A low-noble metal amorphous alloy electrode for alkaline electrolytic water and a method of manufacturing the same

Abstract

The application belongs to the technical field of electrocatalytic functional materials, and particularly relates to a low-noble-metal amorphous alloy electrode for alkaline water electrolysis and a preparation method thereof. 64 Zr 36 , 1-5% of Ru is introduced, Ni 64‑ x Zr 36 Ru x , and the low-noble-metal amorphous alloy electrode is prepared through melting, melt spinning and dealloying treatment, has a dual-function electrocatalytic effect, can be used as a cathode to perform a hydrogen evolution reaction (HER) and can be used as an anode to perform an oxygen evolution reaction (OER), has excellent water electrolysis performance and stability, improves reaction efficiency, and the Ru doping content as a noble metal is low, thereby reducing the raw material cost of the catalyst.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalytic functional materials technology, specifically relating to a low-noble metal amorphous alloy electrode for alkaline water electrolysis and its preparation method. Background Technology

[0002] Hydrogen energy is considered an effective way to solve the energy crisis and environmental problems caused by the overuse of fossil fuels. Among hydrogen production technologies, electrochemical water splitting technology is regarded as one of the most promising hydrogen energy production technologies due to its irreplaceable and unique advantages in energy conversion. This technology is a highly attractive green method for producing hydrogen (H2) and oxygen (O2), including two half-reactions: the hydrogen evolution reaction (HER) at the cathode and the oxygen evolution reaction (OER) at the anode. However, the large-scale application of this technology faces some challenges. Both HER and OER involve complex multi-step and multi-electron conversion processes in the hydrogen evolution and oxygen evolution reactions, resulting in high overpotentials and increased energy consumption. Currently, platinum group metals and their oxides (such as Pt, RuO2 / IrO2) are recognized as the most active electrocatalyst materials in HER and OER, respectively. However, their high cost and scarcity limit their large-scale application.

[0003] Currently, conventional methods for preparing high-efficiency electrocatalysts include hydrothermal synthesis, sol-gel methods, electrochemical deposition, and electrospinning. Hydrothermal synthesis is carried out in a closed, pressure-resistant vessel at temperatures typically exceeding 100°C, requiring high safety standards and exhibiting poor control over the morphology and size of the synthesized product. The sol-gel method has a long synthesis cycle and requires large amounts of organic solvents, making it environmentally unfriendly. Electrochemical deposition deposits materials onto a conductive substrate, but its yield is limited by electrode area and solution mass transfer. Electrospinning has low yields and is highly dependent on solution properties, requiring materials with suitable polymer molecular weight, concentration, viscosity, conductivity, and surface tension. Alkaline water electrolysis for hydrogen production is currently the most mature high-capacity hydrogen production technology with the highest commercialization rate; however, it still suffers from high catalyst costs, low reaction efficiency, high energy consumption, poor catalyst stability, and difficulties in synthesis control. In summary, these shortcomings limit the large-scale preparation and commercial application of high-efficiency electrocatalysts.

[0004] Therefore, it is necessary to develop low-cost, high-performance bifunctional electrocatalysts to reduce the high overpotential of the hydrogen evolution reaction (HER) and accelerate the reaction rate. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a low-noble metal amorphous alloy electrode for alkaline water electrolysis and its preparation method. This invention references existing binary amorphous systems such as Ni… 64 Zr 36 By introducing 1-5% Ru, Ni was designed.64-x Zr 36 Ru x Utilizing its strong amorphous forming ability, a low-noble-metal amorphous alloy electrode is prepared through melting, melt spinning, and dealloying. The material preparation process of this invention is simple, significantly reducing the amount and cost of noble metals in the electrocatalyst, while achieving precise control of the alloy composition, thus obtaining a bifunctional water electrolysis catalyst material with adjustable composition and excellent performance.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of this invention provides a method for preparing a low-noble metal amorphous alloy electrode for alkaline water electrolysis, comprising the following steps: (1) Preparation of master alloy ingot: Ni, Zr and Ru are mixed in a molar ratio of 64-x:36:x and then smelted to obtain master alloy ingot for use. The value of x is 1-5. (2) Preparation of amorphous alloy catalytic ribbon: After cutting the master alloy ingot in step (1), it is placed into a quartz tube with a spray opening, heated and melted under a protective atmosphere, and then sprayed onto the surface of a rotating copper roller for cooling to prepare an amorphous alloy catalytic ribbon for later use. (3) Dealloying treatment: The amorphous alloy catalytic thin strip is cut short, washed with deionized water and dried, and then soaked in HF solution for dealloying treatment. After the treatment is completed, it is taken out, washed with deionized water and dried to obtain the low-noble metal amorphous alloy electrode.

[0007] Furthermore, the value of x is 1.

[0008] Furthermore, the purity of the Ni raw material is 99.995%, and the purity of the Zr and Ru raw materials is 99.95%.

[0009] Furthermore, in step (2), the rotational speed of the copper roller is 3000~3500 r / min.

[0010] Furthermore, in step (3), the shortened amorphous alloy catalytic strip has a length of 20~50 mm, a width of 2~3 mm, and a thickness of 20~40 μm.

[0011] Furthermore, in step (3), the concentration of the HF solution of the shortened amorphous alloy catalytic strip is 0.05~0.2mol / L.

[0012] Furthermore, in step (3), the volume of the HF solution used is 10~60 mL.

[0013] Furthermore, in step (3), the soaking time is 1 to 4 hours.

[0014] A second aspect of the present invention provides a low-noble metal amorphous alloy electrode for alkaline water electrolysis prepared by the above-described preparation method.

[0015] A third aspect of the present invention provides an application of the above-mentioned low-noble metal amorphous alloy electrode in alkaline water electrolysis, wherein the low-noble metal amorphous alloy electrode has a dual-function electrocatalytic effect, serving as both a cathode for hydrogen evolution reaction and an anode for oxygen evolution reaction.

[0016] Compared with the prior art, the beneficial effects of the present invention are: (1) The preparation process is simple, low-cost, and highly reproducible: This invention uses melt spinning combined with selective dealloying strategy to prepare amorphous alloy electrocatalysts. The raw materials are commercial high-purity metals, which are readily available. Furthermore, the high-purity Ni and Zr used as the main raw materials are low-cost, have a short preparation cycle, are simple to operate, and are highly reproducible, making them suitable for large-scale production.

[0017] (2) High tunability of composition: This invention refers to the existing binary amorphous system, namely Ni 64 Zr 36 It has strong amorphous forming ability, and by introducing 1% Ru, Ni was designed. 64 Zr 36 Ru1. Amorphous ribbons can be prepared by appropriately adjusting the ratio of Ni and Ru. Amorphous alloy original ribbons are prepared through this process, and then the electrocatalytic effect is improved by selective dealloying technology.

[0018] (3) Excellent bifunctional electrocatalytic effect: The amorphous alloy catalytic tape prepared by the present invention has a bifunctional electrocatalytic effect. It can be used as a cathode for hydrogen evolution reaction (HER) and as an anode for oxygen evolution reaction. It has excellent water electrolysis performance and stability, and improves reaction efficiency. Attached Figure Description

[0019] Figure 1 The X-ray diffraction patterns are those of the NiZrRu amorphous alloy electrodes obtained in the embodiments and comparative examples of the present invention.

[0020] Figure 2 Linear scanning voltammetry scans of the NiZrRu amorphous alloy electrodes obtained in the embodiments and comparative examples of the present invention during the hydrogen evolution reaction in 1 mol / L KOH solution (compared with platinum-carbon catalyst).

[0021] Figure 3 Linear scanning voltammetry scans of the NiZrRu amorphous alloy electrodes obtained in the embodiments and comparative examples of the present invention during the oxygen evolution reaction in 1 mol / L KOH solution (compared with ruthenium dioxide catalyst).

[0022] Figure 4This is a schematic diagram of the dual-electrode system used for the total water splitting reaction (OWS) of the NiZrRu amorphous alloy electrode obtained in Example 4 of the present invention.

[0023] Figure 5 The linear sweep voltammetry scan of the NiZrRu amorphous alloy electrode obtained in Example 4 of this invention during the total water splitting reaction (OWS) in 1 mol / L KOH solution (compared with platinum carbon catalyst (cathode) || ruthenium dioxide catalyst (anode)).

[0024] Figure 6 The stability test results of the NiZrRu amorphous alloy electrode obtained in Example 4 of this invention during the over-the-sea (OWS) water splitting reaction in 1 mol / L KOH solution (current density: 100 mA / cm²) are shown. 2 Test duration: 200 hours.

[0025] Figure 7 The surface morphology of (a) Ru-1-4h, (b) Ru-1-0h, (c) Ru-1-1h, (d) Ru-1-2h, (e) Ru-1-3, and (f) Ru-1-4h are shown. Detailed Implementation

[0026] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0027] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.

[0028] Example 1: Preparation of a low-noble metal amorphous alloy electrode (Ru-1-1h) for alkaline water electrolysis A master alloy ingot was prepared using a vacuum arc furnace (model GN-1, manufactured by Gena Metal Materials (Dongguan) Metal Co., Ltd., Guangdong). A low-Ru-content amorphous alloy catalytic ribbon was then prepared using equipment (model GN-2, manufactured by Gena Metal Materials (Dongguan) Metal Co., Ltd., Guangdong). The ribbon was then immersed in HF solution to obtain a low-noble-metal amorphous alloy electrode for total water splitting. The process includes the following steps: (1) Ni (purity 99.995%), Zr (purity 99.95%) and Ru (purity 99.95%) were mixed and smelted into a master alloy ingot in a mass percentage ratio of 52.21:46.37:1.43, and a Ni alloy was designed.64 Zr 36 Ru1 alloy, ready for use; (2) Cut the master alloy ingot into several small ingots with a total mass of 8~10g, put them into a quartz tube with a circular opening with a diameter of 1 mm, melt them, and spray them onto the surface of a copper roller with a rotation speed of 3000 r / min to cool them, and obtain amorphous alloy catalytic thin strips with low Ru content for later use. (3) Cut the thin strip into rectangular thin strips with a length of 30 mm, a width of 2 mm and a thickness of 20 μm. Wash and dry with deionized water. Take 3 rectangular thin strips and put them into 50 mL centrifuge tubes. Pour in 45 mL of 0.05 mol / L HF solution to de-alloy them for 1 h to remove part of the Zr on the surface of the thin strip. After soaking, take out the thin strips, wash and dry with deionized water to obtain an amorphous alloy electrode Ru-1-1h with rich surface morphology and enriched Ni and Ru.

[0029] Example 2: Preparation of a low-noble metal amorphous alloy electrode (Ru-1-2h) for alkaline water electrolysis The difference between this embodiment and embodiment 1 is that in step (3), the dealloying time is 2 hours.

[0030] Example 3: Preparation of a low-noble metal amorphous alloy electrode (Ru-1-3h) for alkaline water electrolysis The difference between this embodiment and embodiment 1 is that in step (3), the dealloying time is 3 hours.

[0031] Example 4: Preparation of a low-noble metal amorphous alloy electrode (Ru-1-4h) for alkaline water electrolysis The difference between this embodiment and embodiment 1 is that in step (3), the dealloying time is 4 hours.

[0032] Comparative Example 1: Preparation of a low-noble metal amorphous alloy electrode (Ru-1-0h) for alkaline water electrolysis The difference between this comparative example and Example 1 is that the low Ru content amorphous alloy catalytic tape is not subjected to the dealloying treatment in step (3).

[0033] Test Example 1: Electrode Material Characterization and Performance Testing The NiZrRu amorphous alloy electrodes obtained in Examples 1-4 and Comparative Example 1 were subjected to XRD tests (test step size 5° / min, test range 20~80°), and the test results are as follows. Figure 1 As shown, both the undealloyed and dealloyed samples exhibit broadened diffraction peaks, with no obvious crystalline diffraction peaks, indicating that the obtained samples all maintain an amorphous structure.

[0034] Using a standard three-electrode system, with the Hg / HgO electrode as the reference electrode and the graphite rod electrode as the counter electrode, the NiZrRu amorphous alloy electrodes obtained in Examples 1-4 and Comparative Example 1 were used as working electrodes. The catalytic performance of the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in the water electrolysis reaction was tested using a Gamry 620 electrochemical workstation in 1.0 mol / L KOH solution via linear sweep voltammetry. The scan rate in the linear sweep voltammetry test was 5 mV / s. The test results are as follows: Figures 2-3 As shown. Figure 2 As shown, for the hydrogen evolution reaction, with the increase of dealloying time, the sample at 10 mA / cm 2 The overpotential gradually decreases under these conditions. The NiZrRu amorphous alloy electrode Ru-1-4h at 10 mA / cm²... 2 The overpotential is smaller (37 mV), which is lower than that of commercial platinum-carbon catalysts (51 mV), resulting in higher catalytic activity and better hydrogen evolution reaction catalytic performance. For example... Figure 3 As shown, for the oxygen evolution reaction, the NiZrRu amorphous alloy electrode Ru-1-4h at 10 mA / cm 2 and 100 mA / cm 2 The overpotentials were even smaller, reaching 342 mV and 458 mV respectively, and were within 100 mA / cm². 2 The overpotential is lower than that of commercial ruthenium dioxide catalysts (611 mV), resulting in higher catalytic activity and better oxygen evolution reaction catalytic performance.

[0035] The catalytic performance of the NiZrRu amorphous alloy electrode Ru-1-4h obtained in Example 4 was tested using a dual-electrode system via linear sweep voltammetry and chronovoltammetry. A schematic diagram of the testing setup is shown below. Figure 4 As shown. By Figure 5 It can be seen that the NiZrRu amorphous alloy electrode Ru-1-4h at 100 mA / cm 2 The battery voltage was 1.853 V, which is lower than the 2.028 V of the commercial Pt / C (cathode)||RuO2 (anode) system, indicating that the NiZrRu amorphous alloy electrode Ru-1-4h has better overall water splitting performance. Figure 6 As shown, the NiZrRu amorphous alloy electrode Ru-1-4h operates at a current density of 100 mA / cm². 2 The stability test under the specified conditions for 200 h showed a potential fluctuation of only 24 mV, indicating that the NiZrRu amorphous alloy electrode Ru-1-4h has excellent stability.

[0036] Scanning electron microscopy (SEM) images of the NiZrRu amorphous alloy electrodes obtained in Examples 1-4 and Comparative Example 1 are shown below. Figure 7As shown, SEM cross-sectional view ( Figure 7 a) This indicates that the NiZrRu amorphous alloy electrode Ru-1-4h has a unique "sandwich" structure, consisting of two etched layers and an internal original band. This structure is beneficial for the contact between the catalyst and the electrolyte. Simultaneously, with the extension of the dealloying time (0~4h), the number of "grooves" on the sample surface increases, and the roughness improves. Figure 7 (b~7f) is beneficial to increasing the electrochemical active area, thereby improving the catalytic electrolysis performance of the electrode.

[0037] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A method for preparing a low-noble metal amorphous alloy electrode for alkaline water electrolysis, characterized in that, Includes the following steps: (1) Preparation of master alloy ingot: Ni, Zr and Ru are mixed in a molar ratio of 64-x:36:x and then smelted to obtain master alloy ingot for use. The value of x is 1~5. (2) Preparation of amorphous alloy catalytic ribbon: After cutting the master alloy ingot in step (1), it is placed into a quartz tube with a spray opening, heated and melted under a protective atmosphere, and then sprayed onto the surface of a rotating copper roller for cooling to prepare an amorphous alloy catalytic ribbon for later use. (3) Dealloying treatment: The amorphous alloy catalytic thin strip is cut short, washed with deionized water and dried, and then soaked in HF solution for dealloying treatment. After the treatment is completed, it is taken out, washed with deionized water and dried to obtain the low-noble metal amorphous alloy electrode.

2. The method for preparing a low-noble metal amorphous alloy electrode for alkaline water electrolysis according to claim 1, characterized in that, The value of x is 1.

3. The method for preparing a low-noble metal amorphous alloy electrode for alkaline water electrolysis according to claim 1, characterized in that, In step (2), the rotational speed of the copper roller is 3000~3500 r / min.

4. The method for preparing a low-noble metal amorphous alloy electrode for alkaline water electrolysis according to claim 1, characterized in that, In step (3), the shortened amorphous alloy catalytic strip has a length of 20-50 mm, a width of 2-3 mm, and a thickness of 20-40 μm.

5. The method for preparing a low-noble metal amorphous alloy electrode for alkaline water electrolysis according to claim 1, characterized in that, In step (3), the concentration of the HF solution of the shortened amorphous alloy catalytic strip is 0.05~0.2 mol / L.

6. The method for preparing a low-noble metal amorphous alloy electrode for alkaline water electrolysis according to claim 1, characterized in that, In step (3), the volume of the HF solution used is 10~60 mL.

7. The method for preparing a low-noble metal amorphous alloy electrode for alkaline water electrolysis according to claim 1, characterized in that, In step (3), the soaking time is 1 to 4 hours.

8. A low-noble metal amorphous alloy electrode for alkaline water electrolysis prepared by the preparation method according to any one of claims 1 to 7.

9. The application of a low-noble-metal amorphous alloy electrode as described in claim 8 in alkaline water electrolysis, characterized in that, The low-noble metal amorphous alloy electrode has a dual-function electrocatalytic effect, serving as both a cathode for hydrogen evolution reaction and an anode for oxygen evolution reaction.

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