An ion beam sputtered high-entropy alloy glass electrocatalytic electrode, its preparation method and application

Abstract

This invention discloses an ion beam sputtered high-entropy alloy glass electrocatalytic electrode, its preparation method, and its application. The method includes: firstly, fabricating a nickel microgrid with a three-dimensional nanocone array structure using micro-nano lithography and electrodeposition techniques; then, using the obtained nickel microgrid as a substrate, sputtering and depositing FeCoNiCrMn high-entropy metallic glass on its surface via ion beam sputtering to obtain the catalytic electrode. The preparation method of this invention enhances the uniformity of the high-entropy metallic glass distribution and its adhesion to the substrate; therefore, this integrated catalytic electrode can be directly used as a working electrode. Simultaneously, the preparation method is highly controllable and reproducible, suitable for industrial production. The catalytic electrode prepared by this invention is mainly applied to the water electrolysis reaction in alkaline electrolytes, exhibiting excellent catalytic performance. Its multi-component synergistic effect and high-entropy effect give it high intrinsic catalytic activity and stability. Furthermore, the amorphous structure exposes abundant active sites.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalyst technology, and particularly relates to an ion beam sputtering high-entropy alloy glass electrocatalytic electrode, its preparation method, and its application. Background Technology

[0002] Developing environmentally friendly and renewable energy sources is an inevitable trend to address the negative impacts of traditional fossil fuels. Among these methods, the electrolysis of water using green electricity to produce hydrogen has attracted attention due to its zero carbon emissions. The water electrolysis reaction includes the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). The slow kinetics of these reactions generate overpotentials that reduce energy conversion efficiency, severely hindering the rate of hydrogen production. Noble metal catalysts possess excellent catalytic performance, but their high cost and scarcity limit their large-scale application. Currently, transition metals such as Fe, Co, and Ni exhibit high catalytic activity due to their appropriate adsorption energies for reaction intermediates, and have been extensively studied as catalytic materials for water electrolysis.

[0003] High-entropy metallic glasses not only possess high intrinsic catalytic activity due to lattice distortion and the "cocktail" effect in regulating electronic configuration and shifting d-band centers, but also typically exhibit excellent durability due to their high-entropy and slow diffusion effects. Furthermore, their short-range ordered and long-range disordered atomic arrangement provides a large number of unsaturated coordination sites favorable for reactant adsorption, offering a larger active surface area for catalytic reactions and making them a promising candidate for designing water splitting electrocatalysts.

[0004] The synthesis and preparation processes of common high-entropy electrocatalytic materials are complex and have poor reproducibility. Furthermore, they are mostly in powder form and require inactive binders to be loaded onto conductive substrates, which affects the exposure of active centers, electron transfer, and mass transport. Therefore, there is an urgent need to research and develop a method for preparing an integrated high-entropy metallic glass electrode for water electrolysis. Summary of the Invention

[0005] To address the aforementioned technical problems, the main objective of this invention is to provide an ion beam sputtered high-entropy alloy glass electrocatalytic electrode composed of non-precious metals, and to apply it to water electrolysis under alkaline conditions to achieve excellent catalytic performance and stability.

[0006] Technical solution: The ion beam sputtering high-entropy alloy glass electrocatalytic electrode of the present invention has a three-dimensional ordered array structure, which is composed of FeCoNiCrMn high-entropy metallic glass as the surface layer and nickel microgrid with grown nanocones as the base layer.

[0007] The above-mentioned method for preparing a high-entropy alloy glass electrocatalytic electrode by ion beam sputtering includes the following steps:

[0008] (1) A patterned trench template is obtained on a conductive substrate coated with photoresist by micro-nano photolithography;

[0009] (2) Using a mixed solution of NiSO4•6H2O and NH4Cl as the electroplating solution, and setting the current to a constant value, metallic nickel is electrodeposited in the trench template, and then peeled off to obtain a planar nickel microgrid.

[0010] (3) Electrodeposition was performed using a mixed solution of NiCl2•6H2O, NH4Cl and H3BO3 as an electroplating solution, and nickel nanocones were grown in situ on the surface of the sample obtained in step (2) above.

[0011] (4) Place the sample and sputtering target obtained in step (3) into the rotating sample stage and target stage of the vacuum chamber of the ion beam sputtering equipment, respectively. Close the chamber, evacuate, introduce argon gas as a protective atmosphere, turn on the auxiliary ion source to clean the substrate and remove the surface contaminants and oxide layer.

[0012] (5) The sample stage is rotated at a constant speed, and the baffle is opened for sputtering for 2~20 min to obtain the ion beam sputtered high-entropy alloy glass electrocatalytic electrode.

[0013] As a preferred technical solution, in step (1), the mask contacts the conductive substrate of the spin-coated photoresist and is exposed to a 365nm ultraviolet light source for 10~60 s, and then developed in a 0.5% NaOH solution for 10~60 s. The conductive substrate is one of the materials such as ITO, FTO, and AZO, and the pattern is one of the structures such as square, honeycomb, triangle, ring, and random.

[0014] As a preferred technical solution, in step (2), the concentration of NiSO4•6H2O is 0.1~0.2 mol L-1, the concentration of NH4Cl is 0.1~0.15 mol L-1, nickel foam is used as the cathode, the current density is 1.5 mA cm-2, and the electrodeposition time is 30~50 min.

[0015] As a preferred technical solution, in step (2), the electroplated conductive substrate is immersed in anhydrous ethanol to quickly peel off the planar nickel microgrid, and then soaked, cleaned and dried with deionized water.

[0016] As a preferred technical solution, in step (3), the concentration of NiCl2•6H2O is 0.8~0.9 mol L-1, the concentration of NH4Cl is 0.7~0.8 mol L-1, the concentration of H3BO3 is 1.5~1.7 mol L-1, nickel foam is used as the cathode, the current density is 10~20 mA cm-2, and the electrodeposition time is 5~20 min.

[0017] As a preferred technical solution, in step (4), the sputtering target is a FeCoNiCrMn high-entropy alloy target, the atomic content of each element in the target is 10~30 at.%, the gas pressure is pumped to a vacuum degree below 5.0×10-4 Pa, and the argon flow rate is set to 7 sccm.

[0018] As a preferred technical solution, in step (5), the sample stage rotation speed is 20~30 rpm, the main ion source energy is 500 eV, the beam current intensity is 50~52 mA, and the neutralization intensity is 61~63 mA.

[0019] The FeCoNiCrMn high-entropy metallic glass material obtained by the above method can be used for electrocatalytic reactions, specifically for alkaline water electrolysis to produce hydrogen.

[0020] The present invention has the following advantages:

[0021] 1. This invention selects five transition metals, Fe, Co, Ni, Cr, and Mn, to prepare a high-entropy metallic glass electrocatalytic electrode. By utilizing the high-entropy effect and amorphous characteristics, the intrinsic catalytic activity is improved, the active sites are increased, the overpotential is reduced, and the catalytic performance of the water electrolysis reaction is optimized.

[0022] 2. This invention uses a nickel microgrid prepared by micro-nano lithography and electrodeposition technology as a substrate to prepare an integrated electrode. Taking advantage of its large specific surface area and high conductivity, it promotes the deposition and dispersion of active materials, improves the electron transfer rate, and helps to improve electrocatalytic performance.

[0023] 3. The preparation method of this invention has good controllability and high repeatability. The catalytic material is evenly distributed and has good bonding with the substrate, effectively preventing its detachment during long-term electrocatalysis and avoiding the use of binders. Attached Figure Description

[0024] To more clearly illustrate the core content of this invention, the accompanying drawings involved in the description of the embodiments will be briefly introduced below. It should be noted that the drawings shown below are only schematic diagrams of some embodiments of this invention. For those skilled in the art, other related drawings can be derived from these drawings without additional creative effort, wherein:

[0025] Figure 1 This is a schematic diagram of the fabrication process for the FeCoNiCrMn catalytic electrode on a three-dimensional nickel microgrid in Example 1.

[0026] Figure 2 The X-ray diffraction pattern of the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid prepared in Example 1.

[0027] Figure 3Scanning electron microscope image of the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid prepared in Example 1.

[0028] Figure 4 The OER linear sweep voltammetric curves and Tafel slope plots of the three-dimensional nickel microgrid FeCoNiCrMn catalytic electrodes prepared in Examples 1-4 and the planar nickel microgrid FeCoNiCrMn catalytic electrodes prepared in Comparative Example 1 in 1 M KOH solution are shown.

[0029] Figure 5 The double-layer capacitance (Cdl) of the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid prepared in Example 1 and the FeCoNiCrMn catalytic electrode on the planar nickel microgrid prepared in Comparative Example 1 in 1M KOH solution is shown.

[0030] Figure 6 Chronopotential curve of the FeCoNiCrMn catalytic electrode on a three-dimensional nickel microgrid prepared in Example 1 in 1M KOH solution. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be described in detail and comprehensively below with reference to the accompanying drawings. It should be understood that the embodiments described herein are merely a part of the numerous embodiments of the present invention, and not all of them. Based on the content shown in the embodiments of the present invention, all other embodiments that can be conceived by those skilled in the art without creative work are considered to fall within the protection scope of the present invention. Example 1

[0032] A method for preparing a high-entropy alloy glass electrocatalytic electrode by ion beam sputtering includes the following steps:

[0033] 1. The conductive glass ITO was ultrasonically cleaned with anhydrous ethanol and deionized water for 15 min and then dried. 3 mL of positive photoresist was coated onto the ITO and spin-coated at low speed (500 rpm) for 10 s and high speed (800 rpm) for 30 s, respectively, to ensure uniform distribution of the photoresist. The coated ITO was then transferred to a baking plate and baked at 100°C for 3 min. A honeycomb mask with a 5 μm linewidth and 180 μm period was aligned and placed on the ITO, and exposed to a 365 nm UV light source for 26 s. The photolithographically etched ITO was then developed in a 0.5% NaOH solution for 26 s.

[0034] 2. The nickel foam was ultrasonically cleaned and dried in anhydrous ethanol and deionized water. A mixed solution of 0.15 mol L-1 NiSO4•6H2O and 0.12 mol L-1 NH4Cl was used as the electroplating solution. The solution was stirred thoroughly and heated in a water bath at 45 °C. The nickel foam was used as the anode and the ITO obtained in step (1) was used as the cathode. The solution was deposited at a constant current density of 1.5 mA cm-2 for 40 min using a source plate. The resulting material was immersed in anhydrous ethanol for rapid stripping and then immersed, cleaned and dried in deionized water to obtain a planar nickel microgrid.

[0035] 3. Using a mixed solution of 0.84 mol L-1 NiCl2•6H2O, 0.75 mol L-1 NH4Cl and 1.62 mol L-1 H3BO3 as the electroplating solution, the solution was heated in a water bath at 60°C. The foamed nickel was used as the anode and the planar nickel microgrid obtained in step (2) was used as the cathode. Electroplating was performed at a current density of 10 mA cm-2 for 10 min using a source plate. The resulting material was cleaned with anhydrous ethanol and deionized water and dried to obtain a three-dimensional nickel microgrid with nanocones.

[0036] 4. Using ion beam sputtering, the three-dimensional nickel microgrid obtained in step (3) is used as a substrate and attached to the rotating sample stage with high-temperature tape. The FeCoNiCrMn high-entropy alloy target with an atomic ratio is fixed on the target stage. The chamber is closed and the vacuum chamber is evacuated to 5.0×10-4 Pa. Argon gas is introduced as a protective atmosphere and the flow rate of argon gas is set to 7 sccm. The auxiliary ion source is turned on to clean the substrate and remove the surface contaminants and oxide layer.

[0037] 5. Turn on the main ion source switch, the main ion source energy is 500 eV, the sample stage rotates at a constant speed of 26 rpm, open the baffle for sputtering, the beam current intensity is 51 mA, the neutralization intensity is 63 mA, the sputtering time is 2 min, and finally take out the ion beam sputtered high-entropy alloy glass electrocatalytic electrode. Example 2

[0038] The preparation method of a high-entropy alloy glass electrocatalytic electrode by ion beam sputtering differs from that in Example 1 in that the ion beam sputtering time is changed to 5 min, while the rest is the same as in Example 1. Example 3

[0039] The preparation method of a high-entropy alloy glass electrocatalytic electrode by ion beam sputtering is the same as that in Example 1, except that the ion beam sputtering time is changed to 10 min. Example 4

[0040] The preparation method of a high-entropy alloy glass electrocatalytic electrode by ion beam sputtering differs from that in Example 1 in that the ion beam sputtering time is changed to 20 min, while the rest is the same as in Example 1.

[0041] Comparative Example 1

[0042] A method for preparing a high-entropy metallic glass / nickel microgrid catalytic electrode for water electrolysis includes the following steps:

[0043] (1) The conductive glass ITO was ultrasonically cleaned with anhydrous ethanol and deionized water for 15 min and then dried. 3 mL of positive photoresist was coated on the ITO and spin-coated at a low speed of 500 r s-1 and a high speed of 800 r s-1 for 10 s and 30 s respectively to ensure uniform distribution of the photoresist. The coated ITO was then transferred to a baking plate and baked at 100℃ for 3 min. A honeycomb mask with a linewidth of 5 μm and a period of 180 μm was aligned and placed on the ITO and exposed to a 365 nm ultraviolet light source for 26 s. The photolithographically etched ITO was then placed in a 0.5% NaOH solution for development for 26 s.

[0044] (2) The nickel foam was ultrasonically cleaned and dried in anhydrous ethanol and deionized water; a mixed solution of 0.15 mol L-1 NiSO46H2O and 0.12 mol L-1 NH4Cl was used as the electroplating solution, and the mixture was stirred thoroughly and heated in a water bath at 45°C. The nickel foam was used as the anode and the ITO obtained in step (1) was used as the cathode. The material was deposited at a constant current density of 1.5 mA cm-2 for 40 min using a source plate; the resulting material was immersed in anhydrous ethanol for rapid stripping, and then immersed, cleaned and dried in deionized water to obtain a planar nickel microgrid.

[0045] (3) The planar nickel microgrid obtained in step (2) is used as a substrate and attached to the rotating sample stage with high-temperature tape. The FeCoNiCrMn high-entropy alloy target with an atomic ratio is fixed on the target stage. The chamber is closed and the vacuum chamber is evacuated to 5.0×10-4 Pa. Argon gas is introduced as a protective atmosphere and the flow rate of argon gas is set to 7 sccm. The auxiliary ion source is turned on to clean the substrate and remove the contaminants and oxide layer on the surface.

[0046] (4) Turn on the main ion source switch, the main ion source energy is 500 eV, the sample stage rotates at a constant speed of 26 rpm, open the baffle for sputtering, the beam intensity is 51 mA, the neutralization intensity is 63 mA, the sputtering time is 2 min, and finally take out the high-entropy metal glass / nickel microgrid electrolytic water catalytic electrode.

[0047] Alkaline OER performance test:

[0048] A three-electrode system was used, in which the samples prepared in the examples and comparative examples were cut into 1×1.5 cm² pieces as the working electrode, a platinum sheet electrode as the counter electrode, and an Hg / HgO electrode as the reference electrode. The electrolyte was a 1M KOH solution. Before testing, 500 CV cycles were performed in the range of 1.03–1.13 V vs RHE at a scan rate of 100 mV s⁻¹.

[0049] Figure 2 The X-ray diffraction pattern of the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid prepared in Example 1 shows that the catalytic electrode only has the characteristic peaks of the nickel metal substrate, indicating that an integrated electrode with amorphous material loaded on the surface was obtained.

[0050] Figure 3 The image shows a scanning electron microscope (SEM) image of the FeCoNiCrMn catalytic electrode on a three-dimensional nickel microgrid prepared in Example 1. As shown in the figure, while maintaining the original honeycomb shape, the substrate is conformally coated with a layer of nickel nanocones, exhibiting a good specific surface area, which is beneficial for exposing more active sites in the catalytic material.

[0051] Figure 4 The OER linear sweep voltammetry curves and Tafel slope plots of the FeCoNiCrMn catalytic electrodes on the three-dimensional nickel microgrid prepared in Examples 1-4 and the FeCoNiCrMn catalytic electrode on the planar nickel microgrid prepared in Comparative Example 1 are shown in 1.0 M KOH solution. The overpotential (e.g., of the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid) is also shown. Figure 3 (as shown in a) and Tafel slope (as shown in a) Figure 3 (As shown in b) The values ​​are all lower than those of the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid, indicating that the three-dimensional microstructure is beneficial to improving catalytic performance. By comparison, it can be seen that the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid prepared in Example 1 has an OER overpotential of 296 mV and a Tafel slope of 41.45 mV dec⁻¹ at a current density of 10 mA cm⁻², exhibiting excellent electrocatalytic performance and rapid reaction kinetics. Therefore, the FeCoNiCrMn electrode on the three-dimensional nickel microgrid prepared in Example 1, sputtered for 2 min, is the preferred electrode.

[0052] Figure 5The figure shows the double-layer capacitance (Cdl) of the FeCoNiCrMn catalytic electrode on a three-dimensional nickel microgrid prepared in Example 1 and the FeCoNiCrMn catalytic electrode on a planar nickel microgrid prepared in Comparative Example 1 in 1M KOH solution. As shown in the figure, the Cdl value of the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid is 1.84 mF cm⁻², while the Cdl value of the FeCoNiCrMn catalytic electrode on the planar nickel microgrid is 0.59 mF cm⁻². Under the premise of the same sputtering deposition amount, the electrochemical active surface area of ​​the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid is three times that of the FeCoNiCrMn catalytic electrode on the planar nickel microgrid, indicating that the three-dimensional nanocone structure of the substrate can expose more active sites.

[0053] Figure 6 The chronopotential curves of the FeCoNiCrMn catalytic electrode on a three-dimensional nickel microgrid prepared in Example 1 in 1M KOH solution are shown. Stability tests were conducted at current densities of 10 mA cm⁻² and 100 mA cm⁻², respectively, and the electrode maintained its stability for over 100 h and 30 h, showing no significant overpotential change. The test results indicate that the FeCoNiCrMn catalytic electrode on a three-dimensional nickel microgrid exhibits good stability in the alkaline oxygen evolution reaction.

[0054] The above embodiments are merely examples to clearly illustrate the principles of the present invention, and are not intended to be strict limitations on its implementation. Those skilled in the art should recognize that the scope of the present invention is not limited to the specific embodiments described above, but encompasses various adjustments and variations made without departing from the core ideas or fundamental characteristics of the present invention, all of which are considered to be included within the protection scope of the claims of the present invention.

Claims

1. A method for preparing an ion beam sputtered high-entropy alloy glass electrocatalytic electrode, wherein the prepared ion beam sputtered high-entropy alloy glass electrocatalytic electrode has a three-dimensional ordered array structure, and its composition is a FeCoNiCrMn high-entropy metallic glass surface layer and a nickel microgrid with grown nanocones as the base layer. Its features are, Specifically, the following steps are included: (1) A patterned trench template is obtained on a conductive substrate coated with photoresist by micro-nano photolithography; (2) Using a mixed solution of NiSO4•6H2O and NH4Cl as the electroplating solution, and setting the current to a constant value, metallic nickel is electrodeposited in the trench template, and then peeled off to obtain a planar nickel microgrid. (3) Electrodeposition was performed using a mixed solution of NiCl2•6H2O, NH4Cl and H3BO3 as an electroplating solution, and nickel nanocones were grown in situ on the surface of the sample obtained in step (2) above. (4) Place the sample and sputtering target obtained in step (3) into the rotating sample stage and target stage of the vacuum chamber of the ion beam sputtering equipment, respectively. Close the chamber, evacuate, introduce argon gas as a protective atmosphere, turn on the auxiliary ion source to clean the substrate and remove the surface contaminants and oxide layer. (5) The sample stage is rotated at a constant speed, and the baffle is opened for sputtering for 2~20 min to obtain the ion beam sputtered high-entropy alloy glass electrocatalytic electrode. In step (1), the mask contacts the conductive substrate of spin-coated photoresist and is exposed to a 365 nm ultraviolet light source for 10-60 s, and then developed in a 0.5% NaOH solution for 10-60 s. The conductive substrate is one of ITO, FTO, and AZO materials, and the pattern is one of square, honeycomb, triangle, and ring. In step (2), the concentration of NiSO4•6H2O is 0.1~0.2 mol L. -1 The concentration of NH4Cl is 0.1~0.15 mol / L. -1 Nickel foam was used as the anode, and the current density was 1.5 mA cm⁻¹. -2 The electrodeposition time is 30-50 min; In step (3), the concentration of NiCl2•6H2O is 0.8~0.9 mol L. -1 The concentration of NH4Cl is 0.7~0.8 mol L. -1 The concentration of H3BO3 was 1.5~1.7 mol L. -1 Nickel foam was used as the anode, with a current density of 10~20 mA cm⁻¹. -2 The electrodeposition time is 5~20 min.

2. The method for preparing the ion beam sputtered high-entropy alloy glass electrocatalytic electrode according to claim 1, characterized in that: In step (2), the electroplated conductive substrate is immersed in anhydrous ethanol to quickly peel off the planar nickel microgrid, and then soaked, cleaned and dried with deionized water.

3. The method for preparing the ion beam sputtered high-entropy alloy glass electrocatalytic electrode according to claim 1, characterized in that: In step (4), the sputtering target is a FeCoNiCrMn high-entropy alloy target, and the atomic content of each element in the target is 10~30 at.%. The gas pressure is evacuated to a vacuum degree of 5.0×10⁻⁶. -4 For pressures below Pa, the argon flow rate is set to 7 sccm.

4. The method for preparing the ion beam sputtered high-entropy alloy glass electrocatalytic electrode according to claim 1, characterized in that: In step (5), the sample stage rotation speed is 20~30 rpm, the main ion source energy is 500 eV, the beam current intensity is 50~52mA, and the neutralization intensity is 61~63 mA.

5. An application of an ion beam sputtered high-entropy alloy glass electrocatalytic electrode, wherein the application is the application of the ion beam sputtered high-entropy alloy glass electrocatalytic electrode prepared by the preparation method according to any one of claims 1 to 4 in the water electrolysis catalytic reaction, wherein the water electrolysis catalytic reaction includes hydrogen evolution reaction and oxygen evolution reaction.

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