Cobalt-based amorphous wire prepared based on inner circle hydroentanglement technology and its application in hydrogen production by water electrolysis

Abstract

The application discloses a cobalt-based amorphous wire prepared based on an inner circular hydroentanglement technology and application of the cobalt-based amorphous wire in hydrogen production by electrolysis of water. a Fe b Si c B d Nb e Pt f Ni g Y h C i , wherein each subscript represents the mass percentage of the element in the material, and wherein 67 <= a <= 70, 2 <= b <= 6, 7 <= c <= 9, 11 <= d <= 20, 7 <= e <= 9, 0.5 <= f <= 1, 1.5 <= g <= 3, 0.5 <= h <= 0.9, and 0.5 <= i <= 1. The application constructs an amorphous structure with gradient distribution characteristics by optimizing the amorphous component system and combining the inner circular hydroentanglement technology. The application provides abundant active sites, shortens the ion migration path, improves the charge transfer efficiency and mass transfer efficiency, and reduces the bubble shielding effect. At 10 mA / cm 2 , the overpotential is only 230 mV, which significantly improves the activity of the cobalt-based catalyst, and the application can be applied to the field of hydrogen production by electrolysis of water and realizes industrial-grade green hydrogen production.

Description

Technical Field

[0001] This invention belongs to the field of water electrolysis hydrogen production technology, specifically relating to a cobalt-based amorphous filament prepared based on inner-circle water spinning technology and its application in water electrolysis hydrogen production. Background Technology

[0002] With the continuous growth of global energy demand and the increasing severity of environmental problems, hydrogen, as a clean and efficient energy carrier, has attracted widespread attention. Electrolysis of water is one of the most promising methods for hydrogen production, but its high energy consumption and cost limit its large-scale application. Among existing technologies, noble metal catalysts (such as platinum) possess excellent catalytic performance, but they are expensive and scarce. Therefore, the development of efficient and low-cost non-noble metal catalysts has become a research hotspot. Transition metal materials, due to their high activity and low price, are increasingly used in energy conversion and storage. Transition metal sulfides, oxides, carbides, nitrides, and phosphides all exhibit good electrocatalytic activity.

[0003] Highly crystalline materials typically exhibit excellent structural stability due to the long-range ordered arrangement of their atoms. However, in some cases, this highly ordered crystal structure may hinder the exposure of active sites during electrocatalysis, leading to a significant reduction in catalytic activity. Amorphous alloys are solid-state alloy materials formed by rapidly cooling an alloy melt at an ultra-high rate. During ultra-high-speed rapid cooling, the alloy atoms cannot arrange themselves in an ordered manner to form a crystal structure due to the extremely rapid cooling rate. Therefore, the resulting amorphous alloy exhibits a long-range disordered microstructure, lacking the ordered structural units such as grains and grain boundaries found in crystalline alloys. By controlling the crystallinity of the material to achieve an amorphization transformation, the atomic arrangement changes from a long-range ordered structure to a short-range ordered structure, thereby introducing abundant defect states and highly active unsaturated metal coordination sites within the material. This structural evolution promotes the in-situ activation of previously chemically inert active sites in the oxygen evolution reaction (OER) of the water electrolysis hydrogen production process, significantly enhancing the intrinsic catalytic activity of the OER reaction. For example, reference 1 (Unification of catalytic water oxidation and oxygen reduction reactions: amorphous beat crystalline cobalt iron oxides, Journal of the American Chemical Society, 2014, 136(50): 17530-17536) discloses an amorphous cobalt iron oxide CoFe2O n With n approximately 3.66, the OER activity of amorphous CoFe oxides is significantly better than that of highly crystalline CoFe2O. 4.

[0004] Amorphous wires, as a type of amorphous alloy, have shown great application potential in the field of hydrogen production through water electrolysis due to their unique physical and chemical properties. There are numerous methods for preparing amorphous wires, among which the internal hydrospinning technique has attracted much attention because it can produce continuous amorphous wires with excellent roundness. This method specifically involves introducing an alloy jet of a specific composition into the cooling liquid inside a high-speed rotating copper roller, causing it to cool rapidly and form continuous amorphous wires with round cross-sections. Amorphous wires prepared by the internal hydrospinning method not only possess excellent mechanical properties but also exhibit good corrosion resistance. Furthermore, the dangling bonds and unsaturated coordination sites of amorphous wires are conducive to the adsorption of reactants; the disordered atomic arrangement facilitates ion diffusion and electron transfer; and the flexible metastable structure can spontaneously reconstruct during catalysis, resulting in good adaptability to catalytic reactions. Compared to traditional crystalline catalysts, these amorphous wires possess richer active sites, higher catalytic stability, and unique electrocatalytic performance.

[0005] In water electrolysis hydrogen production equipment, amorphous wires can be directly used as electrode materials. With their excellent comprehensive performance, this material can not only effectively reduce preparation costs but also significantly improve the efficiency and stability of the water electrolysis process, thus opening up a new path for the commercial application of water electrolysis hydrogen production technology. Summary of the Invention

[0006] To address the issue that the high cost and scarcity of precious metal catalysts in existing water electrolysis hydrogen production technologies restrict their large-scale application, this invention proposes a cobalt-based amorphous wire prepared using an inner-circle water spinning technique and its application in water electrolysis hydrogen production. This cobalt-based amorphous wire, prepared through an inner-circle water spinning process, exhibits excellent catalytic activity and stability, while also possessing significant cost advantages, enabling large-scale application and effectively promoting technological development in the field of water electrolysis hydrogen production.

[0007] This invention provides a cobalt-based amorphous wire, the composition of which is Co. a Fe b Si c B d Nb e Pt f Ni g Y h C i The subscripts a, b, c, d, e, f, g, h, and i represent the mass percentage of each element in the alloy composition, where 67≤a≤70, 2≤b≤6, 7≤c≤9, 11≤d≤20, 7≤e≤9, 0.5≤f≤1, 1.5≤g≤3, 0.5≤h≤0.9, 0.5≤i≤1, and a+b+c+d+e+f+g+h+i=100.

[0008] This invention provides a cobalt-based amorphous filament material. By combining a low-content noble metal (Pt) with a high-abundance metallic iron (Fe) and nickel (Ni) composite design, a highly efficient and economical catalyst design is achieved. The Co-Fe-Ni ternary component synergistically optimizes the oxygen evolution reaction (OER), the Pt component enhances the hydrogen evolution reaction (HER), the niobium (Nb), yttrium (Y), and carbon (C) composite elements improve material stability, and the boron (B), silicon (Si), and carbon (C) system precisely regulates the formation of the amorphous structure and its electrical conductivity. Based on the synergistic effect of the multiple components, this cobalt-based amorphous material possesses a unique disordered atomic arrangement structure, providing abundant low-coordination active sites, thereby significantly enhancing catalytic activity. Furthermore, the material exhibits excellent chemical homogeneity and high residual stress characteristics, enabling it to maintain good structural stability even in the highly oxidizing and reducing environments of water electrolysis. In summary, this cobalt-based amorphous material combines high catalytic activity, excellent stability, and long-term durability in the field of water electrolysis for hydrogen production, meeting the application requirements of large-scale industrial-scale green hydrogen production.

[0009] The roles of each element in the cobalt-based amorphous wire provided by this invention are as follows:

[0010] Co: The addition of Co enables the catalyst to exhibit high catalytic activity in the oxygen evolution reaction (OER), especially in the amorphous structure, where surface defects and exposed active sites can significantly enhance reaction kinetics. Therefore, Co is used as the main component of the amorphous filament in this invention, with a mass percentage of 67 wt%~70 wt%.

[0011] Fe: The addition of Fe can form bimetallic active sites with Co, creating a synergistic effect that optimizes the adsorption energy of intermediates, regulates electronic structure, enhances conductivity and catalytic efficiency, reduces reaction overpotential, and partially replaces Co, thus reducing the cost of amorphous wires. Therefore, the mass percentage of Fe in this invention is 2 wt%~6 wt%.

[0012] Si and B are key elements for the formation of amorphous states. B lowers the melting point of the alloy and, together with Si, synergistically promotes the formation of amorphous structures during rapid cooling, enhancing the amorphous formation ability and improving the material's corrosion resistance and mechanical strength. Simultaneously, Si forms a surface oxide layer, increasing the exposure of active sites, while B regulates the electronic states of metal atoms, enhancing catalytic activity and further improving the catalytic activity of the amorphous filaments. Therefore, the mass percentage of Si in this invention is 7 wt%~9 wt%, and the mass percentage of B is 11 wt%~20 wt%.

[0013] Nb: The addition of Nb can improve the corrosion resistance of amorphous wires in electrolyte, prevent anodic oxidation degradation, and extend catalyst lifetime by forming stable oxides or nitrides. Therefore, the mass percentage of Nb in this invention is 7wt%~9wt%.

[0014] The addition of trace amounts of Pt and Ni elements can significantly improve the reaction rate of water electrolysis and synergistically optimize the overall water electrolysis efficiency with Co. Therefore, the mass percentage of Pt in this invention is 0.5 wt%~1 wt%, and the mass percentage of Ni in this invention is 1.5 wt%~3 wt%.

[0015] Y: Rare earth element Y improves the oxidation resistance of materials, refines the microstructure, enhances mechanical stability, or forms a passivation layer on the catalyst surface, reducing the loss of active ingredients. Therefore, the mass percentage of Y in this invention is 0.5 wt%~0.9 wt%.

[0016] C: C acts as a conductive carrier or dopant, promoting charge transfer and increasing specific surface area, providing more reactive sites. Therefore, the mass percentage of C in this invention is 0.5 wt% to 1 wt%.

[0017] Preferably, the cobalt-based amorphous wire has the following compositional formula: Co 68 Fe5Si7B 10 Nb7Pt1Ni1Y 0.5 C 0.5 Co 68 Fe5Si7B 10 Nb7Pt 0.5 Ni 1.5 Y 0.5 C 0.5 or Co 67 Fe5Si7B 11 Nb7Pt 0.5 Ni 1.5 Y 0.5 C 0.5 .

[0018] Preferably, the diameter of the cobalt-based amorphous wire is 5 μm to 300 μm.

[0019] More preferably, the diameter of the cobalt-based amorphous wire is 100 μm to 130 μm.

[0020] Preferably, the atomic structure of the cobalt-based amorphous filament exhibits a gradient distribution from the inside to the outside.

[0021] Gradient pore engineering enables the atomic structure of cobalt-based amorphous wires to exhibit a gradient distribution from the inside to the outside, providing abundant exposure of active sites (such as Co, Pt, and Ni catalytic sites), enhancing the contact area between the electrode and the electrolyte, and shortening the ion migration path through the ordered pore structure, thereby improving charge transfer efficiency and mass transfer efficiency, reducing the bubble shielding effect, and ultimately improving the catalytic activity and structural stability of the amorphous alloy wires.

[0022] More preferably, the structural gradient of the cobalt-based amorphous filament is ≥7%.

[0023] On the other hand, the present invention also provides a method for preparing cobalt-based amorphous wires, the method being based on inner-circle hydrospinning technology and comprising the following steps:

[0024] (1) The cobalt-based amorphous wire is batched and smelted according to the mass percentage of each component to obtain a master alloy; then the master alloy is cast into a rod and cut into multiple small segments of equal size;

[0025] (2) Place the cut rod into a quartz tube with a nozzle at the bottom, and heat the rod to a molten state using an induction coil in an inert gas atmosphere.

[0026] (3) The molten alloy is rapidly cooled by using the inner circular water spinning technology and extruded under the pressure of inert gas to form cobalt-based amorphous metal wire.

[0027] This invention achieves rapid cooling of the alloy through inner-circle hydrospinning technology, prepares cobalt-based amorphous wires with a gradient structure, optimizes its surface strain and electronic structure, thereby significantly improving its catalytic activity and stability in water electrolysis for hydrogen production. By fine-tuning the alloy composition and achieving rapid cooling of the alloy through inner-circle hydrospinning technology, the stability and corrosion resistance of the amorphous material in strong oxidizing and reducing environments are synergistically improved, ensuring its stable performance in long-term use.

[0028] Preferably, the melting in step (1) is carried out by vacuum arc melting;

[0029] Preferably, the diameter of the rod in step (1) is 5 mm.

[0030] Preferably, the length of the cut bar segment in step (2) is 5 mm to 7 mm.

[0031] Preferably, the diameter of the nozzle in step (2) is 0.2 mm to 0.3 mm.

[0032] Based on the inner circular hydrospinning technology, by adjusting the nozzle diameter within the above range, the outer and inner layers of the amorphous filament are cooled to different intensities, resulting in the outer layer rapidly cooling and solidifying to form a completely amorphous structure, while the inner layer cools more slowly, forming nanocrystals or compositional segregation, thus obtaining a cobalt-based amorphous filament with a gradient structure.

[0033] Preferably, the temperature of the induction coil heating in step (2) is 1173℃~1050℃.

[0034] Preferably, the rapid cooling rate in step (3) is 10. 6 K / s ~107 K / s.

[0035] During the spinning process, the cooling rate can be adjusted by changing the flow rate or temperature of the cooling water, or the temperature of the molten alloy, thereby adjusting the microstructure of the filament to achieve the best application requirements.

[0036] Preferably, the inert gas mentioned in step (3) is argon, and the argon pressure is 0.35 MPa to 0.45 MPa.

[0037] By adjusting the argon gas pressure, it can be ensured that the molten alloy is sprayed from the nozzle into the coolant inside the high-speed rotating copper roller in a uniform, smooth, and continuous manner. Therefore, the argon gas pressure of this invention is 0.35 MPa to 0.45 MPa.

[0038] The present invention also provides the application of the cobalt-based amorphous wire in the field of hydrogen production by water electrolysis.

[0039] Preferably, the cobalt-based amorphous wire is wound into a disc-shaped structure and used as a working electrode in the process of producing hydrogen through water electrolysis.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] (1) This invention employs an amorphous composition optimization strategy and combines it with inner-circle hydrospinning technology to construct an amorphous structure system with a gradient distribution characteristic from the inside to the outside. The amorphous structure system provides abundant active sites and shortens the ion migration path through the construction of an ordered pore structure, thereby improving charge transfer efficiency and mass transfer efficiency. Simultaneously, it effectively reduces the bubble shielding effect, achieving a performance of 10 mA / cm². 2 It exhibits an ultra-low overpotential of only 230 mV at current density, achieving a significant improvement in the catalytic activity of cobalt-based catalysts.

[0042] (2) The use of inner-circle water spinning technology can realize the continuous and large-scale production of cobalt-based amorphous wires, providing an scalable process solution for the preparation of industrial water electrolysis hydrogen production catalysts.

[0043] (3) The cobalt-based amorphous wire alloy provided by the present invention has excellent catalytic activity and stability, which can meet the technical requirements of the water electrolysis hydrogen production process and can be applied to the field of industrial-scale green hydrogen production. Attached Figure Description

[0044] Figure 1 A schematic diagram of the inner circular water spinning device provided in this embodiment of the invention.

[0045] Figure 2 A cross-sectional scanning electron microscope image of a cobalt-based amorphous wire provided in an embodiment of the present invention.

[0046] Figure 3This is a schematic diagram of the structure of the water electrolysis hydrogen production device provided in an embodiment of the present invention.

[0047] Figure 4 This is a top view of the water electrolysis hydrogen production apparatus provided in an embodiment of the present invention.

[0048] Figure 5 for Figure 4 A schematic diagram of the cross-section after cutting along BB.

[0049] Figure 6 This is a schematic diagram of the working electrode installation in the water electrolysis hydrogen production device provided in an embodiment of the present invention.

[0050] Figure 7 for Figure 6 A 5x magnified diagram of the number I in the diagram.

[0051] Figure 8 for Figure 6 A schematic diagram of the cross-section after cutting along AA.

[0052] Figure 9 for Figure 8 A 5x magnified diagram of II in the diagram.

[0053] Figure 10 This is a schematic diagram of the assembly of the working electrode and the base plate provided in an embodiment of the present invention.

[0054] Figure 11 The cyclic voltammetry (CV) test diagram provided in Embodiment 1 of the present invention.

[0055] Figure 12 The linear sweep voltammetry (LSV) plot provided in Embodiment 1 of the present invention. Detailed Implementation

[0056] To more clearly illustrate the objectives, technical solutions, and advantages of this invention, the following detailed description will be provided in conjunction with embodiments. Please note that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention are all within the protection scope of this invention.

[0057] The raw materials were purchased from the market.

[0058] Among them: 1-quartz tube, 2-nozzle, 3-cooling water, 4-power supply, 5-oxygen tank or hydrogen tank, 6-crossbeam, 7-tank support, 8-back plate, 9-electrode plate, 10-connector between working electrode and power supply, 11-disc-shaped cobalt-based amorphous wire, 12-pressure rod, 13-fixed seat, 14-base plate, 15-bolt, 16-chamfer.

[0059] Example 1

[0060] Example 1 of the present invention provides an alloy with a Co composition. 68 Fe5Si7B 10 Nb7Pt1Ni1Y 0.5 C 0.5 The preparation method of cobalt-based amorphous wires, with specific steps as follows:

[0061] (1) Weigh the ingredients according to the required elements and proportions, and then weigh the Co after mixing. 68 Fe5Si7B 10 Nb7Pt1Ni1Y 0.5 C 0.5 The alloy raw materials are melted by vacuum arc melting to ensure a purity of over 99.9%, and then cast into a master alloy. After the master alloy is cast into a bar, it is cut into several small segments, each segment being 5 mm to 7 mm in length.

[0062] (2) Place the cut small section of alloy rod into the quartz tube 1 with a nozzle at the bottom, the nozzle ( Figure 1 2) The diameter is 0.2 mm to 0.3 mm. Under the protection of an inert atmosphere, the small section of the rod is heated to 1123°C using an induction coil to make the alloy molten.

[0063] (3) The inner circle water spinning technology is adopted, and cooling water 3 is used for rapid cooling at a cooling rate of 10. 6 K / s-10 7 K / s, the molten alloy is extruded by argon gas with a pressure of 0.35 MPa to 0.45 MPa to form a continuous amorphous alloy wire.

[0064] like Figure 2 As shown, the atomic structure of the prepared cobalt-based amorphous wire exhibits a 7% color difference variation from the inside to the outside in the scanning electron microscope image, indicating a gradient distribution structure from the inside to the outside. Through gradient pore engineering, the atomic structure of the cobalt-based amorphous wire exhibits a gradient distribution from the inside to the outside, providing abundant exposure of active sites (such as Co, Pt, and Ni catalytic sites), enhancing the contact area between the electrode and the electrolyte, and shortening the ion migration path through the ordered pore structure, thereby improving charge transfer efficiency and mass transfer efficiency, reducing the bubble shielding effect, and ultimately improving the catalytic activity and structural stability of the cobalt-based amorphous wire.

[0065] like Figure 3 This is a schematic diagram of a water electrolysis hydrogen production device, further as follows: Figure 4 and 5 As shown, along Figure 4 A schematic diagram of the internal structure of the water electrolysis hydrogen production device obtained after cutting BB ( Figure 5The cobalt-based amorphous wire is coiled into a shape similar to a mosquito coil and placed on the supporting frame to form electrode plate 9, which is then installed in the water electrolysis hydrogen production device. Figure 3 The anode and cathode positions are determined. The electrolytic cell is filled with 1 MkOH electrolyte solution, ensuring the solution evenly covers the electrodes. The working electrode is connected to an external power source via connector 10 to apply voltage to the electrolytic cell and initiate the water electrolysis reaction.

[0066] The specific assembly process is as follows: Figure 6 As shown, after the cobalt-based amorphous wire is wound into a "mosquito coil" shaped disc, a disc-shaped cobalt-based amorphous wire 11 is formed and evenly placed on the base plate 14. The pressure rod 12 is first inserted obliquely into the chamfered position 16 of the central fixing seat 13. Figure 8 and Figure 9 For easy assembly, it is then secured with bolt 15. Figure 7 ).like Figure 5 As shown in Figure BB, the electrode plate 9 is placed into the corresponding groove in the device, with a limit baffle below. The working electrode is connected to the power supply connector 10 via a lead wire, and current is applied to the bottom plate 14. Electrolyte is then added to perform water electrolysis to produce hydrogen. Figure 10 This is a schematic diagram of the structure of plate 9 tilted at a certain angle, highlighting a three-dimensional effect.

[0067] In this study, a cobalt-based amorphous wire was used as the working electrode, a carbon rod as the counter electrode, and an Hg / HgO electrode as the reference electrode. OER activity and stability were tested. OER activity was characterized by LSV testing. Before the OER activity test, the cobalt-based amorphous wire underwent cyclic voltammetry (CV) testing for 20 activation cycles. Figure 11 As shown in the CV cycle graph, a redox peak is observed around 1.05 V vs. RHE, corresponding to Co. 2 ⁺ / Co 3 The redox pair exhibits a redox peak at approximately 1.50 V vs. RHE, corresponding to Co³⁺ / Co. 4 The redox pair eliminated grain boundary defects and exposed low-coordination active sites in the prepared Co-based amorphous alloy wire, optimizing the hydrogen adsorption free energy. Further LSV testing was performed, such as... Figure 12 As shown, at 10 mA / cm 2 The overpotential was 230 mV at a current density, and the OER activity was excellent, indicating that the cobalt-based amorphous filament prepared by inner-circle water spinning can be applied to the field of hydrogen production by water electrolysis.

[0068] Example 2

[0069] The preparation process of Example 2 is basically the same as that of Example 1, except that the component is Co. 68 Fe5Si7B 10 Nb7Pt0.5 Ni 1.5 Y 0.5 C 0.5 .

[0070] Example 3

[0071] The preparation process of Example 3 is basically the same as that of Example 1, except that the component is Co. 67 Fe5Si7B 11 Nb7Pt 0.5 Ni 1.5 Y 0.5 C 0.5 .

Claims

1. A method for preparing a cobalt-based amorphous wire, characterized in that, The cobalt-based amorphous filament is composed of Co. a Fe b Si c B d Nb e Pt f Ni g Y h C i In the subscripts a, b, c, d, e, f, g, h, i represent the mass percentage of an element in the alloy composition, where 67≤a≤70, 2≤b≤6, 7≤c≤9, 11≤d≤20, 7≤e≤9, 0.5≤f≤1, 1.5≤g≤3, 0.5≤h≤0.9, 0.5≤i≤1, and a+b+c+d+e+f+g+h+i=100; The preparation method of cobalt-based amorphous wire is based on the inner-circle hydrospinning technology, including the following steps: (1) the raw materials are batched and smelted according to the mass percentage of each component of the cobalt-based amorphous wire to obtain a master alloy; then the master alloy is cast into a rod and cut into multiple small segments of equal specifications; (2) the cut rod segments are placed in a quartz tube with a nozzle at the bottom, and the rod segments are heated to a completely molten state using an induction coil in an inert gas protective atmosphere; (3) the inner-circle hydrospinning technology is used to achieve rapid cooling, and the molten alloy is extruded under the pressure of the inert gas to form a cobalt-based amorphous metal wire; the diameter of the nozzle is 0.2 mm to 0.3 mm, and the rapid cooling rate is 10. 6 K / s ~10 7 K / s, the inert gas is argon, the argon pressure is 0.35 MPa~0.45 MPa; the diameter of the cobalt-based amorphous wire is 5 μm~300 μm; the heating temperature of the induction coil in step (2) is 1173℃~1050℃.

2. The method for preparing cobalt-based amorphous wire according to claim 1, characterized in that, The compositional formula of the cobalt-based amorphous wire is Co. 67 Fe5Si7B 11 Nb7Pt 0.5 Ni 1.5 Y 0.5 C 0.5 .

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