Nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode and preparation method and application thereof

Abstract

The disclosure provides a nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode and a preparation method and application thereof. The method comprises the following steps: cleaning metal sheets and metal wires with dilute hydrochloric acid and dilute NaOH solution, then cleaning with ultrapure water and vacuum drying; weighing the metals according to the atomic ratio, placing them in an arc furnace for multiple times of smelting under argon protection to obtain alloy ingots; grinding the alloy ingots, cutting them into small pieces, and then placing them in a directional solidification device for heating and stretching into a columnar shape; cutting the columnar alloy ingots into alloy discs with a diamond wire cutting machine; and placing the alloy discs in a KOH solution saturated with N2 for corrosion, and then cleaning to obtain a composite electrode material. The nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode has small pores of 3-5 nm, promotes mass transfer, increases the specific surface area and active site exposure. The high-entropy alloy on the surface regulates the adsorption energy of the reaction intermediates, optimizes the reaction kinetics, and exhibits excellent hydrazine hydrate oxidation and hydrogen evolution performance, providing a material basis for the commercialization of hydrogen production.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and in particular to a nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode, its preparation method, and its application. Background Technology

[0002] Hydrogen energy is a clean and efficient secondary energy source that can serve as a medium for energy interconnection. Electrocatalytic water splitting for hydrogen production, driven by renewable energy sources such as wind and hydropower, is fundamental to the green production and efficient utilization of hydrogen. The oxygen evolution reaction (OER) at the anode of the electrocatalytic water splitting reaction is kineticly slow, requiring a voltage greater than 1.23V (relative to the reversible hydrogen electrode), while the theoretical voltage of the hydrazine hydrate oxidation reaction is only -0.33V (relative to the reversible hydrogen electrode), showing promise in replacing the OER and lowering the voltage required for water splitting to produce hydrogen. Electrocatalytic hydrogen production, consisting of the hydrazine hydrate oxidation reaction coupled to the cathode hydrogen evolution reaction, is a highly promising pathway. The hydrazine hydrate oxidation reaction is a four-electron transfer process involving multiple reaction intermediates; therefore, there is an urgent need to construct electrocatalytic materials with multiple active sites. High-entropy alloys possess diverse active sites, and the adsorption energy for different reaction intermediates can be controlled through electron transfer or / and coordination effects caused by differences in electronegativity between different elements, achieving optimal adsorption / desorption. High-entropy intermetallic compounds are composed of multiple elements replacing one component in an intermetallic compound, yet they still retain the intrinsic thermodynamic stability of intermetallic compounds. Based on the above considerations, this disclosure proposes a nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode, its preparation method, and its applications. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, this disclosure provides a nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode, its preparation method, and its application.

[0004] According to a first aspect of this disclosure, a method for preparing a nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode is provided, characterized by comprising the following steps:

[0005] a. Cleaning the metal: Soak and clean the high-purity Ni, Fe, Co, Cu, Cr, and Mn metal sheets with dilute hydrochloric acid, and remove the oxides on the surface of the Al metal wire with dilute NaOH solution. Then, clean the Ni, Fe, Co, Cu, Cr, and Mn metal sheets and the Al metal wire several times with ultrapure water. Finally, place the Ni, Fe, Co, Cu, Cr, and Mn metal sheets and the Al metal wire that have been cleaned with ultrapure water in a vacuum drying oven.

[0006] b. Melting the alloy ingot: Weigh the Ni, Fe, Co, Cu, Cr, Mn, and Al (which have been washed with ultrapure water) according to an atomic ratio of 15:3:3:3:3:3:70, with a total mass of 10-12g. Place the weighed metals in an electric arc furnace and melt the alloy 8-10 times using argon as a protective gas to obtain a uniform alloy ingot. After the alloy ingot cools to room temperature, open the furnace door and remove the alloy ingot, which is silvery-white.

[0007] c. Preparation of columnar alloy by directional solidification: The oxide layer on the surface of the alloy ingot is sanded off with sandpaper. The alloy ingot is cut into small pieces with a size of less than 9 mm. The small pieces of alloy ingot are placed in the crucible tube of the directional solidification equipment and heated to 1500°C under an argon atmosphere at a heating rate of 10°C / min. The temperature is held at the preset temperature for 10 min. The small pieces of alloy ingot are stretched at a preset stretching speed with a stretching stroke of 10 cm. After stretching is completed and the temperature drops to room temperature, the small pieces of alloy ingot are removed. The small pieces of alloy ingot have a columnar shape with a diameter of 1 cm.

[0008] d. Preparation of alloy sheets: Cut the columnar small alloy ingots with a diamond wire cutter to obtain alloy discs of a preset size;

[0009] e. Chemical dealloying: The alloy disc is placed in a 6M KOH solution saturated with N2 at a preset temperature for corrosion. After corrosion for a certain period of time, when no more bubbles are generated on the surface of the alloy disc, the alloy disc is washed with ultrapure water multiple times to obtain a nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode.

[0010] Preferably, the precursor alloy composition of the alloy ingot in step b is Ni. 15 Fe3Co3Cu3Cr3Mn3Al 70 (at%).

[0011] Preferably, in the directional solidification method for preparing columnar alloys in step c, the preset temperature is 1500℃ and the preset stretching speed is 100μm / s.

[0012] Preferably, the alloy disc of the preset size mentioned in step d has a diameter of 1 cm and a thickness of 400 μm.

[0013] Preferably, in step e, the alloy disc is placed in a 6M KOH solution saturated with N2 at 70°C for etching, and the etching time is 5 hours.

[0014] According to a second aspect of this disclosure, a nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode is provided.

[0015] According to a third aspect of this disclosure, an application of a nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode is provided, characterized in that the composite electrode is used as a hydrazine hydrate oxidation reaction electrode and a hydrogen evolution reaction electrode.

[0016] The principle of this disclosed technical solution is:

[0017] The precursor alloy ingot is prepared by alloying and eutectic template dealloying, a simple and scalable process. First, high-purity metals Ni, Fe, Co, Cu, Cr, Mn, and Al are melted into a precursor alloy ingot Ni using an electric arc furnace. 15 Fe3Co3Cu3Cr3Mn3Al 70 The alloy is stretched into a cylindrical shape using a directional solidification device. The precursor alloy is composed of Al, Al3(NiFeCoCuCrMn)2, and Al 13 Fe4, Al9Co2, CuAl2, Al6Mn, Al3Ni and Al 13 The material is composed of Cr2. It is then cut into thin sheets using wire cutting equipment, and finally, Al is etched away with alkaline solution using a chemical dealloying method to form a nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode. During the chemical dealloying process, the Al in the Al-rich intermetallic compound is etched away, forming pores. Fe, Co, Cu, Cr, and Mn diffuse on the surface of the Al3(NiFeCoCuCrMn)2 ligament to form a high-entropy alloy NiFeCoCuCrMn, thus forming a high-entropy intermetallic compound / high-entropy alloy core-shell structure electrode material.

[0018] The beneficial effects of this disclosed technical solution are:

[0019] The core-shell structured electrode material disclosed herein exhibits a porous structure. The pores facilitate mass transport of electrolyte and gas molecules, increase the specific surface area of ​​the material, and enhance the accessibility of electrocatalytic active sites, exposing more active sites in the electrolyte. The three-dimensional interconnected Ni network facilitates electron transfer during the catalytic reaction. The high-entropy intermetallic compound Al3(NiFeCoCuCrMn)2 possesses thermodynamic stability and acts as the core, exerting strain on the surface high-entropy alloy NiFeCoCuCrMn, thereby regulating the adsorption capacity of the surface high-entropy alloy for adsorbates. The high-entropy alloy, acting as the outer shell, has multiple active site centers, appropriately adsorbing various reactants, reaction intermediates, and products, thus improving reaction kinetics. Therefore, the core-shell structured nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 high-entropy alloy / high-entropy intermetallic compound composite electrode material exhibits excellent catalytic performance in the oxidation of hydrazine hydrate and hydrogen evolution reactions, providing a material basis for large-scale hydrogen production. Attached Figure Description

[0020] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. The drawings are provided for a better understanding of the present invention and are not intended to limit the scope of this disclosure. In the drawings, the same or similar reference numerals denote the same or similar elements, wherein:

[0021] Figure 1 Scanning electron microscope (SEM) images of nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 according to embodiments of this disclosure;

[0022] Figure 2 Energy dispersive spectroscopy (EDS) diagram of nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 according to embodiments of this disclosure;

[0023] Figure 3 X-ray diffraction (XRD) patterns of nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 according to embodiments of this disclosure;

[0024] Figure 4 High-resolution transmission electron microscopy (HRTEM) images of nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 according to embodiments of this disclosure;

[0025] Figure 5 Transmission electron microscopy images and elemental distribution diagrams of nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 according to embodiments of this disclosure;

[0026] Figure 6The polarization curves of the oxidation reaction of nanoporous NiFeCoCuCrMn / Al3 (NiFeCoCuCrMn)2 with hydrazine hydrate in a mixed electrolyte of 1M KOH and 0.1M N2H4 in this embodiment of the present disclosure;

[0027] Figure 7 Tafel diagram of the oxidation reaction of nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 hydrazine hydrate in this embodiment;

[0028] Figure 8 The present invention discloses the hydrogen evolution reaction polarization curve of nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 in 1M KOH electrolyte;

[0029] Figure 9 Tafel diagram of the hydrogen evolution reaction of nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 in this embodiment;

[0030] Figure 10 The polarization curve of the water electrolysis hydrogen production device assembled by nanoporous NiFeCoCuCrMn / Al3 (NiFeCoCuCrMn)2 in this embodiment is shown. The anode electrolyte is a mixed solution of 1MKOH and 0.1MN2H4, and the cathode electrolyte is 1MKOH.

[0031] Figure 11 The stability of the water electrolysis hydrogen production device assembled with nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 in the embodiments of this disclosure. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0033] Example 1

[0034] A method for preparing a nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode, comprising the following steps:

[0035] 1) Cleaning the metal: Soak and clean the high-purity Ni, Fe, Co, Cu, Cr, and Mn metal sheets with dilute hydrochloric acid, and remove the oxides on the surface of the Al metal wire with dilute NaOH solution. Then, clean the Ni, Fe, Co, Cu, Cr, and Mn metal sheets and the Al metal wire several times with ultrapure water. Finally, place the Ni, Fe, Co, Cu, Cr, and Mn metal sheets and the Al metal wire that have been cleaned with ultrapure water in a vacuum drying oven.

[0036] 2) Melting the alloy ingot: Weigh the Ni, Fe, Co, Cu, Cr, Mn, and Al, which have been washed with ultrapure water, according to an atomic ratio of 15:3:3:3:3:3:70. The total mass of the above metals is 10-12g. Place the weighed metals in an electric arc furnace and melt the alloy 8-10 times with argon as the protective gas to obtain a uniform alloy ingot. After the alloy ingot cools to room temperature, open the furnace door and take out the alloy ingot. The alloy ingot is silvery-white.

[0037] 3) Preparation of columnar alloy by directional solidification: The oxide layer on the surface of the alloy ingot is sanded off with sandpaper, and the alloy ingot is cut into small alloy ingots with a size of less than 9 mm. The small alloy ingots are placed in the crucible tube of the directional solidification equipment and heated to 1500℃ under an argon atmosphere at a heating rate of 10℃ / min. The temperature is held at 1500℃ for 10 min, and the small alloy ingots are stretched at a speed of 100 μm / s for a stretching stroke of 10 cm. After stretching is completed and the temperature drops to room temperature, the small alloy ingots are taken out. The small alloy ingots have a columnar shape with a diameter of 1 cm.

[0038] 4) Preparation of alloy sheet: Cut the columnar small alloy ingot with a diamond wire cutter to obtain alloy discs with a diameter of 1 cm and a thickness of 400 μm;

[0039] 5) Chemical dealloying: The alloy disc is placed in a 6M KOH solution saturated with N2 at 70°C for etching. After etching for a certain period of time, when no more bubbles are generated on the surface of the alloy disc, the alloy disc is washed with ultrapure water multiple times to obtain a nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode material.

[0040] The morphology and structural characterization results of the composite electrode material are as follows:

[0041] Figure 1 Scanning electron microscope (SEM) image of a nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode. Figure 2The transmission electron microscopy (TEM) image of the electrode shows that it possesses a nanoporous structure with pore sizes of approximately 3–5 nm. The unique pore structure facilitates mass transport between the electrolyte and gas molecules, increases the specific surface area of ​​the electrode material, exposes more active sites in the electrolyte, and the three-dimensional interconnected Ni network promotes electron transfer during the catalytic reaction. Figure 3 In the XRD pattern, the characteristic peaks at 25.2°, 31.2°, 40.8°, 45.0°, 48.5°, and 65.3° correspond to the (100), (101), (110), (102), (111), and (202) crystal planes of Al3Ni2, respectively. The surface has a low content of NiFeCoCuCrMn high-entropy alloy, and the XRD peaks are not obvious. The characteristic peaks of the NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode are shifted at higher angles relative to the characteristic peaks of Al3(NiCu)2 / NiCu, indicating that FeCoCuCrMn replaces a portion of Ni in Al3Ni2. Figure 4 High-resolution transmission electron microscopy (TEM) images further characterized the core-shell structure of the nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode. For example... Figure 5 The transmission electron microscopy images and corresponding elemental distribution results show that Fe, Co, Cu, Cr, Mn, and Al are uniformly distributed on the Ni ligament.

[0042] Example 2

[0043] The hydrazine hydrate oxidation performance of the composite electrode material obtained in Example 1 was tested in a three-electrode system. In a mixed solution of 1 M KOH and 0.1 M N2H4, the nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode material was used as the working electrode, a carbon rod as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The specific testing procedure is as follows:

[0044] 1) Within a voltage range of -0.05 to 0.15 V (relative to the reversible hydrogen electrode), at a rate of 1 mV / s -1 The scanning speed was used to test the polarization curve of the oxidation reaction of hydrazine hydrate;

[0045] 2) Test its impedance spectrum at 0V, with an amplitude of 5mV and a frequency of 10mHz to 100kHz;

[0046] The characterization results of the hydrogen evolution reaction performance of the nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 electrode material are as follows:

[0047] Figure 6The polarization curves of the hydrazine hydrate oxidation reaction of the nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode were compared with those of the nanoporous NiFeCoCuAl, NiCrMn, and NiCuAl electrodes. At a potential of 100 mV, the Al3(NiFeCoCuCrMn)2 / NiFeCoCuCrMn electrode achieved a polarization of ~1.12 A / cm. -2 The current density is far greater than that of NiCrMnAl (~0.62 A / cm). -2 ), NiFeCoCuAl, (~0.32Acm) -2 NiCuAl (~0.26Acm) -2 The current density of the electrodes. Furthermore, such as... Figure 7 As shown, the Tafel slope of the nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 electrode is as low as ~17 mV dec. -1 The efficiency is significantly lower than that of other comparative electrode materials, indicating that this electrode has excellent performance in the oxidation of hydrazine hydrate.

[0048] Example 3

[0049] The hydrogen evolution reaction performance of the composite electrode material obtained in Example 1 in 1 MKOH was tested. The specific test procedure is as follows:

[0050] 1) Test the polarization curve of the hydrogen evolution reaction, with a voltage range of 0 to -0.40 V (relative to the reversible hydrogen electrode) and a scan rate of 1 mV / s. -1 ;

[0051] 2) Its impedance was tested at -0.1V (relative to the reversible hydrogen electrode), with an amplitude of 5mV and a frequency of 10mHz to 100kHz.

[0052] The characterization results of the hydrogen evolution reaction performance of the nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode are as follows:

[0053] Figure 8 The hydrogen evolution reaction polarization curves of nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2, NiFeCoCuAl, NiCuAl, and Ni electrodes were compared. NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 achieved a polarization of ~1.77 Acm at a voltage of 0.2 V. -2 The current density is far greater than that of NiFeCoCuAl (~0.96 A / cm). -2 ), NiCuAl (~0.35A cm) -2 ) and Ni (~0.14 mA cm -2 Additionally, such as Figure 9 As shown, the Tafel slope of the hydrogen evolution reaction of nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 is as low as 41 mV dec. -1 The value is much smaller than that of other comparative electrodes, indicating that the composite electrode has excellent reaction kinetics.

[0054] Example 4

[0055] The performance of the electrolytic cell hydrogen production system assembled with the composite electrode material obtained in Example 1 was tested. The specific test procedure is as follows:

[0056] 1) The polarization curves of the hydrogen production system in an electrolytic cell assembled with the composite electrode as the cathode and anode were tested. The voltage range was 0–1.0 V, and the scan rate was 1 mV / s. -1 ;

[0057] 2) The stability of the composite electrode was tested at a constant potential of 0.25V for 1000 hours.

[0058] Figure 10 An electrolytic cell assembled with nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 was demonstrated, requiring only 0.9V to drive a 0.5A cm⁻¹ electrolytic cell. -2 The current density. Figure 11 This indicates that the nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 is stable at a current density of 0.25V and a current density of 120mA / cm². -2 The current density indicates that the electrode has excellent electrochemical stability.

[0059] In summary, the nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 disclosed herein possesses a nanoporous structure with pore sizes of approximately 3–5 nm. The unique pore structure facilitates mass transport of electrolyte and gas molecules, increases the specific surface area of ​​the electrode material, and exposes more active sites in the electrolyte. The high-entropy alloy surface has multiple active site centers, which can regulate the adsorption energy of intermediates during the hydrogen evolution reaction and hydrazine hydrate oxidation reaction, thereby achieving optimal adsorption and improving reaction kinetics. Therefore, the nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode exhibits excellent performance in both hydrazine hydrate oxidation and hydrogen evolution reactions, providing a material basis for the large-scale commercial application of hydrogen production via a cathode hydrogen evolution reaction coupled with an anode hydrazine hydrate oxidation reaction.

[0060] The above embodiments are preferred embodiments of this disclosure, but the embodiments of this disclosure are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of this disclosure shall be considered equivalent substitutions and shall be included within the protection scope of this disclosure.

Claims

1. A method for preparing a nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode, characterized in that, Includes the following steps: a. Cleaning the metal: Soak and clean the high-purity Ni, Fe, Co, Cu, Cr, and Mn metal sheets with dilute hydrochloric acid, and remove the oxides on the surface of the Al metal wire with dilute NaOH solution. Then, clean the Ni, Fe, Co, Cu, Cr, and Mn metal sheets and the Al metal wire several times with ultrapure water. Finally, place the Ni, Fe, Co, Cu, Cr, and Mn metal sheets and the Al metal wire that have been cleaned with ultrapure water in a vacuum drying oven. b. Melting the alloy ingot: Weigh the Ni, Fe, Co, Cu, Cr, Mn, and Al (which have been washed with ultrapure water) according to an atomic ratio of 15:3:3:3:3:3:70, with a total mass of 10-12 g. Place the weighed metals in an electric arc furnace and melt the alloy 8-10 times using argon as a protective gas to obtain a uniform alloy ingot. After the alloy ingot cools to room temperature, open the furnace door and remove the alloy ingot, which is silvery-white. c. Preparation of columnar alloy by directional solidification: The oxide layer on the surface of the alloy ingot is sanded off with sandpaper. The alloy ingot is cut into small pieces with a size of less than 9 mm. The small pieces of alloy ingot are placed in the crucible tube of the directional solidification equipment and heated to 1500 ℃ under an argon atmosphere at a heating rate of 10 ℃ / min. The ingot is held at a preset holding temperature for 10 min and stretched at a preset stretching speed with a stretching stroke of 10 cm. After stretching is completed and the temperature drops to room temperature, the small pieces of alloy ingot are removed. The small pieces of alloy ingot have a columnar shape with a diameter of 1 cm. d. Preparation of alloy sheets: Cut the columnar small alloy ingots with a diamond wire cutter to obtain alloy discs of a preset size; e. Chemical dealloying: The alloy disc is placed in a 6 M KOH solution saturated with N2 at a preset corrosion temperature for corrosion. After corrosion for a certain period of time, when no more bubbles are generated on the surface of the alloy disc, the alloy disc is washed with ultrapure water multiple times to obtain a nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode.

2. The method for preparing the nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode according to claim 1, characterized in that: The precursor alloy composition of the alloy ingot in step b is Ni at % 15 Fe3Co3Cu3Cr3Mn3Al 70 .

3. The method for preparing the nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode according to claim 1, characterized in that: In step c, the directional solidification method for preparing columnar alloys has a preset holding temperature of 1500℃ and a preset stretching speed of 100 μm / s.

4. The method for preparing the nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode according to claim 1, characterized in that: The alloy disc of the preset size mentioned in step d has a diameter of 1 cm and a thickness of 400 μm.

5. The method for preparing the nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode according to claim 1, characterized in that: In step e, the alloy disc is placed in a 6 M KOH solution saturated with N2 at 70 °C for corrosion for 5 hours.

6. A nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode obtained by the preparation method according to any one of claims 1-5.

7. The application of the nanoporous NiFeCoCuCrMn / Al3(NiFeCoCuCrMn)2 composite electrode according to claim 6, characterized in that, The composite electrode is used as the electrode for the oxidation reaction of hydrazine hydrate and the hydrogen evolution reaction.

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