Composite electrocatalytic material and preparation method and application thereof
By embedding nickel-iron alloy and loading ruthenium nanoparticles into carbon fiber/carbon nanotube composite films, the problems of high cost and poor conductivity of electrocatalysts have been solved, and a highly efficient and stable process for hydrogen production by water electrolysis has been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HENAN UNIV OF SCI & TECH
- Filing Date
- 2026-04-22
- Publication Date
- 2026-07-21
AI Technical Summary
Existing electrocatalysts are expensive, have poor conductivity, and lack stability, making it difficult to simultaneously meet the requirements of high activity, high stability, and low cost.
A composite electrocatalytic material was prepared by electrospinning using carbon fiber/carbon nanotube composite films as substrates, embedding nickel-iron alloys and loading ruthenium nanoparticles. The electronic structure of the nickel-iron alloys was controlled to optimize the H binding energy of the reactants.
It achieves improved catalytic performance of catalysts while reducing the amount of precious metals used. It is low in cost, has excellent conductivity and good stability, and significantly improves the catalytic activity of hydrogen evolution, oxygen evolution and total water splitting reactions.
Smart Images
Figure CN122428318A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrocatalytic materials technology, specifically to a composite electrocatalytic material, its preparation method, and its application. Background Technology
[0002] Conventional hydrogen production methods, such as gray hydrogen and green hydrogen production, are inefficient and have slow energy conversion rates. In contrast, water electrolysis is highly efficient and has rapid energy conversion, meeting the requirements for high-efficiency hydrogen production. In the field of water electrolysis for hydrogen production, electrocatalysts are the core factor controlling and influencing the hydrogen production effect. Commonly used catalysts in electrocatalysis technology include noble metal-based catalysts (such as Pt, Pd, Ru, and Ir), transition metal-based electrocatalysts, and carbon-based electrocatalysts. However, single-material electrocatalysts typically struggle to simultaneously achieve the three requirements of "high activity, high stability, and low cost."
[0003] An ideal hydrogen evolution catalyst should possess an appropriate H binding energy, the degree of which can be assessed by the value of ΔGH* relative to 0. Adjusting the catalyst composition and electronic structure, and optimizing the ΔGH* value through synergistic effects among multiple components, is key to developing highly efficient hydrogen evolution catalysts. Although noble metals possess excellent electrocatalytic performance, their high cost and rarity limit large-scale production and application. Optimizing the process to reduce the amount of noble metals while ensuring high catalytic performance is a feasible solution to address the sluggish kinetics of oxygen and hydrogen evolution reactions in water electrolysis. To enhance the conductivity of electrocatalysts, designing and synthesizing substrates with high conductivity, especially three-dimensional substrates, is crucial. These substrates not only improve the dispersion of active sites and prevent particle aggregation but also increase the specific surface area, facilitating the complete exposure of active metal sites to the electrolyte solution, thereby accelerating the kinetics of the hydrogen evolution reaction.
[0004] Therefore, it is particularly important to develop efficient electrocatalysts to produce hydrogen through water electrolysis in order to promote the realization of a hydrogen economy. Summary of the Invention
[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a composite electrocatalytic material, its preparation method and application, thereby solving the technical problems of high cost, poor conductivity and lack of stability of common electrocatalysts in the prior art.
[0006] To achieve the above-mentioned technical objectives, the present invention provides a composite electrocatalytic material comprising a substrate, a nickel-iron alloy, and ruthenium nanoparticles; the substrate is a carbon fiber / carbon nanotube composite film, the nickel-iron alloy is embedded in the substrate, and the ruthenium nanoparticles are loaded on the substrate to regulate the electronic structure of the nickel-iron alloy.
[0007] In any embodiment, the loading of the ruthenium nanoparticles on the substrate is 15wt% to 20wt%.
[0008] Furthermore, this invention also proposes a method for preparing a composite electrocatalytic material, comprising the following steps: S1. Soluble nickel salt, soluble iron salt, urea and carbon fiber / carbon nanotube composite film are dispersed in an alcohol solution, and then a hydrothermal reaction is carried out to obtain the first intermediate. S2. The first intermediate is carbonized to obtain the second intermediate; S3. The second intermediate and the soluble ruthenium salt are reduced under the action of a reducing agent to obtain the composite electrocatalytic material.
[0009] In any embodiment, in step S1, the carbon fiber / carbon nanotube composite film is prepared by the following steps: Provide spinning solutions containing polyacrylonitrile and carbon nanotubes; The spinning solution was used to form a precursor film by electrospinning. Subsequently, the precursor film was subjected to pre-oxidation and carbonization treatment to obtain a carbon fiber / carbon nanotube composite film.
[0010] In any embodiment, the mass ratio of polyacrylonitrile to carbon nanotubes in the spinning solution is 1:(0.2-0.3); The parameters for electrospinning are as follows: roller speed is 400 r / min to 600 r / min; distance from syringe to roller is 10 cm to 20 cm; positive electrode voltage is 15 kV to 20 kV; internal temperature and humidity of the electrospinning machine are 25℃ to 40℃ and 30% to 50%, respectively; and the spinning solution push speed is 0.6 mL / h to 1.0 mL / h. The pre-oxidation procedure is as follows: in an air atmosphere, heat to 200℃~300℃ and hold for 4~5 hours; The carbonization process is as follows: in an inert gas atmosphere, the temperature is raised to 850-950℃ and then kept at that temperature for 2-3 hours.
[0011] In any embodiment, in step S1, the temperature of the hydrothermal reaction is 140-160°C, and the hydrothermal reaction time is 10-14 hours.
[0012] In any embodiment, in step S1, the soluble nickel salt is nickel nitrate, and the soluble iron salt is ferric nitrate; and / or, the mass ratio of the soluble nickel salt, the soluble iron salt, and the urea is (0.12-0.14):(0.05-0.07):(0.14-0.16); and / or, the mass ratio of the soluble nickel salt to the carbon fiber / carbon nanotube composite film is (0.12-0.14) g:(50-70) mg.
[0013] In any embodiment, in step S2, the carbonization process is as follows: in a mixed gas of hydrogen and inert gas, the temperature is raised to 450-550°C and then kept at that temperature for 2-3 hours.
[0014] In any embodiment, in step S3, the soluble ruthenium salt is a trivalent ruthenium salt, the reducing agent is sodium borohydride; and / or, the mass ratio of the amount of the soluble ruthenium salt added to the second intermediate is (8-10):20.
[0015] Furthermore, this invention also proposes the application of the above-mentioned composite electrocatalytic material or the composite electrocatalytic material prepared by the above-mentioned preparation method in the electrolysis of water to produce hydrogen.
[0016] Compared with the prior art, the beneficial effects of the present invention include: The composite electrocatalytic material provided by this invention embeds a NiFe alloy into a carbon fiber / carbon nanotube composite film and loads a small amount of Ru nanoparticles. Ru, as a noble metal, can regulate the core electronic structure of the NiFe alloy, optimize the H binding energy (ΔGH*) of the reactants, and achieve synergistic catalysis between noble metals and transition metals. At the same time, the combination of multiple components opens up a new catalytic reaction pathway, effectively solving the problem of sluggish oxygen evolution and hydrogen evolution reaction kinetics in water electrolysis. The prepared composite electrocatalytic material exhibits excellent catalytic activity in hydrogen evolution, oxygen evolution, and total water electrolysis reactions. Therefore, it achieves improved catalytic hydrogen production performance of catalysts while reducing the amount of noble metals used, and is low in cost, has excellent conductivity, and good stability.
[0017] This invention utilizes electrospinning technology to develop a composite electrocatalytic material with an advanced three-dimensional structure. Its unique structure significantly enhances the specific surface area and promotes the full exposure of active sites. A nickel-iron alloy is embedded into a carbon fiber / carbon nanotube composite matrix via a carbonization process, while ruthenium nanoparticles are introduced to modulate the electronic structure of the nickel-iron alloy, thereby enabling the prepared catalyst to exhibit superior hydrogen evolution performance. Thanks to its structural characteristics and the synergistic embedding of alloying elements, this material significantly improves the catalytic efficiency of the hydrogen evolution reaction, ensuring a highly efficient and sustainable water splitting process. Attached Figure Description
[0018] Figure 1 The image shows the X-ray diffraction pattern of the composite electrocatalytic material prepared in Example 1 of this invention.
[0019] Figure 2The images show scanning electron microscope (SEM) images of the carbon fiber / carbon nanotube composite film (i.e., CNFs-CNTs in the figure), the first intermediate (i.e., NiFe-LDH / CNFs-CNTs in the figure), and Ru / Ni3Fe / CNFs-CNTs in Example 1 of the present invention; wherein (a) is CNFs-CNTs; (b) is NiFe-LDH / CNFs-CNTs; and (c) is Ru / Ni3Fe / CNFs-CNTs.
[0020] Figure 3 The image shows a transmission electron microscope (TEM) image of Ru / Ni3Fe / CNFs-CNTs prepared in Example 1.
[0021] Figure 4 The image shows the specific surface area and pore size distribution of Ru / Ni3Fe / CNFs-CNTs prepared in Example 1.
[0022] Figure 5 Linear sweep voltammetry (LSV) curves of the HER reaction of the catalysts prepared for Example 1 and Comparative Examples 1-4 in 1 mol / L potassium hydroxide solution.
[0023] Figure 6 The catalytic materials prepared for Examples 1 and Comparative Examples 1-4 were tested at a current density of 10 mA cm⁻¹. -2 The overpotential of the HER reaction under certain conditions.
[0024] Figure 7 Tafel slope plots of the HER reaction of the catalysts prepared in Example 1 and Comparative Examples 1-4 in 1 mol / L potassium hydroxide solution.
[0025] Figure 8 Linear sweep voltammetry (LSV) curves of the OER reaction of the catalysts prepared in Example 1 and Comparative Examples 1-4 in 1 mol / L potassium hydroxide solution.
[0026] Figure 9 The catalytic materials prepared for Examples 1 and Comparative Examples 1-4 were tested at a current density of 10 mA cm⁻¹. -2 The overpotential of the OER reaction under certain conditions.
[0027] Figure 10 Tafel slope plots of the OER reaction of the catalysts prepared in Example 1 and Comparative Examples 1-4 in 1 mol / L potassium hydroxide solution.
[0028] Figure 11 Linear sweep voltammetry (LSV) curves of the catalytic materials prepared for Example 1 and Comparative Examples 2-4 in the total water electrolysis reaction in 1 mol / L potassium hydroxide solution.
[0029] Figure 12The catalytic materials prepared for Examples 1 and Comparative Examples 2-4 were tested at a current density of 10 mA cm⁻¹. -2 The voltage of the total water splitting reaction under certain conditions.
[0030] Figure 13 The graph shows the operational stability test of the catalytic material prepared in Example 1 during the total water electrolysis reaction in 1 mol / L potassium hydroxide solution. Detailed Implementation
[0031] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values of 1 and 2 are listed, and if maximum range values of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
[0032] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.
[0033] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).
[0034] On one hand, this specific embodiment provides a composite electrocatalytic material, including a substrate, a nickel-iron alloy, and ruthenium nanoparticles; the substrate is a carbon fiber / carbon nanotube composite film, the nickel-iron alloy is embedded in the substrate, and the ruthenium nanoparticles are loaded on the substrate to regulate the electronic structure of the nickel-iron alloy, and the loading amount of the ruthenium nanoparticles on the substrate is 15wt%~20wt%.
[0035] On the other hand, this specific embodiment provides a method for preparing a composite electrocatalytic material, including the following steps: S1. A soluble nickel salt, a soluble iron salt, urea, and a carbon fiber / carbon nanotube composite film are dispersed in an alcohol solution, followed by a hydrothermal reaction to obtain a first intermediate. The hydrothermal reaction temperature is 140-160℃, and the hydrothermal reaction time is 10-14h. The soluble nickel salt includes, but is not limited to, nickel nitrate, and the soluble iron salt includes, but is not limited to, ferric nitrate. The mass ratio of the soluble nickel salt, the soluble iron salt, and the urea is (0.12-0.14):(0.05-0.07):(0.14-0.16). The mass ratio of the soluble nickel salt to the carbon fiber / carbon nanotube composite film is (0.12-0.14)g:(50-70)mg. The alcohol solution is a methanol solution or an ethanol solution.
[0036] S2. The first intermediate is subjected to carbonization treatment to obtain the second intermediate; the carbonization treatment procedure is as follows: in a mixed gas of hydrogen and inert gas, the temperature is raised to 450-550℃ and then kept at the temperature for 2-3 hours; the mixed gas is preferably a mixed gas of H2 and Ar.
[0037] S3. The second intermediate and the soluble ruthenium salt are subjected to a reduction reaction under the action of a reducing agent to obtain the composite electrocatalytic material; the soluble ruthenium salt is a trivalent ruthenium salt, including but not limited to ruthenium trichloride; the reducing agent is preferably sodium borohydride; the mass ratio of the amount of soluble ruthenium salt added to the second intermediate is (8-10):20.
[0038] In some embodiments, the carbon fiber / carbon nanotube composite film is prepared by the following steps: A spinning solution containing polyacrylonitrile and carbon nanotubes is provided; wherein the mass ratio of polyacrylonitrile to carbon nanotubes in the spinning solution is 1:(0.2-0.3); The spinning solution was used to form a precursor film by electrospinning. Subsequently, the precursor film was subjected to pre-oxidation and carbonization treatment to obtain a carbon fiber / carbon nanotube composite film. The parameters for electrospinning are as follows: roller speed is 400 r / min to 600 r / min; distance from syringe to roller is 10 cm to 20 cm; positive electrode voltage is 15 kV to 20 kV; internal temperature and humidity of the electrospinning machine are 25℃ to 40℃ and 30% to 50%, respectively; and the spinning solution push speed is 0.6 mL / h to 1.0 mL / h. The pre-oxidation procedure is as follows: in an air atmosphere, heat to 200℃~300℃ and hold for 4~5 hours; The carbonization process is as follows: in an inert gas atmosphere, the temperature is raised to 850-950℃ and then kept at that temperature for 2-3 hours.
[0039] In some embodiments, polyacrylonitrile and carbon nanotubes are mixed and ground, and then N,N-dimethylformamide is added and stirred at 35-45°C to obtain a spinning solution. The spinning solution is subjected to electrospinning, vacuum drying, pre-oxidation, and heat treatment at 850-950°C for 2-3 hours under a nitrogen atmosphere to obtain the carbon fiber / carbon nanotube composite film. The material ratio of polyacrylonitrile to N,N-dimethylformamide is 1g:(10-14)mL.
[0040] This specific embodiment also proposes a composite electrocatalytic material prepared by the above preparation method or the application of the above composite electrocatalytic material in water electrolysis for hydrogen production.
[0041] This invention utilizes electrospinning technology, employing a strong electric field to transform a solution into nanofibers, thus providing a more convenient, versatile, and cost-effective method for preparing nanofibers. This invention introduces carbon nanotubes (CNTs) during the preparation of nanofiber membranes (CNFs), which not only facilitates CNF dispersion and prevents aggregation but also contributes to the construction of a three-dimensionally interconnected, highly conductive substrate, enhancing the substrate's mechanical properties and structural stability. An electrocatalyst is prepared by loading ruthenium nanoparticles and nickel-iron alloys onto a conductive substrate. The ruthenium nanoparticles combined with the nickel-iron alloy, through the modulation of transition metal materials by ruthenium nanoparticles, alters the core electronic structure via electronic effects, optimizing reactant adsorption; achieving synergistic catalysis, significantly reducing costs, and maximizing the utilization of precious metal resources.
[0042] This invention uses a composite of precious metal particles and transition metal alloys, which reduces the amount of precious metals used and lowers costs compared to the traditional method of using only precious metals.
[0043] This invention enhances the conductivity, mechanical properties, and structural stability of a carbon fiber / carbon nanotube composite film with a hollow nanofiber structure by embedding a nickel-iron alloy into the substrate and simultaneously introducing ruthenium nanoparticles loaded on the substrate, thereby regulating the electronic structure of the nickel-iron alloy and thus enabling the prepared catalyst to exhibit excellent hydrogen evolution performance.
[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0045] In this invention, the terms "some embodiments," "this embodiment," and examples are used to describe a subset of all possible embodiments. However, it is understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with each other without conflict.
[0046] If the application documents contain similar descriptions such as "first / second", the following explanation shall be added: In the following description, the terms "first / second / third" are used only to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first / second / third" may be interchanged in a specific order or sequence where permitted, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.
[0047] In this embodiment, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, object A and / or object B can represent three situations: object A exists alone, object A and object B exist simultaneously, and object B exists alone.
[0048] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially. Example 1
[0049] This embodiment proposes a composite electrocatalytic material, comprising a substrate, a nickel-iron alloy, and ruthenium nanoparticles; the substrate is a carbon fiber / carbon nanotube composite film, the nickel-iron alloy is embedded in the substrate, and the ruthenium nanoparticles are loaded on the substrate to regulate the electronic structure of the nickel-iron alloy. This composite electrocatalytic material is prepared by the following steps: (1) Preparation of carbon fiber / carbon nanotube composite films 1 g of polyacrylonitrile (PAN) and 0.2 g of carbon nanotubes (CNTs) were mixed evenly and thoroughly ground using a three-head grinder for 4 hours to ensure complete mixing. 12 mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred at 40 °C for 12 hours to obtain a spinning solution. The resulting spinning solution was injected into a 20 mL syringe using a No. 21 needle, with the needle tip approximately 15 cm from the aluminum foil collecting plate. An external voltage of 20 kV was applied, the feed rate was 0.75 mL / h, the rotating cylinder speed was 600 r / min, and the temperature and humidity were maintained at 35 °C and 40%, respectively. A precursor film was obtained through electrospinning. The resulting film was vacuum dried at 60 °C for 12 hours to remove residual solvent. It was then pre-oxidized in air at 250 °C for 4 hours in a muffle furnace at a heating rate of 2 °C / min. Subsequently, under a N2 atmosphere, the temperature was increased to 900℃ at a heating rate of 5℃ / min and held for 2 hours for carbonization treatment to obtain carbon fiber / carbon nanotube composite film, denoted as CNFs-CNTs.
[0050] (2) Preparation of NiFe-LDH / CNFs-CNTs 0.1309 g Ni(NO3)2·6H2O, 0.0606 g Fe(NO3)3·9H2O, and 0.1502 g urea were dissolved in 40 mL of methanol and evenly dispersed. 60 mg of carbon fiber / carbon nanotube composite film was added, and the mixture was sonicated for 30 min and stirred for 30 min. The resulting solution was transferred to a reaction vessel and hydrothermally heated at 150 °C for 12 h. After the reaction was complete, the mixture was cooled to room temperature, centrifuged with deionized water and ethanol until neutral, and dried under vacuum at 80 °C to obtain NiFe-LDH / CNFs-CNTs (i.e., the first intermediate).
[0051] (3) Preparation of Ru / Ni3Fe / CNFs-CNTs NiFe-LDH / CNFs-CNTs were heated to 500℃ in a 5% H2 / Ar mixed gas at a heating rate of 5℃ / min and held for 2 h to obtain Ni3Fe / CNFs-CNTs (i.e., the second intermediate). 20 mg of Ni3Fe / CNFs-CNTs were dispersed in 20 mL of deionized water and sonicated for 30 min. 1 mL of RuCl3·3H2O (10 mg / mL) aqueous solution was added, and the mixture was sonicated for 30 min. Then, 10 mL of NaBH4 aqueous solution (2 mg / mL) was added, and the mixture was stirred for 30 min and sonicated for 30 min. The mixture was washed three times by centrifugation with deionized water and freeze-dried to obtain Ru / Ni3Fe / CNFs-CNTs (i.e., the composite electrocatalytic material), with a ruthenium nanoparticle loading of 19.3 wt% on the CNFs-CNTs substrate. Example 2
[0052] This embodiment proposes a composite electrocatalytic material, comprising a substrate, a nickel-iron alloy, and ruthenium nanoparticles; the substrate is a carbon fiber / carbon nanotube composite film, the nickel-iron alloy is embedded in the substrate, and the ruthenium nanoparticles are loaded on the substrate to regulate the electronic structure of the nickel-iron alloy. This composite electrocatalytic material is prepared by the following steps: (1) Preparation of carbon fiber / carbon nanotube composite films 1 g of polyacrylonitrile (PAN) and 0.25 g of carbon nanotubes (CNTs) were mixed evenly and thoroughly ground using a three-head grinder for 4 hours to ensure complete mixing. 14 mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred at 40 °C for 12 hours to obtain a spinning solution. The resulting spinning solution was injected into a 20 mL syringe using a No. 21 needle, with the needle tip approximately 15 cm from the aluminum foil collecting plate. An external voltage of 20 kV was applied, the feed rate was 0.75 mL / h, the rotating cylinder speed was 600 r / min, and the temperature and humidity were maintained at 35 °C and 40%, respectively. A precursor film was obtained through electrospinning. The resulting film was vacuum dried at 60 °C for 12 hours to remove residual solvent. It was then pre-oxidized in air at 280 °C for 4 hours in a muffle furnace at a heating rate of 2 °C / min. Subsequently, under a N2 atmosphere, the temperature was increased to 950℃ at a heating rate of 5℃ / min and held for 2.5h for carbonization treatment to obtain a carbon fiber / carbon nanotube composite film, denoted as CNFs-CNTs.
[0053] (2) Preparation of NiFe-LDH / CNFs-CNTs 0.1403 g Ni(NO3)2·6H2O, 0.05 g Fe(NO3)3·9H2O, and 0.16 g urea were dissolved in 40 mL of methanol and dispersed evenly. 70 mg of carbon fiber / carbon nanotube composite film was then added, and the mixture was sonicated for 30 min and stirred for 30 min. The resulting solution was transferred to a reaction vessel and hydrothermally heated at 140 °C for 14 h. After the reaction was completed, the mixture was cooled to room temperature, centrifuged with deionized water and ethanol until neutral, and dried under vacuum at 80 °C to obtain NiFe-LDH / CNFs-CNTs (i.e., the first intermediate).
[0054] (3) Preparation of Ru / Ni3Fe / CNFs-CNTs NiFe-LDH / CNFs-CNTs were heated to 550℃ in a 5% H2 / Ar mixed gas at a heating rate of 5℃ / min and held for 2 h to obtain Ni3Fe / CNFs-CNTs (i.e., the second intermediate). 20 mg of the Ni3Fe / CNFs-CNTs precursor was dispersed in 20 mL of deionized water and sonicated for 30 min. 0.9 mL of RuCl3·3H2O (10 mg / mL) aqueous solution was added, and the mixture was sonicated for 30 min. Then, 10 mL of NaBH4 aqueous solution (2 mg / mL) was added, and the mixture was stirred for 30 min and sonicated for 30 min. The mixture was washed three times by centrifugation with deionized water and freeze-dried to obtain Ru / Ni3Fe / CNFs-CNTs (i.e., the composite electrocatalytic material), with a ruthenium nanoparticle loading of 17.4 wt% on the CNFs-CNTs substrate. Example 3
[0055] This embodiment proposes a composite electrocatalytic material, comprising a substrate, a nickel-iron alloy, and ruthenium nanoparticles; the substrate is a carbon fiber / carbon nanotube composite film, the nickel-iron alloy is embedded in the substrate, and the ruthenium nanoparticles are loaded on the substrate to regulate the electronic structure of the nickel-iron alloy. This composite electrocatalytic material is prepared by the following steps: (1) Preparation of carbon fiber / carbon nanotube composite films 1 g of polyacrylonitrile (PAN) and 0.3 g of carbon nanotubes (CNT) were mixed evenly and thoroughly ground using a three-head grinder for 4 hours to ensure complete mixing. 14 mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred at 40 °C for 12 hours to obtain a spinning solution. The resulting spinning solution was injected into a 20 mL syringe using a No. 21 needle, with the needle tip approximately 15 cm from the aluminum foil collecting plate. An external voltage of 20 kV was applied, the feed rate was 0.75 mL / h, the rotating cylinder speed was 600 r / min, and the temperature and humidity were maintained at 35 °C and 40%, respectively. A precursor film was obtained through electrospinning. The resulting film was vacuum dried at 60 °C for 12 hours to remove residual solvent. It was then pre-oxidized in air at 230 °C for 5 hours in a muffle furnace at a heating rate of 2 °C / min. Subsequently, under a N2 atmosphere, the temperature was increased to 850℃ at a heating rate of 5℃ / min and held for 3 hours for carbonization treatment to obtain carbon fiber / carbon nanotube composite film, denoted as CNFs-CNTs.
[0056] (2) Preparation of NiFe-LDH / CNFs-CNTs 0.1206 g Ni(NO3)2·6H2O, 0.07 g Fe(NO3)3·9H2O, and 0.1405 g urea were dissolved in 40 mL of methanol and evenly dispersed. 50 mg of carbon fiber / carbon nanotube composite film was added, and the mixture was sonicated for 30 min and stirred for 30 min. The resulting solution was transferred to a reaction vessel and hydrothermally heated at 160 °C for 10 h. After the reaction was complete, the mixture was cooled to room temperature, centrifuged with deionized water and ethanol until neutral, and dried under vacuum at 80 °C to obtain NiFe-LDH / CNFs-CNTs (i.e., the first intermediate).
[0057] (3) Preparation of Ru / Ni3Fe / CNFs-CNTs NiFe-LDH / CNFs-CNTs were heated to 450℃ in a 5% H2 / Ar mixed gas at a heating rate of 5℃ / min and held for 3 h to obtain Ni3Fe / CNFs-CNTs (i.e., the second intermediate). 20 mg of Ni3Fe / CNFs-CNTs were dispersed in 20 mL of deionized water and sonicated for 30 min. 0.8 mL of RuCl3·3H2O (10 mg / mL) aqueous solution was added, and the mixture was sonicated for 30 min. Then, 10 mL of NaBH4 aqueous solution (2 mg / mL) was added, and the mixture was stirred for 30 min and sonicated for 30 min. The mixture was washed three times by centrifugation with deionized water and freeze-dried to obtain Ru / Ni3Fe / CNFs-CNTs (i.e., the composite electrocatalytic material), with a ruthenium nanoparticle loading of 15.5 wt% on the CNFs-CNTs substrate.
[0058] Comparative Example 1 The composite electrocatalytic material in this comparative example is the CNFs-CNTs material prepared in step (1) of Example 1, as detailed below: 1 g of polyacrylonitrile (PAN) and 0.2 g of carbon nanotubes (CNTs) were mixed evenly and thoroughly ground using a three-head grinder for 4 hours to ensure complete mixing. 12 mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred at 40 °C for 12 hours to obtain a spinning solution. The resulting spinning solution was injected into a 20 mL syringe using a No. 21 needle, with the needle tip approximately 15 cm from the aluminum foil collecting plate. An external voltage of 20 kV was applied, the feed rate was 0.75 mL / h, the rotating cylinder speed was 600 r / min, and the temperature and humidity were maintained at 35 °C and 40%, respectively. A precursor film was obtained through electrospinning. The resulting film was vacuum dried at 60 °C for 12 hours to remove residual solvent. It was then pre-oxidized in air at 250 °C for 4 hours in a muffle furnace at a heating rate of 2 °C / min. Subsequently, under a N2 atmosphere, the temperature was increased to 900℃ at a heating rate of 5℃ / min and held for 2 hours for carbonization treatment to obtain carbon fiber / carbon nanotube composite film, denoted as CNFs-CNTs.
[0059] Comparative Example 2 The composite electrocatalytic material proposed in this comparative example is the NiFe-LDH / CNFs-CNTs material prepared in Example 1, as detailed below: (1) Carbon fiber / carbon nanotube composite films (CNFs-CNTs) were prepared using the same method as in Example 1.
[0060] (2) NiFe-LDH / CNFs-CNTs were prepared using the same method as in Example 1. Specifically, 0.1309 g Ni(NO3)2·6H2O, 0.0606 g Fe(NO3)3·9H2O, and 0.1502 g urea were dissolved in 40 mL of methanol, dispersed evenly, and 60 mg CNFs-CNTs were added. The mixture was sonicated for 30 min and stirred for 30 min. The resulting solution was transferred to a reaction vessel and hydrothermally heated at 150 °C for 12 h. After the reaction was completed, the mixture was cooled to room temperature, centrifuged with deionized water and ethanol until neutral, and dried under vacuum at 80 °C to obtain NiFe-LDH / CNFs-CNTs.
[0061] Comparative Example 3 This comparative example presents a composite electrocatalytic material, which differs from Example 1 in that Ru is not added, and is prepared by the following steps: (1) Carbon fiber / carbon nanotube composite films (CNFs-CNTs) were prepared using the same method as in Example 1.
[0062] (2) Dissolve 0.1309 g Ni(NO3)2·6H2O, 0.0606 g Fe(NO3)3·9H2O, and 0.1502 g urea in 40 mL of methanol, disperse evenly, add 60 mg CNFs-CNTs, sonicate for 30 min, stir for 30 min, transfer the resulting solution to a reaction vessel, and hydrothermally heat at 150 °C for 12 h. After the reaction is complete, cool to room temperature, centrifuge with deionized water and ethanol until neutral, and dry under vacuum at 80 °C to obtain NiFe-LDH / CNFs-CNTs.
[0063] (3) NiFe-LDH / CNFs-CNTs were heated to 500℃ in a 5% H2 / Ar mixed gas at a heating rate of 5℃ / min and held for 2h to obtain Ni3Fe / CNFs-CNTs.
[0064] Comparative Example 4 This comparative example presents a composite electrocatalytic material, which differs from Example 1 in that carbon nanotubes are not added in step (1), and is prepared by the following steps: (1) Preparation of carbon fibers (CNFs); 1 g of polyacrylonitrile (PAN) was added to 12 mL of N,N-dimethylformamide (DMF), and stirred at 40 °C for 12 h to obtain a spinning solution. The resulting spinning solution was injected into a 20 mL syringe using a No. 21 needle, with the needle tip approximately 15 cm from the aluminum foil collecting plate. An external voltage of 20 kV was applied, the feed rate was 0.75 mL / h, the rotating cylinder speed was 600 r / min, and the temperature and humidity were maintained at 35 °C and 40%, respectively. Precursor films were obtained via electrospinning. The resulting films were then vacuum-dried at 60 °C for 12 h to remove residual solvent. Pre-oxidation was performed in a muffle furnace at 250 °C for 4 h in air at a heating rate of 2 °C / min. Subsequently, the films were held at 900 °C for 2 h in a N2 atmosphere at a heating rate of 5 °C / min to obtain CNFs.
[0065] (2) Preparation of NiFe-LDH / CNFs 0.1309 g Ni(NO3)2·6H2O, 0.0606 g Fe(NO3)3·9H2O, and 0.1502 g urea were dissolved in 40 mL of methanol, dispersed evenly, and then 60 mg CNFs were added. The mixture was sonicated for 30 min and stirred for 30 min. The resulting solution was transferred to a reaction vessel and hydrothermally heated at 150 °C for 12 h. After the reaction was completed, the solution was cooled to room temperature, centrifuged with deionized water and ethanol until neutral, and dried under vacuum at 80 °C to obtain NiFe-LDH / CNFs.
[0066] (3) Preparation of Ru / Ni3Fe / CNFs NiFe-LDH / CNFs were heated to 500℃ in a 5% H2 / Ar mixed gas at a heating rate of 5℃ / min and held for 2 h to obtain Ni3Fe / CNFs. 20 mg of Ni3Fe / CNFs were dispersed in 20 mL of deionized water and sonicated for 30 min. 1 mL of RuCl3·3H2O (10 mg / mL) aqueous solution was added, and the mixture was sonicated for 30 min. Then, 10 mL of NaBH4 aqueous solution (2 mg / mL) was added, and the mixture was stirred for 30 min and sonicated for 30 min. The mixture was washed three times by centrifugation with deionized water and freeze-dried to obtain Ru / Ni3Fe / CNFs.
[0067] The structure of the Ru / Ni3Fe / CNFs-CNTs composite material prepared in Example 1 above was characterized, and the results are as follows: Depend on Figure 1-3 It can be seen that the composite electrocatalytic material prepared in Example 1 has a three-dimensional interconnected structure, the NiFe alloy particles have uniform particle size, and the Ru nanoparticles are uniformly loaded on the carbon substrate and the NiFe alloy surface at the nanoscale without obvious agglomeration. Furthermore, the NiFe alloy particles are successfully embedded in the CNFs-CNTs substrate and are tightly bound together.
[0068] Combination Figure 4It can be seen that the composite electrocatalytic material prepared in Example 1 has a large specific surface area and abundant mesoporous structure, providing sufficient active sites for catalytic reactions.
[0069] The performance of the Ru / Ni3Fe / CNFs-CNTs composite material (i.e., composite electrocatalytic material) prepared in Example 1 was tested. The test method was as follows: using Hg / HgO as the reference electrode and a graphite carbon rod as the counter electrode, the Ru / Ni3Fe / CNFs-CNTs prepared in Example 1 were dissolved in a mixed solution of ethanol and naphthol and dropped onto carbon paper to prepare the working electrode. This working electrode was then subjected to linear sweep voltammetry (LSV) in 1.0 M KOH solution at a scan rate of 5 mV / s.
[0070] Combination Figure 5 It can be seen that the Ru / Ni3Fe / CNFs-CNTs prepared in Example 1 has significantly better hydrogen evolution catalytic activity than Comparative Example 2 (i.e., NiFe-LDH / CNFs-CNTs in the figure), Comparative Example 3 (i.e., Ni3Fe / CNFs-CNTs in the figure), Comparative Example 1 (CNFs-CNTs), and Comparative Example 4 (Ru / Ni3Fe / CNFs), and is the material with the best hydrogen evolution performance among all tested samples.
[0071] Combination Figure 6 It can be seen that at a current density of 10 mA cm⁻¹ -2 Under the specified conditions, the overpotential of Ru / Ni3Fe / CNFs-CNTs prepared in Example 1 was 63 mV, which was superior to that of NiFe-LDH / CNFs-CNTs (257 mV) and Ni3Fe / CNFs-CNTs (207 mV). This is because the introduction of the noble metal Ru significantly improved the HER performance. The performance of Ru / Ni3Fe / CNFs-CNTs was significantly better than that of Ru / Ni3Fe / CNFs (168 mV) because the carbon nanotubes were embedded inside the fiber, which significantly reduced the charge transfer resistance of the electrode.
[0072] Combination Figure 7 It can be seen that the Ru / Ni3Fe / CNFs-CNTs prepared in Example 1 exhibit a Tafel slope of 64 mV dec. -1 It is significantly lower than that of NiFe-LDH / CNFs-CNTs (194mV dec) -1 ), Ni3Fe / CNFs-CNTs (150mV dec -1 ) and Ru / Ni3Fe / CNFs (118mV dec -1 This demonstrates that the introduction of Ru greatly improves the reaction kinetics of Ru / Ni3Fe / CNFs-CNTs materials.
[0073] Combination Figure 8 It can be seen that the Ru / Ni3Fe / CNFs-CNTs prepared in Example 1 has excellent oxygen evolution catalytic activity, which is far superior to non-noble metal control samples such as NiFe / CNFs-CNTs and CNFs-CNTs, and also superior to the commercial catalyst RuO2.
[0074] Combination Figure 9 It can be seen that at a current density of 10 mA cm⁻¹ -2 Under the specified conditions, the overpotential of Ru / Ni3Fe / CNFs-CNTs is 259 mV, which is superior to Ru / Ni3Fe / CNFs (280 mV), NiFe-LDH / CNFs-CNTs (283 mV), and Ni3Fe / CNFs-CNTs (294 mV), and even superior to the commercial catalyst RuO2 (270 mV). This is because CNTs improve the conductivity of the material, and the interaction between Ru and Ni3Fe optimizes the adsorption energy of oxygen intermediates, thus improving the oxygen evolution reaction (OER) performance.
[0075] Combination Figure 10 It can be seen that the Ru / Ni3Fe / CNFs-CNTs prepared in Example 1 have the smallest Tafel slope (46mV dec). -1 (56mVdec) lower than Ru / Ni3Fe / CNFs -1 (and other control samples) indicate that the OER reaction kinetics of Ru / Ni3Fe / CNFs-CNTs are faster.
[0076] Combination Figure 11 and 12 It can be seen that the Ru / Ni3Fe / CNFs-CNTs prepared in Example 1 is a bifunctional electrocatalyst with both high-efficiency hydrogen evolution and oxygen evolution performance, and the total water splitting voltage is 10 mA cm⁻¹. -2 Under certain conditions, it requires only 1.62V, and its catalytic efficiency is far superior to that of control samples such as NiFe-LDH / CNFs-CNTs (1.86V), Ni3Fe / CNFs-CNTs (1.79V), and Ru / Ni3Fe / CNFs (1.73V), making it a high-quality catalyst for the complete electrolysis of water.
[0077] Combination Figure 13 It can be seen that the Ru / Ni3Fe / CNFs-CNTs prepared in Example 1 have excellent stability in total water hydrolysis cycle.
[0078] Electrolysis performance tests show that the composite electrocatalyst material provided by this invention exhibits low overpotential and high current density in both hydrogen evolution and oxygen evolution reactions. Its catalytic efficiency in the overall water electrolysis reaction is significantly higher than that of control samples such as Ni3Fe / CNFs-CNTs and Ru / Ni3Fe / CNFs. Overall water electrolysis stability tests show that the material's catalytic performance does not significantly decrease after long-term cycling, demonstrating excellent cycle stability and structural stability. It should be noted that the hydrogen production performance of water electrolysis in Examples 2-3 is comparable to that in Example 1.
[0079] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A composite electrocatalytic material, characterized in that, The invention comprises a substrate, a nickel-iron alloy, and ruthenium nanoparticles; the substrate is a carbon fiber / carbon nanotube composite film, the nickel-iron alloy is embedded in the substrate, and the ruthenium nanoparticles are loaded on the substrate to regulate the electronic structure of the nickel-iron alloy.
2. The composite electrocatalytic material according to claim 1, characterized in that, The ruthenium nanoparticles are loaded onto the substrate at a rate of 15 wt% to 20 wt%.
3. A method for preparing a composite electrocatalytic material as described in any one of claims 1 to 2, characterized in that, Includes the following steps: S1. Soluble nickel salt, soluble iron salt, urea and carbon fiber / carbon nanotube composite film are dispersed in an alcohol solution, and then a hydrothermal reaction is carried out to obtain the first intermediate. S2. The first intermediate is carbonized to obtain the second intermediate; S3. The second intermediate and the soluble ruthenium salt are reduced under the action of a reducing agent to obtain the composite electrocatalytic material.
4. The method for preparing the composite electrocatalytic material according to claim 3, characterized in that, In step S1, the carbon fiber / carbon nanotube composite film is prepared by the following steps: Provide spinning solutions containing polyacrylonitrile and carbon nanotubes; The spinning solution was used to form a precursor film by electrospinning. Subsequently, the precursor film was subjected to pre-oxidation and carbonization treatment to obtain a carbon fiber / carbon nanotube composite film.
5. The method for preparing the composite electrocatalytic material according to claim 4, characterized in that, In the spinning solution, the mass ratio of polyacrylonitrile to carbon nanotubes is 1:(0.2-0.3); The pre-oxidation procedure is as follows: in an air atmosphere, heat to 200℃~300℃ and hold for 4~5 hours; The carbonization process is as follows: in an inert gas atmosphere, the temperature is raised to 850-950℃ and then kept at that temperature for 2-3 hours.
6. The method for preparing the composite electrocatalytic material according to claim 3, characterized in that, In step S1, the temperature of the hydrothermal reaction is 140-160℃, and the hydrothermal reaction time is 10-14h.
7. The method for preparing the composite electrocatalytic material according to claim 3, characterized in that, In step S1, the soluble nickel salt is nickel nitrate, and the soluble iron salt is ferric nitrate; and / or, the mass ratio of the soluble nickel salt, the soluble iron salt, and the urea is (0.12-0.14):(0.05-0.07):(0.14-0.16); and / or, the mass ratio of the soluble nickel salt to the carbon fiber / carbon nanotube composite film is (0.12-0.14) g:(50-70) mg.
8. The method for preparing the composite electrocatalytic material according to claim 3, characterized in that, In step S2, the carbonization process is as follows: in a mixed gas of hydrogen and inert gas, the temperature is raised to 450-550℃ and then kept at that temperature for 2-3 hours.
9. The method for preparing the composite electrocatalytic material according to claim 3, characterized in that, In step S3, the soluble ruthenium salt is a trivalent ruthenium salt, and the reducing agent is sodium borohydride; and / or, the mass ratio of the amount of the soluble ruthenium salt added to the mass ratio of the second intermediate is (8-10):
20.
10. The application of a composite electrocatalytic material according to any one of claims 1-2 or a composite electrocatalytic material prepared by any one of claims 3-9 in hydrogen production by water electrolysis.