Thermal oxidation anode for alkaline electrolyzed water and preparation method of thermal oxidation anode
By using thermal oxidation treatment to form a multi-layer catalytic layer during alkaline electrolysis and doping chromium and cerium salts, the problems of poor binding strength and high energy consumption of traditional anode materials are solved, and high efficiency, stable and low-cost electrode performance is achieved.
Patent Information
- Application Number
- CN202411792668.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-07
- Publication Date
- 2025-03-14
AI Technical Summary
During the traditional alkaline water electrolysis process, the anode material Ni/Fe-based catalyst has problems such as high oxygen evolution potential, large energy consumption, and unsatisfactory bonding force between the catalytic layer and the electrode substrate, which limits the further development and application of electrolytic water technology.
The oxide coating is formed on the surface of the nickel matrix by thermal oxidation treatment, and a multi-layer superimposed catalytic layer is formed by multiple brushing and calcining to ensure that the catalytic layer is firmly bonded to the matrix, and doped with chromium and cerium salts to improve catalytic activity and stability.
The stable bonding of the catalytic layer is achieved, the catalytic activity and corrosion resistance of the electrode are improved, the cost is reduced, and the service life of the electrode is extended.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of hydrogen production by water electrolysis, and in particular to a thermal oxidation anode for alkaline water electrolysis and a preparation method thereof. Background Art
[0002] With the rapid development of renewable energy and the rise of the hydrogen energy industry, alkaline water electrolysis, as an important method of hydrogen production, has an increasingly broad application prospect. Alkaline water electrolysis is the process of passing direct current through an alkaline aqueous solution (such as potassium hydroxide or sodium hydroxide solution) to decompose water and produce hydrogen and oxygen. In this process, an oxidation reaction occurs at the anode (positive electrode) to precipitate oxygen; a reduction reaction occurs at the cathode (negative electrode) to precipitate hydrogen. As one of the key components in the electrolysis of water hydrogen production system, the stability and efficiency of the anode's performance are of great significance to improving the efficiency of the entire system and reducing costs. An oxide coating is formed on the surface of the substrate through thermal oxidation treatment to improve its catalytic activity and stability.
[0003] In the process of alkaline water electrolysis, the choice of anode materials has an important influence on the electrolysis efficiency, stability and cost. Transition metal elements, due to their unfilled valence layer d orbitals, can act as electrophiles or nucleophiles to undergo chemical reactions to form intermediates, reduce the activation energy of the reaction, and promote the reaction. Traditional anode materials Ni / Fe-based catalysts are widely used due to their abundant reserves, wide sources, and low costs, but they have problems such as high oxygen evolution potential, high energy consumption, and poor bonding between the catalytic layer and the electrode substrate. These problems limit the further development and application of water electrolysis technology. Summary of the invention
[0004] The technical problem to be solved by the present invention is to provide a thermal oxidation anode for alkaline water electrolysis and a preparation method thereof, wherein the catalytic layers on the electrode surface are firmly bonded and not easy to fall off, and have high catalytic activity and better performance.
[0005] In order to solve the above technical problems, the present invention provides a method for preparing a thermal oxidation anode for alkaline water electrolysis, comprising the following steps:
[0006] Step 1) pretreatment of the substrate: the nickel mesh is sandblasted, degreased, pickled, alkaline washed, and then repeatedly cleaned with deionized water until the surface of the substrate is neutral, and finally rinsed with isopropanol and dried for standby use to obtain a nickel substrate;
[0007] Step 2) Preparation of coating solution: The coating solution includes nickel salt, iron salt and chromium salt, and the nickel salt, iron salt and chromium salt are dissolved in water to obtain a mixed coating solution;
[0008] Step 3) substrate oxidation: the pretreated nickel substrate is subjected to a first stage high temperature oxidation treatment at 300-700° C. in an air atmosphere;
[0009] Step 4) thermal oxidation treatment: coating the prepared coating solution on the nickel substrate that has been subjected to high temperature oxidation treatment, drying the substrate, and then performing a second stage thermal oxidation treatment at 400-900°C;
[0010] Step 5) Repeat the second stage thermal oxidation treatment of step 4) multiple times until the required coating loading is reached to obtain a nickel-based thermal oxidation anode for alkaline water electrolysis.
[0011] Furthermore, the pickling temperature in step 1) is 45° C.-95° C., the concentration of the pickling solution is 15%-35%, and the pickling time is 3h-8h.
[0012] Furthermore, in step 2), the atomic ratio of nickel salt, iron salt and chromium salt is 6-8:1-2:1-3, the iron salt is one of ferric chloride and ferrous sulfate; the chromium salt is one of chromium chloride and chromium nitrate, and the nickel salt is nickel chloride.
[0013] Furthermore, the coating liquid also includes cerium salt, and the atomic ratio of the nickel salt, iron salt, chromium salt and cerium salt is 15-16:1-2:1-3:1-2, the iron salt is one of ferric chloride and ferrous sulfate; the chromium salt is one of chromium chloride and chromium nitrate; the nickel salt is nickel chloride; and the cerium salt is cerium nitrate.
[0014] Furthermore, the coating solution also includes one of sodium citrate, citric acid and isopropanol, the addition amount of sodium citrate and citric acid is consistent with the addition amount of chromium salt, and the addition amount of isopropanol is: 5-30mL of isopropanol is added to every 100ml of water, and the addition of isopropanol does not affect the concentration of metal ions; both citric acid and sodium citrate can form complex ion compounds with metal ions to prevent precipitation; citric acid and sodium citrate will not change valence during the oxidation-reduction process, thereby improving the stability of the electrode. Isopropanol can improve the fluidity and coating properties of the coating solution, and reduce the viscosity and surface tension of the coating solution, making it easier to apply the coating solution on the substrate surface.
[0015] Furthermore, in step 3), the oxidation rate of the nickel substrate is 8°C / min, and the insulation time is 10-40min.
[0016] Furthermore, in step 4), the thermal oxidation temperature is 400-700° C., the holding time is 10-35 min, and the coating method is cross-brushing.
[0017] Furthermore, the loading amount of the thermal oxidation anode coating prepared in step 5) is 10-40 g / m 2 , the second stage thermal oxidation treatment is repeated 10-12 times.
[0018] A thermal oxidation anode for alkaline water electrolysis is prepared by any of the preparation methods described above.
[0019] Beneficial effects of the present invention:
[0020] 1. Nickel, as a relatively cheap and readily available metal, avoids the use of expensive precious metal catalysts, further reducing costs.
[0021] 2. The thermal oxidation anode is made by multiple brushing and calcining methods to form multiple superimposed catalytic layers. The catalytic layers and the catalytic layers and the substrate are firmly bonded and not easy to fall off. After the outer catalytic layer falls off, the inner catalytic layer continues to undergo oxygen evolution reaction due to the same structure and composition as the outer catalytic layer, which will not affect the intensity and stability of the reaction and greatly extend the service life of the electrode.
[0022] 3. The addition of metal salts can form oxides at high temperatures, giving the electrode good corrosion resistance.
[0023] 4. The doping of cerium salt promotes the formation of high-valence state of nickel and improves the catalyst performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 is a surface morphology image of the nickel substrate after pretreatment in Example 1;
[0025] Figure 2 is a topographical image of the surface of the thermal oxidation anode prepared in Example 1;
[0026] Figure 3 is a topographical image of the surface of the thermal oxidation anode prepared in Example 2;
[0027] Figure 4 is a topographical image of the surface of the thermal oxidation anode prepared in Example 5;
[0028] Figure 5 is a topographical image of the surface of the thermally oxidized anode prepared in Example 6;
[0029] Figure 6 It is 5*5cm in test example 2 2 Comparison chart of slot pressure performance. DETAILED DESCRIPTION
[0030] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.
[0031] The preparation method of the thermal oxidation anode for alkaline electrolyzed water of the present invention requires pretreatment of the nickel substrate, the nickel substrate is a nickel mesh, specifically, a sandblasted nickel mesh is used as the substrate, a 40g / L degreasing solution is prepared with detergent, and the cut nickel mesh is immersed in the degreasing solution and heated at 40°C for 6 hours to remove the oil stains on the nickel mesh. The cleaned nickel mesh is rinsed with deionized water, and then ultrasonically cleaned with isopropanol and dried at 100°C. H2SO4 is prepared into a 25% pickling solution, and then the pickling solution is heated to 85°C to pickle the dried nickel mesh for 4.5 hours. The pickled electrode is rinsed with deionized water until neutral, and then ultrasonically cleaned with isopropanol and dried at 85°C for two hours to finally obtain a treated nickel substrate. The surface morphology of the nickel substrate after pretreatment is as shown in the figure. Figure 1 The nickel substrate is prepared and described in detail in the following multiple examples.
[0032] Embodiment 1:
[0033] Preparation of coating liquid: The atomic ratio of NiCl2, FeSO4 and CrCl3 is 8:1:1, and the total metal concentration is 80g / L. The coating liquid is prepared by dissolving them in water according to this ratio.
[0034] The pretreated nickel substrate was subjected to a first-stage high-temperature oxidation treatment at 500° C., with a heating rate of 8° C. / min and a heat preservation time of 40 min to obtain a metal nickel substrate containing an oxide layer.
[0035] The second stage of thermal oxidation treatment: Use a brush to evenly apply the prepared coating liquid on the mesh surface of the nickel substrate, only apply one side, and use a horizontal and vertical alternating coating method. Dry at 60℃ for 30 minutes after each coating. Put the nickel substrate after the coating is dried into a muffle furnace. The first thermal oxidation temperature is 420℃, the heating rate is 8℃ / min, and the heat preservation is 30 minutes. Then carry out multiple second-stage thermal oxidation treatments to obtain the finished product. The second and subsequent thermal oxidation temperatures are 500℃, the heating rate is 8℃ / min, the heat preservation is 35 minutes, and the liquid amount is 30g / m 2 .
[0036] The morphology of the thermal oxidation anode surface is shown in Figure 2 shown.
[0037] Example 2
[0038] Preparation of coating liquid: The atomic ratio of NiCl2, FeSO4 and Cr(NO3)3 is 8:1:1, and the total metal concentration is 80g / L. The coating liquid is prepared by dissolving them in water according to this ratio.
[0039] The pretreated nickel substrate is subjected to a first-stage high-temperature oxidation treatment at 500° C., with a heating rate of 8° C. / min and a heat preservation time of 40 min to obtain a metal nickel substrate containing an oxide layer.
[0040] The second stage of thermal oxidation treatment: Use a brush to evenly apply the prepared coating liquid on the mesh surface of the nickel substrate, only apply one side, and use a horizontal and vertical alternating coating method. Dry in an oven at 60°C for 30 minutes after each coating. Put the nickel substrate after the coating is dried into a muffle furnace. The first thermal oxidation temperature is 420°C, the heating rate is 8°C / min, and the heat preservation is 30 minutes. Subsequently, multiple second-stage thermal oxidation treatments are carried out to obtain the finished product. The second and subsequent thermal oxidation temperatures are 500°C, the heating rate is 8°C / min, the heat preservation is 35 minutes, and the liquid amount is 30g / m 2 .
[0041] The morphology of the thermal oxidation anode surface is shown in Figure 3 shown.
[0042] Example 3
[0043] Preparation of coating liquid: The atomic ratio of NiCl2, FeCl3 and CrCl3 is 8:1:1, and the total metal concentration is 40g / L. The coating liquid is prepared by dissolving them in water according to this ratio.
[0044] The pretreated nickel substrate is subjected to a first-stage high-temperature oxidation treatment at 500°C, with a heating rate of 8°C / min and a heat preservation time of 40min, to obtain a metal nickel substrate containing an oxide layer.
[0045] The second stage of thermal oxidation treatment: Use a brush to evenly apply the prepared coating liquid on the mesh surface of the nickel substrate, only apply one side, and use a horizontal and vertical alternating coating method. Dry in an oven at 60°C for 30 minutes after each coating. Put the nickel substrate after the coating is dried into a muffle furnace. The first thermal oxidation temperature is 420°C, the heating rate is 8°C / min, and the heat preservation is 30 minutes. Subsequently, multiple second-stage thermal oxidation treatments are carried out to obtain the finished product. The second and subsequent thermal oxidation temperatures are 500°C, the heating rate is 8°C / min, the heat preservation is 35 minutes, and the liquid amount is 30g / m 2 .
[0046] Example 4
[0047] Preparation of coating liquid: The atomic ratio of NiCl2, FeSO4 and CrCl3 is 8:1:1, and the total metal concentration is 40g / L. The coating liquid is prepared by dissolving them in water according to this ratio.
[0048] The pretreated nickel substrate is subjected to a first-stage high-temperature oxidation treatment at 500°C, with a heating rate of 8°C / min and a heat preservation time of 40min, to obtain a metal nickel substrate containing an oxide layer.
[0049] The second stage of thermal oxidation treatment: Use a brush to evenly apply the prepared coating liquid on the mesh surface of the nickel substrate, only apply one side, and use a horizontal and vertical alternating coating method. Dry in an oven at 60°C for 30 minutes after each coating. Put the nickel substrate after the coating is dried into a muffle furnace. The first thermal oxidation temperature is 420°C, the heating rate is 8°C / min, and the heat preservation is 30 minutes. Subsequently, multiple second-stage thermal oxidation treatments are carried out to obtain the finished product. The second and subsequent thermal oxidation temperatures are 500°C, the heating rate is 8°C / min, the heat preservation is 35 minutes, and the liquid amount is 30g / m 2 .
[0050] Example 5
[0051] Preparation of coating liquid: The atomic ratio of NiCl2, FeSO4, CrCl3 and Ce(NO3)3 is 7.5:1:1:0.5, and the total metal concentration is 40g / L. The coating liquid is prepared by dissolving them in water according to this ratio.
[0052] The pretreated nickel substrate is subjected to a first-stage high-temperature oxidation treatment at 500°C, with a heating rate of 8°C / min and a heat preservation time of 40min, to obtain a metal nickel substrate containing an oxide layer.
[0053] The second stage of thermal oxidation treatment: Use a brush to evenly apply the prepared coating liquid on the mesh surface of the nickel substrate, only apply one side, and use a horizontal and vertical alternating coating method. Dry in an oven at 60°C for 30 minutes after each coating. Put the nickel substrate after the coating is dried into a muffle furnace. The first thermal oxidation temperature is 420°C, the heating rate is 8°C / min, and the heat preservation is 30 minutes. Subsequently, multiple second-stage thermal oxidation treatments are carried out to obtain the finished product. The second and subsequent thermal oxidation temperatures are 500°C, the heating rate is 8°C / min, the heat preservation is 35 minutes, and the liquid amount is 30g / m 2 .
[0054] The morphology of the thermal oxidation anode surface is shown in Figure 4 shown.
[0055] Example 6
[0056] Preparation of coating liquid: The atomic ratio of NiCl2, FeSO4, CrCl3 and Ce(NO3)3 is 7.5:1:1:0.5. They are dissolved in water in this ratio to prepare the coating liquid. Then, isopropanol is added to the coating liquid in an amount of 20 mL of isopropanol per 100 ml of water. In the final coating liquid, the total metal concentration is 40 g / L.
[0057] The pretreated nickel substrate is subjected to a first-stage high-temperature oxidation treatment at 500°C, with a heating rate of 8°C / min and a heat preservation time of 30min, to obtain a metal nickel substrate containing an oxide layer.
[0058] The second stage of thermal oxidation treatment: Use a brush to evenly apply the prepared coating liquid on the mesh surface of the nickel substrate, only apply it on one side, and use a horizontal and vertical alternating coating method. After each coating, dry it in an oven at 60℃ for 30 minutes. Put the nickel substrate after the coating is dried into a muffle furnace, the thermal oxidation temperature is 550℃, the heating rate is 8℃ / min, and the temperature is kept for 30 minutes. The amount of liquid applied is 15g / m 2 .
[0059] The morphology of the thermal oxidation anode surface is shown in Figure 5 shown.
[0060] Example 7
[0061] Preparation of coating liquid: The atomic ratio of NiCl2, FeSO4, CrCl3 and Ce(NO3)3 is 7.5:1:1:0.5, and the total metal concentration is 40g / L. Dissolve them in water according to this ratio to prepare the coating liquid, and then add sodium citrate with the same mass as CrCl3.
[0062] The pretreated nickel substrate is subjected to a first-stage high-temperature oxidation treatment at 500°C, with a heating rate of 8°C / min and a heat preservation time of 40min, to obtain a metal nickel substrate containing an oxide layer.
[0063] The second stage of thermal oxidation treatment: Use a brush to evenly apply the prepared coating liquid on the mesh surface of the nickel substrate, only apply one side, and use a horizontal and vertical alternating coating method. Dry in an oven at 60°C for 30 minutes after each coating. Put the nickel substrate after the coating is dried into a muffle furnace. The first thermal oxidation temperature is 420°C, the heating rate is 8°C / min, and the heat preservation is 30 minutes. Subsequently, multiple second-stage thermal oxidation treatments are carried out to obtain the finished product. The second and subsequent thermal oxidation temperatures are 500°C, the heating rate is 8°C / min, the heat preservation is 35 minutes, and the liquid amount is 15g / m 2 .
[0064] Example 8
[0065] Preparation of coating liquid: The atomic ratio of NiCl2, FeSO4, CrCl3 and Ce(NO3)3 is 7.5:1:1:0.5, and the total metal concentration is 40g / L. The coating liquid is prepared by dissolving them in water in this ratio, and then adding citric acid in an amount equal to that of CrCl3.
[0066] The pretreated nickel substrate is subjected to a first-stage high-temperature oxidation treatment at 400°C, with a heating rate of 8°C / min and a heat preservation time of 10min, to obtain a metal nickel substrate containing an oxide layer.
[0067] The second stage of thermal oxidation treatment: Use a brush to evenly apply the prepared coating liquid on the mesh surface of the nickel substrate, only apply it on one side, and use a horizontal and vertical alternating coating method. After each coating, dry it in an oven at 60℃ for 30 minutes. Put the nickel mesh after the coating is dried into a muffle furnace, the thermal oxidation temperature is 450℃, the heating rate is 8℃ / min, and the heat is kept for 30 minutes. The amount of liquid applied is 15g / m 2 .
[0068] Test Example 1
[0069] The thermal oxidation electrodes prepared in Examples 1-8 were subjected to three-electrode tests using an Autolabe electrochemical workstation. The reference electrode was a mercury / mercuric oxide electrode, the counter electrode was a nickel electrode, the electrolyte was 1 M KOH, and the test electrode was at 10 mA / cm 2 The oxygen evolution overpotential at the potential is shown in the following table:
[0070] Example 1 Example 2 Example 3 Example 4 Oxygen evolution potential / mV 340 345 438 323 Example 5 Example 6 Example 7 Example 8 Oxygen evolution potential / mV 338 463 290 337
[0071] As can be seen from the table, the best coating solution formula is a composite superposition of nickel, iron, chromium, cerium and sodium citrate. Based on nickel salt and iron salt, adding chromium and cerium improves the activity of the electrode, stabilizes nickel in a high valence state, and provides active sites for the reaction; the addition of sodium citrate makes the ions no longer simply mixed, but interacts with each other to improve the performance of the electrode.
[0072] Test Example 2
[0073] The thermal oxidation electrode prepared in Examples 1, 4, 5, and 7 was used as the anode, the Raney nickel electrode was used as the cathode, and an Agfa-UTP220 diaphragm was used to form an electrolytic cell. The cell pressure was tested at 80°C in 30% KOH. The test area was 5*5cm 2 , the results are shown in the following table:
[0074]
[0075]
[0076] The thermal oxidation electrode not only has a good overpotential, but also has a good cell voltage in a 25 square centimeter tank under industrial conditions. The cell voltage of Ni-Fe-Cr=8:1:1, Cs=40g / L is 10000A / m 2 The current density of Ni-Fe-Cr-Ce=7.5:1:1:0.5, Cs=40g / L is 3mV lower than that of sandblasted nickel mesh at 10000A / m 2 The current density of Ni-Fe-Cr-Ce=7.5:1:1:0.5+sodium citrate, Cs=40g / L is 9mV lower than that of sandblasted nickel mesh at 10000A / m2 The current density is 33mV lower than that of the sandblasted nickel mesh. The lower the voltage, the lower the energy consumption, which means that the prepared thermal oxidation anode provides a good foundation for the next industrial application. The test results also prove the consistency of the overpotential test results.
[0077] Reference Figure 6 The following is a comparison chart of the cell pressure performance in this test example. It can be seen from the figure that reducing the concentration of the coating solution helps to disperse the ions and improve the performance. The cell voltage of Ni-Fe-Cr=8:1:1, Cs=40g / L is 10000A / m 2 The current density of Ni-Fe-Cr-Ce=7.5:1:1:0.5, Cs=40g / L is 3mV lower than that of sandblasted nickel mesh at 10000A / m 2 The current density of Ni-Fe-Cr-Ce=7.5:1:1:0.5+sodium citrate, Cs=40g / L is 9mV lower than that of sandblasted nickel mesh at 10000A / m 2 The current density of the nickel mesh is 33mV lower than that of the sandblasted nickel mesh. The addition of Ce improves the OER kinetics and mass transfer capacity of nickel-iron oxide, thereby improving its catalytic performance; the presence of the complexing agent improves the stability of the electrode.
[0078] The present invention optimizes the nickel matrix pretreatment steps, doping high-valent metal chromium, and successfully prepares a corrosion-resistant, highly stable, low-cost, and efficient alkaline water electrolysis anode through a special thermal oxidation process. 3+ The cation has a special electronic configuration (t 2g 3 e g 0 ), which facilitates charge transfer and electron capture. In particular, chromium (Cr) can exist in multiple oxidation states (from +1 to +6), among which Cr 3+ / Cr 4+ Very stable, during the OER reaction, chromium ions can easily adopt +3 and +4 (even +5) oxidation states, and adjust the electronic structure through synergistic effects with the active substances (Fe or Ni) in the oxygen evolution reaction process, thereby improving the electrocatalytic activity of the catalyst. 3+ The incorporation is a strong Lewis acid that induces electron delocalization around Ni and Fe. At the same time, the formation of additional high-valent Cr during the OER process can buffer the necessary multi-electron process, thereby promoting the loss of electrons from Ni and stabilizing high-valent Ni. The presence of Fe reduces the affinity of Ni surface sites for oxygen, promoting the high oxidation state of Ni (such as Ni 3+ or Ni 4+ ) formation. 3+The high redox performance, high and flexible coordination number, and good cerium electronic / ionic conductivity improve the OER kinetics and mass transfer capacity of nickel-iron oxide, thereby enhancing its catalytic performance. 3+ The strong coupling interface increases the stability of the catalyst, thereby improving the life of the catalyst. 3+ and Ce 2+ Flexible transition between oxidation states, higher oxygen storage capacity, favoring more Ni 3+ or Ni 4+ Active species formation.
[0079] In the above-mentioned multiple embodiments, the amount of liquid is the final loading amount, which is calculated based on the weight gain after each thermal oxidation sintering, and accurately expresses the amount of loading. The amount of loading has an impact on the performance and life of the embodiment. If the loading is too low, the coverage of the catalyst on the substrate cannot reach 100%, which will cause the exposure of the substrate. The nickel of the substrate will be dissolved in the air due to the influence of humidity and impurities, reducing the performance and service life of the thermal oxidation electrode; if the loading is too high, the coating will continue when the coverage reaches 100%, which will not only cover the active sites and reduce the electrode performance, but also increase unnecessary costs.
[0080] The above embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent substitution or change made by a person skilled in the art based on the present invention is within the protection scope of the present invention.
Claims
1. A method for preparing a thermal oxidation anode for alkaline water electrolysis, characterized in that: The following steps are involved: Step 1) pretreatment of the substrate: the nickel mesh is sandblasted, degreased, pickled, alkaline washed, and then repeatedly cleaned with deionized water until the surface of the substrate is neutral, and finally rinsed with isopropanol and dried for standby use to obtain a nickel substrate; Step 2) Preparation of coating solution: The coating solution includes nickel salt, iron salt and chromium salt, and the nickel salt, iron salt and chromium salt are dissolved in water to obtain a mixed coating solution; Step 3) substrate oxidation: the pretreated nickel substrate is subjected to a first stage high temperature oxidation treatment at 300-700° C. in an air atmosphere; Step 4) thermal oxidation treatment: coating the prepared coating solution on the nickel substrate that has been subjected to high temperature oxidation treatment, drying the substrate, and then performing a second stage thermal oxidation treatment at 400-900°C; Step 5) Repeat the second stage thermal oxidation treatment of step 4) multiple times until the required coating loading is reached to obtain a nickel-based thermal oxidation anode for alkaline water electrolysis.
2. The method for preparing a thermal oxidation anode for alkaline water electrolysis according to claim 1, characterized in that: The pickling temperature in step 1) is 45° C.-95° C., the concentration of the pickling solution is 15%-35%, and the pickling time is 3h-8h.
3. The method for preparing a thermal oxidation anode for alkaline water electrolysis according to claim 1, characterized in that: In step 2), the atomic ratio of nickel salt, iron salt and chromium salt is 6-8:1-2:1-3, the iron salt is one of ferric chloride and ferrous sulfate; the chromium salt is one of chromium chloride and chromium nitrate; the nickel salt is nickel chloride.
4. The method for preparing a thermal oxidation anode for alkaline water electrolysis according to claim 1, characterized in that: The coating liquid also includes cerium salt, and the atomic ratio of the nickel salt, iron salt, chromium salt and cerium salt is 15-16:1-2:1-3:1-2. The iron salt is one of ferric chloride and ferrous sulfate; the chromium salt is one of chromium chloride and chromium nitrate; the nickel salt is nickel chloride; and the cerium salt is cerium nitrate.
5. The method for preparing a thermal oxidation anode for alkaline water electrolysis according to claim 4, characterized in that: The coating liquid also includes one of sodium citrate, citric acid and isopropanol. The addition amount of the sodium citrate and citric acid is consistent with the addition amount of the chromium salt. The addition amount of the isopropanol is: 5-30mL of isopropanol is added to every 100ml of water.
6. The method for preparing a thermal oxidation anode for alkaline water electrolysis according to claim 1, characterized in that: In step 3), the oxidation rate of the nickel substrate is 8°C / min, and the holding time is 10-40min.
7. The method for preparing a thermal oxidation anode for alkaline water electrolysis according to claim 1, characterized in that: The thermal oxidation temperature in step 4) is 400-700° C., the heat preservation time is 10-35 minutes, and the coating method is cross brushing.
8. The method for preparing a thermal oxidation anode for alkaline water electrolysis according to claim 1, characterized in that: The loading amount of the thermal oxidation anode coating prepared in step 5) is 10-40 g / m 2 , the second stage thermal oxidation treatment is repeated 10-12 times.
9. A thermal oxidation anode for alkaline water electrolysis, characterized in that: The preparation method is described in any one of claims 1 to 8.
Citation Information
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