Nanoporous co3ti / co composite electrode, method of making and use thereof
By preparing nanoporous Co3Ti/Co composite electrodes, the problem of high cost of precious metal electrode materials has been solved, and efficient hydrogen evolution reaction performance and stability have been achieved, promoting the large-scale application of water electrolyzers.
Patent Information
- Application Number
- CN202411844823.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-16
- Publication Date
- 2025-11-11
- Estimated Expiration
- 2044-12-16
AI Technical Summary
In the existing technology, precious metal platinum-based electrode materials are difficult to apply on a large scale in industrial water electrolysis cells due to their low abundance and high price. There is also a lack of non-precious metal-based electrode materials that are inexpensive, structurally stable, have simple preparation processes, large specific surface area, and strong electron transport and mass transfer capabilities.
A nanoporous Co3Ti/Co composite electrode was prepared by alloying and chemical dealloying methods to form a Co3Ti/Co intermetallic compound/metal composite electrode with a dual-mode pore structure. Combined with directional solidification and wire cutting technology, a seamless integrated nanoporous structure was formed.
This improved the specific surface area and electron transport capacity of the electrode material, promoted water dissociation and hydrogen adsorption/desorption processes, significantly enhanced the performance and stability of the hydrogen evolution reaction, and provided a material basis for large-scale hydrogen production in water electrolyzers.
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Figure CN119392284B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of catalyst technology, and in particular to nanoporous Co3Ti / Co composite electrodes, their preparation methods, and applications. Background Technology
[0002] Hydrogen energy is a clean and efficient secondary energy source. Electrocatalytic water splitting, driven by electricity generated from intermittent renewable energy sources such as solar and wind power, is the most promising method for hydrogen production, achieving the conversion and utilization of electrical and chemical energy through zero-carbon water recycling. Both the hydrogen evolution reaction (HER) at the cathode and the oxygen evolution reaction (OER) at the anode of the water splitting reaction occur at the solid-liquid-gas interface of the electrode system. The reaction rate depends on the mass transfer process between the electrolyte and gas within the electrode channels, the electron transport process between the catalytically active phase and the current collector, and the redox reaction at the catalytically active phase / electrolyte interface. Currently, platinum is the HER electrode material with the highest intrinsic catalytic activity. Although nanostructuring can improve the utilization rate of precious metals, its low abundance and high price make it difficult to apply on a large scale in industrial water electrolyzers. Therefore, exploring non-precious metal-based electrode materials that are inexpensive, structurally stable, have simple preparation processes, large specific surface areas, high intrinsic catalytic activity, and possess both electron transport and mass transfer capabilities is key to improving the performance of water splitting reactions and promoting the application of water electrolyzers. Intermetallic compounds with well-defined atomic structures possess multiple active sites. The adsorption energy of these active sites for reaction intermediates can be modulated through electron transfer arising from differences in electronegativity between elements. Furthermore, intermetallic compounds exhibit intrinsic thermodynamic stability due to their ordered crystal structure, a characteristic that can enhance the service life of electrode materials. Based on these considerations, this disclosure proposes a nanoporous Co3Ti / Co composite electrode, its preparation method, and its applications. Summary of the Invention
[0003] To overcome the shortcomings of the prior art, this disclosure provides a nanoporous Co3Ti / Co composite electrode, its preparation method, and its application.
[0004] According to a first aspect of this disclosure, a method for preparing a nanoporous Co3Ti / Co composite electrode is provided, characterized by comprising the following steps:
[0005] a. Cleaning the metal: Soak and clean the high-purity Co and Ti metal sheets in acetone and dilute hydrochloric acid in sequence, then use dilute NaOH solution to corrode the oxides on the surface of the Al metal sheet, and then clean the Co, Ti and Al metal sheets several times with ultrapure water. After that, place the cleaned Co, Ti and Al metal sheets in a vacuum drying oven to dry for later use.
[0006] b. Melting the alloy ingot: Weigh the Co, Ti, and Al washed with ultrapure water according to an atomic ratio of 22:8:70, with a total mass of 10-12g; place the weighed metals in an electric arc furnace and melt the alloy under an argon atmosphere, igniting the arc 6-10 times to obtain an alloy ingot with uniform composition; after the alloy ingot cools to room temperature, remove the alloy ingot, which is silvery-white.
[0007] c. Preparation of columnar alloy by directional solidification: The oxide layer on the surface of the alloy ingot is sanded off with sandpaper. The alloy ingot is cut into small pieces with a size of less than 9 mm. The small pieces of alloy ingot are placed in the crucible tube of the directional solidification equipment and heated to 1400°C under an argon atmosphere at a heating rate of 10°C / min. The ingot is held at a preset holding temperature for 15 min and stretched at a preset stretching speed with a stretching stroke of 9 cm. After stretching is completed and the temperature drops to room temperature, the small pieces of alloy ingot are removed. The small pieces of alloy ingot have a columnar shape with a diameter of 1 cm.
[0008] d. Preparation of alloy sheets: Cut the columnar small alloy ingots with a diamond wire cutter to obtain alloy discs of a preset size;
[0009] e. Chemical dealloying: The alloy disc is placed in a 6M KOH solution saturated with N2 at a preset corrosion temperature for corrosion. After a certain corrosion time, when no more bubbles are generated on the surface of the alloy disc, the alloy disc is washed with ultrapure water multiple times to obtain a nanoporous Co3Ti / Co composite electrode.
[0010] Preferably, the precursor alloy composition of the alloy ingot in step b is Co. 22 Ti8Al 70 (at%).
[0011] Preferably, in the directional solidification method for preparing columnar alloys in step c, the preset holding temperature is 1400℃ and the preset stretching speed is 100μm / s.
[0012] Preferably, the alloy disc cut in step d has a diameter of 1 cm and a thickness of 400 μm.
[0013] Preferably, in step e, the alloy disc is placed in a 6M KOH solution saturated with N2 at 70°C for 8 hours.
[0014] According to a second aspect of this disclosure, a nanoporous Co3Ti / Co composite electrode is provided.
[0015] According to a third aspect of this disclosure, an application of a nanoporous Co3Ti / Co composite electrode is provided, characterized in that the composite electrode is used as a hydrogen evolution reaction electrode.
[0016] The principle of this disclosed technical solution is:
[0017] This composite electrode material is prepared by alloying and dealloying methods. First, Co, Ti, and Al are melted into Co in an electric arc furnace. 22 Ti8Al 70 The alloy ingot is then stretched into an alloy column shape using a directional solidification device, and then sliced into thin sheets using wire cutting. The precursor alloy is composed of Al 13 It is composed of Co4, Co3Ti, and Al3Ti. Then, the Al in the Al-containing intermetallic compound is etched away by alkaline solution using a chemical dealloying method to form a Co3Ti / Co intermetallic compound / metal composite electrode with a dual-mode pore structure.
[0018] The beneficial effects of this disclosed technical solution are:
[0019] The Co3Ti intermetallic compound described in this disclosure is seamlessly integrated onto nanoporous Co ligaments. The dual-mode pore structure increases the specific surface area of the electrode material, improving electrolyte mass transfer and electron transport capabilities. The Co and Ti sites in the intermetallic compound are conducive to the adsorption of *H and *OH intermediates, respectively, thereby promoting water dissociation and the adsorption / desorption of *H, and enhancing the kinetics of the alkaline hydrogen evolution reaction. Experimental results confirm that this electrode exhibits excellent hydrogen evolution reaction performance, providing a material basis for large-scale hydrogen production applications in water electrolyzers. Attached Figure Description
[0020] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. The drawings are provided for a better understanding of the present invention and are not intended to limit the scope of this disclosure. In the drawings, the same or similar reference numerals denote the same or similar elements, wherein:
[0021] Figure 1 Scanning electron microscope (SEM) images of nanoporous Co3Ti / Co composite electrodes according to embodiments of this disclosure;
[0022] Figure 2 1. Transmission electron microscopy (HRTEM) images of nanoporous Co3Ti / Co composite electrodes according to embodiments of this disclosure;
[0023] Figure 3 Energy dispersive spectroscopy (EDS) diagram of nanoporous Co3Ti / Co composite electrode according to embodiments of this disclosure;
[0024] Figure 4 X-ray diffraction (XRD) pattern of nanoporous Co3Ti / Co composite electrode according to embodiments of this disclosure;
[0025] Figure 5The hydrogen evolution reaction polarization curve of the nanoporous Co3Ti / Co composite electrode in 1M KOH electrolyte according to the embodiments of this disclosure;
[0026] Figure 6 Tafel diagram of the hydrogen evolution reaction of the nanoporous Co3Ti / Co composite electrode in the embodiments of this disclosure;
[0027] Figure 7 Impedance spectra of nanoporous Co3Ti / Co in 1M KOH electrolyte according to embodiments of this disclosure;
[0028] Figure 8 The hydrogen evolution reaction stability of nanoporous Co3Ti / Co in the embodiments of this disclosure. Detailed Implementation
[0029] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.
[0030] Example 1
[0031] A method for preparing a nanoporous Co3Ti / Co composite electrode, comprising the following steps:
[0032] 1) Cleaning the metal: Soak and clean the high-purity Co and Ti metal sheets in acetone and dilute hydrochloric acid in sequence, corrode the oxides on the surface of the Al metal sheet with dilute NaOH solution, and then wash the Co, Ti and Al metals multiple times with ultrapure water. Place them in a vacuum drying oven to dry for 8 hours.
[0033] 2) Melting the alloy ingot: Weigh the Co, Ti, and Al metals (washed with ultrapure water) according to an atomic ratio of Co:Ti:Al of 22:8:70, and weigh 3.63g of Co flakes, 1.07g of Ti flakes, and 5.30g of Al flakes. Place the weighed metals in an electric arc furnace and melt the alloy under an argon atmosphere, repeating the arc melting process 6-10 times to achieve uniformity of the alloy composition. After the metal ingot cools to room temperature, remove the alloy; the alloy is silvery-white. The composition of the alloy ingot is Co. 22 Ti8Al 70 (at%);
[0034] 3) Preparation of columnar alloy by directional solidification: The oxide layer on the surface of the alloy ingot is sanded off with sandpaper, and the alloy ingot is cut into small alloy ingots with a size of less than 9 mm. The small alloy ingots are placed in the crucible tube of the directional solidification equipment and heated to 1400℃ under an argon atmosphere at a heating rate of 10℃ / min. The temperature is held at 1400℃ for 15 min, and the alloy is stretched at a speed of 100 μm / s for a stretching stroke of 9 cm. After the stretching is completed and the temperature drops to room temperature, the small alloy ingots are taken out. The small alloy ingots have a columnar shape with a diameter of 1 cm.
[0035] 4) Preparation of alloy sheet: Cut the columnar small alloy ingot with a diamond wire cutter to obtain alloy discs with a diameter of 1 cm and a thickness of 400 μm;
[0036] 5) Preparation of porous electrode material by chemical dealloying method: The alloy disc is placed in a 6M KOH solution saturated with N2 at 70°C for etching. After 8 hours, when no more bubbles are generated on the surface of the alloy disc, the alloy disc is washed with ultrapure water multiple times to obtain a nanoporous Co3Ti / Co composite electrode material.
[0037] The morphology and structural characterization results of the composite electrode material are as follows:
[0038] Figure 1 This is a scanning electron microscope image of a nanoporous Co3Ti / Co electrode, which exhibits a dual-mode pore structure with a macropore size of approximately 200 nm. Figure 2 The results indicate that the pore size is approximately 3 nm. Macropores facilitate mass transport of electrolyte and gas molecules, while micropores can increase the specific surface area of the electrode material and improve the utilization rate of active sites. The three-dimensional interconnected Co network promotes electron transfer during the hydrogen evolution reaction. Figure 3 This indicates that the atomic ratio of Co, Ti, and Al in the nanoporous Co3Ti / Co is 81:13:6. Figure 4 In the XRD pattern, the characteristic peaks at 41.6°, 44.3°, 47.4°, and 75.9° correspond to the (100), (002), (101), and (110) crystal planes of Co, respectively, and the characteristic peaks at 43.5°, 50.6°, and 74.2° correspond to the (111), (200), and (220) crystal planes of Co3Ti, respectively, proving that the electrode is composed of Co and Co3Ti intermetallic compounds.
[0039] Example 2
[0040] The hydrogen evolution reaction performance of the composite electrode material obtained in Example 1 was tested in a three-electrode system. In 1 MKOH, the nanoporous Co3Ti / Co composite electrode material was used as the working electrode, the Ag / AgCl electrode as the reference electrode, and a carbon rod as the counter electrode. The specific test procedure is as follows:
[0041] 1) Within a voltage range of 0 to -0.15V (relative to the reversible hydrogen electrode), at a rate of 1mV / s -1 The scanning speed was used to test the polarization curve of the hydrogen evolution reaction;
[0042] 2) Test its impedance spectrum at -0.1V, with the frequency set to 10mHz~100kHz and the amplitude set to 5mV;
[0043] 3) The stability of the nanoporous Co3Ti / Co composite electrode was tested for 1000 hours at a voltage of -0.1V (relative to the reversible hydrogen electrode).
[0044] The characterization results of the hydrogen evolution reaction performance of the nanoporous Co3W-WNi4 / Ni electrode material are as follows:
[0045] Figure 5 The hydrogen evolution reaction polarization curves of a nanoporous Co3Ti / Co intermetallic compound / metal composite electrode and a nanoporous Co monometallic electrode were compared. The Co3Ti / Co electrode requires only ~120 mV overpotential to drive a 2 A cm⁻¹ electrode. -2 The current density is much smaller than the overpotential of the Co (~360mV) electrode. Furthermore, as... Figure 6 As shown, the Tafel slope of the nanoporous Co3Ti / Co electrode is as low as ~33 mV dec. -1 The efficiency is significantly lower than that of Co electrode materials, indicating that the Co3Ti / Co electrode exhibits excellent hydrogen evolution reaction performance. For example... Figure 7 As shown, the charge transfer resistance of the nanoporous Co3Ti / Co electrode is much lower than that of the nanoporous Co electrode, further demonstrating the fast reaction kinetics of the nanoporous Co3Ti / Co electrode. Furthermore, stability tests were conducted on this electrode at a potential of -0.1V (relative to the reversible hydrogen electrode), as shown... Figure 8 As shown, the generated current density can remain stable at ~1.3 A cm⁻¹ for 1000 hours. -2 This indicates that the nanoporous Co3Ti / Co electrode material exhibits excellent stability in the hydrogen evolution reaction. This is due to the stable nanoporous structure of the electrode and the seamless anchoring of the intermetallic compound Co3Ti nanoparticles onto the robust Co ligaments. The coherent interface formed between Co3Ti and the Co ligaments further enhances the electrode's service performance.
[0046] In summary, the Co3Ti / Co intermetallic compound described in this disclosure is seamlessly integrated onto a Co ligament with a dual-mode porous structure, with macropores approximately 200 nm in size and micropores approximately 3 nm in size. The dual-mode porous structure increases the specific surface area of the electrode material, improving electrolyte mass transfer and electron transport capabilities. The Co and Ti sites in the intermetallic compound are conducive to the adsorption of *H and *OH intermediates, respectively, thereby promoting water dissociation and the adsorption / desorption of *H, and enhancing the kinetics of the alkaline hydrogen evolution reaction. Electrochemical testing results demonstrate that the nanoporous Co3Ti / Co electrode exhibits excellent hydrogen evolution reaction performance, providing a material basis for large-scale hydrogen production in alkaline water electrolysis cells.
[0047] The above embodiments are preferred embodiments of this disclosure, but the embodiments of this disclosure are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of this disclosure shall be considered equivalent substitutions and shall be included within the protection scope of this disclosure.
Claims
1. A method for preparing a nanoporous Co3Ti / Co composite electrode, characterized in that, Includes the following steps: a. Cleaning the metal: Soak and clean the high-purity Co and Ti metal sheets in acetone and dilute hydrochloric acid in sequence, then use dilute NaOH solution to corrode the oxides on the surface of the Al metal sheet, and then clean the Co, Ti and Al metal sheets several times with ultrapure water. After that, place the cleaned Co, Ti and Al metal sheets in a vacuum drying oven to dry for later use. b. Melting the alloy ingot: Weigh the Co, Ti, and Al washed with ultrapure water according to an atomic ratio of 22:8:70, with a total mass of 10-12 g; place the weighed metals in an electric arc furnace and melt the alloy under an argon atmosphere, igniting the arc 6-10 times to obtain an alloy ingot with uniform composition; after the alloy ingot cools to room temperature, remove the alloy ingot, which is silvery-white. c. Preparation of columnar alloy by directional solidification: The oxide layer on the surface of the alloy ingot is sanded off with sandpaper. The alloy ingot is cut into small pieces with a size of less than 9 mm. The small pieces of alloy ingot are placed in the crucible tube of the directional solidification equipment and heated to 1400 ℃ under an argon atmosphere at a heating rate of 10 ℃ / min. The ingot is held at a preset holding temperature for 15 min and stretched at a preset stretching speed with a stretching stroke of 9 cm. After stretching is completed and the temperature drops to room temperature, the small pieces of alloy ingot are removed. The small pieces of alloy ingot have a columnar shape with a diameter of 1 cm. d. Preparation of alloy sheets: Cut the columnar small alloy ingots with a diamond wire cutter to obtain alloy discs of a preset size; e. Chemical dealloying: The alloy disc is placed in a 6 M KOH solution saturated with N2 at a preset corrosion temperature for corrosion. After a certain corrosion time, when no more bubbles are generated on the surface of the alloy disc, the alloy disc is washed with ultrapure water multiple times to obtain a nanoporous Co3Ti / Co composite electrode.
2. The method for preparing the nanoporous Co3Ti / Co composite electrode according to claim 1, characterized in that: The precursor alloy composition of the alloy ingot in step b is Co at 100% (at%). 22 Ti8Al 70 .
3. The method for preparing the nanoporous Co3Ti / Co composite electrode according to claim 1, characterized in that: In step c, the directional solidification method for preparing columnar alloys has a preset holding temperature of 1400 ℃ and a preset stretching speed of 100 μm / s.
4. The method for preparing the nanoporous Co3Ti / Co composite electrode according to claim 1, characterized in that: The alloy disc in step d has a diameter of 1 cm and a thickness of 400 μm.
5. The method for preparing the nanoporous Co3Ti / Co composite electrode according to claim 1, characterized in that: In step e, the alloy disc is placed in a 6 M KOH solution saturated with N2 at 70 °C for 8 hours.
6. A nanoporous Co3Ti / Co composite electrode obtained by the preparation method according to any one of claims 1-5.
7. The application of the nanoporous Co3Ti / Co composite electrode according to claim 6, characterized in that, The composite electrode is used as the hydrogen evolution reaction electrode.