A ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst, its preparation method and application

Abstract

The present application discloses a ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst, its preparation method and application, belonging to the technical field of electrocatalytic water splitting for hydrogen production. The ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst provided by the present application adopts in-situ growth of a nanoparticle composite of ruthenium metal and nickel cobalt MOF on the surface of carbon cloth. By ultrasonically mixing an aqueous solution of dipotassium 2,6-naphthalenedicarboxylate, a nickel source and a cobalt source, and performing a hydrothermal reaction with the carbon cloth treated with concentrated nitric acid, a carbon cloth modified with nickel cobalt MOF is obtained. Then, an aqueous solution of ruthenium trichloride and sodium thiosulfate is subjected to a hydrothermal reaction with it again to obtain the ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst. The nanoparticle composite of ruthenium metal and nickel cobalt MOF grown in-situ on the surface of carbon cloth has the advantages of being applicable in the whole pH range, having good stability and being directly used as a working electrode, and has wide applications in electrocatalytic hydrogen evolution.

Description

Technical Field

[0001] This application belongs to the technical field of electrocatalytic water splitting for hydrogen production, and particularly relates to a ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Hydrogen energy is a clean, efficient, and renewable secondary energy source, and is expected to play an active role in solving a series of major global problems such as global warming, air pollution, and energy shortage. Electrolytic water splitting for hydrogen production is a promising green and efficient hydrogen production technology, which has the advantages of simple process, no pollution, and high purity of hydrogen obtained. Therefore, it is necessary to develop electrocatalysts with high catalytic activity and stability to improve the efficiency of electrolytic water splitting for hydrogen production, and provide a research basis for the future development of sustainable clean hydrogen energy.

[0003] Transition metal compounds are inexpensive, and due to their multiple valence states, adjustable electronic structures, and ability to undergo various oxidation-reduction reactions, they have excellent catalytic properties and are expected to replace noble metals as the next-generation catalytic materials for electrolytic water splitting for hydrogen production. For example, the prior art with the application publication number CN 117070990 A discloses a Ru / CoP / CC composite nanowire array electrocatalyst. A cobalt source, NH4F, and urea are added to water, stirred until transparent, and carbon cloth is added for hydrothermal reaction; then a ruthenium source is added for vacuum holding to obtain a Ru / CoOH / CC composite nanowire array; the phosphorus source is calcined in an argon atmosphere to obtain a Ru / CoP / CC composite nanowire array electrocatalyst, which shows good catalytic activity in the electrocatalytic hydrogen evolution reaction.

[0004] However, the above-mentioned electrocatalyst has the following problems: First, it only shows good catalytic performance under acidic and alkaline conditions, and has a narrow application range; second, the active components are easily oxidized to amorphous phosphates in the air during the electrolytic water reaction, and the structural stability is poor; third, the preparation process is cumbersome and the conditions are harsh, which is not conducive to industrial production. Summary of the Invention

[0005] This application discloses a ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst, a preparation method thereof, and an application thereof, aiming to solve the technical problems of narrow pH application range, poor stability, and harsh preparation conditions of existing electrocatalysts during use.

[0006] To achieve the above object, the technical solution of this application is:

[0007] The first aspect of this application provides a ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst, which includes carbon cloth and a composite of ruthenium metal and nickel cobalt MOF nanoparticles grown in-situ on the surface of the carbon cloth.

[0008] The second aspect of the present application provides a method for preparing the ruthenium-nickel-cobalt MOF / carbon cloth electrocatalyst described in the first aspect, and the method includes:

[0009] Ultrasonically mix an aqueous solution of dipotassium 2,6-naphthalenedicarboxylate, a nickel source, and a cobalt source to obtain a precursor solution;

[0010] Place the carbon cloth in concentrated nitric acid for modification to obtain a hydrophilic carbon cloth;

[0011] Immerse the hydrophilic carbon cloth in the precursor solution for a first hydrothermal reaction, separate and collect to obtain a nickel-cobalt MOF-modified carbon cloth;

[0012] Perform a second hydrothermal reaction on an aqueous solution of ruthenium trichloride and sodium thiosulfate with the nickel-cobalt MOF-modified carbon cloth, and separate and collect from the product to obtain a ruthenium-nickel-cobalt MOF / carbon cloth electrocatalyst;

[0013] Wherein, the first hydrothermal reaction and the second hydrothermal reaction are the same or different.

[0014] Preferably in combination with the second aspect, the nickel source is one or more of nickel sulfate, nickel nitrate, and nickel chloride.

[0015] Preferably in combination with the second aspect, the cobalt source is one or more of cobalt nitrate, cobalt chloride, and cobalt sulfate.

[0016] Preferably in combination with the second aspect, the molar ratio of dipotassium 2,6-naphthalenedicarboxylate, nickel source, cobalt source, and ruthenium trichloride is 1.25:1:1:0.1 - 0.5.

[0017] Preferably in combination with the first aspect, the geometric area of the hydrophilic carbon cloth is 3.0×4.0 cm 2 .

[0018] Preferably in combination with the first aspect, the mass fraction of the concentrated nitric acid is 60 - 70%.

[0019] Preferably in combination with the first aspect, the temperature for modifying the carbon cloth in concentrated nitric acid is 80 - 100 °C, and the time is 1 - 5 h.

[0020] Preferably in combination with the first aspect, the temperature of the first hydrothermal reaction and the second hydrothermal reaction is 60 - 120 °C, and the time is 10 - 20 h.

[0021] The third aspect of the present application provides the application of the ruthenium-nickel-cobalt MOF / carbon cloth electrocatalyst prepared by the preparation method described in the second aspect in electrocatalytic hydrogen evolution.

[0022] Compared with the prior art, the advantages or beneficial effects of the embodiments of the present application at least include:

[0023] The ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst provided by this application uses in-situ growth of a nanoparticle composite of ruthenium metal and nickel cobalt MOF on the surface of the carbon cloth. On the one hand, the nickel cobalt MOF and ruthenium metal nanoparticles are in-situ grown on the carbon cloth in a coupled manner, which can enable the ruthenium metal nanoparticles to be uniformly and stably loaded onto the nickel cobalt MOF, thereby enhancing the electron occupancy state through the electron coupling effect, fully exposing the high-density active sites, and significantly improving the catalytic performance. On the other hand, the ruthenium metal nanoparticles, nickel cobalt MOF framework structure, and high-density active sites can produce a synergistic effect, thereby optimizing the electronic structure of the electrocatalyst, greatly increasing the number of catalytic active sites, accelerating the electron transfer ability between substances, reducing the hydrogen binding free energy, effectively improving the atomic utilization rate, and enabling it to have excellent hydrogen evolution performance in the whole pH range. Description of the Drawings

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments recorded in this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 SEM images of the Ru / CC, 1-NiCo-MOF / CC, and 1-Ru / NiCo-MOF / CC electrocatalysts prepared in the embodiments of this application;

[0026] Figure 2 XPS image of the 1-Ru / NiCo-MOF / CC electrocatalyst prepared in the embodiments of this application;

[0027] Figure 3 Electrocatalytic hydrogen evolution performance images of the bare CC, 1-NiCo-MOF / CC, Ru / CC, and 1-Ru / NiCo-MOF / CC electrocatalysts prepared in the embodiments of this application;

[0028] Figure 4 Overpotential diagrams of the 1-Ru / NiCo-MOF / CC, Ru / CC, and 1-NiCo-MOF / CC electrocatalysts prepared in the embodiments of this application at current densities of -10, -50, and -100 mA / cm 2 ;

[0029] Figure 5 Electrochemical impedance spectra diagrams of the 1-Ru / NiCo-MOF / CC, Ru / CC, and 1-NiCo-MOF / CC electrocatalysts prepared in the embodiments of this application;

[0030] Figure 6Overpotential diagrams of the 1-Ru / NiCo-MOF / CC, Ru / CC, and 1-NiCo-MOF / CC electrocatalysts prepared in the embodiments of this application when reaching a current density of -10 mA / cm 2 2. Detailed implementation manners

[0031] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts shall fall within the scope of protection of this application.

[0032] In the following description of this embodiment, the term "and / or" is used to describe the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, B exists alone, and both A and B exist simultaneously. Among them, A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0033] In the following description of this embodiment, the term "at least one" means one or more, and "a plurality" means two or more. "At least one (item)" or its similar expression below refers to any combination of these items, including any combination of single item (item) or plural items (items). For example, "at least one (item) of a, b, or c", or, "at least one (item) of a, b, and c" can both represent: a, b, c, a-b (that is, a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple respectively.

[0034] Those skilled in the art should understand that in the following description of the embodiments of this application, the sequence numbers do not mean the order of execution, and some or all steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of this application.

[0035] The terms used in the embodiments of this application are only for the purpose of describing specific embodiments, and are not intended to limit this application. The singular forms "a" and "the" used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0036] It should be noted that all raw materials and / or reagents in the embodiments of this application are purchased on the market or prepared by conventional methods well-known to those skilled in the art. For example, dipotassium 2,6-naphthalenedicarboxylate, nickel source, cobalt source, concentrated nitric acid, etc. are all obtained by purchasing on the market.

[0037] In a first aspect, an embodiment of the present application provides a ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst, including a carbon cloth and a nanoparticle composite of ruthenium metal and nickel cobalt MOF in-situ grown on the surface of the carbon cloth.

[0038] Among them, on the one hand, nickel cobalt MOF and ruthenium metal nanoparticles are in-situ grown on the carbon cloth in a coupled manner, which can enable the ruthenium metal nanoparticles to be uniformly and stably loaded onto the nickel cobalt MOF, thereby enhancing the electron occupancy state through the electron coupling effect, fully exposing the high-density active sites, and significantly improving the catalytic performance; on the other hand, the ruthenium metal nanoparticles, the nickel cobalt MOF framework structure, and the high-density active sites can produce a synergistic effect, thereby optimizing the electronic structure of the electrocatalyst, greatly increasing the number of catalytic active sites, accelerating the electron transfer ability between substances, reducing the hydrogen binding free energy, effectively improving the atomic utilization rate, and enabling it to have excellent hydrogen evolution performance in the whole pH range.

[0039] In a second aspect, an embodiment of the present application provides a preparation method of the ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst of the present application. The preparation method of the present application includes:

[0040] Ultrasonically mixing an aqueous solution of dipotassium 2,6-naphthalenedicarboxylate, a nickel source, and a cobalt source to obtain a precursor solution;

[0041] Modifying the carbon cloth in concentrated nitric acid to obtain a hydrophilic carbon cloth;

[0042] Immersing the hydrophilic carbon cloth in the precursor solution for a first hydrothermal reaction, separating and collecting to obtain a carbon cloth modified with nickel cobalt MOF;

[0043] Performing a second hydrothermal reaction on an aqueous solution of ruthenium trichloride and sodium thiosulfate with the carbon cloth modified with nickel cobalt MOF, and separating and collecting from the product to obtain a ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst;

[0044] Among them, the first hydrothermal reaction and the second hydrothermal reaction are the same or different.

[0045] In a specific embodiment, the nickel source is preferably one or more of nickel sulfate, nickel nitrate, and nickel chloride; the cobalt source is preferably one or more of cobalt nitrate, cobalt chloride, and cobalt sulfate. Among them, these nickel sources and cobalt sources are common, easily available, and stable, and can generate stable nickel cobalt MOF materials under hydrothermal conditions.

[0046] In a specific embodiment, the molar ratio of dipotassium 2,6-naphthalenedicarboxylate, nickel source, cobalt source, and ruthenium trichloride is preferably 1.25:1:1:0.1-0.5. Among them, first, with Ni 2+ and Co 2+Taking bimetallic ions as the metal source and dipotassium 2,6-naphthalenedicarboxylate as the organic ligand, due to the strong coordination ability of the carboxyl functional group, self-assembly occurs between them and the bimetallic ions to form a nickel-cobalt bimetallic MOF material growing on the surface of carbon cloth. Subsequently, ruthenium trichloride is reduced to ruthenium metal using sodium thiosulfate as the reducing agent. By controlling the molar ratios of dipotassium 2,6-naphthalenedicarboxylate, nickel source, cobalt source, and ruthenium trichloride, uniform and stable ruthenium metal nanoparticles can be prepared and stably composited on NiCo-MOF, so that the prepared electrocatalyst exhibits good electrocatalytic performance.

[0047] In a specific embodiment, the geometric area of the hydrophilic carbon cloth is preferably 3.0×4.0 cm 2 . Among them, the composite of ruthenium metal nanoparticles and nickel-cobalt MOF nanoparticles can grow in situ, uniformly and stably, on the surface of the carbon cloth, endowing the material with excellent electrocatalytic hydrogen evolution performance. When used as a working electrode for electrocatalytic hydrogen evolution testing, it can be arbitrarily cut to meet the test requirements.

[0048] In a specific embodiment, the temperature for modifying the carbon cloth in concentrated nitric acid is preferably 80-100 °C, and the time is preferably 1-5 h. Among them, by controlling the reaction time and temperature of the carbon cloth in concentrated nitric acid, the carbon cloth can be acidified more fully while maintaining its integrity, resulting in a substrate material with a high specific surface area and good mechanical properties.

[0049] In a specific embodiment, the temperatures of the first hydrothermal reaction and the second hydrothermal reaction are preferably 60-120 °C, and the times are preferably 10-20 h. Among them, by controlling the time and temperature of the first hydrothermal reaction, NiCo bimetallic MOF grows in situ on the carbon cloth. By controlling the time and temperature of the second hydrothermal reaction, ruthenium metal nanoparticles are uniformly and stably composited on the nickel-cobalt MOF, enabling the prepared ruthenium-nickel-cobalt MOF / carbon cloth electrocatalyst to exhibit excellent hydrogen evolution performance across the entire pH range.

[0050] This application uses a two-step hydrothermal method to in-situ grow a composite of ruthenium metal nanoparticles and nickel-cobalt MOF nanoparticles on the surface of carbon cloth. After the surface modification of the carbon cloth, it is rich in a large number of hydrophilic groups -OH and -O energy groups, providing favorable conditions for the uniform in-situ growth of nickel-cobalt MOFs, facilitating the nucleation and growth of nickel-cobalt MOF. This in-situ growth greatly enhances the "bonding" between nickel-cobalt MOF and carbon cloth, has good electrochemical stability, and the preparation process is simple and easy to implement, making it suitable for large-scale production.

[0051] In a third aspect, the embodiments of the present application also provide the application of the ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst in the electrocatalytic hydrogen evolution reaction. Among them, based on the advantages of the ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst described above, which is applicable in the full pH range, has good stability, and can be directly used as a working electrode. Therefore, when the ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst prepared in the present application is used in the electrocatalytic hydrogen evolution reaction, it can exhibit good electrocatalytic performance.

[0052] The technical solutions of the present application will be further described below in conjunction with specific embodiments.

[0053] Example 1

[0054] This example provides a preparation method of a 1-ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst, which specifically includes:

[0055] S101: Weigh 20 mg of dipotassium 2,6-naphthalenedicarboxylate and dissolve it in 10 mL of water; weigh 16.26 mg of nickel sulfate hexahydrate and 18 mg of cobalt nitrate hexahydrate and dissolve them in 10 mL of water, and ultrasonically mix the above two aqueous solutions;

[0056] S102: Immerse a 3.0×4.0 cm 2 carbon cloth in 68% concentrated nitric acid and reflux at 100 °C for 1 h to obtain a hydrophilic carbon cloth, and place the obtained hydrophilic carbon cloth and the mixed solution in a reaction kettle, react at 60 °C for 12 h, wash and dry to obtain a carbon cloth material modified with NiCo bimetallic MOF (1-NiCo-MOF / CC);

[0057] S103: Weigh 3.5 mg of RuCl3 and 37.5 mg of Na2S2O3 and dissolve them in 20 mL of water, and transfer the above solution to a reaction kettle containing NiCo-MOF / CC, react at 100 °C for 10 h, wash and dry to obtain a 1-ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst (1-Ru / NiCo-MOF / CC).

[0058] Example 2

[0059] This example provides a preparation method of a 2-ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst, which specifically includes:

[0060] S201: Weigh 20 mg of dipotassium 2,6-naphthalenedicarboxylate and dissolve it in 10 mL of water, weigh 16.2 mg of nickel sulfate hexahydrate and 18 mg of cobalt nitrate hexahydrate and dissolve them in 10 mL of water, and ultrasonically mix the above two aqueous solutions;

[0061] S202: Immerse a 3.0×4.0 cm 2The carbon cloth was refluxed in 68% concentrated nitric acid at 100 °C for 1 h to obtain hydrophilic carbon cloth. The obtained hydrophilic carbon cloth and the mixed solution were placed in a reaction kettle and reacted at 60 °C for 12 h. After washing and drying, the carbon cloth material modified with NiCo bimetallic MOF can be obtained;

[0062] S203: Weigh 1.28 mg of RuCl3 and 37.5 mg of Na2S2O3 and dissolve them in 20 mL of water. Then transfer the above solution to a reaction kettle containing NiCo-MOF / CC and react at 100 °C for 10 h. After washing and drying, the 2-ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst (2-Ru / NiCo-MOF / CC) can be obtained.

[0063] Example 3

[0064] This example provides a preparation method of 3-ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst, which specifically includes:

[0065] S301: Weigh 20 mg of dipotassium 2,6-naphthalenedicarboxylate and dissolve it in 10 mL of water. Weigh 16.26 mg of nickel sulfate hexahydrate and 18 mg of cobalt nitrate hexahydrate and dissolve them in 10 mL of water. Ultrasonically mix the above two aqueous solutions;

[0066] S302: Take a 3.0×4.0 cm 2 The carbon cloth was refluxed in 68% concentrated nitric acid at 100 °C for 1 h to obtain hydrophilic carbon cloth. The obtained hydrophilic carbon cloth and the mixed solution were placed in a reaction kettle and reacted at 60 °C for 12 h. After washing and drying, the carbon cloth material modified with NiCo bimetallic MOF can be obtained;

[0067] S303: Weigh 6.4 mg of RuCl3 and 37.5 mg of Na2S2O3 and dissolve them in 20 mL of water. Then transfer the above solution to a reaction kettle containing NiCo-MOF / CC and react at 100 °C for 10 h. After washing and drying, the 3-ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst (3-Ru / NiCo-MOF / CC) can be obtained.

[0068] Example 4

[0069] This example provides a preparation method of 4-ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst, which specifically includes:

[0070] S401: Weigh 20 mg of dipotassium 2,6-naphthalenedicarboxylate and dissolve it in 10 mL of water. Weigh 16.26 mg of nickel sulfate hexahydrate and 18 mg of cobalt nitrate hexahydrate and dissolve them in 10 mL of water. Ultrasonically mix the above two aqueous solutions;

[0071] S402: Take a 3.0×4.0 cm 2The carbon cloth was refluxed in 68% concentrated nitric acid at 80 °C for 5 h to obtain hydrophilic carbon cloth. The obtained hydrophilic carbon cloth and the mixed solution were placed in a reaction kettle and reacted at 100 °C for 20 h. After washing and drying, the carbon cloth material modified with NiCo bimetallic MOF can be obtained;

[0072] S403: Weigh 3.5 mg of RuCl3 and 37.5 mg of Na2S2O3 and dissolve them in 20 mL of water. Transfer the above solution to a reaction kettle containing NiCo-MOF / CC and react at 120 °C for 15 h. After washing and drying, the 4-ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst (4-Ru / NiCo-MOF / CC) can be obtained.

[0073] Example 5

[0074] This example provides a preparation method of 5-ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst, which specifically includes:

[0075] S501: Weigh 20 mg of dipotassium 2,6-naphthalenedicarboxylate and dissolve it in 10 mL of water. Weigh 16.26 mg of nickel sulfate hexahydrate and 18 mg of cobalt nitrate hexahydrate and dissolve them in 10 mL of water. Ultrasonically mix the above two aqueous solutions;

[0076] S502: Take a 3.0×4.0 cm 2 The carbon cloth was refluxed in 68% concentrated nitric acid at 90 °C for 3 h to obtain hydrophilic carbon cloth. The obtained hydrophilic carbon cloth and the mixed solution were placed in a reaction kettle and reacted at 80 °C for 15 h. After washing and drying, the carbon cloth material modified with NiCo bimetallic MOF can be obtained;

[0077] S503: Weigh 3.5 mg of RuCl3 and 37.5 mg of Na2S2O3 and dissolve them in 20 mL of water. Transfer the above solution to a reaction kettle containing NiCo-MOF / CC and react at 120 °C for 15 h. After washing and drying, the 5-ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst (5-Ru / NiCo-MOF / CC) can be obtained.

[0078] The 1-Ru / NiCo-MOF / CC, 2-Ru / NiCo-MOF / CC, 3-Ru / NiCo-MOF / CC, 4-Ru / NiCo-MOF / CC, and 5-Ru / NiCo-MOF / CC prepared in the examples of this application have similar electrochemical properties. Therefore, the 1-Ru / NiCo-MOF / CC prepared in Example 1 of this application is used as a representative for performance testing.

[0079] At the same time, to verify the electrochemical properties of the ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst prepared in the above examples, this application provides the following comparative examples for detailed description.

[0080] Comparative Example 1

[0081] This example provides a preparation method of Ru / CC electrocatalyst, which specifically includes:

[0082] S601: Immerse a 3.0×4.0 cm 2 carbon cloth in 68% concentrated nitric acid and reflux at 100 °C for 1 h to obtain a hydrophilic carbon cloth;

[0083] S602: Weigh 3.5 mg of RuCl3 and 37.5 mg of Na2S2O3, dissolve them in 20 mL of water, transfer the above solution to a reaction kettle containing the hydrophilic carbon cloth, react at 100 °C for 10 h, wash and dry to obtain a ruthenium / carbon cloth electrocatalyst (Ru / CC).

[0084] Comparative Example 2

[0085] This example provides a preparation method of pure carbon cloth electrocatalyst, which specifically includes:

[0086] S701: Immerse a 3.0×4.0 cm 2 carbon cloth in 68% concentrated nitric acid and reflux at 100 °C for 1 h to obtain a hydrophilic carbon cloth (bareCC).

[0087] To verify the morphology and structure of the ruthenium-nickel-cobalt MOF / carbon cloth electrocatalyst prepared in the examples of this application, the structure of the electrocatalyst prepared in the examples was characterized, and the results are Figure 1 as shown. Among them, Figure 1 are the SEM images of Ru / CC, 1-NiCo-MOF / CC and 1-Ru / NiCo-MOF / CC electrocatalysts.

[0088] According to Figure 1 It can be seen that, among them, in the Ru / CC electrocatalyst in Figure a), it can be clearly found that ruthenium metal nanoparticles are evenly distributed on the fibers of the carbon cloth; Figure b) shows the in-situ growth of 1-NiCo-MOF nanosheet structure on the carbon cloth fibers; Figure c) shows the nanoparticle morphology of the composite material of ruthenium metal nanoparticles and nickel-cobalt MOF prepared by a two-step hydrothermal method in-situ grown on the carbon cloth.

[0089] To verify the component composition of the ruthenium-nickel-cobalt MOF / carbon cloth electrocatalyst prepared in the examples of this application, XPS testing was performed on the structure of the electrocatalyst prepared in the examples, and the results are Figure 2 as shown, among which, Figure 2 is the XPS diagram of 1-Ru / NiCo-MOF / CC.

[0090] According to Figure 2It can be seen that Ru, Ni, Co, O, N, and C elements coexist in the 1-Ru / NiCo-MOF / CC electrocatalyst, indicating the growth of a nanoparticle composite of ruthenium metal and nickel-cobalt MOF on the carbon cloth.

[0091] To verify the catalytic performance of the ruthenium-nickel-cobalt MOF / carbon cloth electrocatalyst prepared in the embodiments of this application, the 1-Ru / NiCo-MOF / CC electrocatalyst prepared in Example 1 was directly used as the working electrode, and the geometric area of the working electrode was 1.0×1.0 cm 2 , the calomel electrode was used as the reference electrode, and the platinum electrode was used as the counter electrode. The electrocatalytic hydrogen evolution performance was tested in 1.0 mol / L potassium hydroxide solution, 0.5 mol / L sulfuric acid solution, and 1.0 mol / L phosphate buffer solution, and the results are Figures 3 to 6 shown.

[0092] Among them, Figure 3 are the electrocatalytic hydrogen evolution performance diagrams of CC, 1-NiCo-MOF / CC, Ru / CC, and 1-Ru / NiCo-MOF / CC electrocatalysts; Figure 4 are the overpotential diagrams of 1-Ru / NiCo-MOF / CC, Ru / CC, and 1-NiCo-MOF / CC electrocatalysts at current densities of -10, -50, and -100 mA / cm 2 ; Figure 5 are the electrochemical impedance spectra diagrams of 1-Ru / NiCo-MOF / CC, Ru / CC, and 1-NiCo-MOF / CC electrocatalysts;

[0093] Figure 6 are the overpotential diagrams of 1-Ru / NiCo-MOF / CC, Ru / CC, and 1-NiCo-MOF / CC electrocatalysts to reach a current density of -10 mA / cm 2 under full pH conditions.

[0094] According to Figure 3 it can be seen that the bare carbon cloth is inert in the electrocatalytic hydrogen evolution reaction. After growing NiCo MOF on its surface, the 1-NiCo-MOF / CC catalyst has electrocatalytic hydrogen evolution activity; after growing Ru nanoparticles on the CC surface, Ru / CC has good electrocatalytic hydrogen evolution activity; after growing both Ru and NiCo MOF on the CC surface, 1-Ru / NiCo-MOF / CC has excellent electrocatalytic hydrogen evolution activity.

[0095] According to Figure 4 it can be seen that for the 1-Ru / NiCo-MOF / CC electrocatalyst, when the current density reaches -10 mA / cm 2 , the required overpotential is 71 mV, and when the current density reaches -50 mA / cm2 The overpotential required when it is [specific condition] is 146 mV. If the current density reaches -100 mA / cm 2 the overpotential required is 204 mV. It is found that the overpotential is much smaller than that of the Ru / CC and 1-NiCo-MOF / CC electrocatalysts when they reach the corresponding current density.

[0096] According to Figure 5 It can be seen that compared with the Ru / CC and 1-NiCo-MOF / CC electrocatalysts, the prepared 1-Ru / NiCo-MOF / CC electrocatalyst has the smallest electrochemical impedance. This indicates that by compounding Ru and NiCo-MOF, it is beneficial to accelerate the electron transfer of the composite electrocatalyst and will enhance the electrocatalytic hydrogen evolution reaction activity.

[0097] According to Figure 6 It can be seen that the prepared Ru / CC, 1-NiCo-MOF / CC and 1-Ru / NiCo-MOF / CC electrocatalysts can be used for the electrocatalytic hydrogen evolution reaction under all pH conditions, and the 1-Ru / NiCo-MOF / CC electrocatalyst shows better electrocatalytic activity than Ru / CC and 1-NiCo-MOF / CC in the whole pH range. Among them, the overpotentials required for the 1-Ru / NiCo-MOF / CC to reach a current density of -10 mA / cm 2 are 71, 178 and 75 mV respectively under acidic (pH = 0), neutral (pH = 7.0) and alkaline (pH = 14) conditions.

[0098] The difference between the 1-NiCo-MOF / CC electrocatalyst prepared in this application and the 1-Ru / NiCo-MOF / CC electrocatalyst obtained in Example 1 is that no ruthenium modification is carried out. The addition of ruthenium metal nanoparticles results in a high overpotential, a high Tafel slope, and a high electrochemical impedance of the electrocatalyst. The difference between the Ru / CC electrocatalyst obtained in Comparative Example 1 of this application and the 1-Ru / NiCo-MOF / CC electrocatalyst obtained in Example 1 is that NiCo-MOF is not added. The electron coupling effect between NiCo-MOF nanoparticles and ruthenium metal nanoparticles enhances the electron occupancy state, thereby fully exposing the high-density active sites to improve the catalytic performance and further improve its hydrogen evolution performance. The difference between the pure carbon cloth obtained in Comparative Example 2 of this application and the 1-Ru / NiCo-MOF / CC electrocatalyst obtained in Example 1 is that ruthenium-modified NiCo-MOF is not added, and it does not have electrochemical properties. Therefore, an aqueous solution of dipotassium 2,6-naphthalenedicarboxylate, a nickel source, and a cobalt source is ultrasonically mixed and hydrothermally reacted with the carbon cloth treated with concentrated nitric acid to obtain a solution of nickel cobalt MOF-modified carbon cloth. Ruthenium trichloride and sodium thiosulfate are added and hydrothermally reacted again to obtain a ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst, which is a composite of ruthenium metal nanoparticles in-situ grown on the surface of the carbon cloth and nickel cobalt MOF. It has the advantages of being applicable in the whole pH range, having good stability, and can be directly used as a working electrode.

[0099] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0100] The above embodiments are only used to illustrate the technical solutions of this application, rather than limiting this application. Although this application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of this application.

Claims

1. A ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst, characterized in that, It includes a carbon cloth and a nanoparticle composite of ruthenium metal and nickel-cobalt MOF in-situ grown on the surface of the carbon cloth; The preparation method of the ruthenium-nickel-cobalt MOF / carbon cloth electrocatalyst includes: Ultrasonically mixing an aqueous solution of dipotassium 2,6-naphthalenedicarboxylate, a nickel source, and a cobalt source to obtain a precursor solution; Modifying the carbon cloth in concentrated nitric acid to obtain a hydrophilic carbon cloth; Immersing the hydrophilic carbon cloth in the precursor solution for a first hydrothermal reaction, separating and collecting to obtain a nickel-cobalt MOF-modified carbon cloth; Performing a second hydrothermal reaction on an aqueous solution of ruthenium trichloride and sodium thiosulfate with the nickel-cobalt MOF-modified carbon cloth, and separating and collecting from the product to obtain a ruthenium-nickel-cobalt MOF / carbon cloth electrocatalyst; Wherein, the first hydrothermal reaction and the second hydrothermal reaction are the same or different.

2. The preparation method of the ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst according to claim 1, characterized in that, The nickel source is one or more of nickel sulfate, nickel nitrate, and nickel chloride.

3. The preparation method of the ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst according to claim 1, wherein The cobalt source is one or more of cobalt nitrate, cobalt chloride, and cobalt sulfate.

4. The preparation method of the ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst according to claim 1, characterized in that, The molar ratio of the dipotassium 2,6-naphthalenedicarboxylate, the nickel source, the cobalt source, and the ruthenium trichloride is 1.25:1:1:0.1 - 0.

5.

5. The preparation method of the ruthenium-nickel-cobalt MOF / carbon cloth electrocatalyst according to claim 1, wherein, The geometric area of the hydrophilic carbon cloth is 3.0×4.0 cm 2 .

6. The preparation method of the ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst according to claim 1, characterized in that, The mass fraction of the concentrated nitric acid is 60 - 70%.

7. The preparation method of the ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst according to claim 1, wherein, The temperature for modifying the carbon cloth in concentrated nitric acid is 80 - 100 °C, and the time is 1 - 5 h.

8. The preparation method of the ruthenium-nickel cobalt MOF / carbon cloth electrocatalyst according to claim 1, characterized in that, The temperature of the first hydrothermal reaction and the second hydrothermal reaction is 60 - 120 °C, and the time is 10 - 20 h.

9. Application of a ruthenium-nickel-cobalt MOF / carbon cloth electrocatalyst prepared by the preparation method of the ruthenium-nickel-cobalt MOF / carbon cloth electrocatalyst according to any one of claims 1 - 8 in electrocatalytic hydrogen evolution.

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