Multi-component ruthenium-nickel-based metal nanosheet as well as preparation method and application thereof

Abstract

The invention provides a multi-component ruthenium-nickel-based metal nanosheet as well as a preparation method and application thereof, and relates to the technical field of catalysts. The invention provides a multi-component ruthenium-nickel-based metal nanosheet. The multi-component ruthenium-nickel-based metal nanosheet is a two-dimensional nanosheet with a core-shell structure, the core-shell structure comprises a core metal element and a shell metal element, the core metal element comprises a nickel element and an auxiliary metal element, the auxiliary metal element comprises one or more of a cobalt element, a copper element, an iron element and a manganese element, and the shell metal element is a ruthenium element. The multi-component ruthenium-nickel-based metal nanosheet provided by the invention is efficient and stable, is applied to an alkaline membrane fuel cell, and has excellent anode hydroxide electrocatalytic performance. The invention provides the preparation method of the multi-component ruthenium-nickel-based metal nanosheet, and the preparation method is simple, feasible and convenient for mass production.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and particularly relates to a multi-component ruthenium-nickel-based metal nanosheet and a preparation method and application thereof. Background Art

[0002] Alkaline membrane fuel cells are efficient and clean energy conversion devices that generate electrical energy through chemical reactions. Alkaline membrane fuel cells use anion membranes, and their working principle is to electrochemically react hydrogen and oxygen under the action of a catalyst to generate electrical energy and water. The energy density of alkaline membrane fuel cells is much higher than that of traditional fuel cells, so they have obvious advantages in terms of energy utilization efficiency.

[0003] However, the hydrogen oxidation reaction at the anode of alkaline membrane fuel cells still lacks an effective catalyst and is difficult to meet the commercial requirements for activity and stability. Currently, platinum catalysts are widely used for the hydrogen oxidation reaction at the anode of alkaline membrane fuel cells. However, in the current industrial hydrogen production process, a certain amount of CO is carried. Even after purification treatment, it is difficult to completely remove CO and it will increase the cost to a certain extent. These residual CO will enter the battery with hydrogen, strongly poisoning the Pt active sites of the platinum catalyst, resulting in poor catalyst activity and low stability. Constructing an anode hydrogen oxidation catalyst with good activity and stability is a technical problem that urgently needs to be solved. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a multi-component ruthenium-nickel-based metal nanosheet and a preparation method and application thereof. The multi-component ruthenium-nickel-based metal nanosheet provided by the present invention is highly efficient and stable, and has excellent electrocatalytic performance for anode hydrogen oxidation when applied to alkaline membrane fuel cells.

[0005] To achieve the above-mentioned invention purpose, the present invention provides the following technical solutions: The present invention provides a multi-component ruthenium-nickel-based metal nanosheet, and the multi-component ruthenium-nickel-based metal nanosheet is a two-dimensional nanosheet with a core-shell structure; the core-shell structure includes a core metal element and a shell metal element, the core metal element includes nickel element and an auxiliary metal element, the auxiliary metal element includes one or more of cobalt element, copper element, iron element and manganese element, and the shell metal element is ruthenium element.

[0006] Preferably, the molar percentage content of each metal element in the multi-component ruthenium-nickel-based metal nanosheet is independently 8-50%.

[0007] Preferably, the diameter of the multi-component ruthenium-nickel-based metal nanosheet is 8-15 nm, the total thickness is 1.5-2.5 nm, and the shell layer thickness is 1.2-1.7 nm.

[0008] The present invention provides a preparation method of the multi-component ruthenium-nickel-based metal nanosheet, including the following steps: Mix a ruthenium source, a nickel source, a reducing agent and a first organic solvent to carry out a first reduction reaction to obtain a first reaction solution; Mix an auxiliary metal precursor and a second organic solvent to obtain an auxiliary metal precursor dispersion; the auxiliary metal precursor includes one or more of a cobalt source, a copper source, an iron source and a manganese source; Mix the auxiliary metal precursor dispersion with the first reaction solution to carry out a second reduction reaction to obtain the multi-component ruthenium-nickel-based metal nanosheets; The temperatures of the first reduction reaction and the second reduction reaction are independently 150-200 °C, and the times are independently 150-200 min.

[0009] Preferably, the ruthenium source includes triruthenium dodecacarbonyl or ruthenium acetylacetonate; the nickel source includes nickel acetylacetonate or nickel chloride; the cobalt source includes cobalt acetylacetonate or cobalt dichloride; the copper source includes copper acetylacetonate or copper chloride; the iron source includes iron acetylacetonate or iron chloride; the manganese source includes manganese acetylacetonate or manganese chloride.

[0010] Preferably, the reducing agent includes one or more of glucose, ascorbic acid and cetyltrimethylammonium chloride; the mass ratio of the reducing agent to the ruthenium source is 15-25:1.

[0011] Preferably, the first organic solvent and the second organic solvent independently include one or more of oleylamine, benzyl alcohol and ethylene glycol.

[0012] Preferably, the mixing of the ruthenium source, the nickel source, the reducing agent and the first organic solvent and the mixing of the auxiliary metal precursor and the second organic solvent are both carried out under ultrasonic conditions; the power of the ultrasonic is 60-100 W, and the time is 60-120 min.

[0013] The present invention provides the application of the multi-component ruthenium-nickel-based metal nanosheets described in the above technical solutions or the multi-component ruthenium-nickel-based metal nanosheets prepared by the preparation method described in the above technical solutions as a catalyst in the anodic hydrogen oxidation reaction of an alkaline membrane fuel cell.

[0014] Preferably, the electrolyte for the anodic hydrogen oxidation reaction of the alkaline membrane fuel cell is a potassium hydroxide solution, and the concentration of the potassium hydroxide solution is 0.05-0.2 mol / L.

[0015] The present invention provides a multi-component ruthenium-nickel-based metal nanosheet. Compared with the prior art, the present invention has the following beneficial effects: The multi-component ruthenium-nickel-based metal nanosheets provided by the present invention have a core-shell structure. The core element can regulate the electronic structure of the shell through ligand effect and strain effect, thereby optimizing the catalytic reaction performance; the core element can adjust the electronic structure of the outer shell ruthenium and the adsorption energy of reaction intermediates, thereby improving the CO removal ability (enhancing anti-poisoning performance) and the hydrogen oxidation ability; in addition, the core metal element includes nickel element and auxiliary metal element. With the increase of core entropy, the lattice stability of the nanosheets will be stronger, and the stability can be further improved. The nanosheet structure of the multi-component ruthenium-nickel-based metal nanosheets has a large specific surface area, which can provide more active sites, enabling it to fully contact with reactants as a catalyst; and the two-dimensional structure of the core-shell nanosheets can provide a short mass transfer path, reducing the diffusion resistance of reactants and products.

[0016] Therefore, the multi-component ruthenium-nickel-based metal nanosheets provided by the present invention are highly efficient and stable, and have excellent anodic hydrogen oxidation electrocatalytic performance when applied to alkaline membrane fuel cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 TEM image of the ruthenium-nickel-cobalt core-shell nanosheets prepared in Example 1; Figure 2 TEM image of the ruthenium-nickel-iron-manganese core-shell nanosheets prepared in Example 3; Figure 3 Aberration-corrected TEM image of the ruthenium-nickel-cobalt-copper-iron-manganese core-shell nanosheets prepared in Example 4; Figure 4 Polarization curves of hydrogen oxidation reaction for the ruthenium-nickel-cobalt core-shell nanosheets (RuNiCo) prepared in Example 1, the ruthenium-nickel-cobalt-copper-iron-manganese core-shell nanosheets (RuNiCoCuFeMn) prepared in Example 4, and commercial platinum-carbon (Pt / C); Figure 5 Lifetimes of the ruthenium-nickel-cobalt-copper-iron-manganese core-shell nanosheets (RuNiCoCuFeMn) prepared in Example 4, the ruthenium-nickel metal nanosheets (RuNi) in Comparative Example 1, and commercial platinum-carbon (Pt / C) measured at a constant voltage of 0.1V in an environment of CO and hydrogen (CO content 1000 ppm); DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The present invention provides a multi-component ruthenium-nickel-based metal nanosheet, and the multi-component ruthenium-nickel-based metal nanosheet is a two-dimensional nanosheet with a core-shell structure; the core-shell structure includes a core metal element and a shell metal element, the core metal element includes a nickel element and an auxiliary metal element, the auxiliary metal element includes one or more of cobalt element, copper element, iron element and manganese element, and the shell metal element is a ruthenium element.

[0019] In the present invention, when the auxiliary metal element includes one of cobalt element, copper element, iron element and manganese element, the formed multi-component ruthenium-nickel-based metal nanosheets are binary low-entropy nanosheets (in terms of the core metal element); when the auxiliary metal element includes two of cobalt element, copper element, iron element and manganese element, the formed multi-component ruthenium-nickel-based metal nanosheets are ternary medium-entropy core-shell nanosheets; when the auxiliary metal element includes three of cobalt element, copper element, iron element and manganese element, the formed multi-component ruthenium-nickel-based metal nanosheets are quaternary high-entropy core-shell nanosheets; when the auxiliary metal element includes four of cobalt element, copper element, iron element and manganese element, the formed multi-component ruthenium-nickel-based metal nanosheets are quinary high-entropy core-shell nanosheets. In the present invention, the shell metal element, i.e., ruthenium element, exists in the form of a single substance; the core metal element exists in the form of an alloy to form a multi-metal core.

[0020] The present invention uses nickel element and the auxiliary metal element as the core metal elements of the core-shell structure. These metal elements themselves have good electrical conductivity, and there are a large number of freely movable electrons inside them. These electrons can move directionally under the action of an electric field to form an electric current, thus forming a good electron conduction channel. The present invention uses ruthenium element as the shell metal element of the core-shell structure. Ruthenium element has strong anti-toxicity and low cost compared with Pt catalyst; however, the activity of pure ruthenium is insufficient. By forming a core-shell structure, the core element adjusts the electronic structure of the outer shell ruthenium element and the adsorption energy of reaction intermediates, thereby improving the CO removal ability and the hydrogen oxidation ability; in addition, with the increase of core entropy, the lattice stability of the nanosheets will be stronger, further improving the stability; at the same time, the core element and the shell element will be combined together through chemical bonds or other interaction forces, enabling the core-shell to be tightly combined and also able to share part of the external force.

[0021] In the present invention, the molar percentage content of each metal element in the multi-component ruthenium-nickel-based metal nanosheets is preferably independently 8-50%, and can be 8%, 9%, 10%, 12%, 13%, 14%, 17%, 20%, 21%, 22%, 23%, 28%, 30%, 31%, 32%, 35%, 40%, 41%, 46% or 48%.

[0022] In the present invention, the diameter of the multi-component ruthenium-nickel-based metal nanosheets is preferably 8-15 nm, and can be 8, 9, 10, 11, 12, 13, 14 or 15 nm. The total thickness is preferably 1.5-2.5 nm, and can be 1.5, 2 or 2.5 nm. The shell thickness is preferably 1.2-1.7 nm, and can be 1.2, 1.3, 1.4, 1.5, 1.6 or 1.7 nm. By controlling the diameter, total thickness and shell thickness of the multi-component ruthenium-nickel-based metal nanosheets within the above ranges, the present invention is beneficial to increasing the active sites, optimizing the mass transfer process, improving the electron conduction efficiency, and thus enhancing the catalytic activity. At the same time, it can also enhance the structural stability and improve the anti-poisoning ability.

[0023] The multi-component ruthenium-nickel-based metal nanosheets provided by the present invention have a core-shell structure. The core element can regulate the electronic structure of the shell through ligand effect and strain effect, thereby optimizing the catalytic reaction performance. Moreover, the core-shell structure of the nanosheets can provide protection for the internal active components, preventing them from being oxidized, dissolved or agglomerated during the reaction process. The outer shell layer can block the erosion of the external environment on the inner core, and at the same time can also inhibit the grain growth and agglomeration of the inner core material. Meanwhile, the nanosheet structure of the multi-component ruthenium-nickel-based metal nanosheets has a large specific surface area, which can provide more active sites, enabling it to come into full contact with the reactants as a catalyst. And the two-dimensional structure of the core-shell nanosheets can provide a short mass transfer path, reducing the diffusion resistance of reactants and products.

[0024] The present invention provides a preparation method for the multi-component ruthenium-nickel-based metal nanosheets described in the above technical solutions, comprising the following steps: Mix a ruthenium source, a nickel source, a reducing agent and a first organic solvent to carry out a first reduction reaction to obtain a first reaction solution; Mix an auxiliary metal precursor and a second organic solvent to obtain an auxiliary metal precursor dispersion; the auxiliary metal precursor includes one or more of a cobalt source, a copper source, an iron source and a manganese source; Mix the auxiliary metal precursor dispersion and the first reaction solution to carry out a second reduction reaction to obtain the multi-component ruthenium-nickel-based metal nanosheets.

[0025] In the present invention, unless otherwise specified, the raw materials involved are commercially available products well-known to those skilled in the art.

[0026] The present invention mixes a ruthenium source, a nickel source, a reducing agent and a first organic solvent to carry out a first reduction reaction to obtain a first reaction solution.

[0027] In the present invention, the ruthenium source preferably includes triruthenium dodecacarbonyl or ruthenium acetylacetonate; the nickel source preferably includes nickel acetylacetonate or nickel chloride; the reducing agent preferably includes one or more of glucose, ascorbic acid, and cetyltrimethylammonium chloride; the first organic solvent preferably includes one or more of oleylamine, benzyl alcohol, and ethylene glycol.

[0028] In the present invention, the mixing of the ruthenium source, nickel source, reducing agent, and first organic solvent is preferably carried out under ultrasonic conditions; the power of the ultrasonic wave is preferably 60 - 100 W, which can be 70, 80, 90, or 100 W, and the time is preferably 60 - 120 min, which can be 60, 70, 80, or 100 min; the mixture results in a turbid and homogeneous colloidal dispersion (or colloidal precursor dispersion). In the present invention, the concentration of the ruthenium source in the colloidal dispersion is preferably 0.7 - 1.3 mg / mL, the concentration of the nickel source is preferably 0.5 - 1 mg / mL, and the mass ratio of the reducing agent to the ruthenium source is preferably 15 - 25:1, which can be 20:1.

[0029] In the present invention, the temperature of the first reduction reaction is 150 - 200 °C, which can be 160, 170, 180, or 190 °C, and the time is 150 - 200 min, which can be 160, 170, 180, or 190 min. The present invention preferably transfers the colloidal dispersion to an oil bath pot for oil bath heating, and after the colloidal dispersion is heated to 150 - 200 °C, it is kept warm for the first reduction reaction.

[0030] During the first reduction reaction, the nickel source first undergoes a reduction reaction by obtaining electrons provided by the reducing agent to form nanosheets, and then ruthenium gradually grows on the nickel nanosheets under the drive of temperature and time, thereby forming Ni@Ru core-shell nanosheets. In the present invention, the first reaction solution is a black colloidal dispersion.

[0031] The present invention mixes the auxiliary metal precursor and the second organic solvent to obtain an auxiliary metal precursor dispersion.

[0032] In the present invention, the auxiliary metal precursor includes one or more of a cobalt source, a copper source, an iron source, and a manganese source; the cobalt source preferably includes cobalt acetylacetonate or cobalt dichloride; the copper source preferably includes copper acetylacetonate or copper chloride; the iron source preferably includes iron acetylacetonate or iron chloride; the manganese source preferably includes manganese acetylacetonate or manganese chloride. In the present invention, the second organic solvent preferably includes one or more of oleylamine, benzyl alcohol, and ethylene glycol.

[0033] In the present invention, the mixing of the auxiliary metal precursor and the second organic solvent is preferably carried out under ultrasonic conditions; the power of the ultrasonic wave is preferably 60-100 W, which can be 60, 70, 80, 90 or 100 W, and the time is preferably 60-120 min, which can be 60, 70, 80, 90 or 120 min. In the present invention, the concentration of each metal element in the auxiliary metal precursor dispersion is preferably 0.1 mg / mL. In the present invention, the auxiliary metal precursor dispersion is a turbid and uniform colloidal dispersion (or called colloidal precursor dispersion).

[0034] After obtaining the auxiliary metal precursor dispersion and the first reaction solution, in the present invention, the auxiliary metal precursor dispersion and the first reaction solution are mixed to carry out a second reduction reaction to obtain the multi-component ruthenium-nickel-based metal nanosheets.

[0035] In the present invention, the volume ratio of the auxiliary metal precursor dispersion to the first reaction solution is preferably 1:10.

[0036] In the present invention, the temperature of the second reduction reaction is preferably 150-200 °C, which can be 160, 170, 180 or 190 °C, and the time is preferably 150-200 min, which can be 160, 170, 180 or 190 min. In the present invention, the auxiliary metal precursor dispersion is preferably added to the first reaction solution, and after mixing evenly, the obtained mixed dispersion is transferred to an oil bath for oil bath heating. After the mixed dispersion is heated to 150-200 °C, it is kept warm to carry out the second reduction reaction.

[0037] During the second reduction process, the auxiliary metal elements are further reduced on the Ni@Ru core-shell nanosheets. Driven by temperature and time, they diffuse inward to form the final multi-component core-shell nanosheets. During the first reduction and the second reduction processes, the formation of the core-shell structure is mainly related to the element diffusion properties. Driven by temperature and time, non-noble elements tend to diffuse inward, and noble metals diffuse outward; the later-added non-noble auxiliary metals will grow on the initially formed Ni@Ru nanosheets, and as the temperature and time increase, the auxiliary metals diffuse inward.

[0038] After the second reduction reaction, in the present invention, the obtained reaction solution (black colloidal dispersion) is preferably centrifuged and washed to obtain the multi-component ruthenium-nickel-based metal nanosheets. In the present invention, the operation of the centrifugal washing is preferably: after the reaction solution is cooled to room temperature, ethanol is added thereto, and then centrifugation is carried out; the role of the ethanol is to separate the precipitate product and remove the impurities that may exist on the surface of the product; the rotation speed of the centrifugation can be 1500-3000 r / min, and the time can be 3-7 min.

[0039] Due to the synergistic effect among their constituent elements, multi-component alloy catalysts often exhibit more excellent performance than single-component materials. Different elements can respectively promote different steps in the reaction, or change the electron cloud density of the active sites through electronic interactions, thereby improving the catalytic activity. In addition, the core-shell structure can precisely regulate the surface properties and electronic structure of the catalyst by adjusting the thickness, composition, and structure of the core and shell, so as to optimize its catalytic activity and selectivity for specific reactions. Additionally, the nanosheet structure has a large specific surface area, which can provide more active sites, increase the contact area between the catalyst and the reactants, enable the active sites to be more fully exposed on the surface, and is conducive to the adsorption of reactants and the desorption of products. Therefore, the design of multi-component core-shell nanosheet materials provides a new research direction for constructing highly efficient and stable anodic hydrogen oxidation catalysts. However, finding a simple method to prepare multi-component core-shell nanosheet materials with controllable structure and composition is a major challenge. Based on the wet chemical organic phase preparation method, the ruthenium source, nickel source, and reducing agent are dissolved in an organic solvent. After heating to obtain a stable structure, the auxiliary metal element is dissolved in the organic solvent and added to the solution with the stable structure, and then heated continuously to prepare multi-component ruthenium-nickel-based metal nanosheets (multi-component ruthenium-nickel-based core-shell nanosheets). The present invention prepares multi-component ruthenium-nickel-based metal nanosheets with highly efficient and stable catalytic performance by a simple and feasible method. The conditions are mild, the operation is simple, it is convenient for large-scale production, and it can be better applied to commercial production; moreover, the element composition (such as the elements and element content and proportion in different parts of the shell) and microstructure (such as the thickness, diameter and other dimensions of the core-shell nanosheets) of the multi-component ruthenium-nickel-based metal nanosheets are controllable: by controlling the types of core-shell elements, the concentration of the reducing agent, the reaction temperature, the reaction time and other conditions, the reaction kinetics of the formation process of the multi-component ruthenium-nickel-based core-shell nanosheets can be more precisely regulated, making the microstructure of the multi-component ruthenium-nickel-based metal nanosheets controllable, which is of great significance in the research of low-content multi-metal alloys.

[0040] The present invention provides the application of the multi-component ruthenium-nickel-based metal nanosheets described in the above technical solutions or the multi-component ruthenium-nickel-based metal nanosheets prepared by the preparation method described in the above technical solutions as catalysts in the anodic hydrogen oxidation reaction of an alkaline membrane fuel cell. The present invention has no special requirements for the alkaline membrane fuel cell, and the alkaline membrane fuel cells well-known to those skilled in the art are all applicable to the present invention. In the present invention, the electrolyte of the alkaline membrane fuel cell is preferably a potassium hydroxide solution, and the concentration of the potassium hydroxide solution is preferably 0.05-0.2 mol / L, and can be 0.05, 0.1 or 0.2 mol / L. The multi-component ruthenium-nickel-based metal nanosheets provided by the present invention are highly efficient and stable, have good anti-CO poisoning ability, and exhibit excellent anodic hydrogen oxidation electrocatalytic performance when applied to an alkaline membrane fuel cell.

[0041] To further illustrate the present invention, the following is a detailed description of the multi-component ruthenium-nickel-based metal nanosheets provided by the present invention, their preparation methods and applications in combination with examples, but they should not be construed as limiting the protection scope of the present invention.

[0042] Example 1 The preparation of multi-component ruthenium-nickel-based metal nanosheets (ruthenium-nickel-cobalt core-shell nanosheets) is as follows: (1) Dissolve triruthenium dodecacarbonyl, nickel acetylacetonate, and glucose in oleylamine at concentrations of 1 mg / mL, 0.5 mg / mL, and 20 mg / mL respectively, and ultrasonicate (ultrasonic power is 80 W) for 80 min to obtain a turbid and uniform colloidal precursor dispersion; (2) Transfer the colloidal precursor dispersion obtained in step (1) to an oil bath and heat it in the oil bath. After heating to 170 °C, keep it warm for a total of 180 min to obtain a black colloidal dispersion, then stop heating and take it out for later use; (3) Dissolve cobalt dichloride in oleylamine at a concentration of 0.1 mg / mL, and ultrasonicate (ultrasonic power is 80 W) for 80 min to obtain a turbid and uniform colloidal precursor dispersion; (4) Add 1 mL of the turbid and uniform colloidal precursor dispersion obtained in step (3) to 10 mL of the black colloidal dispersion taken out in step (2), mix well to obtain a black colloidal mixed dispersion; (5) Transfer the black colloidal dispersion obtained in step (4) to an oil bath and heat it in the oil bath. After heating to 170 °C, keep it warm for a total of 180 min, then stop heating. After the reaction vessel cools to room temperature, add 3 mL of ethanol to the obtained black colloidal dispersion, and then centrifuge at 3000 r / min for 3 min to obtain ruthenium-nickel-cobalt core-shell nanosheets (denoted as RuNiCo), with a diameter of 8 nm, a total thickness of 2 nm, and a shell thickness of 1.5 nm. The molar percentage content of each metal element in the ruthenium-nickel-cobalt core-shell nanosheets is: Ru 48%, Ni 31%, Co 21%.

[0043] Example 2 The preparation of multi-component ruthenium-nickel-based metal nanosheets (ruthenium-nickel-copper core-shell nanosheets) is as follows: (1) Dissolve ruthenium acetylacetonate, nickel acetylacetonate, and ascorbic acid in ethylene glycol at concentrations of 1 mg / mL, 0.5 mg / mL, and 20 mg / mL respectively, and ultrasonicate (ultrasonic power is 90 W) for 70 min to obtain a turbid and uniform colloidal precursor dispersion; (2) Transfer the colloidal precursor dispersion obtained in step (1) to an oil bath and heat it in the oil bath. After heating to 170 °C, keep it warm for a total of 180 min to obtain a black colloidal dispersion, then stop heating and take it out for later use; (3) Disperse copper acetylacetonate in ethylene glycol at a concentration of 0.1 mg / mL and ultrasonicate (ultrasonic power is 90 W) for 70 min to obtain a turbid and uniform colloidal precursor dispersion; (4) Add 1 mL of the turbid and uniform colloidal precursor dispersion obtained in step (3) to 10 mL of the black colloidal dispersion taken out and reserved in step (2), mix evenly to obtain a black colloidal mixed dispersion; (5) Transfer the black colloidal dispersion obtained in step (4) to an oil bath for oil bath heating. After heating to 170 °C, keep it warm for a total of 180 min, then stop heating. After the reaction vessel cools to room temperature, add 3 mL of ethanol to the obtained black colloidal dispersion, and then centrifuge at 2500 r / min for 3 min to obtain ruthenium-nickel-copper core-shell nanosheets (denoted as RuNiCu), with a diameter of 8 nm, a total thickness of 2 nm, and a shell thickness of 1.5 nm. The molar percentage content of each metal element in the ruthenium-nickel-copper core-shell nanosheets is: Ru 46%, Ni 32%, Cu 22%.

[0044] Example 3 Preparation of multi-component ruthenium-nickel-based metal nanosheets (ruthenium-nickel-iron-manganese core-shell nanosheets), the steps are as follows: (1) Disperse dodecacarbonyltriruthenium, nickel chloride, and cetyltrimethylammonium chloride in oleylamine at concentrations of 1 mg / mL, 0.5 mg / mL, and 20 mg / mL respectively, and ultrasonicate (ultrasonic power is 100 W) for 60 min to obtain a turbid and uniform colloidal precursor dispersion; (2) Transfer the colloidal precursor dispersion obtained in step (1) to an oil bath for oil bath heating. After heating to 170 °C, keep it warm for a total of 180 min to obtain a black colloidal dispersion, then stop heating and take it out for use; (3) Disperse ferric chloride and manganese chloride in oleylamine at a concentration of 0.1 mg / mL respectively, and ultrasonicate (ultrasonic power is 100 W) for 60 min to obtain a turbid and uniform colloidal precursor dispersion; (4) Add 1 mL of the turbid and uniform colloidal precursor dispersion obtained in step (3) to 10 mL of the black colloidal dispersion taken out and reserved in step (2), mix evenly to obtain a black colloidal mixed dispersion; (5) The black colloidal mixed dispersion obtained in step (4) was transferred to an oil bath and heated in an oil bath until it reached 170° C. and then kept warm for 180 minutes. The heating was then stopped. After the reaction vessel was cooled to room temperature, 3 mL of ethanol was added to the obtained black colloidal dispersion, followed by centrifugation at 2500 rpm for 3 minutes to obtain ruthenium nickel iron manganese core-shell nanosheets (denoted as RuNiFeMn) having a diameter of 8 nm, a total thickness of 2 nm, and a shell thickness of 1.5 nm. The molar percentages of the metal elements in the ruthenium nickel iron manganese core-shell nanosheets were as follows: Ru 41%, Ni 28%, Fe 17%, and Mn 14%.

[0045] Example 4 The preparation steps of multi-component ruthenium nickel-based metal nanosheets (ruthenium nickel cobalt copper iron manganese core-shell nanosheets) are as follows: (1) Ruthenium acetylacetonate, nickel chloride, and hexadecyltrimethylammonium chloride were dispersed in benzyl alcohol at concentrations of 1 mg / mL, 0.5 mg / mL, and 20 mg / mL, respectively, and ultrasonicated (ultrasonic power of 100 W) for 60 min to obtain a turbid and uniform colloidal precursor dispersion; (2) Transfer the colloidal precursor dispersion obtained in step (1) to an oil bath for oil bath heating, heat to 170°C and then keep warm for a total of 180 minutes to obtain a black colloidal dispersion, then stop heating and take out for use; (3) Cobalt dichloride, copper chloride, ferric chloride, and manganese chloride were dispersed in benzyl alcohol at a concentration of 0.1 mg / mL and ultrasonicated (ultrasonic power of 100 W) for 60 min to obtain a turbid and uniform colloidal precursor dispersion; (4) Add 1 mL of the turbid and uniform colloidal precursor dispersion obtained in step (3) to 10 mL of the black colloidal dispersion taken out for use in step (2), and mix them evenly to obtain a black colloidal mixed dispersion; (5) The black colloidal mixed dispersion obtained in step (4) was transferred to an oil bath and heated in an oil bath until it reached 170°C and then kept warm for 180 minutes. The heating was then stopped. After the reaction vessel cooled to room temperature, 3 mL of ethanol was added to the obtained black colloidal dispersion, followed by centrifugation at 2500 rpm for 3 minutes to obtain ruthenium nickel cobalt copper iron manganese core-shell nanosheets (denoted as RuNiCoCuFeMn) with a diameter of 8 nm, a total thickness of 2 nm, and a shell thickness of 1.5 nm. The molar percentage of each metal element in the ruthenium nickel cobalt copper iron manganese core-shell nanosheets was: Ru 35%, Ni 23%, Co 12%, Cu 13%, Fe 9%, and Mn 8%.

[0046] Comparative Example 1 The preparation steps of ruthenium nickel metal nanosheets are as follows: (1) Ru₃(CO)₁₂, Ni(acac)₂, and glucose were dispersed in oleylamine at concentrations of 1 mg / mL, 0.5 mg / mL, and 20 mg / mL, respectively, and sonicated (ultrasonic power: 80 W) for 80 min to obtain a turbid and homogeneous colloidal precursor dispersion. (2) The colloidal precursor dispersion obtained in step (1) was transferred to an oil bath for heating. After heating to 170 °C, it was kept warm for a total of 180 min to obtain a black colloidal dispersion. Then, the heating was stopped. After the reaction vessel cooled to room temperature, ethanol was added to the obtained black colloidal dispersion, and then centrifuged at 3000 r / min for 3 min to obtain ruthenium-nickel metal nanosheets (denoted as RuNi).

[0047] Figure 1 is the transmission electron microscopy image of the ruthenium-nickel-cobalt core-shell nanosheets prepared in Example 1. Figure 2 is the transmission electron microscopy image of the ruthenium-nickel-iron-manganese core-shell nanosheets prepared in Example 3. Figure 1 and Figure 2 shows the morphology and structural characteristics of the core-shell nanosheets, which have a thickness of nanoscale and a two-dimensional nanosheet morphology, with a thickness of about 2 nm. Figure 3 is the aberration-corrected electron microscopy image of the ruthenium-nickel-cobalt-copper-iron-manganese core-shell nanosheets prepared in Example 4. It can be seen that the core-shell nanosheets have been formed, and ruthenium acts as the shell element to wrap the core structure formed by nickel and the auxiliary metal.

[0048] Figure 4 are the hydrogen oxidation reaction polarization curves of the ruthenium-nickel-cobalt core-shell nanosheets (RuNiCo) prepared in Example 1, the ruthenium-nickel-cobalt-copper-iron-manganese core-shell nanosheets (RuNiCoCuFeMn) prepared in Example 4, and commercial platinum-carbon (Pt / C). The curves were tested under the conditions of a scanning rate of 5 mV / s, a rotation speed of 1600 r / min, and pure hydrogen. The test was carried out using a three-electrode system, with the electrode loaded with the catalyst (the ruthenium-nickel-cobalt core-shell nanosheets prepared in Example 1, the ruthenium-nickel-cobalt-copper-iron-manganese core-shell nanosheets prepared in Example 4, or commercial platinum-carbon) as the working electrode, a carbon rod as the counter electrode, and a saturated calomel electrode as the reference electrode. The electrolyte was 0.1 mol / L potassium hydroxide solution. Figure 4 The curves shown indicate that when using the ruthenium-nickel-cobalt core-shell nanosheets as the catalyst, the anodic current increases sharply with the increase of the potential, indicating its high catalytic performance for hydrogen oxidation in alkaline membranes and higher than that of commercial platinum-carbon; the ruthenium-nickel-cobalt-copper-iron-manganese core-shell nanosheets can quickly reach a very large current at a very small potential, indicating that this catalyst is very easy to undergo the hydrogen oxidation reaction.

[0049] Figure 5The lifetimes of the ruthenium-nickel-cobalt-copper-iron-manganese core-shell nanosheets (RuNiCoCuFeMn) of Example 4, the ruthenium-nickel metal nanosheets (RuNi) of Comparative Example 1, and commercial platinum-carbon (Pt / C) were measured under a constant voltage of 0.1 V in an environment of CO and hydrogen (CO content: 1000 ppm). From Figure 5 It can be seen that under the condition of a constant potential of 0.1 V, the performance of commercial platinum-carbon (Pt / C) remained 19.4% of its initial performance at 2 h, and the performance of the ruthenium-nickel metal nanosheets (RuNi) of Comparative Example 1 remained 30.7% of its initial performance at 2 h; while the performance of RuNiCoCuFeMn only decreased by 9.9% until 6 h, indicating that in terms of anti-poisoning performance, the ruthenium-nickel-based core-shell nanosheets are superior to the ruthenium-nickel metal nanosheets of the comparative example and commercial platinum-carbon, and have good stability.

[0050] The above are only the preferred embodiments of the present invention, and do not impose any formal restrictions on the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A multi-component ruthenium-nickel-based metal nanosheet, characterized in that, The multi-component ruthenium-nickel-based metal nanosheets are two-dimensional nanosheets with a core-shell structure; the core-shell structure includes a core metal element and a shell metal element, the core metal element includes nickel element and an auxiliary metal element, the auxiliary metal element includes one or more of cobalt element, copper element, iron element and manganese element, and the shell metal element is ruthenium element.

2. The multi-component ruthenium-nickel-based metal nanosheet according to claim 1, wherein The molar percentage content of each metal element in the multi-component ruthenium-nickel-based metal nanosheets is independently 8-50%.

3. The multi-component ruthenium-nickel-based metal nanosheets according to claim 1, characterized in that, The diameter of the multi-component ruthenium-nickel-based metal nanosheets is 8-15 nm, the total thickness is 1.5-2.5 nm, and the shell layer thickness is 1.2-1.7 nm.

4. The preparation method of the multi-component ruthenium-nickel-based metal nanosheets according to any one of claims 1 to 3, characterized in that, It includes the following steps: Mix a ruthenium source, a nickel source, a reducing agent and a first organic solvent to carry out a first reduction reaction to obtain a first reaction solution; Mix an auxiliary metal precursor and a second organic solvent to obtain an auxiliary metal precursor dispersion; the auxiliary metal precursor includes one or more of a cobalt source, a copper source, an iron source and a manganese source; Mix the auxiliary metal precursor dispersion with the first reaction solution to carry out a second reduction reaction to obtain the multi-component ruthenium-nickel-based metal nanosheets; The temperature of the first reduction reaction and the second reduction reaction is independently 150-200 °C, and the time is independently 150-200 min.

5. The preparation method according to claim 4, wherein The ruthenium source includes dodecacarbonyltriruthenium or ruthenium acetylacetonate; the nickel source includes nickel acetylacetonate or nickel chloride; the cobalt source includes cobalt acetylacetonate or cobalt dichloride; the copper source includes copper acetylacetonate or copper chloride; the iron source includes iron acetylacetonate or iron chloride; the manganese source includes manganese acetylacetonate or manganese chloride.

6. The preparation method according to claim 4 or 5, characterized in that, The reducing agent includes one or more of glucose, ascorbic acid and cetyltrimethylammonium chloride; the mass ratio of the reducing agent to the ruthenium source is 15-25:

1.

7. The preparation method according to claim 4, characterized in that, The first organic solvent and the second organic solvent independently include one or more of oleylamine, benzyl alcohol and ethylene glycol.

8. The preparation method according to claim 4, characterized in that, The mixing of the ruthenium source, the nickel source, the reducing agent and the first organic solvent and the mixing of the auxiliary metal precursor and the second organic solvent are both carried out under the condition of ultrasonic; the power of the ultrasonic is 60-100 W, and the time is 60-120 min.

9. Application of the multi-component ruthenium-nickel-based metal nanosheets according to any one of claims 1-3 or the multi-component ruthenium-nickel-based metal nanosheets prepared by the preparation method according to any one of claims 4-8 as a catalyst in the anodic hydrogen oxidation reaction of an alkaline membrane fuel cell.

10. The application according to claim 9, characterized in that, The electrolyte of the anodic hydrogen oxidation reaction of the alkaline membrane fuel cell is a potassium hydroxide solution, and the concentration of the potassium hydroxide solution is 0.05-0.2 mol / L.

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