Nickel-tantalum alloy catalytic electrode, preparation method and application thereof

Abstract

The present application relates to the technical field of catalytic electrode material preparation, in particular to a nickel-tantalum alloy catalytic electrode and a preparation method and application thereof, wherein a nickel source, a tantalum source and aluminum powder are mixed uniformly, and then are pressed into a shape in a mold, the shaped blank is sintered in an atmosphere furnace or a vacuum furnace, the sintering temperature is 400-800 DEG C, the holding time is 1-4 h, and the nickel-tantalum alloy catalytic electrode is obtained after cooling. The present application forms a Ni3Ta alloy catalytic phase on a nickel skeleton through a high-temperature sintering process, and prepares a nickel-tantalum alloy catalytic electrode with a three-dimensional porous structure, the Ni3Ta alloy catalytic phase optimizes hydrogen atom adsorption and conversion kinetics, and improves the catalytic activity of the electrode. The present application does not need complex equipment or noble metal loading, is suitable for large-scale production, and the prepared nickel-tantalum alloy catalytic electrode has excellent catalytic activity, excellent permeability and good large-current stability, and is expected to overcome the technical bottleneck that the catalytic activity and durability of electrode materials are difficult to balance in the existing alkaline water electrolysis technology.

Description

Technical Field

[0001] This invention relates to the field of catalytic electrode material preparation technology, specifically a nickel-tantalum alloy catalytic electrode, its preparation method, and its application. Background Technology

[0002] Currently, alkaline electrolyzer technology is the most mature and lowest-cost among water electrolysis hydrogen production technologies. However, its energy conversion efficiency and hydrogen production efficiency are relatively low, failing to meet the demands of large-scale, high-purity hydrogen production. Improving the activity of electrode materials can effectively enhance the efficiency of alkaline electrolyzers. Nickel-based materials are currently the most widely used electrode materials in alkaline water electrolysis hydrogen production due to their low cost, relatively mature technology, and good stability in alkaline solutions. However, nickel-based materials also have some significant drawbacks: firstly, their catalytic activity is limited, resulting in high overpotentials in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), leading to increased energy consumption and lower efficiency. Secondly, nickel-based materials lack stability, easily corroding under high temperature, high-concentration alkaline solutions, and high current densities, resulting in a short electrode lifespan and requiring frequent replacement.

[0003] Patent CN202410845516.X utilizes the reaction of nickel carbonyl vapor with a high-temperature nickel mesh in a decomposer, causing the nickel carbonyl vapor to decompose into metallic nickel and carbon monoxide. The decomposed metallic nickel is deposited on the surface of the high-temperature nickel mesh, forming a catalytic surface with a fine micro-nano surface structure. The prepared nickel catalytic electrode material has achieved a certain technological breakthrough. Patent CN202211732016.2 uses copper as a substrate and prepares a tantalum-tungsten-doped catalytic electrode through tungsten and tantalum co-doping, which has lower electron transfer resistance and enhanced conductivity.

[0004] Although existing nickel-based and tantalum-doped materials have demonstrated unique properties in the field of water electrolysis catalysis, the application and research of nickel-tantalum alloy catalytic electrode materials combining the two are currently lacking. Compared with single metals, alloying can achieve continuous modulation of the electronic structure of metal sites, showing great potential in optimizing the adsorption and conversion kinetics of hydrogen atoms, with catalytic activity and stability far exceeding those of single metal catalysts. Furthermore, current nickel-based catalytic electrodes suffer from the challenge of simultaneously achieving good balance between the porosity (water and air permeability) and mechanical properties of thin metal sheet materials. Summary of the Invention

[0005] To address the above problems, this invention provides a nickel-tantalum alloy catalytic electrode, its preparation method, and its application. A Ni3Ta alloy catalytic phase is formed on a nickel framework using a high-temperature sintering process, resulting in a nickel-tantalum alloy catalytic electrode with a three-dimensional porous structure. The Ni3Ta alloy catalytic phase optimizes the hydrogen atom adsorption and conversion kinetics, thereby enhancing the electrode's catalytic activity. This invention requires no complex equipment or precious metal loading, making it suitable for large-scale production. The prepared nickel-tantalum alloy catalytic electrode exhibits excellent catalytic activity, outstanding permeability, and good high-current stability, potentially overcoming the technical bottleneck of balancing catalytic activity and durability in existing alkaline water electrolysis technologies.

[0006] The method for preparing a nickel-tantalum alloy catalytic electrode according to the present invention specifically includes the following steps: (1) Select a mold of appropriate specifications according to the size of the target product, weigh a certain amount of nickel powder, tantalum source powder and aluminum powder, and mix them evenly to form a mixed powder.

[0007] For example, the shape, size, and thickness of the electrode are determined based on actual needs, and a mold is designed or selected accordingly. The required mass of raw material powder is estimated by multiplying volume and density. The preferred mass ratio of nickel powder to tantalum source powder is 1:(0.2-0.5). The mass of aluminum powder is based on the mass of tantalum source powder, preferably 0.8-1.5% of the mass of tantalum source powder. Too low a proportion of tantalum source powder will result in insufficient content of the generated nickel-tantalum alloy catalytic phase, reducing catalytic efficiency. Too high a proportion of tantalum source powder will easily cause the nickel-tantalum alloy layer to be too thick and completely cover the nickel surface, resulting in a decrease in electrode conductivity. Insufficient nickel powder content will easily cause the sintered electrode sheet to shrink, while excessive nickel powder content will easily cause the sintered electrode sheet to expand. Therefore, appropriate amounts of nickel powder and tantalum source powder are key to ensuring accurate electrode sheet dimensions and good performance. On this basis, the core purpose of adding a small amount of aluminum powder is that: nickel powder and tantalum source powder have poor compatibility, and aluminum powder has a low melting point, so it can act as a "binder" to effectively fuse the nickel powder and tantalum source powder together. The amount of aluminum powder used must be strictly determined based on the content of tantalum source powder. Too much aluminum powder will result in too much liquid aluminum content, leading to residual pores or segregation in the material after sintering. Too little aluminum powder will result in insufficient bonding effect of liquid aluminum. Therefore, it is preferable to set the aluminum powder mass to 0.8-1.5% of the tantalum source powder mass, and the particle size of the aluminum powder to be 20-50 nm.

[0008] Preferably, the particle size range of the nickel powder is 2-50 µm. Experiments have shown that a nickel powder particle size exceeding 50 µm will cause difficulties in pressing and sintering, while a nickel powder particle size less than 2 µm will result in a product with a small pore size, which is not conducive to the mass transfer of water and bubbles.

[0009] The tantalum source powder is preferably tantalum powder or tantalum chloride (TaCl5) powder, and the particle size of the tantalum source powder is preferably 100-800 nm. This size allows the nano-sized tantalum source powder to fully react on the nickel surface with a large particle size to form a nickel-tantalum alloy catalytic phase, while also preserving the three-dimensional framework structure of nickel.

[0010] (2) The mixed powder obtained in step (1) is loaded into a stainless steel mold, and then the stainless steel mold is placed in a hydraulic press for pressing and molding. The metal billet is then demolded. The preferred pressing pressure range is 1-10 t. Pressure control aims to construct a porous morphology of the metal billet. Excessive pressure will inhibit the formation of a three-dimensional porous structure in the metal billet, resulting in increased density and decreased specific surface area of ​​the formed metal billet. Insufficient pressure will lead to poor structural integrity of the metal billet, easy pulverization, and increased difficulty in subsequent sintering.

[0011] (3) The metal blank obtained in step (2) is placed in an atmosphere furnace or a vacuum furnace for sintering. The sintering atmosphere of the atmosphere furnace is one of argon, nitrogen, hydrogen or argon-hydrogen mixture. After sintering, it is cooled to room temperature and taken out to obtain a nickel-tantalum alloy catalytic electrode.

[0012] In this step, the hydrogen gas fraction in the argon-hydrogen mixture is preferably 5-20%, and the argon gas fraction is preferably 80-95%. The sintering temperature is preferably 400-800℃, the heating rate is preferably 2-20℃ / min, and the holding time is 1-4 h. Strict control of temperature and heating rate is required during the sintering process. If the temperature is too low, the atomic reactions will be insufficient, failing to effectively generate the nickel-tantalum alloy catalytic phase and making it difficult to form a robust three-dimensional framework structure, resulting in poor self-supporting mechanical properties of the electrode. If the temperature is too high, the alloy electrode will shrink significantly, its porosity will decrease, and the mass transfer efficiency during the catalytic process will be inhibited.

[0013] The core purpose of sintering using argon, nitrogen, hydrogen, an argon-hydrogen mixture, or a vacuum environment is to prevent excessive oxidation of the nickel-tantalum alloy catalytic phase. Extensive oxidation of the nickel-tantalum alloy catalytic phase leads to a sharp decline in its catalytic activity. Sintering using argon, nitrogen, hydrogen, an argon-hydrogen mixture, or a vacuum environment effectively inhibits the excessive oxidation of the nickel-tantalum alloy catalytic phase, thus ensuring its catalytic activity.

[0014] The holding time also significantly impacts electrode performance. Insufficient holding time leads to inadequate atomic diffusion between nickel powder and tantalum source powder particles, resulting in poor particle bonding and consequently, poor electrode mechanical strength and conductivity. Excessive holding time not only causes particle growth, reduced porosity, and smaller pore size, hindering material transport, but also results in higher energy consumption, lower production efficiency, and increased production costs.

[0015] Further, if tantalum chloride powder is selected as the tantalum source powder, then step (3) is as follows: the obtained metal blank is placed in a ceramic boat, covered, and then placed in an atmosphere furnace for sintering. The sintering atmosphere is an argon-hydrogen mixture. First, the temperature is raised to 400°C at a heating rate of 2~20°C / min and held for 2 h. Then, the temperature is raised to 800°C at a heating rate of 2~20°C / min and held for 2 h. After completion, the temperature is cooled to room temperature and taken out to obtain a nickel-tantalum alloy catalytic electrode.

[0016] Furthermore, depending on the selected mold, the shape of the nickel-tantalum alloy catalytic electrode prepared in step (3) can be square, round, cross-shaped, etc.

[0017] Furthermore, the nickel-tantalum alloy catalytic electrode obtained by the aforementioned preparation method exhibits a three-dimensional porous structure with well-connected three-dimensional framework and abundant pores. Its main phases are Ni and Ni3Ta, making it an electrode material with Ni3Ta alloy catalytic phase attached to a nickel framework.

[0018] Furthermore, the tensile strength of this nickel-tantalum alloy catalytic electrode is 15-35 MPa.

[0019] This invention also provides a nickel-tantalum alloy catalytic electrode prepared according to the aforementioned method, which can be used for hydrogen production by water electrolysis under alkaline conditions. Under the same experimental conditions, the nickel-tantalum alloy catalytic electrode prepared by this invention exhibits a lower hydrogen evolution overpotential than commercial Pt wafers. At the same overpotential, the nickel-tantalum alloy catalytic electrode prepared by this invention exhibits a higher current density than commercial Pt wafers, demonstrating that the nickel-tantalum alloy catalytic electrode prepared by this invention has superior catalytic hydrogen evolution performance. Furthermore, the current density of the nickel-tantalum alloy catalytic electrode shows almost no decay during long-term hydrogen evolution tests, indicating its excellent durability and stability.

[0020] Compared with the prior art, the present invention has the following beneficial effects: (1) In this invention, nickel powder, tantalum powder / tantalum chloride (TaCl5) powder, and aluminum powder are mixed evenly, pressed into shape, and then sintered in one piece to prepare a nickel-tantalum alloy catalytic electrode with a three-dimensional porous structure. During the sintering process, nickel and tantalum source alloy to form a Ni3Ta alloy catalytic phase on the nickel framework. This Ni3Ta alloy catalytic phase can achieve continuous modulation of the electronic structure of metal sites, optimize the adsorption and conversion kinetics of hydrogen atoms, and significantly improve the catalytic activity of the electrode. At the same time, the Ni3Ta alloy catalytic phase enhances the corrosion resistance of the electrode in alkaline environments and extends its service life. This invention adopts a conventional high-temperature sintering process, which does not require complex equipment or precious metal loading, and is suitable for large-scale production.

[0021] (2) This invention uses a high-temperature sintering process to form a Ni3Ta alloy catalytic phase on a nickel framework, thus preparing a nickel-tantalum alloy catalytic electrode with a three-dimensional porous structure. The three-dimensional framework is well connected and rich in pores (SEM image), giving the nickel-tantalum alloy catalytic electrode a rich microporous structure, which promotes the rapid transport of water molecules and bubbles and improves mass transfer efficiency. These pore structures are beneficial for electrolyte permeation and gas release, making it suitable for high current density operation.

[0022] (3) Under the same experimental conditions, the nickel-tantalum alloy catalytic electrode prepared in this invention exhibits a lower overpotential compared to commercially available Pt sheets. In the water contact angle experiment, the water contact angle of the nickel-tantalum alloy catalytic electrode becomes 0° after 0.03 s, indicating that the nickel-tantalum alloy catalytic electrode prepared in this invention has excellent permeability (water permeability), which is beneficial for the electrolyte to fully contact the active sites of the electrode. The nickel-tantalum alloy catalytic electrode at 1000 mA cm⁻¹ -2 After 165 hours of continuous electrolysis at the specified current density, the current density remained almost constant. Therefore, the nickel-tantalum alloy catalytic electrode prepared by this invention possesses excellent catalytic activity, outstanding water permeability, and good high-current stability. It is expected to overcome the technical challenge of balancing catalytic activity and durability of electrode materials in existing alkaline water electrolysis technologies, demonstrating broad market application potential. Attached Figure Description

[0023] Figure 1 This is a SEM image of the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in Example 1.

[0024] Figure 2 This is the EDS diagram of the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in Example 1.

[0025] Figure 3 These are the polarization curves of the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in Example 1 and a commercial Pt sheet.

[0026] Figure 4 The figures show the chronocurrent curves of the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in Example 1 at different current densities.

[0027] Figure 5 This is a comparison of the water contact angles of the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in Example 1 with those of nickel foam and commercial Pt sheets.

[0028] Figure 6 The Ni3Ta / Ni-800 (0.9 g) electrode material prepared in Example 1 was tested at 1000 mA cm⁻¹. -2 Chronocurrent curves of continuous electrolysis for 165 hours at current density.

[0029] Figure 7 This is a comparison of the polarization curves of the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in Example 1 at 25℃ and 60℃.

[0030] Figure 8 This is a SEM image of the Ni3Ta / Ni-750 (0.9 g) electrode material prepared in Example 2.

[0031] Figure 9 This is the EDS diagram of the Ni3Ta / Ni-750 (0.9 g) electrode material prepared in Example 2.

[0032] Figure 10 The images show the XRD patterns of the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in Example 1 and the Ni3Ta / Ni-750 (0.9 g) electrode material prepared in Example 2.

[0033] Figure 11 These are the polarization curves of the Ni3Ta / Ni-750 (0.9 g) electrode material prepared in Example 2 and the commercial Pt sheet.

[0034] Figure 12 This is a comparison chart of the mechanical properties of the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in Example 1, the Ni3Ta / Ni-750 (0.9 g) electrode material prepared in Example 2, and nickel foam.

[0035] Figure 13 This is a SEM image of the Ni3Ta / Ni-800 (0.8 g) electrode material prepared in Example 3.

[0036] Figure 14 This is the EDS diagram of the Ni3Ta / Ni-800 (0.8 g) electrode material prepared in Example 3.

[0037] Figure 15 The image shows the XRD pattern of the Ni3Ta / Ni-800 (0.8 g) electrode material prepared in Example 3.

[0038] Figure 16 These are the polarization curves of the Ni3Ta / Ni-800 (0.8 g) electrode material prepared in Example 3 and the commercial Pt sheet.

[0039] Figure 17 The image shows the oxygen evolution polarization curve of the Ni3Ta / Ni-800 (0.8 g) electrode material prepared in Example 3 under alkaline conditions.

[0040] Figure 18These are the polarization curves of the Ni3Ta / Ni-800 (TaCl5) electrode material prepared in Example 4 and a commercial Pt sheet. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0042] The present invention will be described in detail below with reference to specific embodiments. Unless otherwise specified, all conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Raw materials and reagents used, unless otherwise specified, are all commercially available products. Unless otherwise specified, the scientific and technical terms and experimental methods in this invention are based on the conventional understanding and existing standard methods of those skilled in the art. It should be understood that the parameters such as temperature and holding time involved in this invention are approximate values ​​and are used for illustrative purposes; those skilled in the art can make reasonable adjustments according to actual needs.

[0043] Example 1: (1) Take 2 g of nickel powder with an average particle size of 5 µm, 0.9 g of tantalum powder with an average particle size of 500 nm and 13.5 mg of aluminum powder with an average particle size of 50 nm and mix them evenly to obtain a mixed powder.

[0044] (2) Select a stainless steel mold with a circular inner cavity and a diameter of 20 mm, assemble a stainless steel base and a stainless steel sleeve, put a stainless steel gasket in the stainless steel sleeve, then put the mixed powder from step (1) into the stainless steel sleeve, then put in another stainless steel gasket and put in a stainless steel pressure column, press it on a hydraulic press, the pressing pressure is 1 t, and demold to obtain a metal blank.

[0045] (3) The metal billet obtained in step (2) is vertically placed into an argon atmosphere furnace for sintering. The sintering temperature is 800℃, the heating rate is 10℃ / min, and the holding time is 2 h. After sintering, it is cooled to room temperature and taken out to obtain a nickel-tantalum alloy catalytic electrode, denoted as Ni3Ta / Ni-800 (0.9 g).

[0046] Figure 1This is a SEM image of the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in this embodiment. It can be seen that the Ni3Ta / Ni-800 (0.9 g) electrode material exhibits a three-dimensional porous structure with a well-connected three-dimensional framework and abundant pores. Some attached particles were also observed on the three-dimensional framework, which are a small amount of unreacted tantalum.

[0047] Figure 2 The image shows the EDS (Enhanced Power Spectroscopy) of the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in this embodiment. It can be seen that Ni and Ta elements are distributed on the three-dimensional framework, indicating the successful synthesis of the nickel-tantalum alloy catalytic phase. Furthermore, the three-dimensional framework shows the coexistence of Ta and O, indicating that a small portion of Ta has formed tantalum oxide.

[0048] The Ni3Ta / Ni-800 (0.9 g) electrode material prepared in this embodiment was used as the working electrode, a graphite electrode as the counter electrode, and a mercuric oxide electrode as the reference electrode. The electrolyte was a 1 mol / L KOH solution. The polarization curve of the Ni3Ta / Ni-800 (0.9 g) electrode material was measured using an electrochemical workstation. Figure 3 Chronocurrent curves of Ni3Ta / Ni-800 (0.9 g) electrode materials at different current densities ( Figure 4 The polarization curves of commercial Pt wafers were tested using the same method. Figure 3 ).

[0049] Depend on Figure 3 As can be seen, under the same experimental conditions, the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in this embodiment exhibits a lower overpotential compared to commercial Pt sheets. At the same overpotential, the current density of the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in this embodiment is higher than that of commercial Pt sheets, demonstrating that the Ni3Ta / Ni-800 (0.9 g) electrode material possesses superior catalytic hydrogen evolution performance.

[0050] Figure 4 The figures show the chronoamperometry curves of the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in this embodiment after electrolysis for a certain period of time at different current densities. It can be seen that the Ni3Ta / Ni-800 (0.9 g) electrode has good stability at different current densities.

[0051] Figure 5This is a comparison of the water contact angles of the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in this embodiment with those of nickel foam and commercial Pt sheets. It can be seen that after 0.03 s, the water contact angle of the Ni3Ta / Ni-800 (0.9 g) electrode material becomes 0°, while the water contact angles of nickel foam and commercial Pt sheets are 114.89° and 78.71°, respectively, after 2 s. This indicates that the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in this embodiment has excellent permeability (water permeability).

[0052] Figure 6 The Ni3Ta / Ni-800 (0.9 g) electrode material prepared in this embodiment is tested at 1000 mA cm⁻¹. -2 The chronoamperometry curves after 165 hours of continuous electrolysis at high current density show that the current density remains almost unchanged after 165 hours of continuous electrolysis at high current density, indicating that the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in this embodiment has excellent stability in use.

[0053] Using the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in this embodiment as the working electrode, a graphite electrode as the counter electrode, and a mercuric oxide electrode as the reference electrode, and a 1 mol / L KOH solution as the electrolyte, the polarization curves of the Ni3Ta / Ni-800 (0.9 g) electrode material at 25 °C and 60 °C were measured using an electrochemical workstation. The results are as follows: Figure 7 As shown, under the same overpotential, the current density of the Ni3Ta / Ni-800 (0.9 g) electrode material at 60℃ is higher than that at 25℃, indicating that the Ni3Ta / Ni-800 (0.9 g) electrode can operate in a high-temperature environment.

[0054] Example 2: (1) Take 2 g of nickel powder with an average particle size of 5 µm, 0.9 g of tantalum powder with an average particle size of 500 nm and 13.5 mg of aluminum powder with an average particle size of 50 nm and mix them evenly to obtain a mixed powder.

[0055] (2) Select a stainless steel mold with a square inner cavity and a side length of 20 mm, assemble a stainless steel base and a stainless steel sleeve, put a stainless steel gasket in the stainless steel sleeve, then put the mixed powder from step (1) into the stainless steel sleeve, then put in another stainless steel gasket and put in a stainless steel pressure column, press it on a hydraulic press, the pressing pressure is 1 t, and demold to obtain a metal blank.

[0056] (3) The metal billet obtained in step (2) is vertically placed into a nitrogen atmosphere furnace for sintering. The sintering temperature is 750℃, the heating rate is 15℃ / min, and the holding time is 2 h. After sintering, it is cooled to room temperature and taken out to obtain a nickel-tantalum alloy catalytic electrode, denoted as Ni3Ta / Ni-750 (0.9 g).

[0057] Figure 8 This is a SEM image of the Ni3Ta / Ni-750 (0.9 g) electrode material prepared in this embodiment. It can be seen that the Ni3Ta / Ni-750 (0.9 g) electrode material exhibits a three-dimensional porous structure with a well-connected three-dimensional framework and abundant pores. Some attached particles were also observed on the three-dimensional framework, which are a small amount of unreacted tantalum.

[0058] Figure 9 The image shows the EDS (Enhanced Power Spectroscopy) of the Ni3Ta / Ni-750 (0.9 g) electrode material prepared in this embodiment. It can be seen that Ni and Ta elements are distributed on the three-dimensional framework, indicating the successful synthesis of the nickel-tantalum alloy catalytic phase. Furthermore, the three-dimensional framework shows the coexistence of Ta and O, indicating that a small portion of Ta has formed tantalum oxide.

[0059] Figure 10 The images show the XRD patterns of the Ni3Ta / Ni-800 (0.9 g) electrode material prepared in Example 1 and the Ni3Ta / Ni-750 (0.9 g) electrode material prepared in this example. The diffraction peaks of nickel, tantalum, tantalum oxide, and Ni3Ta alloy can be seen from the figures. The diffraction peaks of tantalum and tantalum oxide are relatively small. Therefore, the main phases of Ni3Ta / Ni-800 (0.9 g) and Ni3Ta / Ni-750 (0.9 g) electrode materials are Ni and Ni3Ta alloy. Examples 1 and 2 prepare electrode materials with Ni3Ta alloy catalytic phase attached to a nickel skeleton.

[0060] The Ni3Ta / Ni-750 (0.9 g) electrode material prepared in this example was compared with a commercial Pt sheet using the same testing method as in Example 1. The polarization curves of the Ni3Ta / Ni-750 (0.9 g) electrode material and the commercial Pt sheet were tested, as shown below. Figure 11 As shown, under the same experimental conditions, the Ni3Ta / Ni-750 (0.9 g) electrode material prepared in this embodiment exhibits a lower overpotential. At the same overpotential, the current density of the Ni3Ta / Ni-750 (0.9 g) electrode material prepared in this embodiment is higher than that of commercial Pt sheets, demonstrating that the Ni3Ta / Ni-750 (0.9 g) electrode material possesses superior catalytic hydrogen evolution performance.

[0061] The Ni3Ta / Ni-800 (0.9 g) electrode material prepared in Example 1, the Ni3Ta / Ni-750 (0.9 g) electrode material prepared in Example 2, and the foamed nickel wire were processed into tensile standard samples. Their mechanical properties were then tested at a displacement rate of 0.2 mm / min. The results are as follows: Figure 12 As shown, the tensile strengths of the nickel-tantalum alloy catalytic electrode materials prepared in Examples 1 and 2 are 33 MPa and 19 MPa, respectively, which are much higher than the tensile strength of nickel foam (1.3 MPa), proving that the nickel-tantalum alloy catalytic electrode prepared in this invention has good mechanical stability.

[0062] Example 3: (1) Take 2 g of nickel powder with an average particle size of 10 µm, 0.8 g of tantalum powder with an average particle size of 700 nm and 12 mg of aluminum powder with an average particle size of 20 nm and mix them evenly to obtain a mixed powder.

[0063] (2) Select a stainless steel mold with a circular inner cavity and a diameter of 20 mm, assemble a stainless steel base and a stainless steel sleeve, put a stainless steel gasket in the stainless steel sleeve, then put the mixed powder from step (1) into the stainless steel sleeve, then put in another stainless steel gasket and put in a stainless steel pressure column, press it on a hydraulic press, the pressing pressure is 2 t, and demold to obtain a metal blank.

[0064] (3) The metal billet obtained in step (2) is vertically placed into an argon atmosphere furnace for sintering. The sintering temperature is 800℃, the heating rate is 20℃ / min, and the holding time is 2 h. After sintering, it is cooled to room temperature and taken out to obtain a nickel-tantalum alloy catalytic electrode, denoted as Ni3Ta / Ni-800 (0.8 g).

[0065] Figure 13 This is a SEM image of the Ni3Ta / Ni-800 (0.8 g) electrode material prepared in this embodiment. It can be seen that the Ni3Ta / Ni-800 (0.8 g) electrode material exhibits a three-dimensional porous structure with a well-connected three-dimensional framework and abundant pores. Some attached particles were also observed on the three-dimensional framework, which are a small amount of unreacted tantalum.

[0066] Figure 14 The image shows the EDS (Enhanced Power Spectroscopy) of the Ni3Ta / Ni-800 (0.8 g) electrode material prepared in this embodiment. It can be seen that Ni and Ta elements are distributed on the three-dimensional framework, indicating the successful synthesis of the nickel-tantalum alloy catalytic phase. Furthermore, the three-dimensional framework shows the coexistence of Ta and O, indicating that a small portion of Ta has formed tantalum oxide.

[0067] Figure 15The image shows the XRD pattern of the Ni3Ta / Ni-800 (0.8 g) electrode material prepared in this embodiment. The diffraction peaks of nickel, tantalum, tantalum oxide, and Ni3Ta alloy can be seen from the figure. The diffraction peaks of tantalum and tantalum oxide are relatively small. Therefore, the main phases of the Ni3Ta / Ni-800 (0.8 g) material are Ni and Ni3Ta. Example 3 prepared an electrode material with Ni3Ta alloy catalytic phase attached to a nickel skeleton.

[0068] The polarization curves of the Ni3Ta / Ni-800 (0.8 g) electrode material and commercial Pt sheets were tested using the same test method as in Example 1. Figure 16 As shown, under the same experimental conditions, the Ni3Ta / Ni-800 (0.8 g) electrode material prepared in this embodiment exhibits a lower overpotential compared to commercial Pt sheets. At the same overpotential, the current density of the Ni3Ta / Ni-800 (0.8 g) electrode material prepared in this embodiment is higher than that of commercial Pt sheets, demonstrating that the Ni3Ta / Ni-800 (0.8 g) electrode material possesses superior catalytic hydrogen evolution performance.

[0069] Using Ni3Ta / Ni-800 (0.8 g) electrode material as the working electrode, a graphite electrode as the counter electrode, and a mercuric oxide electrode as the reference electrode, with a 1 mol / L KOH solution as the electrolyte, the oxygen evolution polarization curve of the Ni3Ta / Ni-800 (0.8 g) electrode material under alkaline conditions was measured using an electrochemical workstation. The results are as follows: Figure 17 As shown, the Ni3Ta / Ni-800 (0.8 g) electrode exhibits a high current density in the oxygen evolution reaction, demonstrating that the Ni3Ta / Ni-800 (0.8 g) electrode material has excellent catalytic oxygen evolution performance.

[0070] Example 4: (1) Take 2 g of nickel powder with an average particle size of 5µm, 1.5 g of tantalum chloride (TaCl5) powder with an average particle size of 100 nm and 12 mg of aluminum powder with an average particle size of 20 nm and mix them evenly to obtain a mixed powder.

[0071] (2) Select a stainless steel mold with a circular inner cavity and a diameter of 20 mm, assemble a stainless steel base and a stainless steel sleeve, put a stainless steel gasket in the stainless steel sleeve, then put the mixed powder from step (1) into the stainless steel sleeve, then put in another stainless steel gasket and put in a stainless steel pressure column, press it on a hydraulic press, the pressing pressure is 1 t, and demold to obtain a metal blank.

[0072] (3) The metal blank obtained in step (2) is placed in a ceramic boat, covered, and then placed in an atmosphere furnace for sintering. The sintering atmosphere is a hydrogen-argon mixture, in which the hydrogen gas fraction is 10% and the argon gas fraction is 90%. The temperature is first raised to 400℃ at a heating rate of 10℃ / min and held for 2 h. After the holding period, the temperature is raised to 800℃ at a heating rate of 10℃ / min and held for 2 h. After sintering, the temperature is cooled to room temperature and removed to obtain a nickel-tantalum alloy catalytic electrode, denoted as Ni3Ta / Ni-800(TaCl5).

[0073] Using the Ni3Ta / Ni-800(TaCl5) electrode material prepared in this embodiment as the working electrode, the polarization curves of the Ni3Ta / Ni-800(TaCl5) electrode material and commercial Pt sheets were tested according to the same test method as in Example 1. Figure 18 As shown, under the same experimental conditions, the Ni3Ta / Ni-800(TaCl5) electrode material prepared in this embodiment exhibits a lower overpotential compared to commercial Pt sheets. At the same overpotential, the current density of the Ni3Ta / Ni-800(TaCl5) electrode material prepared in this embodiment is higher than that of commercial Pt sheets, demonstrating that the Ni3Ta / Ni-800(TaCl5) electrode material possesses superior catalytic hydrogen evolution performance.

[0074] The above description is merely an embodiment of the present invention and is not intended to limit the present invention in any way. The present invention can also have other embodiments based on the above structure and function, which will not be listed hereafter. Therefore, any simple modifications, equivalent changes, and alterations made by those skilled in the art to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a nickel-tantalum alloy catalytic electrode, characterized by Includes the following steps: (1) Select a suitable mold according to the size of the target product, weigh a certain amount of nickel powder, tantalum source powder and aluminum powder, mix them evenly to form a mixed powder, the mass ratio of nickel powder to tantalum source powder is 1:(0.2-0.5), and the mass of aluminum powder is 0.8-1.5% of the mass of tantalum source powder; (2) The mixed powder obtained in step (1) is loaded into a stainless steel mold, and then the stainless steel mold is placed in a hydraulic press to press and form, and the metal blank is demolded. (3) The metal blank obtained in step (2) is placed in an atmosphere furnace or a vacuum furnace for sintering. The sintering atmosphere of the atmosphere furnace is one of argon, nitrogen, hydrogen or argon-hydrogen mixture. The sintering temperature is 400~800℃ and the holding time is 1~4 h. After sintering, it is cooled to room temperature and taken out to obtain a nickel-tantalum alloy catalytic electrode.

2. The method of making a nickel-tantalum alloy catalytic electrode according to claim 1, wherein: In step (1), the particle size of nickel powder is 2-50 μm, the particle size of tantalum source powder is 100-800 nm, and the particle size of aluminum powder is 20-50 nm. The tantalum source powder is tantalum powder or tantalum chloride powder.

3. The method of making a nickel-tantalum alloy catalytic electrode of claim 1, wherein: The pressing pressure in step (2) is 1-10t.

4. The method of making a nickel-tantalum alloy catalytic electrode as defined in claim 1, wherein: In step (3), the heating rate during sintering is 2~20℃ / min, and the hydrogen gas fraction in the argon-hydrogen mixture is 5-20%, and the argon gas fraction is 80-95%.

5. The method of making a nickel-tantalum alloy catalytic electrode as defined in claim 2, wherein: If tantalum chloride powder is selected as the tantalum source powder, then in step (3), the obtained metal blank is placed in a ceramic boat, covered, and then placed in an atmosphere furnace for sintering. The sintering atmosphere is an argon-hydrogen mixture. First, the temperature is raised to 400°C at a heating rate of 2~20°C / min and held for 2 hours. Then, the temperature is raised to 800°C at a heating rate of 2~20°C / min and held for 2 hours. After completion, the temperature is cooled to room temperature and taken out to obtain a nickel-tantalum alloy catalytic electrode.

6. The method of making a nickel-tantalum alloy catalytic electrode as defined in claim 1, wherein: Depending on the mold chosen, the nickel-tantalum alloy catalytic electrode is at least circular, square, or cross-shaped.

7. The method of making a nickel-tantalum alloy catalytic electrode according to any one of claims 1 to 5, wherein: The obtained nickel-tantalum alloy catalytic electrode exhibits a three-dimensional porous structure with a well-connected three-dimensional framework and abundant pores. Its main phases are Ni and Ni3Ta, making it an electrode material with a Ni3Ta alloy catalytic phase attached to a nickel framework.

8. The method of making a nickel-tantalum alloy catalytic electrode according to any one of claims 1 to 5, wherein: The tensile strength of the obtained nickel-tantalum alloy catalytic electrode is 15-35 MPa.

9. The nickel-tantalum alloy catalytic electrode obtained by any one of the preparation methods described in claims 1-5.

10. The application of the nickel-tantalum alloy catalytic electrode obtained by any one of the preparation methods described in claims 1-5 in the electrolysis of water to produce hydrogen under alkaline conditions.

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