Ion beam sputtering high-entropy alloy glass electro-catalysis electrode and preparation method and application thereof

Abstract

The invention discloses an ion beam sputtering high-entropy alloy glass electro-catalysis electrode and a preparation method and application thereof.The method comprises the steps that firstly, a nickel micro-grid of a three-dimensional nanocone array structure is prepared through the micro-nano photoetching and electro-deposition technology, and then the obtained nickel micro-grid serves as a substrate; the catalytic electrode can be prepared by sputtering and depositing FeCoNiCrMn high-entropy metal glass on the surface through an ion beam sputtering method. According to the preparation method, the distribution uniformity of the high-entropy metal glass and the adhesive force of the high-entropy metal glass and the substrate can be enhanced, so that the integrated catalytic electrode can be directly used as a working electrode; meanwhile, the preparation method is high in controllability, high in repeatability and suitable for industrial production. The prepared catalytic electrode is mainly applied to water electrolysis reaction in alkaline electrolyte and shows excellent catalytic performance, the multi-element synergistic effect and the high-entropy effect enable the catalytic electrode to have high intrinsic catalytic activity and stability, and in addition, the amorphous structure exposes abundant active sites.

Description

Technical Field

[0001] The invention belongs to the technical field of electrocatalysts, and in particular relates to an ion beam sputtering high entropy alloy glass electrocatalytic electrode and a preparation method and application thereof. Background Art

[0002] The development of environmentally friendly and renewable energy is an inevitable trend to cope with the negative impact of traditional fossil fuels. Among them, the method of using green electricity to electrolyze water to produce hydrogen has attracted attention due to its zero carbon emissions. The water electrolysis reaction includes hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The overpotential generated by its slow kinetics reduces the energy conversion efficiency and seriously hinders the rate of hydrogen production. Precious metal catalysts have good catalytic performance, but their high price and scarcity limit their large-scale application. At present, transition metal elements such as Fe, Co, and Ni have shown high catalytic activity due to their appropriate adsorption energy for reaction intermediates, and have been widely studied as catalytic materials for water electrolysis.

[0003] High entropy metallic glass not only has high catalytic intrinsic activity due to the lattice distortion effect and the "cocktail" effect to adjust the electronic configuration and move the d-band center, but also usually exhibits excellent durability due to its high entropy effect and slow diffusion effect. In addition, due to the short-range ordered and long-range disordered atomic arrangement structure, it has a large number of unsaturated coordinations that are beneficial to the adsorption of reactants, which can provide a larger active surface area for catalytic reactions and is expected to become an ideal solution for the design of water splitting electrocatalysts.

[0004] The synthesis and preparation process of common high-entropy electrocatalytic materials is relatively complicated, with poor reproducibility, and most of them are in powder form, requiring the use of inactive binders to load them onto conductive substrates, which affects the exposure of active centers, electron transfer, and mass transfer. Therefore, it is urgent to research and develop a method for preparing an integrated high-entropy metallic glass electrode for water electrolysis. Summary of the invention

[0005] In order to solve the above technical problems, the main purpose of the present invention is to provide an ion beam sputtered high entropy alloy glass electrocatalytic electrode composed of non-precious metals, and apply it to the electrolysis of water under alkaline conditions to achieve excellent catalytic performance and stability.

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

[0007] The above-mentioned method for preparing the ion beam sputtering high entropy alloy glass electrocatalytic electrode comprises the following steps: (1) obtaining a patterned groove template on a conductive substrate coated with a photoresist by micro-nano lithography; (2) using a mixed solution of NiSO4•6H2O and NH4Cl as the electroplating solution, setting the current to a constant value, electro-depositing metal nickel in the groove template, and then peeling off to obtain a planar nickel microgrid; (3) using a mixed solution of NiCl2•6H2O, NH4Cl and H3BO3 as an electroplating solution for electrodeposition, and in situ growing nickel nanocones on the surface of the sample obtained in the above step (2); (4) placing the sample and sputtering target obtained in the above step (3) on the rotating sample table and target table of the vacuum chamber of the ion beam sputtering equipment respectively, closing the chamber, evacuating the chamber, introducing argon gas as a protective atmosphere, turning on the auxiliary ion source to clean the substrate and remove the surface pollutants and oxide layer; (5) The sample stage rotates at a constant speed, and the baffle is opened for sputtering for 2 to 20 minutes to obtain an ion beam sputtered high entropy alloy glass electrocatalytic electrode.

[0008] As a preferred technical solution, in the step (1), the mask contacts the conductive substrate on which the photoresist is spin-coated, is exposed to a 365nm ultraviolet light source for 10 to 60 seconds, and then is developed in a 0.5% NaOH solution for 10 to 60 seconds, the conductive substrate is one of materials such as ITO, FTO, AZO, etc., and the pattern is one of structures such as a grid, a honeycomb, a triangle, a ring, and a random structure.

[0009] As a preferred technical solution, in the 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.

[0010] As a preferred technical solution, in step (2), the electroplated conductive substrate is immersed in anhydrous ethanol to quickly peel off the flat nickel microgrid, and then immersed in deionized water, washed and dried.

[0011] As a preferred technical solution, in the 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 used is 10~20 mA cm-2, and the electrodeposition time is 5~20 min.

[0012] 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 evacuated to a vacuum degree of less than 5.0×10-4 Pa, and the flow rate of argon gas is set to 7 sccm.

[0013] 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 intensity is 50-52 mA, and the neutralization intensity is 61-63 mA.

[0014] The FeCoNiCrMn high entropy metallic glass material obtained by the above method can be used for electrocatalytic reactions, specifically for hydrogen production by alkaline water electrolysis.

[0015] The present invention has the following advantages: 1. The present invention selects five transition metals, FeCoNiCrMn, to prepare a high-entropy metallic glass electrocatalytic electrode, and utilizes the high-entropy effect and amorphous properties to improve the intrinsic catalytic activity, increase the active sites, reduce the overpotential, and optimize the catalytic performance of the water electrolysis reaction.

[0016] 2. The present invention uses the nickel microgrid prepared by micro-nano lithography and electrodeposition technology as a substrate to prepare an integrated electrode, utilizing its advantages of large specific surface area and high conductivity to promote the deposition and dispersion of active substances, increase the electron transfer rate, and help improve the electrocatalytic performance.

[0017] 3. The preparation method of the present invention has good controllability and high repeatability. The catalytic material is evenly distributed and well bonded to the substrate, which effectively prevents the catalytic material from falling off during long-term electrocatalysis and avoids the use of a binder. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly explain the core content of the present invention, the following is a brief introduction to the drawings involved in the description of the embodiments. It should be noted that the drawings shown below are only schematic diagrams of some embodiments of the present invention. For professionals in this field, other related drawings can be derived from these drawings without additional creative efforts, including: Figure 1 Schematic diagram of the processing of preparing FeCoNiCrMn catalytic electrode on three-dimensional nickel microgrid in Example 1.

[0019] Figure 2 This is the X-ray diffraction pattern of the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid prepared in Example 1.

[0020] Figure 3 This is a scanning electron microscope image of the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid prepared in Example 1.

[0021] Figure 4 OER linear sweep voltammetry curves and Tafel slope diagrams of the FeCoNiCrMn catalytic electrode 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 in 1 M KOH solution.

[0022] Figure 5 Graph showing 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 1 M KOH solution.

[0023] Figure 6 This is the chronopotentiometry diagram of the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid prepared in Example 1 in 1 M KOH solution. DETAILED DESCRIPTION

[0024] The technical solution of the embodiment of the present invention will be described in detail and comprehensively through the accompanying drawings in the embodiment of the present invention. It should be clear that the embodiment described here is only a part of the many embodiments of the present invention, not all. Based on the content shown in the embodiment of the present invention, all other embodiments that can be conceived by ordinary technicians in this field without performing creative work are deemed to be within the scope of protection of the present invention. Example 1

[0025] A method for preparing an ion beam sputtering high entropy alloy glass electrocatalytic electrode comprises the following steps: 1. The conductive glass ITO was ultrasonically cleaned with anhydrous ethanol and deionized water for 15 min and 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. After the photoresist was evenly distributed, it was moved to the baking board and baked at 100°C for 3 min; a honeycomb mask with a line width of 5 μm and a period of 180 μm was aligned and placed on the ITO, exposed to a 365 nm ultraviolet light source for 26 s, and the photolithographic ITO was placed in a 0.5% NaOH solution for development for 26 s.

[0026] 2. Ultrasonic cleaning and drying of nickel foam in anhydrous ethanol and deionized water; using a mixed solution consisting of 0.15 mol L-1 NiSO4•6H2O and 0.12 mol L-1 NH4Cl as the electroplating solution, stirring thoroughly and heating in a water bath at 45°C, using the nickel foam as the anode and the ITO obtained in step (1) as the cathode, and using a source meter to deposit at a constant current density of 1.5 mA cm-2 for 40 min; soaking the obtained material in anhydrous ethanol for rapid stripping, and soaking in deionized water, washing and drying to obtain a planar nickel microgrid.

[0027] 3. Use a mixed solution consisting 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, heat it in a water bath at 60°C, use nickel foam as the anode, and the planar nickel microgrid obtained in step (2) as the cathode, and use a source meter to electroplate at a current density of 10 mA cm-2 for 10 min; the obtained material is washed with anhydrous ethanol and deionized water, and dried to obtain a three-dimensional nickel microgrid with grown nanocones.

[0028] 4. Using an ion beam sputtering method, the three-dimensional nickel microgrid obtained in step (3) is used as a substrate, attached to a rotating sample stage with a high-temperature tape, and a FeCoNiCrMn high-entropy alloy target with an equiatomic ratio is fixed on the target stage; the chamber is closed, the pressure of 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 to remove surface pollutants and oxide layers.

[0029] 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 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

[0030] A method for preparing a high entropy alloy glass electrocatalytic electrode by ion beam sputtering is different from Example 1 in that the ion beam sputtering time is changed to 5 min, and the other aspects are the same as Example 1. Example 3

[0031] A method for preparing a high entropy alloy glass electrocatalytic electrode by ion beam sputtering is different from that in Example 1, except that the ion beam sputtering time is changed to 10 min, and the other aspects are the same as in Example 1. Example 4

[0032] A method for preparing a high entropy alloy glass electrocatalytic electrode by ion beam sputtering is different from Example 1 in that the ion beam sputtering time is changed to 20 min, and the other aspects are the same as Example 1.

[0033] Comparative Example 1 A method for preparing a high entropy metallic glass / nickel microgrid water electrolysis catalytic electrode comprises the following steps: (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. After the photoresist was evenly distributed, it was moved to a baking board and baked at 100°C for 3 min. A honeycomb mask with a line width 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 photolithographic ITO was placed in a 0.5% NaOH solution for development for 26 s.

[0034] (2) ultrasonically cleaning and drying the nickel foam in anhydrous ethanol and deionized water; using a mixed solution consisting of 0.15 mol L-1 NiSO46H2O and 0.12 mol L-1 NH4Cl as an electroplating solution, stirring the solution thoroughly and heating the solution in a water bath at 45°C, using the nickel foam as an anode and the ITO obtained in step (1) as a cathode, and depositing the solution at a constant current of 1.5 mA cm-2 for 40 min using a source surface; soaking the obtained material in anhydrous ethanol for rapid stripping, and soaking it in deionized water, cleaning it and drying it to obtain a planar nickel microgrid.

[0035] (3) The flat nickel microgrid obtained in step (2) is used as a substrate and attached to a rotating sample stage with a high-temperature tape, and a FeCoNiCrMn high-entropy alloy target with an equiatomic ratio is fixed on the target stage; the chamber is closed, the pressure of the vacuum chamber is evacuated to 5.0×10-4 Pa, and 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 to remove surface pollutants and oxide layers.

[0036] (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 metallic glass / nickel microgrid water electrolysis catalytic electrode.

[0037] Alkaline OER performance test: A three-electrode system was used, in which the samples prepared in the examples and comparative examples were cut into 1×1.5 cm2 as the working electrode, the counter electrode was a platinum sheet electrode, the reference electrode was a Hg / HgO electrode, and the electrolyte was a 1M KOH solution. Before the test, 500 CV cycles were performed in the range of 1.03~1.13 V vs RHE with a scan rate of 100 mV s-1.

[0038] 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 characteristic peaks of the base nickel metal, indicating that an integrated electrode with amorphous material loaded on the surface is obtained.

[0039] Figure 3 This is a scanning electron microscope image of the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid prepared in Example 1. As shown in the figure, the substrate maintains the original honeycomb shape while a layer of nickel nanocones is conformally coated on the surface, showing a good specific surface area, which is conducive to exposing more active sites of the catalytic material.

[0040] Figure 4 OER linear sweep voltammetric curves and Tafel slopes of the FeCoNiCrMn catalytic electrode 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 in 1.0 M KOH solution. The overpotential of the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid (e.g. Figure 3 a) and the Tafel slope (as Figure 3 b) are lower than the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid, indicating that the three-dimensional microstructure is conducive to improving the 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, and has excellent electrocatalytic performance and fast reaction kinetics. Therefore, the FeCoNiCrMn on the three-dimensional nickel microgrid sputtered for 2 min prepared in Example 1 is used as the preferred electrode.

[0041] Figure 5The 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. As can be seen from the figure, the Cdl value of the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid is 1.84 mF cm-2, and 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 electrochemically active surface area of ​​the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid is 3 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.

[0042] Figure 6 The chronopotentiometry diagram of the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid prepared in Example 1 in 1M KOH solution. The stability test was carried out at current densities of 10 mA cm-2 and 100 mA cm-2, which can be maintained for more than 100 hours and 30 hours respectively. The curve is stable and does not show obvious overpotential changes. The test results show that the FeCoNiCrMn catalytic electrode on the three-dimensional nickel microgrid has good stability in the alkaline oxygen evolution reaction.

[0043] The above embodiments are only used as examples to clearly explain the principles of the present invention, rather than strictly limiting its implementation methods. Those skilled in the art should recognize that the scope of the present invention is not limited to the above specific embodiments, but covers various forms of adjustments and changes to the present invention without violating the core ideas or basic characteristics of the present invention, which are deemed to be included in the scope of protection of the claims of the present invention.

Claims

1. An ion beam sputtered high entropy alloy glass electrocatalytic electrode, characterized in that: The catalytic electrode presents a three-dimensional ordered array structure, and its composition is that the surface layer is FeCoNiCrMn high entropy metallic glass, and the base layer is a nickel microgrid with nanocones grown on it.

2. A method for preparing the ion beam sputtered high entropy alloy glass electrocatalytic electrode according to claim 1, characterized in that: The specific steps include: (1) obtaining a patterned groove template on a conductive substrate coated with a photoresist by micro-nanolithography; (2) using a mixed solution of NiSO4•6H2O and NH4Cl as the electroplating solution, setting the current to a constant value, electro-depositing metal nickel in the groove template, and then peeling off to obtain a planar nickel microgrid; (3) using a mixed solution of NiCl2•6H2O, NH4Cl and H3BO3 as an electroplating solution for electrodeposition, and in situ growing nickel nanocones on the surface of the sample obtained in the above step (2); (4) placing the sample and sputtering target obtained in the above step (3) on the rotating sample table and target table of the vacuum chamber of the ion beam sputtering equipment respectively, closing the chamber, evacuating the chamber, introducing argon gas as a protective atmosphere, turning on the auxiliary ion source to clean the substrate and remove the surface pollutants and oxide layer; (5) The sample stage rotates at a constant speed, and the baffle is opened for sputtering for 2 to 20 minutes to obtain an ion beam sputtered high entropy alloy glass electrocatalytic electrode.

3. The method for preparing a high entropy alloy glass electrocatalytic electrode by ion beam sputtering according to claim 2, characterized in that: In the step (1), the mask contacts the conductive substrate on which the photoresist is spin-coated, is exposed to a 365 nm ultraviolet light source for 10 to 60 seconds, and then is developed in a 0.5% NaOH solution for 10 to 60 seconds. The conductive substrate is one of materials such as ITO, FTO, and AZO, and the pattern is one of structures such as a grid, a honeycomb, a triangle, a ring, and a random structure.

4. The method for preparing a high entropy alloy glass electrocatalytic electrode by ion beam sputtering according to claim 2, characterized in that: 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 cathode, and the current density was 1.5 mA cm -2 The electrodeposition time is 30 to 50 min.

5. The method for preparing a high entropy alloy glass electrocatalytic electrode by ion beam sputtering according to claim 2, characterized in that: In the step (2), the electroplated conductive substrate is immersed in anhydrous ethanol to quickly peel off the flat nickel microgrid, and then immersed in deionized water, washed and dried.

6. The method for preparing a high entropy alloy glass electrocatalytic electrode by ion beam sputtering according to claim 2, characterized in that: 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 was used as cathode, and the current density used was 10~20 mA cm -2 , the electrodeposition time is 5~20 min.

7. The method for preparing a high entropy alloy glass electrocatalytic electrode by ion beam sputtering according to claim 2, characterized in that: In the 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.%, and the gas pressure is pumped to a vacuum degree of 5.0×10 -4 Below Pa, the flow rate of argon gas was set to 7 sccm.

8. The method for preparing a high entropy alloy glass electrocatalytic electrode by ion beam sputtering according to claim 2, characterized in that: In the step (5), the sample stage rotation speed is 20-30 rpm, the main ion source energy is 500 eV, the beam intensity is 50-52 mA, and the neutralization intensity is 61-63 mA.

9. An application of an ion beam sputtered high entropy alloy glass electrocatalyst electrode, the application being the application of the ion beam sputtered high entropy alloy glass electrocatalyst electrode described in claim 1 or the ion beam sputtered high entropy alloy glass electrocatalyst electrode prepared by the preparation method described in any one of claims 2 to 8 in a catalytic reaction of water electrolysis, wherein the catalytic reaction of water electrolysis includes but is not limited to a hydrogen evolution reaction and an oxygen evolution reaction.

Images