Double-layer raney nickel electrode, preparation method and application

Abstract

The application provides a double-layer Raney nickel electrode, a preparation method and application. 3+ The preparation method of the double-layer Raney nickel electrode comprises the following steps: providing a conductive base material; immersing the conductive base material in a solution containing Fe ions to perform a surface uniform etching reaction, so as to obtain an iron modified conductive base material; loading a Raney nickel type alloy powder on the iron modified conductive base material, so as to obtain a composite conductive base material; immersing the composite conductive base material in an alkaline solution to perform an activation reaction, so as to obtain the double-layer Raney nickel electrode. The double-layer Raney nickel electrode prepared by the application has high stability and high catalytic activity, has a good effect in electrolysis of water to generate hydrogen, and has high generation efficiency. Moreover, the preparation method of the application is simple, convenient to operate, and suitable for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical hydrogen production technology, and particularly relates to a double-layer Raney nickel electrode, its preparation method and application. Background Technology

[0002] In water electrolysis for hydrogen production, Raney nickel is an important non-precious metal catalyst for the hydrogen evolution reaction (HER) due to its high specific surface area and good catalytic activity. The traditional preparation method involves coating or thermally spraying a nickel-aluminum alloy onto a substrate (such as a nickel mesh), followed by etching away the aluminum phase with an alkaline solution to form a porous structure. However, to improve the adhesion between the catalyst layer and the substrate and prevent it from detaching during use, existing technologies typically pre-treat the substrate to increase its roughness. The most common pre-treatment method is physical sandblasting. While sandblasting the nickel mesh surface followed by thermal spraying of the catalyst layer effectively increases mechanical adhesion, sandblasting particles larger than the mesh openings can cause unnecessary clogging, thus affecting the water electrolysis process. Furthermore, this physical treatment method does not provide catalytic activity due to interface roughening and may introduce additional resistance due to contamination, hindering efficient charge transfer from the substrate to the catalyst layer, resulting in decreased electrode activity and stability. This, in turn, affects the hydrogen production efficiency of water electrolysis. Therefore, this invention provides a double-layer Raney nickel electrode, its preparation method, and its application to solve the problem of sandblasting affecting substrate charge transfer in existing technologies. Summary of the Invention

[0003] The main objective of this invention is to provide a double-layer Raney nickel electrode, its preparation method, and its application, aiming to solve the technical problem that sandblasting treatment affects the charge transport of the substrate in the prior art.

[0004] To achieve the above objectives, the present invention provides a method for preparing a double-layer Raney nickel electrode, comprising:

[0005] S1: Provides a conductive substrate.

[0006] S2: Immerse the conductive substrate in an Fe-containing solution. 3+ A uniform surface etching reaction is carried out in a solution of ions to obtain an iron-modified conductive substrate.

[0007] S3: Load Raney nickel alloy powder onto the iron-modified conductive substrate to obtain a composite conductive substrate.

[0008] S4: The composite conductive substrate is immersed in an alkaline solution to carry out an activation reaction, thereby obtaining the double-layer Raney nickel electrode.

[0009] According to an embodiment of this application, the Fe-containing 3+ The solution contains one or more of the ions FeCl3 and Fe(NO3)3.

[0010] The Fe-containing 3+Fe in solution of ions 3+ The molar concentration of ions is 0.1~1.0 mol / L.

[0011] According to an embodiment of this application, the etching reaction temperature is 25~80°C, and the etching reaction duration is 5~30 min.

[0012] According to an embodiment of this application, the Raney nickel alloy powder includes nickel powder and aluminum powder.

[0013] The mass ratio of the nickel powder to the aluminum powder is (65~75):(25~35).

[0014] According to an embodiment of this application, the thickness of the Raney nickel alloy powder loaded on the iron-modified conductive substrate is 10~100μm.

[0015] According to embodiments of this application, the alkaline solution comprises an alkali metal hydroxide.

[0016] The alkali metal hydroxide includes one or more of NaOH and KOH.

[0017] The mass fraction of the alkali metal hydroxide is 5-45%.

[0018] According to an embodiment of this application, the activation reaction temperature is 60~90°C.

[0019] The activation reaction lasts for 0.5 to 4 hours.

[0020] According to an embodiment of this application, the conductive substrate includes a nickel mesh.

[0021] The present invention also provides a double-layer Raney nickel electrode, which is prepared by the double-layer Raney nickel electrode preparation method described above.

[0022] The present invention also provides an application of the above-described double-layer Raney nickel electrode in hydrogen production by water electrolysis.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] The above-described double-layer Raney nickel electrode, its preparation method, and its application involve immersing the conductive substrate in an Fe-containing solution. 3+ After a uniform surface etching reaction in an ionic solution, an iron-modified conductive substrate is obtained. Unlike traditional physical methods, this invention uses a chemical etching method to etch the conductive substrate, not only forming a micron-level rough surface but also retaining the iron component as an interface modification layer. Specifically, iron (Fe) 2+ / Fe 3+The iron-modified conductive substrate is deposited in situ and firmly adhered to the etched conductive substrate surface in the form of iron hydroxide, iron oxide, or zero-valent iron, forming an active interface layer rich in iron. The alloy powder is then loaded onto the iron-modified conductive substrate to obtain a composite conductive substrate. The iron component of the active interface layer and the alloy elements undergo interdiffusion. After immersing the composite conductive substrate in an alkaline solution, an activation reaction occurs, dissolving aluminum. At this point, the iron in the active interface layer may partially dissolve or be reconstructed, ultimately forming a transition region rich in Fe-Ni alloy or compound between the conductive substrate and the Raney nickel layer, exhibiting excellent electronic conductivity. The double-layer Raney nickel electrode prepared by this invention possesses high stability and high catalytic activity, demonstrating excellent performance and high efficiency in hydrogen production through water electrolysis. Furthermore, the preparation method of this invention is simple, convenient to operate, and suitable for industrial production. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0026] Figure 1 This is an optical micrograph of the nickel mesh after the etching reaction in Example 1 of the present invention;

[0027] Figure 2 This is a cross-sectional SEM image of the double-layer Raney nickel electrode prepared in Example 1 of the present invention;

[0028] Figure 3 This is an EDS line scan of the double-layer Raney nickel electrode prepared in Example 1 of the present invention;

[0029] Figure 4 An optical micrograph of the interface of the double-layer Raney nickel electrode prepared in Example 1 of the present invention after a stability test.

[0030] Figure 5 Optical micrograph of the interface of the Raney nickel electrode prepared in Comparative Example 1 after stability testing;

[0031] Figure 6 The electrochemical polarization (JU) curves are shown for the double-layer Raney nickel electrode prepared in Example 1, the Raney nickel electrode prepared in Comparative Example 1, and the Raney nickel electrode prepared in Comparative Example 2 of the present invention.

[0032] Figure 7 The electrochemical impedance spectroscopy (EIS) spectra of the double-layer Raney nickel electrode prepared in Example 1 and the Raney nickel electrode prepared in Comparative Example 1 are shown.

[0033] Figure 8 The electrochemical potential-time (Ut) curves are shown for the double-layer Raney nickel electrode prepared in Example 1 and the Raney nickel electrode prepared in Comparative Example 2.

[0034] The realization of the objective, functional characteristics and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0037] To achieve the above objectives, the present invention provides a method for preparing a double-layer Raney nickel electrode, comprising:

[0038] S1: Provides a conductive substrate.

[0039] In some embodiments, the conductive substrate comprises a nickel mesh. The nickel mesh possesses excellent conductivity, ensuring a uniform current distribution across the entire electrode. This contributes to improved electrochemical performance of the electrode, reduces electrode polarization, and thus enhances electrode efficiency and stability. The mesh structure of the nickel mesh allows current to be transmitted through multiple channels, preventing current concentration at a single point and reducing the risk of localized overheating and electrode damage.

[0040] In some embodiments, one or more of acetone and ethanol of analytical purity are used to clean the nickel mesh. Acetone and ethanol have good solubility and volatility, which can effectively dissolve and remove organic matter and some inorganic impurities from the surface of the nickel mesh, ensuring a clean surface. At the same time, the increased number of active sites on the clean nickel mesh surface is beneficial for subsequent chemical reactions and coating adhesion.

[0041] S2: Immerse the conductive substrate in an Fe-containing solution. 3+ A uniform surface etching reaction is carried out in a solution of ions to obtain an iron-modified conductive substrate.

[0042] In some embodiments, the conductive substrate is immersed in an Fe-containing solution. 3+After a uniform surface etching reaction is performed in an ion solution, the conductive substrate is removed and directly dried to obtain an iron-modified conductive substrate.

[0043] In some embodiments, drying directly after removing the conductive substrate ensures that the iron-modified layer is retained.

[0044] In some embodiments, the conductive substrate is immersed in an Fe-containing solution. 3+ The equation for a uniform surface etching reaction in a solution of ions is:

[0045] Ni + 2Fe 3+ → Ni 2+ + 2Fe 2+

[0046] Through etching, not only can micron-scale rough surfaces be formed on conductive substrates, but more importantly, one of the reaction products, iron (Fe), is also produced. 2+ / Fe 3+ Iron oxides or hydroxides will be deposited in situ in the form of ferric hydroxide, ferric oxide, or zero-valent iron, and will uniformly and firmly adhere to the surface of the etched conductive substrate, forming an active interface layer rich in iron. Iron oxides or hydroxides can serve as active sites, promoting electrochemical reactions and improving the catalytic efficiency of the electrode.

[0047] In some embodiments, the etching reaction is relatively mild, achieving a roughness sufficient for strong coating adhesion, thus realizing uniform etching of the entire surface of the conductive substrate.

[0048] S3: Load Raney nickel alloy powder onto the iron-modified conductive substrate to obtain a composite conductive substrate.

[0049] In some embodiments, Raney nickel alloy powder is loaded onto the iron-modified conductive substrate by plasma spraying to obtain a composite conductive substrate.

[0050] In some embodiments, the spraying voltage is 750~850A; the spraying power is 40~60kW; and the spraying temperature is 4000~5000℃. The adhesion time of the sprayed material is extremely short (the spray gun is sprayed along a predetermined trajectory by a robotic arm; the Raney nickel alloy powder melts at extremely high temperatures, and in a single sweep, the molten Raney nickel alloy powder has already combined with the conductive substrate). During the high-temperature spraying process, the iron component at the interface may interdiffuse with the Raney nickel alloy.

[0051] In some embodiments, the Raney nickel alloy powder itself possesses high catalytic activity, and the iron modification layer can further enhance the performance of these active sites. The iron modification layer can provide additional active sites, promoting electrochemical reactions and improving the catalytic efficiency of the electrode. Additionally, the iron modification layer can form a protective film on the surface of the conductive substrate, reducing electrolyte corrosion. Simultaneously, the loading of the Raney nickel alloy powder can further enhance the structural stability of the electrode, reducing structural changes during long-term use.

[0052] S4: The composite conductive substrate is immersed in an alkaline solution to carry out an activation reaction, thereby obtaining the double-layer Raney nickel electrode.

[0053] In some embodiments, the composite conductive substrate is immersed in an alkaline solution, and through an activation reaction, aluminum is dissolved to form a porous Raney nickel layer. At this time, iron at the interface may partially dissolve or remodel, ultimately forming a transition region rich in Fe-Ni alloys or compounds between the substrate and the Raney nickel layer, exhibiting excellent electronic conductivity. The activation reaction, through the action of the alkaline solution, removes oxides and other impurities from the surface of the composite conductive substrate and can also form a porous structure, significantly increasing the specific surface area of ​​the electrode and exposing more stable active sites. These active sites can more effectively catalyze electrochemical reactions, improving the electrode's reaction efficiency and stability in complex environments.

[0054] It should be noted that the preparation method of the double-layer Raney nickel electrode described in this invention does not involve sandblasting.

[0055] The above-described method for preparing and applying a double-layer Raney nickel electrode involves immersing the conductive substrate in an Fe-containing solution. 3+ After reacting in an ion-etching solution, an iron-modified conductive substrate is obtained. Unlike traditional physical methods, this invention uses a chemical etching method to etch the conductive substrate, not only forming a micron-level rough surface but also retaining the iron component as an interface modification layer. Specifically, iron (Fe) 2+ / Fe 3 + The iron will be deposited in situ and firmly adhered to the etched conductive substrate surface in the form of iron hydroxide, iron oxide, or zero-valent iron, forming an active interface layer rich in iron. The alloy powder is then loaded onto the iron-modified conductive substrate to obtain a composite conductive substrate. The iron component of the active interface layer and the alloy elements will interdiffusion. After immersing the composite conductive substrate in an alkaline solution, an activation reaction occurs, dissolving aluminum. At this point, the iron in the active interface layer may partially dissolve or reconstruct, ultimately forming a transition region rich in Fe-Ni alloy or compound between the conductive substrate and the Raney nickel layer, exhibiting excellent electronic conductivity. Furthermore, the preparation method of this invention is simple, convenient to operate, and suitable for industrial production.

[0056] In some embodiments, the Fe-containing 3+ The solution contains one or more of the ions FeCl3 and Fe(NO3)3.

[0057] The Fe-containing 3+ Fe in solution of ions 3+ The molar concentration of ions is 0.1~1.0 mol / L.

[0058] In some embodiments, a single-component ferric chloride solution is used as the etchant, achieving a milder and more controllable pure oxidation etching process compared to existing methods that employ strong acid corrosion or mixed etching. This process effectively avoids problems such as uneven etching and substrate damage (e.g., hydrogen embrittlement) caused by hydrogen generation and strong acid corrosion, and can form a more uniform and rough structure.

[0059] In some embodiments, the Fe-containing 3+ Fe in solution of ions 3+ The molar concentration of ions is 0.1~0.8 mol / L.

[0060] In some embodiments, the Fe-containing 3+ Fe in solution of ions 3+ The molar concentration of ions is 0.4~0.6 mol / L.

[0061] In some embodiments, the etching reaction temperature is 25~80°C, and the etching reaction duration is 5~30 min.

[0062] In some embodiments, the etching reaction temperature is 50~70°C, and the etching reaction duration is 10~20 min.

[0063] In some embodiments, the etching reaction temperature is 55~65°C, and the etching reaction duration is 10~20 min.

[0064] In some embodiments, the Raney nickel alloy powder comprises nickel powder and aluminum powder.

[0065] The mass ratio of the nickel powder to the aluminum powder is (65~75):(25~35).

[0066] In some embodiments, the mass ratio of the nickel powder to the aluminum powder is (68~72):(28~32).

[0067] In some embodiments, the average particle size of the nickel powder is 25-45 μm; and the average particle size of the aluminum powder is 35-55 μm. The appropriate particle size allows the mixed powder to have good flowability during spraying, which is beneficial for forming a uniform coating.

[0068] In some embodiments, the thickness of the Raney nickel alloy powder loaded on the iron-modified conductive substrate is 10~100μm.

[0069] In some embodiments, the thickness of the Raney nickel alloy powder loaded on the iron-modified conductive substrate is 40~80μm.

[0070] In some embodiments, the alkaline solution comprises an alkali metal hydroxide.

[0071] The alkali metal hydroxide includes one or more of NaOH and KOH.

[0072] The alkali metal hydroxide has a mass fraction of 5-45%. The alkaline solution effectively dissolves Al in the coating, forming a porous structure. This porous structure significantly increases the specific surface area of ​​the electrode, providing more active sites for subsequent electrochemical reactions. Controlling the activation temperature and the mass fraction of the solute in the alkaline solution ensures moderate reactivity, leading to a stable porous structure, enhanced mechanical stability of the electrode, and reduced structural collapse or peeling during use.

[0073] In some embodiments, the alkali metal hydroxide includes one of NaOH and KOH.

[0074] In some embodiments, the alkali metal hydroxide has a mass fraction of 10-45%.

[0075] In some embodiments, the alkali metal hydroxide has a mass fraction of 20-40%.

[0076] In some embodiments, the alkali metal hydroxide has a mass fraction of 15-35%.

[0077] In some embodiments, the activation reaction is carried out at a temperature of 60-90°C.

[0078] The activation reaction lasts for 0.5 to 4 hours.

[0079] In some embodiments, the activation reaction is carried out at a temperature of 70-90°C.

[0080] The activation reaction lasts for 1 to 4 hours.

[0081] In some embodiments, the activation reaction is carried out at a temperature of 75-85°C.

[0082] The activation reaction lasts for 2 to 4 hours.

[0083] The present invention also provides a double-layer Raney nickel electrode, which is prepared by the double-layer Raney nickel electrode preparation method described above.

[0084] The double-layer Raney nickel electrode prepared by this invention has high stability and high catalytic activity, and has a good effect in hydrogen production by water electrolysis with high generation efficiency.

[0085] The present invention also provides an application of the above-described double-layer Raney nickel electrode in hydrogen production by water electrolysis.

[0086] The working electrode is the aforementioned double-layer Raney nickel electrode, and the electrolyte is one or more alkaline solutions, namely potassium hydroxide and sodium hydroxide, with a molar concentration of 0.1~1.0 mol / L. Specifically, the electrolyte can be a KOH solution with a molar concentration of 1.0 mol / L; the current density is 4~6 kA / m. 2 or 4~5kA / m 2 or 5~6kA / m 2 Specifically, 5 kA / m 2 The reaction temperature is 75~85℃, specifically 80℃. In addition, in the three-electrode system, the reference electrode is Hg / HgO, and the counter electrode is a nickel sheet electrode.

[0087] In some embodiments, the double-layer Raney nickel electrode exhibits high catalytic activity and good stability. It has broad application prospects in the field of efficient water electrolysis for hydrogen production, and can significantly reduce hydrogen production costs and improve hydrogen production efficiency.

[0088] To further illustrate the present invention, the following examples are provided:

[0089] Example 1

[0090] 1. A method for preparing a double-layer Raney nickel electrode, comprising the following steps:

[0091] S1: Provide a conductive substrate, which is a nickel mesh. Clean the nickel mesh with ultrasonic in acetone.

[0092] S2: The cleaned nickel mesh was immersed in a 0.5 mol / L FeCl3 solution (etching solution) for uniform surface etching. The nickel mesh was then removed and dried directly to obtain an iron-modified conductive substrate. The etching temperature was 60℃, and the etching time was 15 min. See also... Figure 1 , Figure 1 This is an optical micrograph of a nickel mesh after etching in Example 1 of the present invention, showing a uniformly etched micron-scale rough structure.

[0093] S3: A composite conductive substrate is obtained by loading Raney nickel alloy powder onto an iron-modified conductive substrate using a plasma spraying process. The Raney nickel alloy powder is a mixture of nickel and aluminum powders; the mass ratio of nickel to aluminum powder is 70:30. The thickness of the alloy coating on the composite conductive substrate is 80 μm. The plasma spraying parameters are: spraying voltage of 800 A; spraying power of 50 kW; and spraying temperature of 5000 °C.

[0094] S4: The composite conductive substrate was immersed in a 30% (w / w) NaOH solution for activation to obtain a double-layer Raney nickel electrode. The activation temperature was 80℃ and the activation time was 2 hours.

[0095] It should be noted that the double-layer Raney nickel electrode prepared in Example 1 is simply referred to as the E-Fe electrode. See [link to documentation]. Figure 2 The cross-sectional SEM image of the fabricated double-layer Raney nickel electrode shows a double-layer structure. See also... Figure 3 The enrichment peak of Fe element at the interface is clearly visible as the image passes through the interface from the nickel mesh substrate to the Raney nickel layer.

[0096] In Example 1, a three-electrode system was used to test the hydrogen evolution performance of the prepared double-layer Raney nickel electrode. The working electrode was the double-layer Raney nickel electrode prepared in Example 1, the reference electrode was Hg / HgO, the counter electrode was a nickel sheet electrode, the electrolyte was a 1.0 mol / L KOH solution, the test temperature was 80℃, and the test was conducted at 5 kA / m 2 The potential of the working electrode is measured under current density.

[0097] The E-Fe electrode achieved a speed of 500 mA / cm². 2 The overpotential at current density is 1.12 V, and electrochemical impedance spectroscopy (EIS) shows an extremely low charge transfer resistance (Rct) of 0.4 Ω cm⁻¹. 2 Perform a 500-hour constant current test (@500 mA / cm). 2 After that, the voltage drop is negligible. See also Figure 4 The optical micrograph of the interface of the prepared double-layer Raney nickel electrode after stability testing showed that the interface was good, without cracks or peeling.

[0098] Example 2

[0099] In Example 2, the etching solution was changed compared to Example 1.

[0100] The etching solution was a Fe(NO3)3 solution with a molar concentration of 0.5 mol / L. Other conditions were the same as in Example 1; the electrode finally obtained in Example 2 was a double-layer Raney nickel electrode.

[0101] The bilayer Raney nickel electrode prepared in Example 2 achieved a speed of 500 mA / cm². 2 The overpotential at current density is 1.03 V. A 500-hour constant current test was performed (@500 mA / cm²). 2 After that, the voltage drop is negligible and the interface remains intact.

[0102] Example 3

[0103] In Example 3, the concentration of the etching solution was changed compared to Example 1.

[0104] The etching solution was FeCl3 with a molar concentration of 0.2 mol / L. Other conditions were the same as in Example 1; the electrode finally obtained in Example 3 was a double-layer Raney nickel electrode.

[0105] The bilayer Raney nickel electrode prepared in Example 3 achieved a speed of 500 mA / cm². 2 The overpotential at current density is 1.09 V. A 500-hour constant current test was performed (@500 mA / cm²). 2 After that, the voltage drop is negligible and the interface remains intact.

[0106] Comparative Example 1

[0107] In this comparative example 1, compared to example 1, sandblasting was used instead of step S2 of example 1.

[0108] In Comparative Example 1, the sandblasting treatment method was as follows: the nickel mesh was sandblasted with 120-mesh white corundum abrasive until the surface was uniformly rough, and then thoroughly blown away to remove abrasive residue. Other conditions were the same as in Example 1; the electrode finally obtained in Comparative Example 1 was a Raney nickel electrode, denoted as the D-Sandblast electrode.

[0109] In Comparative Example 1, a three-electrode system was used to test the hydrogen evolution performance of the Raney nickel electrode prepared in Comparative Example 1. The working electrode was the Raney nickel electrode prepared in Comparative Example 1, the reference electrode was Hg / HgO, the counter electrode was a nickel sheet electrode, the electrolyte was a 1.0 mol / L KOH solution, the test temperature was 80℃, and the electrode was tested at 5 kA / m². 2 The potential of the working electrode is measured under current density.

[0110] Testing revealed that the initial overpotential of the D-Sandblast electrode was 1.23 V (110 mV higher than that of the E-Fe electrode). Most importantly, its charge transfer resistance was significantly greater than that of the E-Fe electrode, indicating poorer interfacial conductivity. (See [link to relevant documentation]). Figure 7 After the same 100-hour stability test, the D-Sandblast electrode showed a significant voltage increase, such as... Figure 5The optical micrograph of the interface of the Raney nickel electrode prepared in Comparative Example 1 after the stability test shows local coating peeling.

[0111] Comparative Example 2

[0112] In Comparative Example 2, compared to Example 1, acid treatment was used instead of step S2 in Example 1.

[0113] In Comparative Example 2, the acid treatment method was as follows: the nickel mesh was immersed in dilute sulfuric acid with a molar concentration of 0.5 mol / L for 15 min to remove the oxide film, followed by washing and drying with water. Other conditions were the same as in Example 1. This method only cleaned the surface of the nickel mesh without introducing significant roughness or iron components. The electrode finally obtained in Comparative Example 2 was a Raney nickel electrode, denoted as the D-Acid electrode.

[0114] In Comparative Example 2, a three-electrode system was used to test the hydrogen evolution performance of the Raney nickel electrode prepared in Comparative Example 1. The working electrode was the Raney nickel electrode prepared in Comparative Example 1, the reference electrode was Hg / HgO, the counter electrode was a nickel sheet electrode, the electrolyte was a 1.0 mol / L KOH solution, the test temperature was 80℃, and the electrode was tested at 5 kA / m². 2 The potential of the working electrode is measured under current density.

[0115] Testing revealed that the D-Acid electrode performed the worst, exhibiting a high initial overpotential of 1.25 V and failing within a short period (20 h) due to coating peeling (see [link]). Figure 8 ).

[0116] Analysis example 1

[0117] See Figure 6 The figures show the electrochemical polarization (JU) curves of the double-layer Raney nickel electrode prepared in Example 1, the Raney nickel electrode prepared in Comparative Example 1, and the Raney nickel electrode prepared in Comparative Example 2. Among them, the E-Fe electrode has the highest electrocatalytic initiation activity and a larger current density at the same potential, indicating that its catalytic performance is superior. Figure 7 The images show the electrochemical impedance spectroscopy (EIS) spectra of the double-layer Raney nickel electrode prepared in Example 1 and the Raney nickel electrode prepared in Comparative Example 1. The diameter of the arc on the E-Fe electrode is smaller than that on the D-Sandblast electrode, indicating that it has lower charge transfer resistance and higher charge transfer efficiency in the electrochemical reaction. Figure 8 The electrochemical potential-time (Ut) curves are shown for the double-layer Raney nickel electrode prepared in Example 1 and the Raney nickel electrode prepared in Comparative Example 2. The materials E-Fe and D-Acid were analyzed in a 1 mol / L KOH electrolyte at 80 °C with a current density of 5 kA / m. 2Electrochemical stability under the specified conditions was assessed. The E-Fe electrode prepared in Example 1 maintained a nearly stable potential throughout the test, indicating excellent electrochemical stability and strong potential controllability under these conditions. In contrast, the D-Acid electrode prepared in Comparative Example 2 exhibited drastic potential fluctuations in the initial stage of the test, followed by no significant sustained signal, possibly indicating a loss of electrochemical activity. It was unable to maintain a stable electrochemical reaction under these current density and electrolyte conditions.

[0118] The aforementioned double-layer Raney nickel electrode, its preparation method, and its application involve immersing a conductive substrate in an Fe-containing... 3+ After reacting in an ion-etching solution, an iron-modified conductive substrate is obtained. Unlike traditional physical methods, this invention uses a chemical etching method to etch the conductive substrate, not only forming a micron-level rough surface but also retaining the iron component as an interface modification layer. Specifically, iron (Fe) 2+ / Fe 3+ The iron will be deposited in situ and firmly adhered to the etched conductive substrate surface in the form of iron hydroxide, iron oxide, or zero-valent iron, forming an active interface layer rich in iron. The alloy powder is then loaded onto the iron-modified conductive substrate to obtain a composite conductive substrate. The iron component of the active interface layer and the alloy elements will interdiffusion. After immersing the composite conductive substrate in an alkaline solution, an activation reaction occurs, dissolving aluminum. At this point, the iron in the active interface layer may partially dissolve or reconstruct, ultimately forming a transition region rich in Fe-Ni alloy or compound between the conductive substrate and the Raney nickel layer, exhibiting excellent electronic conductivity. Furthermore, the preparation method of this invention is simple, convenient to operate, and suitable for industrial production.

[0119] In summary, the above-described technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for preparing a double-layer Raney nickel electrode, characterized in that, include: S1: Provides a conductive substrate; S2: Immerse the conductive substrate in an Fe-containing solution. 3+ A uniform surface etching reaction is carried out in an ion solution to obtain an iron-modified conductive substrate; S3: Load Raney nickel alloy powder onto the iron-modified conductive substrate to obtain a composite conductive substrate; S4: The composite conductive substrate is immersed in an alkaline solution to carry out an activation reaction, thereby forming a transition region rich in Fe-Ni alloy or compound between the conductive substrate and the Raney nickel layer, thus obtaining the double-layer Raney nickel electrode.

2. The method for preparing a double-layer Raney nickel electrode according to claim 1, characterized in that, The Fe-containing 3+ The solution contains one or more of the ions FeCl3 and Fe(NO3)3; The Fe-containing 3+ Fe in solution of ions 3+ The molar concentration of ions is 0.1~1.0 mol / L.

3. The method for preparing a double-layer Raney nickel electrode according to claim 1, characterized in that, The etching reaction temperature is 25~80℃, and the etching reaction duration is 5~30 min.

4. The method for preparing a double-layer Raney nickel electrode according to claim 1, characterized in that, The Raney nickel alloy powder includes nickel powder and aluminum powder; The mass ratio of the nickel powder to the aluminum powder is (65~75):(25~35).

5. The method for preparing a double-layer Raney nickel electrode according to claim 1, characterized in that, The thickness of the Raney nickel alloy powder loaded on the iron-modified conductive substrate is 10~100μm.

6. The method for preparing a double-layer Raney nickel electrode according to claim 1, characterized in that, The alkaline solution includes alkali metal hydroxides; The alkali metal hydroxide includes one or more of NaOH and KOH; The mass fraction of the alkali metal hydroxide is 5-45%.

7. The method for preparing a double-layer Raney nickel electrode according to claim 1, characterized in that, The activation reaction is carried out at a temperature of 60~90℃; The activation reaction lasts for 0.5 to 4 hours.

8. The method for preparing a double-layer Raney nickel electrode according to claim 1, characterized in that, The conductive substrate includes a nickel mesh.

9. A double-layer Raney nickel electrode, characterized in that, It was prepared using the method for preparing a double-layer Raney nickel electrode as described in any one of claims 1 to 8.

10. The application of a double-layer Raney nickel electrode as described in claim 9 in hydrogen production by water electrolysis.

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