Nano-porous multi-component nitride / high-entropy alloy (NiFeCo) 3 (MoCr) 3N / HEA composite electrode and preparation method and application thereof

Abstract

The invention provides a nano-porous multi-component nitride / high-entropy alloy (NiFeCo) 3 (MoCr) 3N / HEA composite electrode as well as a preparation method and application of the nano-porous multi-component nitride / high-entropy alloy (NiFeCo) 3 (MoCr) 3N / HEA composite electrode. Comprising the steps of weighing metal according to an atomic ratio, and smelting repeatedly to obtain an alloy ingot; cutting by a diamond wire cutting machine to obtain an alloy sheet; placing the alloy sheet in a N2 saturated KOH solution for corrosion, cleaning to obtain a (MoCr) (NiFeCo) 4 / HEA composite electrode material, and carrying out heat treatment on the (MoCr) (NiFeCo) 4 / HEA composite electrode material to obtain a NiFeCoMoCrO / HEA composite material; and then the composite material is placed in a tube furnace to be subjected to heat treatment in a mixed atmosphere of argon and ammonia gas, and the nano-porous multi-component nitride / high-entropy alloy (NiFeCo) 3 (MoCr) 3N / HEA composite electrode is obtained. The (NiFeCo) 3 (MoCr) 3N particles with the width of about 200 nm are anchored on a nano-porous high-entropy alloy framework, and the porous structure promotes mass transfer and improves the specific surface area and active site exposure. The (NiFeCo) 3 (MoCr) 3N multi-component nitride forms an N-doped NiFeCoMoCrOOH high-entropy oxyhydroxide in the oxygen evolution reaction process, the N-doped NiFeCoMoCrOOH high-entropy oxyhydroxide serves as an electrocatalytic active site of the oxygen evolution reaction, moderate adsorption / desorption of a reaction intermediate is achieved, and excellent oxygen evolution reaction catalytic performance is shown.

Description

Technical Field

[0001] This disclosure relates to the field of catalyst technology, and in particular to nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrodes, their preparation methods, and applications. Background Technology

[0002] Hydrogen energy, due to its cleanliness and high energy density, is considered a promising alternative to fossil fuels. Electrochemical water splitting for hydrogen production, powered by electricity from renewable energy sources such as solar or wind, is an environmentally friendly energy conversion pathway. The oxygen evolution reaction (OER) at the anode of the electrocatalytic water splitting reaction involves multiple reaction intermediates, resulting in slow reaction kinetics that severely limit the hydrogen production efficiency of electrolyzer devices. Therefore, developing efficient OER electrode materials is crucial. Multicomponent catalytic materials can regulate the adsorption energy of different reaction intermediates through electron transfer and / or coordination effects caused by differences in electronegativity between different elements, achieving optimal adsorption / desorption and improving intrinsic catalytic activity. Based on the above considerations, this disclosure proposes a nanoporous multicomponent nitride / alloy (NiFeCo)3(MoCr)3N / HEA 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 multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode, its preparation method, and its application.

[0004] According to a first aspect of this disclosure, a method for preparing a nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode is provided, comprising the following steps:

[0005] a. Melting the alloy ingot: Weigh pure Ni, Fe, Co, Mo, Cr, and Al metal sheets according to an atomic ratio of 13:2:2:6:2:75, 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.

[0006] b. Preparation of alloy sheet: Cut the alloy ingot with a diamond wire cutter to obtain an alloy sheet of a certain thickness;

[0007] c. Chemical dealloying: The alloy sheet is placed in a 6M KOH solution saturated with N2 at 70°C for corrosion. After corrosion for a certain period of time, when no more bubbles are generated on the surface of the alloy sheet, the alloy sheet is washed with ultrapure water multiple times to obtain a nanoporous (MoCr)(NiFeCo)4 / HEA composite electrode material, which is then dried in a vacuum drying oven.

[0008] d. Oxidation heat treatment: The above composite electrode material is placed in a tube furnace and heat-treated in an air atmosphere. After being held at a preset temperature for a certain time, it is cooled to room temperature to form NiFeCoMoCrO / HEA composite material.

[0009] e. Nitriding heat treatment: The above NiFeCoMoCrO / HEA composite material is placed in a tube furnace and heat-treated in a mixed atmosphere of argon and ammonia. After being held at a preset temperature for a certain time, it is cooled to room temperature to obtain a nanoporous multi-component nitride / high entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode.

[0010] According to a second aspect of this disclosure, a nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode is provided.

[0011] According to a third aspect of this disclosure, an application of a nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode is provided, wherein the composite electrode is used as an oxygen evolution reaction electrode material.

[0012] The principle of this disclosed technical solution is:

[0013] It is prepared using alloying / dealloying and heat treatment methods, and can be operated on a large scale. First, high-purity metals Ni, Fe, Co, Mo, Cr, and Al are melted into precursor alloy ingots Ni in an electric arc furnace. 13 Fe2Co2Mo6Cr2Al 75The material is cut into thin sheets using wire cutting equipment, and then Al is etched away with alkaline solution using a chemical dealloying method to form a nanoporous (MoCr)(NiFeCo)4 / HEA composite electrode. During the chemical dealloying process, Al in the Al-rich intermetallic compounds is etched away, forming pores. Fe, Co, Cr, Mn, and residual Al diffuse onto the Ni ligament surface to form a high-entropy alloy NiFeCoMoCrAl. The multi-component intermetallic compound (MoCr)(NiFeCo)4 is anchored in situ on the surface of the high-entropy alloy NiFeCoMoCrAl, thus forming the (MoCr)(NiFeCo)4 / HEA electrode material. This material is then placed in a tube furnace and held at 300 °C for 2 hours in an air atmosphere, where (MoCr)(NiFeCo)4 is oxidized to NiFeCoMoCrO, forming NiFeCoMoCrO / HEA. Finally, it was placed in a tube furnace and held at 900 °C for 2 hours in a mixed atmosphere of argon and ammonia (ammonia content 10%). NiFeCoMoCrO was nitrided to (NiFeCo)3(MoCr)3N, forming a nanoporous multi-component nitride / high entropy alloy (NiFeCo)3(MoCr)3N / HEA material.

[0014] The beneficial effects of this disclosed technical solution are:

[0015] The (NiFeCo)3(MoCr)3N multi-component nitride nanoparticles disclosed herein are seamlessly integrated onto a nanoporous NiFeCoMoCrAl high-entropy alloy ligament. This integrated electrode structure is beneficial for improving electrolyte mass transfer and electron transport capabilities. At the oxygen evolution reaction potential, (NiFeCo)3(MoCr)3N degenerates into N-doped NiFeCoMoCrOOH high-entropy hydroxyl oxides, serving as active sites for the oxygen evolution reaction and achieving moderate adsorption / desorption of reaction intermediates, thereby improving the oxygen evolution reaction kinetics. Experimental results demonstrate that this material possesses excellent catalytic performance for the oxygen evolution reaction, providing a material basis for large-scale hydrogen production through electrocatalytic water splitting. Attached Figure Description

[0016] 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:

[0017] Figure 1 Scanning electron microscope (SEM) images of nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA according to embodiments of this disclosure;

[0018] Figure 2Energy dispersive spectroscopy (EDS) diagrams of nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA according to embodiments of this disclosure;

[0019] Figure 3 X-ray diffraction (XRD) patterns of nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA according to embodiments of this disclosure;

[0020] Figure 4 High-resolution transmission electron microscopy (HRTEM) images of nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA according to embodiments of this disclosure;

[0021] Figure 5 The oxygen evolution reaction polarization curves of nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA in 1MKOH electrolyte according to embodiments of this disclosure;

[0022] Figure 6 Tafel diagram of the oxygen evolution reaction of nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA in embodiments of this disclosure;

[0023] Figure 7 Impedance spectra of nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA in 1M KOH electrolyte according to embodiments of this disclosure;

[0024] Figure 8 The oxygen evolution reaction stability of nanoporous multi-component nitride / high entropy alloy (NiFeCo)3(MoCr)3N / HEA in the embodiments of this disclosure. Detailed Implementation

[0025] 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.

[0026] Example 1

[0027] A method for preparing a nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode, comprising the following steps:

[0028] 1) Melting alloy ingots: Weigh pure Ni, Fe, Co, Mo, Cr, and Al metal sheets according to an atomic ratio of 13:2:2:6:2:75, with a total mass of 10-12 g; place the weighed metals in an electric arc furnace, using argon as a protective gas, and melt the alloy 8-10 times, repeating the melting process to obtain a uniform alloy ingot; wait for the alloy ingot to cool to room temperature, open the furnace door and remove the alloy ingot, which is silvery-white;

[0029] 2) Preparation of alloy sheet: The alloy ingot is cut with a diamond wire cutter to obtain an alloy sheet with a thickness of 400 μm;

[0030] 3) Chemical dealloying: The alloy sheet is placed in a 6 M KOH solution saturated with N2 at 70 °C for corrosion. After 3 hours of corrosion, no more bubbles are generated on the surface of the alloy sheet. The alloy sheet is washed with ultrapure water multiple times to obtain a nanoporous (MoCr)(NiFeCo)4 / HEA composite electrode material, which is then dried in a vacuum drying oven.

[0031] 4) Oxidation heat treatment: The above composite electrode material is placed in a tube furnace and heat-treated in an air atmosphere. The temperature is raised to 300 °C at a heating rate of 5 °C / min, held for 2 hours, and then cooled to room temperature to form NiFeCoMoCrO / HEA composite material.

[0032] 5) Nitriding heat treatment: The above NiFeCoMoCrO / HEA composite material was placed in a tube furnace and heat-treated in a mixed atmosphere of argon and ammonia (ammonia content 10%). The temperature was raised to 900 °C at a heating rate of 5 °C / min, held for 2 hours, and then cooled to room temperature to obtain a nanoporous multi-component nitride / high entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode.

[0033] The morphology and structural characterization results of the nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode material disclosed herein are as follows:

[0034] Figure 1 Scanning electron microscopy images of the nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode show that (NiFeCo)3(MoCr)3N particles with a width of approximately 200 nm are anchored on the nanoporous high-entropy alloy framework. Figure 2 The energy dispersive spectroscopy (EDS) further confirms that nitrogen (N) is enriched on the nanoparticles, while Ni, Fe, Co, Mo, Cr, and Al are uniformly distributed. Figure 3In the XRD pattern, the characteristic peaks at 40.9°, 43.2°, 45.4°, 72.7°, and 77.5° correspond to the (221), (310), (311), (510), and (520) crystal planes of Ni3Mo3N, respectively, while the characteristic peaks at 44.0°, 51.3°, and 75.9° correspond to the (111), (200), and (220) crystal planes of Ni, respectively. The Ni3Mo3N peaks of (NiFeCo)3(MoCr)3N / HEA are shifted to higher angles compared to the peaks on the standard card, indicating that Fe, Co, and Cr randomly replace Ni and Mo atoms in Ni3Mo3N to form the (NiFeCo)3(MoCr)3N multi-component nitride. Figure 4 In the high-resolution transmission electron microscope images, 0.218 nm and 0.208 nm correspond to the (221) crystal plane of (NiFeCo)3(MoCr)3N and the (111) crystal plane of HEA, respectively, further confirming the existence of this composite structure.

[0035] Example 2

[0036] The oxygen evolution reaction performance of the nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode material obtained in Example 1 was tested in a three-electrode system. The nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode material was used as the working electrode in 1M KOH electrolyte, a carbon rod as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The specific test procedure is as follows:

[0037] 1) Within a voltage range of 1.2 ~ 1.8 V (relative to the reversible hydrogen electrode), at 1 mV s −1 The scanning speed was used to test the polarization curve of the oxidation reaction;

[0038] 2) Test its impedance spectrum at a potential of 1.55 V, with an amplitude of 5 mV and a frequency of 10 mHz ~ 100 kHz;

[0039] The characterization results of the oxygen evolution reaction performance of the disclosed nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA electrode material are as follows:

[0040] Figure 5 The oxygen evolution reaction polarization curves of the disclosed nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode were compared with those of nanoporous Ni3Mo3N / Ni and N-Ni / Ni electrodes. At a potential of 1.53 V, the disclosed nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA electrode can achieve a polarization of ~2.5 A cm⁻¹. −2The current density is far greater than that of Ni3Mo3N / Ni (~0.06 A cm⁻¹). −2 ), N-Ni / Ni (~0.02 A cm −2 The current density of the electrodes. Furthermore, such as... Figure 6 As shown, the Tafel slope of the disclosed nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA electrode is as low as ~30 mV dec. −1 The oxygen evolution reaction performance is significantly lower than that of other comparative electrode materials, indicating that this electrode has excellent oxygen evolution reaction performance. Figure 7 As shown, the charge transfer resistance of the disclosed nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA electrode is much smaller than that of Ni3Mo3N / Ni and N-Ni / Ni, demonstrating that the disclosed nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA electrode exhibits fast reaction kinetics. Furthermore, stability tests were performed on the electrode at a potential of 1.5 V (relative to the reversible hydrogen electrode), such as... Figure 8 As shown, the generated current density can remain stable at ~1.0 A cm⁻¹ for 1000 hours. −2 This demonstrates that the nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA electrode material disclosed herein exhibits excellent oxygen evolution reaction stability.

[0041] In summary, the (NiFeCo)3(MoCr)3N multi-component nitride nanoparticles described in this disclosure are seamlessly integrated on the surface of a porous high-entropy alloy (HEA). During the oxygen evolution reaction (OER), these (NiFeCo)3(MoCr)3N multi-component nitrides form N-doped NiFeCoMoCrOOH high-entropy hydroxyl oxides, which serve as electrocatalytic active sites for the OER, achieving appropriate adsorption / desorption of reaction intermediates. Therefore, the nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode provided in this disclosure exhibits excellent OER performance, providing a material basis for the large-scale commercial application of water electrolysis for hydrogen production.

[0042] 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 multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode, characterized in that, Includes the following steps: a. Melting the alloy ingot: Weigh pure Ni, Fe, Co, Mo, Cr, and Al metal sheets according to an atomic ratio of 13:2:2:6:2:75, 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. b. Preparation of alloy sheet: Cut the alloy ingot with a diamond wire cutter to obtain an alloy sheet of a certain thickness; c. Chemical dealloying: The alloy sheet is placed in a 6M KOH solution saturated with N2 at 70°C for corrosion. After corrosion for a certain period of time, when no more bubbles are generated on the surface of the alloy sheet, the alloy sheet is washed with ultrapure water multiple times to obtain a nanoporous (MoCr)(NiFeCo)4 / HEA composite electrode material, which is then dried in a vacuum drying oven. d. Oxidation heat treatment: The above composite electrode material is placed in a tube furnace and heat-treated in an air atmosphere. After being held at a preset temperature for a certain time, it is cooled to room temperature to form NiFeCoMoCrO / HEA composite material. e. Nitriding heat treatment: The above NiFeCoMoCrO / HEA composite material is placed in a tube furnace and heat-treated in a mixed atmosphere of argon and ammonia. After being held at a preset temperature for a certain time, it is cooled to room temperature to obtain a nanoporous multi-component nitride / high entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode.

2. The method for preparing the nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode according to claim 1, characterized in that: The precursor alloy composition of the alloy ingot in step b is Ni at % 13 Fe2Co2Mo6Cr2Al 75 .

3. The method for preparing the nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode according to claim 1, characterized in that: The thickness of the alloy sheet after cutting in step b is 400 μm.

4. The method for preparing the nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode according to claim 1, characterized in that: In step c, the alloy sheet is placed in a 6 M KOH solution saturated with N2 at 70 °C for corrosion for 3 hours.

5. The method for preparing the nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode according to claim 1, characterized in that: In step d, the composite electrode material is placed in a tube furnace and heat-treated in an air atmosphere. The temperature is raised to 300 °C at a heating rate of 5 °C / min, held for 2 hours, and then cooled to room temperature.

6. The method for preparing the nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode according to claim 1, characterized in that: In step e, the NiFeCoMoCrO / HEA composite material is placed in a tube furnace and heat-treated in a mixed atmosphere of argon and ammonia, wherein the ammonia content is 10%. The temperature is raised to 900 °C at a heating rate of 5 °C / min, held for 2 hours, and then cooled to room temperature.

7. A nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode obtained by the preparation method according to any one of claims 1-6.

8. The application of the nanoporous multi-component nitride / high-entropy alloy (NiFeCo)3(MoCr)3N / HEA composite electrode according to claim 7, characterized in that, The composite electrode is used as the electrode material for the oxygen evolution reaction.

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