium hydroxide solution at 80 °C with a current of 1 A / cm. -2 The morphology of the electrode cross-section after 20 hours of operation is shown in the following figures. Figure 4 As shown, where Figure 4 (a) shows the cross-section of the NiFe LDH catalyst electrode prepared by the dual-potential step chronoamperometry method in Example 1, and (b) shows the cross-section of the NiFe LDH catalyst electrode prepared by the negative potential deposition method in Comparative Example 1. Figure 4 As can be seen from the above, there is a clear transition layer between the catalyst prepared by the dual-potential step chronoamperometry method in Example 1 and the substrate, while there are voids between the catalyst prepared by the negative potential deposition method in Comparative Example 1 and the substrate.

[0126] The NiFe LDH catalyst electrode prepared in Example 1 was analyzed by energy dispersive spectroscopy (EDS) in a 6M sodium hydroxide solution at 80°C at a frequency of 1 A / cm. -2 Micro-region composition analysis of the electrode cross-section was performed after 20 hours of operation, and the results are as follows: Figure 5 As shown, where Figure 5 (a) is an electrode cross-section diagram, (b) is an elemental distribution diagram of Fe, and (c) is an elemental distribution diagram of Ni. Figure 5 As can be seen, the catalyst constituent elements are embedded in the substrate, indicating that the transition layer is firmly bonded to the substrate.

[0127] Using 6M sodium hydroxide solution, under industrial alkaline water electrolysis conditions at 80°C, at a rate of 1 A / cm -2The constant current stability of the catalyst electrodes prepared in Examples 2-7 was tested, and the results are shown in Table 2. As can be seen from Table 2, the present invention has universality for catalysts with different metal compositions.

[0128] Table 2. Constant current stability of the catalyst electrodes prepared in Examples 2-7

[0129] Using 6M sodium hydroxide solution, under industrial alkaline water electrolysis conditions at 80°C, at a rate of 1 A / cm -2 The current was used to test the stable operating time of the catalyst electrode prepared by Comparative Examples 2-14. The results are shown in Table 3. It can be seen from Table 3 that the stable operating time of the catalyst electrode prepared by the negative potential deposition method is longer than that of the catalyst electrode prepared by the hydrothermal synthesis method, but shorter than that of the catalyst electrode prepared by the dual potential step chronoamperometry method (Table 2).

[0130] Table 3. Steady operating time of catalyst electrodes prepared in Comparative Examples 1-14

[0131] Scanning electron microscopy was used to characterize the catalyst electrodes prepared in Comparative Examples 1-3 and 8-10, respectively, in 6M sodium hydroxide solution at 80℃ with a flux of 1 A / cm. -2 The morphology after stable operation until catalyst deactivation is as follows: Figure 6 and Figure 7 As shown, where Figure 6 Image (a) in Comparative Example 1 shows the morphology of the NiFe LDH catalyst electrode prepared by the negative potential deposition method after catalyst deactivation. Figure 6 Image (b) in Comparative Example 3 shows the morphology of the Ni LDH catalyst electrode prepared by the negative potential deposition method after catalyst deactivation. Figure 6 Image (c) in Comparative Example 2 shows the morphology of the NiCo LDH catalyst electrode prepared by the negative potential deposition method after catalyst deactivation. Figure 7 Image (a) in the figure shows the morphology of the NiFe LDH catalyst electrode prepared by the hydrothermal synthesis method in Comparative Example 8 after catalyst deactivation. Figure 7 Image (b) shows the morphology of the Ni LDH catalyst electrode prepared by the hydrothermal synthesis method in Comparative Example 8 after catalyst deactivation. Figure 7 Image (c) in the diagram shows the morphology of the NiCo LDH catalyst electrode prepared by the hydrothermal synthesis method in Comparative Example 8 after catalyst deactivation. Figure 6 As can be seen, the LDH catalyst obtained by the negative potential deposition method exhibits large-area detachment after long-term stability testing under operating conditions, leading to catalyst failure; from Figure 7 As can be seen from the results, the LDH catalyst obtained by the hydrothermal synthesis method exhibited a large amount of agglomeration after stability testing, and the catalyst layer cracked and peeled off from the substrate.

[0132] The growth of the catalyst prepared in Example 8 after etching and deposition for 60 s was observed using scanning electron microscopy. The results are as follows: Figure 8 As shown, where Figure 8 In the image, (a) shows the morphology magnified 50,000 times, and (b) shows the morphology magnified 10,000 times. Figure 8 As can be seen, the catalyst on the electrode surface is uniformly nucleated with dense nucleation sites.

[0133] The growth of the catalyst prepared by negative potential deposition for 60 s in Comparative Example 15 was observed using scanning electron microscopy. The results are as follows: Figure 9 As shown, where Figure 9 In the image, (a) shows the morphology magnified 50,000 times, and (b) shows the morphology magnified 10,000 times. Figure 9 As can be seen, there are few nucleation sites on the electrode surface, and the catalyst agglomerates and grows on a small number of nucleation sites.

[0134] The catalyst electrodes prepared in Comparative Examples 8 and 16 were ultrasonically cleaned to remove the surface catalyst layer, yielding a nickel substrate. The etching process of the substrate was then observed using a scanning electron microscope. The results are as follows: Figure 10 As shown, where Figure 10 (a) in the image is the nickel substrate after hydrothermal reaction in Comparative Example 8, and (b) is the nickel substrate after hydrothermal reaction in Comparative Example 16. Figure 10 As can be seen, the substrate etching in Comparative Example 8 is not obvious, with only a few uneven etching pits; while in Comparative Example 16, after the addition of halogen ions, the substrate shows large-area etching, but the etching is uneven, with the etching pits concentrated at locations such as grain boundaries.

[0135] The growth of the catalysts prepared in Examples 9-11 and 16-18 was observed using scanning electron microscopy, and the results are as follows: Figure 11 and Figure 12 As shown, where Figure 11 (a) in the image is the NiFe LDH catalyst electrode prepared in Example 9. Figure 11 (b) in the figure is the Ni LDH catalyst electrode prepared in Example 11. Figure 11 (c) in the figure represents the NiCo LDH catalyst electrode prepared in Example 10. Figure 12 (a) in the image is the NiFe LDH catalyst electrode prepared in Example 16. Figure 12 (b) in the figure is the Ni LDH catalyst electrode prepared in Example 18. Figure 12(c) in the image represents the NiCoLDH catalyst electrode prepared in Example 17. From... Figure 11 It can be seen that the catalyst obtained at too low an etching potential is related to... Figure 3 (b) The negative potential deposition method showed no significant difference, but cracking occurred. Figure 12 As can be seen, the catalyst obtained with an excessively high etching potential exhibits a large number of cracks, indicating that both excessively high and excessively low etching potentials can affect the bonding between the catalyst and the substrate, making the catalyst prone to detachment.

[0136] Using 6M sodium hydroxide solution, under industrial alkaline water electrolysis conditions at 80°C, at a rate of 1 A / cm -2 The current was used to test the stable operating time of the catalyst electrodes prepared in Examples 9-22. The results are shown in Table 4. It can be seen from Table 4 that the stable operating time of the catalyst electrode obtained by etching with a positive potential of 1V is longer than that with a positive potential of 2V, but shorter than that with a positive potential of 1.5V (Table 2).

[0137] Table 4. Stable operating time of catalyst electrodes prepared in Examples 9-22

[0138] The growth of the catalysts prepared in Examples 23-25 ​​and 30-32 was observed using scanning electron microscopy, and the results are as follows: Figure 13 and Figure 14 As shown, where Figure 13 (a) in the image is the NiFe LDH catalyst electrode prepared in Example 23. Figure 13 (b) in the figure is the Ni LDH catalyst electrode prepared in Example 25. Figure 13 (c) in the figure represents the NiCo LDH catalyst electrode prepared in Example 24. Figure 14 (a) in the figure is the NiFe LDH catalyst electrode prepared in Example 30. Figure 14 (b) in the figure is the Ni LDH catalyst electrode prepared in Example 32. Figure 14 (c) in the image represents the NiCo LDH catalyst electrode prepared in Example 31. From... Figure 13 As can be seen, when the deposition potential is too low, LDH is difficult to grow. Figure 14 As can be seen, when the deposition potential is too high, the catalyst dissolves and cracks.

[0139] Using 6M sodium hydroxide solution, under industrial alkaline water electrolysis conditions at 80°C, at a rate of 1 A / cm -2The current was used to test the stable operating time of the catalyst electrodes prepared in Examples 23-36. The results are shown in Table 5. It can be seen from Table 5 that the stable operating time of the catalyst electrode obtained by applying a negative potential of -0.4V is longer than that of applying a negative potential of -1.6V, but shorter than that of applying a negative potential of -0.7V (Table 2).

[0140] Table 5. Stable operating time of catalyst electrodes prepared in Examples 23-36

[0141] Using 6M sodium hydroxide solution, under industrial alkaline water electrolysis conditions at 80°C, at a rate of 1 A / cm -2 The constant current stability of the catalyst electrodes prepared in Examples 37-48 was tested, and the results are shown in Table 6. It can be seen from Table 6 that when the metal ion concentration is too low, the performance improvement of LDH is not obvious, and when the metal ion concentration is too high, the stability will decrease.

[0142] Table 6. Constant current stability of catalyst electrodes with different metal ion concentrations

[0143] The catalyst electrodes prepared in Examples 49-76 were subjected to ultrasonic cleaning to remove the surface catalyst layer, yielding the substrate. The etching of the substrate was then observed using a scanning electron microscope. The results are shown in Table 7. Figure 15 As shown, where Figure 15 In Example 59, (a) is the nickel substrate after reaction at an etching potential of 1.2V; (b) is the nickel substrate after reaction at an etching potential of 1.5V in Example 1; and (c) is the nickel substrate after reaction at an etching potential of 1.8V in Example 60. Figure 15 As can be seen, excessively high potentials can lead to large-area etching on the substrate surface, which is detrimental to the uniform growth of the catalyst. Table 7 shows that the potentials at which uniform small etching pits appear differ for different metal substrates.

[0144] Table 7. Etching of the substrate at different etching potentials

[0145] The growth of the catalyst prepared in Example 77 was observed using scanning electron microscopy, and the results are as follows: Figure 16 As shown, where Figure 16 In the image, (a) shows the morphology magnified 900 times, and (b) shows the morphology magnified 10,000 times. Figure 16 As can be seen, large-area etching pits appear on the electrode surface, and the catalyst preferentially nucleates and grows in the etching pits, resulting in uneven catalyst growth.

[0146] The growth of the NiFe LDH catalysts prepared in Examples 78-80 was observed using scanning electron microscopy, and the results are as follows: Figure 17 As shown in Table 8, Figure 17 (a) is the catalyst prepared in Example 78, (b) is the catalyst prepared in Example 79, and (c) is the catalyst prepared in Example 80. Figure 17 As can be seen, the nickel foam substrate nucleates and partially grows at a deposition potential of -0.6V, grows uniformly at a deposition potential of -0.8V, and cracks appear at a deposition potential of -1.0V, indicating that the deposition potential affects the bonding force between the catalyst and the substrate.

[0147] The actual NiFe LDH catalyst electrode prepared in Example 81 is shown below. Figure 18 As shown.

[0148] The electrodes prepared in Example 81 were observed at different locations using a scanning electron microscope, and the results are as follows: Figure 19 As shown, where Figure 19 (a) in the middle is Figure 18 Topographic view of the middle electrode position 1, (b) is Figure 18 Topographic image at position 2 of the middle electrode, (c) is Figure 18 Topographic image at position 3 of the middle electrode, (d) is Figure 18 Topographic image at position 4 of the middle electrode, (e) is Figure 18 Topographic image of position 5 of the middle electrode, from Figure 19 As can be seen, the catalyst grows uniformly and has a consistent morphology in each region of the electrode.

[0149] The electrode prepared in Example 81 was used as the anode in an alkaline electrolytic cell, such as... Figure 20 As shown, using 6M sodium hydroxide solution, under industrial alkaline water electrolysis conditions at 80°C, the flow rate was 1 A / cm. -2 Operating with current, the result is as follows Figure 21 As shown, from Figure 21 As can be seen, the electrode exhibits excellent stability in the alkaline electrolytic cell.

[0150] Therefore, the present invention employs the above-mentioned interface-strong bonding multimetal hydroxide catalyst electrode, its preparation method and application, resulting in a multimetal hydroxide catalyst electrode with high uniformity and strong bonding force with the substrate, which can operate stably under the high temperature, high alkalinity and operating current density of industrial alkaline water electrolysis for hydrogen production.

[0151] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a multimetal hydroxide catalyst electrode with strong interfacial bonding, characterized in that: Includes the following steps: S1. Pre-treat the metal substrate; S2. Add deposition solution to the electrolytic cell, use a metal substrate as the working electrode and a platinum sheet as the counter electrode, and perform deposition using the dual-potential step chronoamperometry method. After deposition, a strongly bonded multimetal hydroxide catalyst electrode is obtained.

2. The method for preparing a strongly interfacially bonded multimetal hydroxide catalyst electrode according to claim 1, characterized in that: In S1, the metal substrate includes Ni-based metal, Fe-based metal, Cu-based metal, Cr-based metal, Ti-based metal, NiFe-based binary alloy, NiCu-based binary alloy, NiCr-based binary alloy, or multi-element alloy.

3. The method for preparing a strongly interfacially bonded multimetal hydroxide catalyst electrode according to claim 1, characterized in that: In S1, the pretreatment methods for the metal substrate include acid washing, alkaline washing, physical polishing, or electrochemical reduction.

4. The method for preparing a strongly interfacially bonded multimetal hydroxide catalyst electrode according to claim 1, characterized in that: In S1, the structure of the metal substrate includes sheet-like, mesh-like, or foam-like structures.

5. The method for preparing a strongly interfacially bonded multimetal hydroxide catalyst electrode according to claim 1, characterized in that: The specific steps of the dual-potential step chronoamperometry in S2 are as follows: first, a positive potential is applied to the surface of the metal substrate for etching, and then the potential is applied instantaneously to a negative potential for catalyst deposition.

6. The method for preparing a strongly interfacially bonded multimetal hydroxide catalyst electrode according to claim 5, characterized in that: The applied positive potential is 0.5~3V, the etching time is 30~300s, the applied negative potential is -0.4~-2V, and the catalyst deposition time is 60~3600s.

7. The method for preparing a strongly interfacially bonded multimetal hydroxide catalyst electrode according to claim 1, characterized in that: In S2, the sedimentation solution includes any two or more of the following: solutions of nitrate, sulfate, chloride, acetate, and oxalate of Co and Mn ions, and solutions of nitrate, sulfate, chloride, and acetate of Ni, Fe, Zn, and Cr ions.

8. The method for preparing a strongly interfacially bonded multimetal hydroxide catalyst electrode according to claim 7, characterized in that: The concentration of metal ions in the sediment is 0.01~1 mol / L.

9. A multi-metal hydroxide catalyst electrode with strong interfacial bonding, characterized in that: The electrode was prepared using the method described in any one of claims 1 to 8 for preparing a strongly interfacially bonded multimetal hydroxide catalyst.

10. An application of a polymetallic hydroxide catalyst electrode with strong interfacial bonding, characterized in that: The interfacially strongly bonded multimetal hydroxide catalyst electrode of claim 9 is used as the anode in alkaline water electrolysis for hydrogen production.

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