Preparation method and application of low-cost high-activity electrolytic water catalytic electrode material

Abstract

The invention discloses a preparation method and application of a low-cost high-activity electrolyzed water catalytic electrode material, the preparation method comprises the following steps: foam nickel is used as a matrix, ultrasonic pickling activation, chemical plating and heat treatment are carried out in sequence, and a chemical plating solution comprises nickel sulfate, hydrazine hydrate, a complexing agent and a stabilizer. According to the preparation method, metal nickel is subjected to in-situ reduction deposition on a three-dimensional foamed nickel substrate through chemical plating, a catalytic coating which has homology and strong binding force with the substrate is formed, the problem that a traditional sprayed Raney nickel catalyst is prone to falling off is effectively solved, and therefore the prepared water electrolysis catalytic electrode has high catalytic activity and high coating binding force, and moreover, the water electrolysis catalytic electrode is suitable for large-scale popularization and application. The preparation process is environment-friendly and low in cost, and has a wide application prospect in the field of hydrogen production by electrolysis of water.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water electrolysis catalytic electrode materials, and particularly relates to a low-cost high-activity water electrolysis catalytic electrode material preparation method and application thereof. BACKGROUND

[0002] Water electrolysis is an important green hydrogen production technology. At present, domestic water electrolysis catalytic electrodes generally use braided nickel mesh as the substrate and spray Reni nickel as the catalyst. This technology is mature and has occupied a dominant position in the market. However, this technology has obvious limitations: first, the two-dimensional planar structure of the braided nickel mesh substrate is limited, making it difficult to achieve a multiple breakthrough in the number of active sites of the catalytic material; second, in the harsh operating environment of high pressure and strong alkali, the sprayed Reni nickel catalyst has poor adhesion to the substrate and is easily detached, resulting in a sharp decline in the electrolysis performance of the electrode and an increase in the energy consumption of the electrolysis cell; in addition, frequent replacement and cleaning of the electrode also increase the operating cost at the application end.

[0003] Therefore, there is an urgent need in the art for a water electrolysis catalytic electrode material preparation method that has high catalytic activity, high plating layer adhesion, and low cost. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art and provide a low-cost high-activity water electrolysis catalytic electrode material preparation method and application thereof. The prepared electrode material has the advantages of high catalytic activity, strong plating layer adhesion, and low manufacturing cost.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] In a first aspect, the present application provides a low-cost high-activity water electrolysis catalytic electrode material preparation method, which comprises the following steps:

[0007] S100, selecting a foamed nickel substrate and performing activation treatment;

[0008] This step specifically refers to selecting a foamed nickel substrate with suitable parameters, immersing the selected foamed nickel substrate in a 1-3 mol / L hydrochloric acid solution, and then performing ultrasonic cleaning to remove the surface oxides of the foamed nickel substrate and roughen it, thereby increasing its specific surface area and bonding sites, and then rinsing it with pure water until it is neutral. The ultrasonic cleaning time is 2-10 min, the ultrasonic power is 100-300 W, and the parameters of the foamed nickel substrate are as follows: PPI 90-130, areal density 250-800 g / m2, and thickness 0.5-2.0 mm.

[0009] S200, immersing the activated foamed nickel substrate in a pre-configured chemical plating solution for chemical plating, wherein the chemical plating solution comprises nickel sulfate, hydrazine hydrate, a complexing agent, and a stabilizing agent.

[0010] The pre-configured electroless plating solution composition and its ratio are specifically as follows:

[0011]

[0012] The pre-configured electroless plating solution needs to be adjusted in pH value before electroless plating, specifically, first, the pH value of the electroless plating solution is adjusted to neutral by using ammonia water, since the ammonia water is weakly alkaline, it cannot adjust the pH value to be very high, after the pH value of the electroless plating solution reaches neutral, the pH value of the electroless plating solution is adjusted to 9-11 by using 5-15 Wt% sodium hydroxide solution, the adjustment of the pH value by using ammonia water in the early stage is conducive to the stability of the electroless plating solution; the nickel sulfate in the electroless plating solution is used to provide nickel ions, the EDTA and sodium citrate can form stable complexes with the nickel ions in the nickel sulfate, the thiourea is used to prevent self-decomposition reaction in the electroless plating solution, the hydrazine hydrate is used to reduce the nickel ions into metal nickel and uniformly and firmly deposit the metal nickel on the three-dimensional skeleton of the foamed nickel substrate, under the comprehensive action of the thiourea, the sodium citrate, the EDTA and the hydrazine hydrate, the pH value of the electroless plating solution can be stabilized, and thus the influence of the pH fluctuation on the quality of the plating layer can be avoided.

[0013] The temperature of the electroless plating is 65-85 ℃, the plating time is 45-120 min, and after the electroless plating is completed, the electroless plating solution needs to be washed by using pure water until neutral.

[0014] S300, heat treating the electrode material treated by the electroless plating under a hydrogen-nitrogen mixed atmosphere, in this step, the heat treating temperature is 450-650 ℃, and the heat treating time is 5-20 min, by heat treating, the internal stress can be eliminated, the metallurgical bonding between the plating layer and the substrate can be enhanced, and the microstructure of the catalytic material can be further optimized, and the intrinsic catalytic activity thereof can be improved.

[0015] In the second aspect, the application further provides that the low-cost high-activity electrolytic water catalytic electrode material prepared by the preparation method is applied to an electrolytic water hydrogen production electrode, and an electrolytic water hydrogen production electrode is prepared.

[0016] Compared with the prior art, the application has the following beneficial technical effects:

[0017] (1) High catalytic activity: the three-dimensional porous foamed nickel is selected as the substrate in the application, the huge specific surface area thereof provides more deposition sites for the deposition of nickel, the nickel plating layer formed by electroless plating is combined closely with the foamed nickel substrate, and after heat treatment optimization, the catalytic activity of the final electrode is improved by more than 70% compared with the original foamed nickel, and is improved by more than 55% compared with the traditional Raney nickel electrode.

[0018] (2) Extremely high plating layer adhesion: the present application realizes the "nickel-nickel" homologous combination of the plating layer and the foam nickel substrate by in-situ reduction and deposition of metal nickel on the foam nickel substrate through the electroless plating process, and the same kind of metals have better lattice matching degree and similar physical and chemical properties, so that a more compact and stable intermetallic bond is formed, and the plating layer weight loss rate is less than 0.008 g / cm 2 , the adhesion is much better than that of heterogeneous materials (such as sprayed Raney nickel), in contrast, the electrodeposition between different kinds of metals may result in weak adhesion due to factors such as lattice mismatch and thermal expansion coefficient difference, and interface separation or cracks may easily occur, therefore, the preparation method provided by the present application effectively solves the world-wide problem that the catalyst is easy to fall off in a strong corrosive environment.

[0019] (3) Simple process and environmental protection: the preparation method provided by the present application is simple and easy to scale up, and the reduction product of the reducing agent hydrazine hydrate is nitrogen and water, which is friendly to the environment and has no harmful residues, and meets the green manufacturing requirements.

[0020] (4) Low cost: in the present application, the main raw material is nickel, which is much lower than the noble metal catalysts such as platinum and iridium, and at the same time, the combination of the foam nickel substrate and the electroless plating process reduces the cost by about 75% compared with the traditional braided nickel mesh loaded Raney nickel electrode under the same electrode specification, which has extremely high commercial value. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description, and obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0022] Figure 1 is the flow chart of the preparation method of the low-cost high-activity electrolytic water catalytic electrode material in some embodiments of the present application,

[0023] Figure 2 is the scanning electron microscope scanning graph of the electrolytic water catalytic electrode material prepared in Example 1 of the present application under different magnifications,

[0024] Figure 3 is the scanning electron microscope scanning graph of the electrolytic water catalytic electrode material prepared in Example 1 of the present application under the condition of 500 times,

[0025] Figure 4 is the energy spectrum analysis spectrum of two points randomly taken from the scanning electron microscope scanning graph under the condition of 500 times,

[0026] Figure 5is a schematic diagram showing the comparison of overpotential tests of the electrodes prepared in Example 1, Comparative Example 1, and a pure foamed nickel material in the embodiments. DETAILED DESCRIPTION

[0027] The ranges disclosed herein are defined by the endpoints as their lower and upper limits, the endpoints defining the particular range. Ranges can be included or excluded from the ranges as if these ranges were expressly delineated herein, and any combination of ranges is contemplated, i.e., any lower limit can be combined with any upper limit to form a range. For example, if a range of 60-120 and a range of 80-110 are listed, it is understood that a range of 60-110 and a range of 80-120 are also contemplated. Furthermore, if a minimum range value of 1 and 2 are listed, and if a maximum range value of 3, 4, and 5 are listed, then the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, the use of a numerical range "a-b" to describe a variable means that any and every number within the range is contemplated, unless otherwise indicated. For example, the use of the numerical range "0-5" to describe a variable means that all real numbers between 0 and 5, are contemplated, even if that range is not specifically listed. Also, when a parameter is stated to be an integer ≥ 2, it is equivalent to state that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0028] The use of the terms "including" and "comprising" in this application are open, unless otherwise expressly specified. For example, the terms "including" and "comprising" can mean that other components can also be included or comprised, or can mean that only the listed components are included or comprised.

[0029] The term "or" in this application is inclusive, unless otherwise expressly specified. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, any of the following satisfy the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0030] As shown in Figure 1 The present application provides a low-cost high-activity electrolytic water catalytic electrode material preparation method, which comprises the following steps:

[0031] S100, selecting a foamed nickel substrate and performing activation treatment;

[0032] The step is specifically: selecting a foam nickel substrate with suitable parameters, immersing the selected foam nickel substrate in a 1-3 mol / L hydrochloric acid solution, and then performing ultrasonic cleaning to remove the surface oxides of the foam nickel substrate and roughen it, thereby increasing its specific surface area and binding sites, and then rinsing with pure water until neutral, wherein the ultrasonic cleaning time is 2-10 min, the ultrasonic power is 100-300 W, and the parameters of the foam nickel substrate are: PPI 90-130, surface density 250-800 g / m2, and thickness 0.5-2.0 mm.

[0033] S200, immersing the activated foam nickel substrate in a pre-configured chemical plating solution for chemical plating, wherein the chemical plating solution comprises nickel sulfate, hydrazine hydrate, a complexing agent, and a stabilizer.

[0034] In this step, the composition and ratio of the pre-configured chemical plating solution are specifically:

[0035]

[0036] In the pre-configured chemical plating solution, nickel sulfate is used to provide nickel ions, EDTA and sodium citrate can form stable complexes with nickel ions in nickel sulfate, thiourea is used to prevent self-decomposition reactions in the chemical plating solution, and hydrazine hydrate is used to reduce nickel ions to metallic nickel and uniformly and firmly deposit them on the three-dimensional framework of the foam nickel substrate. To reduce the impact of pH fluctuations on the quality of the plating layer, the pH of the pre-configured chemical plating solution needs to be stabilized at 9-11. The specific adjustment steps are: first, use ammonia water to adjust the pH of the chemical plating solution to neutral, which is conducive to the stability of the chemical plating solution. Since ammonia water is weakly alkaline, it cannot adjust the pH to a very high level. After the pH of the chemical plating solution reaches neutral, use a 5-15 Wt% sodium hydroxide solution to adjust the pH of the chemical plating solution to 9-11, and then stabilize the pH of the chemical plating solution under the combined action of thiourea, sodium citrate, EDTA, and hydrazine hydrate.

[0037] The temperature of the chemical plating is 65-85℃, and the plating time is 45-120 min. After the chemical plating is completed, the electrode material needs to be rinsed with pure water until neutral.

[0038] S300, performing heat treatment on the electrode material after chemical plating treatment in a hydrogen-nitrogen mixed atmosphere. In this step, the heat treatment temperature is 450-650℃, and the heat treatment time is 5-20 min. Through heat treatment, internal stress can be eliminated, the metallurgical bonding between the plating layer and the substrate can be enhanced, and the microstructure of the catalytic material can be further optimized, thereby improving its intrinsic catalytic activity.

[0039] In the above embodiment, the three-dimensional porous foam nickel is selected as the substrate, the large specific surface area of which provides more deposition sites for nickel deposition, and the in-situ reduction and deposition of metal nickel on the foam nickel substrate through electroless plating realizes the "nickel-nickel" homologous combination of the plating layer and the foam nickel substrate, and the weight loss rate of the plating layer is less than 0.008 g / cm 2 , the bonding force is much better than that of heterogeneous materials, and the reduction product of the reducing agent hydrazine hydrate is nitrogen and water, which is environmentally friendly, has no harmful residues, meets the green manufacturing requirements, and the main raw material is nickel, so the cost is much lower than that of platinum, iridium and other noble metal catalysts; after heat treatment optimization, the catalytic activity of the final electrode is improved by more than 75% compared with the original foam nickel, and more than 55% compared with the traditional Raney nickel electrode. Therefore, the electrolytic water catalytic electrode material prepared by the preparation method has the advantages of high catalytic activity, strong plating layer bonding force and low production cost.

[0040] The application also provides an application of the low-cost high-activity electrolytic water catalytic electrode material, which applies the low-cost high-activity electrolytic water catalytic electrode material prepared by the above preparation method to an electrolytic water hydrogen production electrode, and then prepares an electrolytic water hydrogen production electrode.

[0041] Based on the description of the above low-cost high-activity electrolytic water catalytic electrode material preparation method, the low-cost high-activity electrolytic water catalytic electrode material prepared by the above preparation method is applied to an electrolytic water hydrogen production electrode, and the prepared electrolytic water hydrogen production electrode has the same beneficial technical effects, which will not be described here.

[0042] In order to better illustrate the working principle and beneficial effects of the technical scheme of the present application, the low-cost high-activity electrolytic water catalytic electrode material prepared by the preparation method provided by the present application will be described below.

[0043] Example 1

[0044] 1) Select foam nickel substrate: select foam nickel with PPI of 90, surface density of 250 g / m2 and thickness of 0.5 mm, immerse the selected foam nickel substrate in a pre-configured 1 mol / L hydrochloric acid solution, and perform acid pickling on the foam nickel substrate under a 100 W ultrasonic power for 2 min, and then wash with pure water until neutral;

[0045] 2) The composition ratio of the pre-configured electroless plating solution is: nickel sulfate 70 g / L, EDTA 25 g / L, thiourea 0.001 g / L, hydrazine hydrate 30 mL / L, sodium citrate 10 g / L, and then adjust the pH value of the electroless plating solution to 9 with ammonia and 20 g / L NaOH; then immerse the activated foam nickel substrate into the plating solution, and apply plating under a constant temperature condition of 65 DEG C for 120 min, and then wash with pure water until neutral after the plating is completed;

[0046] 3) Place the electroless plated electrode material in a nitrogen-hydrogen mixed atmosphere with a volume ratio of 1:2 and heat treat it at 450℃ for 20 min.

[0047] The electrode material prepared in Example 1 was subjected to scanning electron microscopy and energy dispersive spectroscopy analysis, such as... Figures 2-4 As shown, Figure 2 In the diagram, 2a represents the electron microscope scan image of the electrode material at 50x magnification, 2b represents the electron microscope scan image of the electrode material at 100x magnification, 2c represents the electron microscope scan image of the electrode material at 200x magnification, and 2d represents the electron microscope scan image of the electrode material at 1000x magnification. Figure 3 This shows the electron microscope scan image of the electrode material under 500x magnification.

[0048] from Figure 2 and Figure 3 As can be seen, the electroless nickel plating layer on the electrode material is dendritic and evenly distributed at the corners of the ribs, with no visible defects such as cracks, fissures, or broken segments at the interface; from Figure 4 As can be seen, the electrode material is composed of pure nickel, achieving a homologous "nickel-nickel" bond between the coating and the nickel foam substrate. This indicates that the dendritic structure of the electrode material significantly increases the specific surface area of ​​exposed nickel, thereby effectively increasing the number of active sites. Furthermore, the homologous bonding between the coating and the substrate is far superior to that of heterogeneous materials. Moreover, further heat treatment adjusts the nickel lattice in the coating, further increasing the number of nickel active sites, thus achieving the goal of constructing a highly active three-dimensional porous metal electrode material.

[0049] Example 2

[0050] 1) Selecting a nickel foam substrate: Select nickel foam with a PPI of 130, a surface density of 800 g / m², and a thickness of 2.0 mm. Immerse the selected nickel foam substrate in a pre-prepared 3 mol / L hydrochloric acid solution and acid-wash the nickel foam substrate for 10 min under 300 W ultrasonic power. Then rinse with pure water until neutral.

[0051] 2) The pre-prepared chemical plating solution has the following composition: nickel sulfate 90g / L, EDTA 55g / L, thiourea 0.01g / L, hydrazine hydrate 60mL / L, sodium citrate 40g / L. The pH of the chemical plating solution is then adjusted to 11 with ammonia and 25g / L NaOH. The activated nickel foam substrate is then immersed in the plating solution and plated at a constant temperature of 85℃ for 45 minutes. After plating is completed, it is rinsed with pure water until neutral.

[0052] 3) Place the electroless plated electrode material in a nitrogen-hydrogen mixed atmosphere with a volume ratio of 2:3 and heat treat it at 650℃ for 5 minutes.

[0053] Example 3

[0054] 1) Selecting the foam nickel substrate: selecting the foam nickel with PPI of 110, surface density of 500 g / m2 and thickness of 1.5 mm, immersing the selected foam nickel substrate in a pre-configured 2 mol / L hydrochloric acid solution, acid washing the foam nickel substrate under a 200 W ultrasonic power for 5 min, and then washing with pure water until neutral;

[0055] 2) The pre-configured chemical plating solution has a composition ratio of: nickel sulfate 80 g / L, EDTA 40 g / L, thiourea 0.005 g / L, hydrazine hydrate 40 mL / L, sodium citrate 30 g / L, and adjusting the pH value of the chemical plating solution to 10 with ammonia water and 30 g / L NaOH; then immersing the activated foam nickel substrate into the plating solution, and plating at 75°C constant temperature for 80 min, and then washing with pure water until neutral after plating is completed;

[0056] 3) Placing the electrode material treated by chemical plating into a nitrogen-hydrogen mixed atmosphere with a volume ratio of 1:3, and heat treating at 550°C for 10 min.

[0057] Comparative Example 1

[0058] Using a traditional method: spraying Raney nickel catalyst on the same specification of woven nickel mesh, and performing alkaline activation treatment.

[0059] The electrode materials obtained in Examples 1-3 and Comparative Example 1 were tested for bonding strength and catalytic activity, and the performance test results are shown in Table 1. Among them, the bonding strength test is specifically: using ultrasonic oscillation method to test the weight loss rate of the electrode material coating; the catalytic activity test is specifically: in a 30wt% KOH solution at 80°C, the hydrogen evolution overpotential of the electrode prepared by the electrode material at 0.1 A / cm 2 current density was tested.

[0060] Table 1 Performance test results of electrode materials prepared in Examples 1-3 and Comparative Example 1

[0061] Loss in weight (g / cm 2 ) Hydrogen evolution overpotential (V) at a current density of 0.1 A / cm2 Example 1 0.007 0.108 Example 2 0.006 0.120 Example 3 0.008 0.112 Comparative Example 1 0.05 0.268

[0062] As can be seen from Table 1, the weight loss rates of the electrode materials prepared in Examples 1-3 are all less than 0.008 g / cm 2 , while the weight loss rate of the electrode material prepared in Comparative Example 1 is 0.05 g / cm 2 , so compared with Comparative Example 1, the electrode material prepared by the preparation method provided by the present application has higher coating bonding strength and catalytic activity.

[0063] Meanwhile, in order to further illustrate the beneficial technical effects of the catalytic activity of the electrode material prepared by the application, the electrode prepared by the pure nickel foam material is synchronously tested for the catalytic activity performance, such as Figure 5 Figure 5 The overpotential test comparison diagram of the electrode prepared by example 1, comparative example 1 and the pure nickel foam material is shown.

[0064] From Figure 5 It can be seen that, under the current density of 0.1A / cm 2 , the overpotential of the electrode prepared by example 1 is 0.108V, the overpotential of the electrode prepared by comparative example 1 is 0.268V, and the overpotential of the electrode prepared by the pure nickel foam material is 0.373V, so it can be known that the catalytic activity of the electrode prepared by example 1 is greatly improved compared with the pure nickel foam and the traditional Raney nickel electrode.

[0065] From the above, it can be known that the electrolytic water catalytic electrode material prepared by the preparation method provided by the application has the advantages of high catalytic activity, strong plating layer bonding force and low manufacturing cost.

[0066] The above provides a low-cost high-activity electrolytic water catalytic electrode material preparation method and its application. In this paper, specific examples are applied to illustrate the principles and implementation modes of the application, and the above examples are only used to help understand the core idea of the application. It should be pointed out that for ordinary skilled persons in the technical field, some improvements and modifications can be made to the application without departing from the principles of the application, and these improvements and modifications also fall within the protection scope of the claims of the application.​

Claims

1. A method for preparing a low-cost high-activity water electrolysis catalytic electrode material, characterized by, The method comprises the following steps: S100, selecting a foamed nickel matrix and performing activation treatment; S200, immersing the foamed nickel matrix after activation treatment in a pre-configured chemical plating solution to perform chemical plating, wherein the chemical plating solution comprises nickel sulfate, hydrazine hydrate, a complexing agent and a stabilizer; S300, performing heat treatment on the electrode material after chemical plating treatment under a nitrogen-hydrogen mixed gas atmosphere.

2. The production method according to claim 1, characterized by, The parameters of the foamed nickel matrix are as follows: PPI 90-130, surface density 250-800 g / m2, and thickness 0.5-2.0 mm.

3. The production method according to claim 2, characterized by, The activation treatment in the step S100 is specifically as follows: after the selected foamed nickel matrix is immersed in a 1-3 mol / L hydrochloric acid solution, ultrasonic cleaning is performed to remove the surface oxides of the foamed nickel matrix and to roughen; then pure water is used for washing until neutral, wherein the ultrasonic cleaning time is 2-10 min, and the ultrasonic power is 100-300 W.

4. The production method according to claim 3, characterized by, In the step S200, the temperature of the chemical plating is 65-85℃, and the plating time is 45-120 min.

5. The preparation method according to claim 4, characterized in that, In the step S200, the composition and the ratio of the pre-configured chemical plating solution are specifically as follows:

6. The production method according to claim 5, wherein In the step S200, the pre-configured chemical plating solution needs to be adjusted in pH value, and the specific adjustment steps are as follows: first, the pH value of the chemical plating solution is adjusted to neutral by using ammonia water, and then the pH value is adjusted to 9-11 by using a 5-15 Wt% sodium hydroxide solution.

7. The production method according to claim 6, wherein In the step S300, the heat treatment temperature is 450-650℃, and the heat treatment time is 5-20 min.

8. The preparation method according to claim 7, characterized in that, In the step S300, the volume ratio of nitrogen to hydrogen in the nitrogen-hydrogen mixed gas atmosphere is 1:2-3.

9. The use of a low-cost high-activity water electrolysis catalytic electrode material, characterized by, The low-cost high-activity electrolytic water catalytic electrode material prepared by the preparation method of any one of claims 1-8 is applied to an electrolytic water hydrogen production electrode, and an electrolytic water hydrogen production electrode is prepared.

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