Multi-grain-boundary ZnFeCoNiMnCu-coated Cu water electrolysis catalyst as well as preparation method and application thereof

Abstract

The invention discloses a multi-grain-boundary ZnFeCoNiMnCu-coated Cu water electrolysis catalyst as well as a preparation method and application thereof, and belongs to the technical field of hydrogen production by water electrolysis. The preparation method of the multi-grain-boundary ZnFeCoNiMnCu-coated Cu electrolytic water catalyst comprises the following steps: preparing an aqueous solution containing Zn < 2 + >, Fe < 3 + >, Co < 2 + >, Ni < 2 + >, Mn < 2 + > and citric acid, and electrically depositing a ZnFeCoNiMnCu amorphous layer on a Cu sheet containing a micro-nano porous structure by taking the solution as an electroplating solution to obtain the multi-grain-boundary ZnFeCoNiMnCu-coated Cu electrolytic water catalyst. The surface of the prepared multi-grain-boundary ZnFeCoNiMnCu-coated Cu water electrolysis catalyst is a catalyst layer with a three-dimensional nano-porous multi-grain-boundary structure. The catalytic activity and the stability of the catalyst are improved, the preparation cost is reduced, and the catalyst has a wide application prospect and a remarkable economic value in the field of hydrogen production by electrolysis of water.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen production by electrolysis of water, and particularly relates to a polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] As the demand for clean energy grows, hydrogen production from water electrolysis has attracted much attention. High-entropy alloys have broad prospects in the field of electrocatalysis, and a variety of high-entropy alloy catalysts have been used for hydrogen production from water electrolysis. For example, Chinese invention patent CN115584526A (A thin film catalyst for oxygen evolution reaction in water electrolysis and its preparation method) discloses that a (FeCoNiCuZn)O thin film catalyst prepared by radio frequency magnetron sputtering using metal plates such as Fe and Co as target materials can be used to catalyze hydrogen production from water electrolysis. However, the catalyst prepared by this method has the defect of a single nanorod scale structure, which affects the number of active sites and charge conduction, making it difficult to meet the requirements of efficient catalysis. Therefore, the development of new structural water electrolysis catalysts is of great significance to meet industrial application requirements. Summary of the Invention

[0003] The purpose of the present invention is to provide a polycrystalline boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst and its preparation method and application, so as to solve the problems of unreasonable structural design, insufficient active sites and poor charge conduction ability of existing water electrolysis catalysts. Through a unique process design, the method generates a ZnFeCoNiMnCu layer with a polycrystalline boundary structure on the surface of a Cu carrier, and the generated high-entropy polycrystalline boundary alloy catalyst layer contains elements in the carrier. At the same time, the three-dimensional nanopore structure of the polycrystalline boundary can significantly increase the number of active sites and optimize the charge conduction path, thereby effectively improving the activity and stability of the catalyst. At the same time, the preparation method is relatively simple, has low equipment requirements, has a wide range of raw materials, is cost-controlled, and can achieve large-scale industrial production.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] One of the technical solutions of the present invention is to provide a method for preparing a polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst, comprising the following steps:

[0006] Formulated with Zn 2+ 、Fe 3+ 、Co 2+ 、Ni 2+ 、Mn 2+ and an aqueous solution of citric acid, using the solution as an electroplating solution to electrodeposit a ZnFeCoNiMnCu amorphous layer on a Cu sheet containing a micro-nano porous structure to obtain the polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst.

[0007] Optionally, the Zn 2+ The source of Fe is Zn(NO3)2·6H2O; 3+ The source of the Co 2+ The source is Co(NO3)2·6H2O; the Ni 2+ The source of Mn is Ni(NO3)2·6H2O; 2+ The source is Mn(NO3)2·4H2O.

[0008] Preferably, the Zn-containing 2+ 、Fe 3+ 、Co 2+ 、Ni 2+ 、Mn 2+ and citric acid aqueous solutions, the concentrations of each substance are 0.01~0.1mol / L, 0.01~0.1mol / L, 0.01~0.1mol / L, 0.01~0.1mol / L, 0.01~0.1mol / L, 0.01~0.1mol / L and 0.01~0.2mmol / L, respectively.

[0009] Preferably, the thickness of the Cu sheet containing the micro-nano porous structure is 200-600 μm.

[0010] Preferably, a three-electrode system is used during the electrodeposition, wherein a Cu sheet containing a micro-nano porous structure is used as a working electrode.

[0011] More preferably, a pulse voltage is used during the electrodeposition.

[0012] Further preferably, the frequency of the pulse voltage is 0.1 to 10 seconds; and the number of times the pulse voltage is operated is 5 to 500 times.

[0013] Optionally, the Cu sheet containing the micro-nano porous structure is prepared by dissolving the Al element in the AlCu alloy sheet with an acid solution.

[0014] Preferably, the atomic ratio of Cu to Al in the AlCu alloy sheet is 1.5:8.5 to 2.5:6.5.

[0015] Preferably, the acid solution is a HCl solution with a concentration of 1.5 to 2.5 M; and the dissolution time is 1 to 12 hours.

[0016] The second technical solution of the present invention is to provide a polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared according to the preparation method of the polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst.

[0017] The third technical solution of the present invention is to provide an application of the above-mentioned polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst in hydrogen production by water electrolysis.

[0018] The beneficial technical effects of the present invention are as follows:

[0019] The polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared by this invention has a catalyst layer with a three-dimensional nanoporous polycrystalline structure on its surface. This improves the catalyst's catalytic activity and stability while reducing its production cost. It has broad application prospects and significant economic value in the field of hydrogen production by water electrolysis.

[0020] In the polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared by this invention, the presence of polycrystalline boundaries significantly increases the specific surface area of ​​the catalyst, significantly increasing the number of active sites. Furthermore, the polycrystalline boundary structure optimizes the charge conduction path, thereby enhancing the intrinsic activity of the catalyst.

[0021] The examples show that the ZnFeCoNiMnCu@Cu electrolytic water catalyst prepared by the present invention has a high conductivity and high conductivity in 1M KOH solution at 10 and 400 mA·cm -2 At a current density of 1.5 GHz, the overpotential of the hydrogen evolution reaction in water electrolysis was as low as 20 and 156 mV, and after 2000 hours of operation, it still maintained 400 mA cm -2 There is no obvious current density decay. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a scanning electron microscope image of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 1 of the present invention.

[0023] Figure 2 This is a transmission electron microscope image of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 1 of the present invention.

[0024] Figure 3 This is a high-resolution transmission electron micrograph of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 1 of the present invention.

[0025] Figure 4 This is a bar chart of the element content of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 1 of the present invention.

[0026] Figure 5 This is the XRD pattern of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 1 of the present invention.

[0027] Figure 6This is the linear sweep voltammetry curve of the hydrogen evolution reaction of the polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 1 of the present invention.

[0028] Figure 7 This is a constant current stability diagram of the hydrogen evolution reaction of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 1 of the present invention.

[0029] Figure 8 This is a scanning electron microscope image of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 2 of the present invention.

[0030] Figure 9 This is the linear sweep voltammetry curve of the hydrogen evolution reaction of the polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 2 of the present invention.

[0031] Figure 10 This is a scanning electron microscope image of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 3 of the present invention.

[0032] Figure 11 This is the linear sweep voltammetry curve of the hydrogen evolution reaction of the polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 3 of the present invention.

[0033] Figure 12 This is a scanning electron microscope image of the multi-grain boundary FeCoNiMnCu@Cu water electrolysis catalyst prepared in Comparative Example 1 of the present invention.

[0034] Figure 13 This is the linear sweep voltammetry curve of the hydrogen evolution reaction of the multi-grain boundary FeCoNiMnCu@Cu water electrolysis catalyst prepared in Comparative Example 1 of the present invention.

[0035] Figure 14 This is a scanning electron microscope image of the multi-grain boundary CoNiMnCu@Cu prepared in Comparative Example 2 of the present invention.

[0036] Figure 15 This is the linear sweep voltammetry curve of the hydrogen evolution reaction of the multi-grain boundary CoNiMnCu@Cu water electrolysis catalyst prepared in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0037] Various exemplary embodiments of the present invention are now described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention.

[0038] It should be pointed out that the matters not described in detail in the present invention are conventional operating means in this field and are not the focus of the present invention.

[0039] In addition, for numerical ranges in the present invention, it is understood that each intervening value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any stated value or stated range, and any other stated value or intervening value in the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention.

[0041] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0042] Example 1

[0043] Preparation of polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst:

[0044] (1) Cu (99% purity) and Al (99% purity) metals were arc melted at 2000°C in a N2 atmosphere. The atomic percentages of Cu and Al elements were 20%:80%.

[0045] (2) The AlCu alloy obtained in step (1) was subjected to furnace cooling and cutting procedures to prepare AlCu alloy sheets of 1 cm×1.5 cm×400 μm.

[0046] (3) The AlCu alloy sheet prepared in step (2) was immersed in a 2M HCl solution for 4 h to chemically dealloy and remove Al.

[0047] (4) The dealloyed sample in step (3) was rinsed three times with ultrapure water to remove the residual chemical substances in the nanopores, thereby obtaining a micro-nano porous Cu skeleton metal sheet.

[0048] (5) Take 0.4040 g of Fe(NO3)3·9H2O, 0.29746 g of Zn(NO3)2·6H2O, 0.36739 g of Co(NO3)2·6H2O, 0.2907 g of Ni(NO3)2·6H2O, 0.2510 g of Mn(NO3)2·4H2O and 0.9606 g of anhydrous citric acid and dissolve them in 50 mL of H2O to obtain an electroplating solution.

[0049] (6) Using the nanoporous Cu skeleton metal sheet, graphite rod electrode and saturated calomel electrode cleaned in step (4) as the working electrode, counter electrode and reference electrode, respectively, and the plating solution prepared in step (5) as the deposition electrolyte, a three-electrode system is assembled.

[0050] (7) Under a pulse voltage of -1 V (relative to a saturated calomel electrode), the pulse mode was run 10 times with 0.5 s on / 0.5 s off to electrodeposit a ZnFeCoNiMnCu amorphous layer on a micro-nano porous Cu skeleton metal sheet to obtain a polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst.

[0051] Figure 1 This is a scanning electron microscope image of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 1. Figure 1 A three-dimensional porous network structure with multi-level pores interwoven can be clearly observed, including micron-sized macropores and mesopores / micropores, similar to a "honeycomb-sponge" composite structure. This multi-level pore system can expose abundant active sites and increase the contact area with the electrolyte; at the same time, the macropores act as "channels" and the micropores / mesopores act as "reaction site carriers", thereby accelerating mass transfer and promoting the transport of protons and electrons and the escape of H2 in the hydrogen evolution reaction. The overall block structure size is about 15-20μm (length / width dimensions), the size of the single-level pores (macropores) is mostly 1-5μm, the pore wall thickness and the internal meso / micropore size are submicron to tens of nanometers, constructing a "macro-meso-micro" cross-scale pore system that adapts to the multi-scale mass transfer and reaction requirements in the hydrogen evolution reaction.

[0052] Figure 2 This is a transmission electron microscope image of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 1. Figure 2 It can be clearly observed that the ZnFeCoNiMnCu-based catalytic material presents a composite structure of "nanoparticle agglomerates + multi-level pores". The agglomerates are composed of a large number of sub-100nm nanoparticles, which are interconnected and stacked; the nanoparticles are accumulated to form mesoscopic-macroscopic multi-level pores, with pore sizes ranging from tens to hundreds of nanometers, constructing a three-dimensional through-channel network; the particles maintain a certain degree of dispersion and form a continuous conductive network through moderate agglomeration.

[0053] Figure 3 This is a high-resolution transmission electron microscopy image of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 1. Figure 3A multilayer heterostructure with orderly stacking of nanoscale crystal planes can be clearly observed. The regularly arranged atomic lattice fringes are clearly visible, and the orientation and spacing of the lattice fringes vary from region to region, forming a composite system of interwoven polycrystalline domains. This structure enhances the catalytic activity of the hydrogen evolution reaction through crystal face synergy. Furthermore, the multilayer heterogeneous stacking can create a "microinterface electric field," promoting charge transfer during the proton adsorption-reduction-desorption process and accelerating the HER kinetics.

[0054] Figure 4 This is the element content diagram of the polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 1. Figure 4 The atomic ratios of various elements in the ZnFeCoNiMnCu@Cu catalyst can be clearly observed (Zn / Fe / Co / Ni / Mn / Cu = 0.08 / 0.48 / 0.28 / 32.67 / 0.04 / 66.44).

[0055] Figure 5 This is the XRD pattern of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 1. Figure 5 It can be clearly observed that by comparing with the standard cards (Cu2O PDF#78-2076, CuO PDF#89-5895, Cu PDF#85-1326), the characteristic diffraction peaks (111), (200), and (220) of Cu element are clearly presented at about 43.3°, 50.4°, and 74.1° (matching PDF#85-1326). The peaks are sharp and strong, indicating that the Cu crystal phase has good crystallinity and forms a regular face-centered cubic (fcc) crystal structure. This high crystallinity Cu matrix can provide a stable electron transport skeleton for electrocatalytic hydrogen evolution; the surface active sites anchor the substrate; at the same time, compared with the standard peaks of Cu2O (PDF#78-2076) and CuO (PDF#89-5895), no significant Cu + / Cu 2+ The oxidation phase diffraction peak indicates that Cu in the sample is primarily present in a single-element state, with a low degree of surface oxidation. This is beneficial for HER: it avoids the additional charge transport resistance introduced by the oxidation phase and ensures rapid electron transfer during the catalytic process.

[0056] Figure 6 This is the linear sweep voltammetry curve of the hydrogen evolution reaction of the polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 1. Figure 6It can be clearly observed that as the overpotential moves from 0V to -0.15V, the current density gradually increases, reflecting the changes in the HER activity of the material under different driving voltages. The curve shows a typical "activation-reaction acceleration" characteristic. In the high overpotential range, the slope of the current density with the overpotential increases, indicating that the HER reaction kinetics are accelerated and the material is sensitive to changes in overpotential. From the curve, it can be observed that when the overpotential increases, the current density increases rapidly, indicating that the material can achieve significant HER current at low driving voltages.

[0057] Figure 7 This is the constant current stability diagram of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 1. Figure 7 It can be clearly observed that the polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst has no significant current decay after 2000 hours of service, indicating that the surface active sites of the polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst have not undergone irreversible deactivation. This reflects the strong interface bonding between the catalyst and the Cu substrate, and the fact that the catalyst's crystal structure has not undergone phase transformation or collapse.

[0058] Example 2

[0059] Preparation of polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst:

[0060] (1) Arc melting of Cu (99%) and Al (99%) metals at 1000°C in a N2 atmosphere, with the atomic percentages of Cu and Al being 20%:80%.

[0061] (2) The AlCu alloy obtained in step (1) was subjected to furnace cooling and cutting procedures to prepare AlCu alloy sheets of 1 cm×1.5 cm×200 μm.

[0062] (3) The AlCu alloy sheet prepared in step (2) was immersed in a 1.5 M HCl solution for 1 h to chemically dealloy and remove Al.

[0063] (4) The dealloyed sample in step (3) was rinsed twice with ultrapure water to remove the residual chemical substances in the nanopores, thereby obtaining a micro-nano porous Cu skeleton metal sheet.

[0064] (5) Take 0.1 g of Fe(NO3)3·9H2O, 0.1 g of Zn(NO3)2·6H2O, 0.1 g of Co(NO3)2·6H2O, 0.1 g of Ni(NO3)2·6H2O, 0.1 g of Mn(NO3)2·4H2O and 0.1 g of anhydrous citric acid and dissolve them in 10 mL of H2O to obtain a plating solution.

[0065] (6) Using the micro-nano porous Cu skeleton metal sheet, graphite rod electrode and saturated calomel electrode cleaned in step (4) as the working electrode, counter electrode and reference electrode, respectively, and using the plating solution prepared in step (5) as the deposition electrolyte, a three-electrode system is assembled.

[0066] (7) Under a pulse voltage of -1 V (relative to a saturated calomel electrode), the pulse mode was run 5 times with 0.1 s on / 0.1 s off to electrodeposit a ZnFeCoNiMnCu amorphous layer on a micro-nano porous Cu skeleton metal sheet to obtain a polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst.

[0067] Figure 8 This is a scanning electron microscope image of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 2. Figure 8 It can be clearly observed that the material as a whole is a sponge-like macroporous network, with the macropore size ranging from "several nanometers to more than twenty nanometers", and the pores are interconnected to form an open three-dimensional transmission channel; mesoscopic wrinkle / micropore structure: nanoscale wrinkles and mesopores are distributed on the surface of the macropore wall, constructing a "macropore-mesopore" multi-level pore system; hierarchical structure synergy: macroscopic macropores ensure rapid penetration of electrolyte and efficient escape of H2, and mesoscopic wrinkles / micropores greatly increase the specific surface area and expose more active sites, realizing the spatial synergy of "mass transfer-reaction-product desorption".

[0068] Figure 9 This is the linear sweep voltammetry curve of the hydrogen evolution reaction of the polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 2. Figure 9 It can be clearly observed that as the overpotential moves from 0V to -0.2V, the current density gradually increases, reflecting the change in HER activity of the material under different driving voltages. The curve shows a typical "activation-reaction acceleration" feature. In the high overpotential range, the slope of the current density as the overpotential changes increases, indicating that the HER reaction kinetics are accelerated and the material responds sensitively to changes in overpotential. It can be observed from the curve that when the overpotential increases, the current density increases rapidly, indicating that the material can achieve significant HER current at a low driving voltage. It should be noted that although the HER activity of the ZnFeCoNiMnCu@Cu water electrolysis catalyst in Example 2 is slightly lower than that in Example 1, the activity is still very excellent.

[0069] Example 3

[0070] Preparation of polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst:

[0071] (1) Arc melting of Cu (99%) and Al (99%) metals at 3000°C in N2 atmosphere.

[0072] (2) The AlCu alloy obtained in step (1) was subjected to furnace cooling and cutting procedures to prepare AlCu alloy sheets of 1 cm×1.5 cm×300 μm.

[0073] (3) The AlCu alloy sheet prepared in step (2) was immersed in a 2.5M HCl solution for 12 hours to chemically dealloy and remove Al.

[0074] (4) The dealloyed sample in step (3) was rinsed five times with ultrapure water to remove the residual chemical substances in the nanopores, thereby obtaining a micro-nano porous Cu skeleton metal sheet.

[0075] (5) Take 2 g of Fe(NO3)3·9H2O, 2 g of Zn(NO3)2·6H2O, 2 g of Co(NO3)2·6H2O, 2 g of Ni(NO3)2·6H2O, 2 g of Mn(NO3)2·4H2O and 2 g of anhydrous citric acid and dissolve them in 90 mL of H2O to obtain an electroplating solution.

[0076] (6) Using the micro-nano porous Cu skeleton metal sheet, graphite rod electrode and saturated calomel electrode cleaned in step (4) as the working electrode, counter electrode and reference electrode, respectively, and using the plating solution prepared in step (5) as the deposition electrolyte, a three-electrode system is assembled.

[0077] (7) Under a pulse voltage of -1 V (relative to a saturated calomel electrode), the ZnFeCoNiMnCu amorphous layer was electrodeposited on the micro-nano porous Cu skeleton metal sheet in a 10s on / 10s off pulse mode for 100 runs to obtain a polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst.

[0078] Figure 10 This is a scanning electron microscope image of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 3. Figure 10 It can be clearly observed that the material as a whole constructs a three-dimensional interconnected macroscopic pore network and obvious large-sized pores, and the macroscopic pore size is mostly in the range of 5-20μm. These macroscopic pores are like a "channel network", providing space for the rapid penetration of the electrolyte and the efficient escape of hydrogen products, avoiding the accumulation of bubbles on the catalyst surface and ensuring the continuous reaction. Fine mesoscopic protrusions and microporous structures are distributed on the pore walls of the macroscopic pores and the surface of the material. The pore wall is composed of a large number of nano- to submicron-scale protrusions, wrinkles and micropores, forming a multi-level pore system of "macropores-mesoscopic / micropores". This type of structure greatly increases the specific surface area of ​​the material, can expose more HER active sites, such as metal atom surfaces, grain boundaries, defects, etc., and improves the HER activity. + adsorption and reactivity.

[0079] Figure 11 This is the linear sweep voltammetry curve of the hydrogen evolution reaction of the polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared in Example 3. Figure 11 It can be clearly observed that as the overpotential moves from 0V to -0.25V, the current density gradually increases, reflecting the change in HER activity of the material under different driving voltages. The curve shows a typical "activation-reaction acceleration" feature. In the high overpotential range, the slope of the current density as the overpotential changes increases, indicating that the HER reaction kinetics are accelerated and the material responds sensitively to changes in overpotential. It can be observed from the curve that when the overpotential increases, the current density increases rapidly, indicating that the material can achieve significant HER current at a low driving voltage. It should be noted that although the HER activity of the ZnFeCoNiMnCu@Cu water electrolysis catalyst in Example 3 is slightly reduced compared to Example 1, the activity is still very excellent.

[0080] Comparative Example 1

[0081] Preparation of polycrystalline FeCoNiMnCu@Cu water electrolysis catalyst:

[0082] (1) Arc melting of Cu (99%) and Al (99%) metals at 2000°C in N2 atmosphere.

[0083] (2) The AlCu alloy obtained in step (1) was subjected to furnace cooling and cutting procedures to prepare AlCu alloy sheets of 1 cm×1.5 cm×400 μm.

[0084] (3) The AlCu alloy sheet prepared in step (2) was immersed in a 2M HCl solution for 4 h to chemically dealloy and remove Al.

[0085] (4) The dealloyed sample in step (3) was rinsed three times with ultrapure water to remove the residual chemical substances in the nanopores, thereby obtaining a micro-nano porous Cu skeleton metal sheet.

[0086] (5) 0.4040 g of Fe(NO3)3·9H2O, 0.36739 g of Co(NO3)2·6H2O, 0.2907 g of Ni(NO3)2·6H2O, 0.2510 g of Mn(NO3)2·4H2O and 0.9606 g of anhydrous citric acid were dissolved in 50 mL of H2O to obtain a plating solution.

[0087] (6) Using the micro-nano porous Cu skeleton metal sheet, graphite rod electrode and saturated calomel electrode cleaned in step (4) as the working electrode, counter electrode and reference electrode, respectively, and using the plating solution prepared in step (5) as the deposition electrolyte, a three-electrode system is assembled.

[0088] (7) Under a pulse voltage of -1 V (relative to a saturated calomel electrode), the pulse mode was run 10 times with 0.5 s on / 0.5 s off to electrodeposit an FeCoNiMnCu amorphous layer on a micro-nano porous Cu skeleton metal sheet to obtain a polycrystalline FeCoNiMnCu@Cu water electrolysis catalyst.

[0089] Figure 12 This is a scanning electron microscope image of the multi-grain boundary FeCoNiMnCu@Cu water electrolysis catalyst prepared in Comparative Example 1. Figure 12 The material clearly demonstrates a three-dimensional interconnected macroscopic pore system, with pore sizes ranging from approximately 2 to 10 μm. Fine mesoscopic pores and nanoscale protrusions are distributed along the pore walls and the material's outer surface. The pore walls are composed of numerous interconnected mesoscopic pores and nanoscale structural units, forming a multi-level pore system of "macropores-mesopores-nanostructure."

[0090] Figure 13 This is the linear sweep voltammetry curve of the hydrogen evolution reaction of the multi-grain boundary FeCoNiMnCu@Cu water electrolysis catalyst prepared in comparative example 1. Figure 13 It can be clearly observed that as the overpotential moves from 0V to -0.28V, the current density gradually increases, reflecting the change in HER activity of the material under different driving voltages. The curve shows a typical "activation-reaction acceleration" feature. In the high overpotential range, the slope of the current density as the overpotential changes increases, indicating that the HER reaction kinetics are accelerated and the material responds sensitively to changes in overpotential. It can be observed from the curve that when the overpotential increases, the current density increases rapidly, indicating that the material can achieve significant HER current at a low driving voltage. It should be noted that compared to Example 1, the HER activity of the FeCoNiMnCu@Cu water electrolysis catalyst in Comparative Example 1 is significantly reduced, indicating the excellence of the five-element high entropy alloy composite ZnFeCoNiMnCu@Cu water electrolysis hydrogen production performance.

[0091] Comparative Example 2

[0092] Preparation of polycrystalline CoNiMnCu@Cu water electrolysis catalyst:

[0093] (1) Arc melting of Cu (99%) and Al (99%) metals at 2000°C in N2 atmosphere.

[0094] (2) The AlCu alloy obtained in step (1) was subjected to furnace cooling and cutting procedures to prepare AlCu alloy sheets of 1 cm×1.5 cm×400 μm.

[0095] (3) The AlCu alloy sheet prepared in step (2) was immersed in a 2M HCl solution for 4 h to chemically dealloy and remove Al.

[0096] (4) The dealloyed sample in step (3) was rinsed three times with ultrapure water to remove the residual chemical substances in the nanopores, thereby obtaining a micro-nano porous Cu skeleton metal sheet.

[0097] (5) 0.36739 g of Co(NO3)2·6H2O, 0.2907 g of Ni(NO3)2·6H2O, 0.2510 g of Mn(NO3)2·4H2O and 0.9606 g of anhydrous citric acid were dissolved in 50 mL of H2O to obtain an electroplating solution.

[0098] (6) Using the micro-nano porous Cu skeleton metal sheet, graphite rod electrode and saturated calomel electrode cleaned in step (4) as the working electrode, counter electrode and reference electrode, respectively, and using the plating solution prepared in step (5) as the deposition electrolyte, a three-electrode system is assembled.

[0099] (7) Under a pulse voltage of -1 V (relative to a saturated calomel electrode), the pulse mode was run 10 times with 0.5 s on / 0.5 s off to electrodeposit a CoNiMnCu amorphous layer on a micro-nano porous Cu skeleton metal sheet to obtain a polycrystalline CoNiMnCu@Cu water electrolysis catalyst.

[0100] Figure 14 This is a scanning electron microscope image of the multi-grain boundary CoNiMnCu@Cu water electrolysis catalyst prepared in comparative example 2. Figure 14 The macro-mesoscopic pore network can be clearly observed in the material, and a three-dimensional interconnected multi-level pore system is constructed. The pore size spans a wide range, ranging from hundreds of nanometers to several microns. Among them, the wider pores serve as the "main channels" to accelerate the penetration of electrolytes and the escape of hydrogen; the fine pores are distributed on the walls of the main channels and inside the agglomerates, forming a hierarchical structure of "main channels-branch channels", which greatly expands the specific surface area. Nanoscale particle accumulation and microporous structure can be observed on the pore walls and the surface of the agglomerates. These nanostructured units are interconnected to construct a rich active site exposure interface, and the micropores further increase the surface roughness and specific surface area, which is beneficial to H + Adsorption and reaction.

[0101] Figure 15 This is the linear sweep voltammetry curve of the hydrogen evolution reaction of the multi-grain boundary CoNiMnCu@Cu water electrolysis catalyst prepared in comparative example 2. Figure 15It can be clearly observed that as the overpotential moves from 0V to -0.32V, the current density gradually increases, reflecting the change in HER activity of the material under different driving voltages. The curve shows a typical "activation-reaction acceleration" feature. In the high overpotential range, the slope of the current density as the overpotential changes increases, indicating that the HER reaction kinetics are accelerated and the material responds sensitively to changes in overpotential. It can be observed from the curve that when the overpotential increases, the current density increases rapidly, indicating that the material can achieve significant HER current at a low driving voltage. It should be noted that compared to Example 1, the HER activity of the CoNiMnCu@Cu water electrolysis catalyst in Comparative Example 2 is significantly reduced, indicating the excellence of the five-element high entropy alloy composite ZnFeCoNiMnCu@Cu water electrolysis hydrogen production performance.

[0102] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing a polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst, characterized in that: The following steps are involved: Formulated with Zn 2+ 、Fe 3+ 、Co 2+ 、Ni 2+ 、Mn 2+ and an aqueous solution of citric acid, using the solution as an electroplating solution to electrodeposit a ZnFeCoNiMnCu amorphous layer on a Cu sheet containing a micro-nano porous structure to obtain the polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst.

2. The preparation method of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst according to claim 1, characterized in that: The Zn-containing 2+ 、Fe 3+ 、Co 2+ 、Ni 2+ 、Mn 2+ and citric acid aqueous solutions, the concentrations of each substance are 0.01~0.1mol / L, 0.01~0.1mol / L, 0.01~0.1mol / L, 0.01~0.1mol / L, 0.01~0.1mol / L, 0.01~0.1mol / L and 0.01~0.2mmol / L, respectively.

3. The preparation method of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst according to claim 1, characterized in that: The thickness of the Cu sheet containing the micro-nano porous structure is 200-600 μm.

4. The preparation method of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst according to claim 1, characterized in that: A three-electrode system is used during the electrodeposition, wherein a Cu sheet containing a micro-nano porous structure is used as a working electrode.

5. The preparation method of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst according to claim 4, characterized in that: A pulse voltage is used during the electrodeposition.

6. The method for preparing the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst according to claim 5, characterized in that: The frequency of the pulse voltage is 0.1 to 10 seconds; the number of times the pulse voltage is operated is 5 to 500 times.

7. The preparation method of the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst according to claim 1, characterized in that: The Cu sheet containing the micro-nano porous structure is prepared by dissolving the Al element in the AlCu alloy sheet with acid solution.

8. The method for preparing the multi-grain boundary ZnFeCoNiMnCu@Cu water electrolysis catalyst according to claim 7, characterized in that: The atomic ratio of Cu and Al in the AlCu alloy sheet is 1.5:8.5 to 2.5:6.5; the acid solution is a HCl solution with a concentration of 1.5 to 2.5 M; and the dissolution time is 1 to 12 hours.

9. A polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst prepared according to the method for preparing a polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst according to any one of claims 1 to 8.

10. Use of the polycrystalline ZnFeCoNiMnCu@Cu water electrolysis catalyst according to claim 9 in hydrogen production by water electrolysis.

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