Preparation method and application of anion exchange membrane electrolysis water hydrogen evolution catalyst

Abstract

The application relates to a preparation method and application of an anion exchange membrane water electrolysis hydrogen evolution catalyst. The preparation comprises the following steps: dissolving a soluble nickel salt and a soluble cobalt salt in deionized water respectively, mixing and ultrasonic treating the two solutions to configure a precursor reaction solution; adding 85% phosphoric acid solution and 98% sulfuric acid solution into the precursor reaction solution and performing shearing treatment; placing the obtained solution into a polytetrafluoroethylene reaction kettle, reacting under high-temperature conditions, and obtaining a catalyst precursor after reaction through centrifugation, cleaning and drying; and calcining the catalyst precursor under a nitrogen atmosphere to obtain the anion exchange membrane water electrolysis hydrogen evolution catalyst. The application has the advantages that a hydrothermal calcination synthesis method is adopted, phosphorus elements and sulfur elements are introduced in the preparation process, a non-noble metal AEM water electrolysis hydrogen evolution catalyst is synthesized, the electronic conduction capacity of the catalyst is significantly improved, and the catalytic activity and stability of the catalyst are improved.

Description

Technical Field

[0001] This invention relates to the field of catalyst materials technology, specifically to a method for preparing and applying an anion exchange membrane catalyst for hydrogen evolution in water electrolysis. Background Technology

[0002] Electrolysis of water to produce hydrogen has been a core technology for the large-scale production of green hydrogen and has seen rapid development in recent years. Among them, anion exchange membrane (AEM) electrolysis combines the low-cost material advantages of alkaline water electrolysis with the high efficiency and rapid response advantages of proton exchange membrane (PEM) water electrolysis, and is regarded as the next generation of water electrolysis technology with great industrialization potential.

[0003] In anion exchange membrane (AEM) water electrolysis, the hydrogen evolution reaction (HER) at the cathode and the oxygen evolution reaction (OER) at the anode jointly determine the overall electrolysis efficiency. However, under high current density conditions, the overpotential, conductivity, stability, and interfacial mass transfer capacity of the HER at the cathode directly affect the operating voltage, energy consumption, and lifespan of the electrolyzer. Therefore, developing high-performance HER catalysts at the cathode is crucial for improving the overall efficiency of AEM water electrolysis.

[0004] At present, there are obvious shortcomings of AEM electrolysis hydrogen evolution catalysts: (1) Although noble metal catalysts have excellent performance, they are expensive and scarce, making it difficult to apply them on a large scale; (2) Non-noble metal catalysts have insufficient active sites, poor conductivity, poor stability at high current density, poor compatibility with AEM membrane interface, and large mass transfer resistance, which cannot meet the needs of industrial applications; (3) Currently commonly used electrolysis hydrogen evolution catalysts, such as platinum carbon and NiFe-LDH, are difficult to prepare and difficult to achieve large-scale preparation.

[0005] Therefore, developing highly active, highly stable, low-cost, and easily prepared non-precious metal hydrogen evolution catalysts is crucial for promoting the industrialization of AEM water electrolysis technology. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for preparing and applying an efficient, stable and low-cost anion exchange membrane electrolysis hydrogen evolution catalyst. This method can solve the problems existing in the prior art, such as high cost of noble metal catalysts, insufficient active sites of non-noble metal catalysts, poor conductivity, poor stability at high current density and poor compatibility with AEM membrane interface, large mass transfer resistance, high difficulty in preparing commonly used water electrolysis hydrogen evolution catalysts, and difficulty in achieving large-scale preparation.

[0007] To solve the above-mentioned technical problems, the technical solution of the present invention is: a method for preparing an anion exchange membrane water electrolysis hydrogen evolution catalyst, comprising the following steps: S1. Dissolve soluble nickel salt and soluble cobalt salt in deionized water respectively, mix the two solutions, and sonicate them to prepare a precursor reaction solution. S2. Add 85% phosphoric acid solution and 98% sulfuric acid solution to the prepared precursor reaction solution, and perform shearing treatment; S3. Place the solution obtained in step S2 into a polytetrafluoroethylene reactor and react it under high temperature conditions. After the reaction is completed, centrifuge, wash and dry to obtain the catalyst precursor. S4. The catalyst precursor prepared in step S3 is calcined under a nitrogen atmosphere to obtain the anion exchange membrane water electrolysis hydrogen evolution catalyst.

[0008] Further, in step S1, the soluble nickel salt is one or more of nickel nitrate, nickel chloride, nickel sulfate, and nickel sulfite, and the concentration of the soluble nickel salt solution is 2 mol / L; the soluble cobalt salt is one or more of cobalt nitrate, cobalt chloride, and cobalt sulfate, and the concentration of the soluble cobalt salt solution is 2 mol / L; the volume ratio of the soluble nickel salt solution to the soluble cobalt salt solution is 10:1.

[0009] Further, in step S2, the volume ratio of the precursor reaction solution to the phosphoric acid solution is 10:1-10:2, the volume ratio of the precursor reaction solution to the sulfuric acid solution is 50:1-50:2, the shearing speed is 800-1000 rpm, and the shearing time is 20-40 minutes.

[0010] Furthermore, in step S3, the reaction temperature is 120℃-150℃, the heating rate is 5-10℃ / min, and the reaction time is 2h-8h.

[0011] Furthermore, in step S3, the cleaning solution used is anhydrous ethanol, and after cleaning, the solution is placed in a 60°C oven for drying.

[0012] Furthermore, in step S4, the calcination temperature under a nitrogen atmosphere is 400℃-500℃, and the calcination time is 3-4 hours.

[0013] The present invention also provides an application of the above-mentioned anion exchange membrane water electrolysis hydrogen evolution catalyst in anion exchange membrane water electrolysis hydrogen evolution.

[0014] The advantages of this invention are as follows: This invention adopts a hydrothermal calcination synthesis method, introduces phosphorus and sulfur elements in the preparation process, and synthesizes a non-precious metal AEM water electrolysis hydrogen evolution catalyst, which significantly improves the electronic conduction ability of the catalyst, improves the catalytic activity and stability of the catalyst, and is low in cost, simple to prepare, and can realize large-scale preparation. The addition of phosphoric acid and sulfuric acid solutions during the hydrothermal process, along with shearing treatment, adjusts the pH of the reaction solution, thereby regulating the reaction rate and resulting in a more uniform morphology of the catalyst precursor product with more catalytic sites. Furthermore, during the reaction, phosphorus and sulfur can form coordination bonds with nickel and cobalt, effectively improving their utilization rate. Simultaneously, the introduction of sulfur into the catalyst improves the hydrophilicity / hydrophobicity of the catalyst surface, allowing the generated hydrogen to rapidly detach from the catalyst, thus enhancing mass transfer efficiency. Attached Figure Description

[0015] Figure 1 The images show the SEM and EDS images of the hydrogen evolution catalyst prepared in Example 1 of this invention. Figure 2 The polarization curves are those of the hydrogen evolution catalysts prepared in Examples 1-4 of this invention. Figure 3 The electrode morphology and electrolyzer pattern diagrams are shown for the hydrogen evolution catalysts prepared in Examples 1-4 of this invention. Figure 4 The results of voltage tests at different temperatures after the hydrogen evolution catalyst prepared in Example 2 of this invention was loaded into the tank; Figure 5 The results of the long-term stability test of the hydrogen evolution catalyst prepared in Example 2 of this invention are shown. Figure 6 The polarization curves are those of the hydrogen evolution catalysts prepared in Example 2, Comparative Examples 1 and 2 of the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments will enable those skilled in the art to more fully understand this invention, but do not limit the invention to the scope of the described embodiments.

[0017] This specific embodiment adopts the following technical solution: a method for preparing an anion exchange membrane water electrolysis hydrogen evolution catalyst, comprising the following steps: S1. Dissolve soluble nickel salt and soluble cobalt salt in deionized water respectively, mix the two solutions, and sonicate them to prepare a precursor reaction solution. The soluble nickel salt is one or more of nickel nitrate, nickel chloride, nickel sulfate, and nickel sulfite, and the concentration of the soluble nickel salt solution is 2 mol / L; the soluble cobalt salt is one or more of cobalt nitrate, cobalt chloride, and cobalt sulfate, and the concentration of the soluble cobalt salt solution is 2 mol / L; the volume ratio of the soluble nickel salt solution to the soluble cobalt salt solution is 10:1.

[0018] S2. Add 85% phosphoric acid solution and 98% sulfuric acid solution to the prepared precursor reaction solution, and perform shearing treatment; the volume ratio of precursor reaction solution to phosphoric acid solution is 10:1-10:2, the volume ratio of precursor reaction solution to sulfuric acid solution is 50:1-50:2, the shearing speed is 800-1000 rpm, and the shearing time is 20-40 minutes.

[0019] S3. Place the solution obtained in step S2 into a polytetrafluoroethylene (PTFE) reactor. The PTFE reactor can be selected with a volume of 500 mL, 1000 mL, or 2000 mL, depending on the volume of the reactants. The reaction was carried out under high temperature conditions, with a reaction temperature of 120℃-150℃, a heating rate of 5-10℃ / min, and a reaction time of 2h-8h. After the reaction was completed, the catalyst precursor was obtained by centrifugation, washing, and drying. The washing solution used was anhydrous ethanol, and after washing, the catalyst was placed in a 60℃ oven for drying.

[0020] S4. The catalyst precursor prepared in step S3 is calcined under a nitrogen atmosphere to obtain anion exchange membrane water electrolysis hydrogen evolution catalyst. The calcination temperature under a nitrogen atmosphere is 400℃-500℃ and the calcination time is 3-4h.

[0021] Example 1: Weigh 1 mol of nickel nitrate and dissolve it in 500 mL of deionized water, and dissolve 0.1 mol of cobalt nitrate in 50 mL of deionized water. Mix the two solutions and sonicate until completely dissolved. Then weigh 55 mL of 85% phosphoric acid solution and 11 mL of 98% sulfuric acid solution, mix them, and shear them at a speed of 900 rpm for 30 min. Place the sheared solution in a 1000 mL polytetrafluoroethylene reactor and set the oven heating rate to 5 °C / min, the reaction temperature to 120 °C, and the reaction time to 6 h.

[0022] After the reaction was completed, the precursor was washed with anhydrous ethanol, centrifuged and dried to obtain the catalyst precursor. After washing, it was placed in a 60°C oven for drying. Subsequently, the precursor was calcined under a nitrogen atmosphere at a temperature of 400°C for 3 hours to obtain the target hydrogen evolution catalyst, named NiCo-PS.

[0023] Example 2: Weigh 1 mol of nickel nitrate and dissolve it in 500 mL of deionized water, and dissolve 0.1 mol of cobalt nitrate in 50 mL of deionized water. Mix the two solutions and sonicate until completely dissolved. Then weigh 110 mL of 85% phosphoric acid solution and 22 mL of 98% sulfuric acid solution, mix them, and shear them at a speed of 1000 rpm for 40 min. Place the sheared solution in a 1000 mL polytetrafluoroethylene reactor and set the oven heating rate to 5 °C / min, the reaction temperature to 120 °C, and the reaction time to 6 h.

[0024] After the reaction was completed, the precursor was washed with anhydrous ethanol, centrifuged and dried to obtain the catalyst precursor. After washing, it was placed in a 60°C oven for drying. Subsequently, the precursor was calcined under a nitrogen atmosphere at a temperature of 400°C for 3 hours to obtain the target hydrogen evolution catalyst.

[0025] Example 3: Weigh 2 mol of nickel nitrate and dissolve it in 1000 mL of deionized water, and dissolve 0.2 mol of cobalt nitrate in 100 mL of deionized water. Mix the two solutions and sonicate until completely dissolved. Then weigh 110 mL of 85% phosphoric acid solution and 44 mL of 98% sulfuric acid solution, mix them, and shear them at a speed of 1000 rpm for 40 min. Place the sheared solution in a 2000 mL polytetrafluoroethylene reactor and set the oven heating rate to 5 °C / min, the reaction temperature to 120 °C, and the reaction time to 6 h.

[0026] After the reaction was completed, the precursor was washed with anhydrous ethanol, centrifuged and dried to obtain the catalyst precursor. After washing, it was placed in a 60°C oven for drying. Subsequently, the precursor was calcined under a nitrogen atmosphere at a temperature of 400°C for 3 hours to obtain the target hydrogen evolution catalyst.

[0027] Example 4: Weigh 1 mol of nickel nitrate and dissolve it in 500 mL of deionized water, and dissolve 0.1 mol of cobalt nitrate in 50 mL of deionized water. Mix the two solutions and sonicate until completely dissolved. Then weigh 55 mL of 85% phosphoric acid solution and 11 mL of 98% sulfuric acid solution, mix them, and shear them at 900 rpm for 30 min. Place the sheared solution in a 200 mL polytetrafluoroethylene reactor and set the oven heating rate to 5 °C / min, the reaction temperature to 120 °C, and the reaction time to 2 h.

[0028] After the reaction was completed, the precursor was washed with anhydrous ethanol, centrifuged and dried to obtain the catalyst precursor. After washing, it was placed in a 60°C oven for drying. Subsequently, the precursor was calcined under a nitrogen atmosphere at a temperature of 400°C for 3 hours to obtain the target hydrogen evolution catalyst.

[0029] Application testing: To test the catalyst performance, the powdered catalysts prepared in Examples 1-4 were fabricated into membrane electrodes and tested in a tank. First, an appropriate amount of catalyst powder was taken to prepare a slurry. The specific preparation process was as follows: hydrogen evolution catalyst and an anion exchange resin solution with a mass fraction of 5% were taken and uniformly dispersed in a mixed solution of ethanol and deionized water at a mass ratio of 3:1, wherein the volume ratio of ethanol to deionized water was 3:1, and the solid content of the slurry was 20 mg / mL.

[0030] The above-mentioned slurry was sprayed onto the surface of the AEM membrane using ultrasonic spraying equipment. The AEM membrane thickness was 75 μm, and the spraying loading was 1.2 mg / cm². The prepared membrane electrode was then assembled into an electrolyzer structure consisting of: a cathode plate, a cathode diffusion layer, a hydrogen evolution catalyst layer, an AEM membrane, an anode diffusion electrode, and an anode plate. The anode diffusion electrode was a self-developed NiFe-based self-supporting non-precious metal catalyst, and the cathode diffusion layer was nickel felt. The active reaction area of ​​the electrolyzer was 5 cm × 5 cm. The assembled electrolyzer was tested using the following methods: (1) Voltage test at different temperatures: 1A / cm² electrical density voltage test was performed at temperatures of 25℃, 40℃, 60℃ and 80℃ respectively; (2) Long-term stability test: Long-term stability test was conducted under the conditions of 1A / cm² electrical density, 60℃ and 1M KOH.

[0031] The test process and results are as follows: Figure 1-5 As shown, where, Figure 1 SEM and EDS images of the catalyst prepared in Example 1; Figure 2 The polarization curves are for the catalysts prepared in Examples 1-4; Figure 3 The images show the electrode morphology and electrolytic cell pattern of the catalysts prepared in Examples 1-4. Figure 3 In the diagram, (1) is the prepared CCM membrane electrode, (2) is the OER catalyst, and (3) and (4) are the AEM electrolyzers; Figure 4 The graph shows the voltage test results of the catalyst prepared in Example 2 at different temperatures after it was loaded into the tank. Figure 5 This is a graph showing the long-term stability test results of the catalyst prepared in Example 2 in the tank; Figure 6 The polarization curves are for the hydrogen evolution catalysts prepared in Example 2, Comparative Example 1, and Comparative Example 2.

[0032] Depend on Figure 1It can be seen that the hydrogen evolution catalyst has a uniform morphology and is free of impurities; Depend on Figure 2 The polarization curves show that, at an electrical density of 0.5 A / cm², the overpotentials are 344 mV, 257 mV, 284 mV, and 295 mV, respectively, indicating that the catalyst in Example 2 exhibits the best electrochemical performance. Depend on Figure 4 It can be seen that the catalyst material has good electrochemical performance at different temperatures, with a voltage of 1.88V at an electrical density of 1A / cm² and a temperature of 60℃, which is the best among non-precious metal catalysts. Depend on Figure 5 It can be seen that the single-cell voltage of the catalyst is about 1.88V, and no degradation phenomenon was observed after 70 hours of testing, indicating good stability.

[0033] Comparative Example 1: Compared with Example 2, no cutting process was performed, and the remaining steps were the same as in Example 2.

[0034] Comparative Example 2: Compared with Example 2, no sulfuric acid was added, and the remaining steps were the same as in Example 2.

[0035] Depend on Figure 6 It can be seen that after changing the synthesis conditions of Example 2, the catalyst products prepared by Comparative Example 1 and Comparative Example 2 showed a significant decrease in performance. At an electrical density of 0.5 A / cm², the overpotentials were 381 mV and 368 mV, respectively, which were inferior to those of Examples 1-4.

[0036] This specific embodiment employs a hydrothermal calcination synthesis method, introducing phosphorus and sulfur elements during the preparation process to synthesize a non-precious metal AEM water electrolysis hydrogen evolution catalyst. Phosphoric acid and sulfuric acid solutions are added during the hydrothermal process, and shearing treatment is performed to adjust the pH of the reaction solution, thereby regulating the reaction rate and resulting in a catalyst precursor product with uniform morphology and more catalytic sites. Furthermore, during the reaction, phosphorus and sulfur elements can form coordination bonds with nickel and cobalt, effectively improving the utilization rate of nickel and cobalt. The introduction of phosphorus into the catalyst can significantly improve its electronic conductivity, as well as its catalytic activity and stability. The introduction of sulfur into the catalyst improves the hydrophilicity and hydrophobicity of the catalyst surface, allowing the generated hydrogen to rapidly detach from the catalyst, thereby improving mass transfer efficiency. Moreover, it is low in cost, simple to prepare, and can be produced in large quantities and on a large scale.

[0037] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an anion exchange membrane catalyst for hydrogen evolution in water electrolysis, characterized in that: Includes the following steps: S1. Dissolve soluble nickel salt and soluble cobalt salt in deionized water respectively, mix the two solutions, and sonicate them to prepare a precursor reaction solution. S2. Add 85% phosphoric acid solution and 98% sulfuric acid solution to the prepared precursor reaction solution, and perform shearing treatment; S3. Place the solution obtained in step S2 into a polytetrafluoroethylene reactor and react it under high temperature conditions. After the reaction is completed, centrifuge, wash and dry to obtain the catalyst precursor. S4. The catalyst precursor prepared in step S3 is calcined under a nitrogen atmosphere to obtain the anion exchange membrane water electrolysis hydrogen evolution catalyst.

2. The method for preparing an anion exchange membrane electrolysis hydrogen evolution catalyst according to claim 1, characterized in that: In step S1, the soluble nickel salt is one or more of nickel nitrate, nickel chloride, nickel sulfate, and nickel sulfite, and the concentration of the soluble nickel salt solution is 2 mol / L; the soluble cobalt salt is one or more of cobalt nitrate, cobalt chloride, and cobalt sulfate, and the concentration of the soluble cobalt salt solution is 2 mol / L; the volume ratio of the soluble nickel salt solution to the soluble cobalt salt solution is 10:

1.

3. The method for preparing an anion exchange membrane electrolysis hydrogen evolution catalyst according to claim 1, characterized in that: In step S2, the volume ratio of the precursor reaction solution to the phosphoric acid solution is 10:1-10:2, the volume ratio of the precursor reaction solution to the sulfuric acid solution is 50:1-50:2, the shearing speed is 800-1000 rpm, and the shearing time is 20-40 minutes.

4. The method for preparing an anion exchange membrane electrolysis hydrogen evolution catalyst according to claim 1, characterized in that: In step S3, the reaction temperature is 120℃-150℃, the heating rate is 5-10℃ / min, and the reaction time is 2h-8h.

5. The method for preparing an anion exchange membrane electrolysis hydrogen evolution catalyst according to claim 1, characterized in that: In step S3, the cleaning solution used is anhydrous ethanol, and after cleaning, the solution is placed in a 60°C oven for drying.

6. The method for preparing an anion exchange membrane electrolysis water evolution hydrogen catalyst according to claim 1, characterized in that: In step S4, the calcination temperature under a nitrogen atmosphere is 400℃-500℃, and the calcination time is 3-4 hours.

7. The application of the anion exchange membrane electrolysis hydrogen evolution catalyst according to any one of claims 1-6 in anion exchange membrane electrolysis hydrogen evolution.

Images