Carbon-coupled nickel-iron double-metal hydroxide and in-situ rapid preparation method and application thereof

Abstract

The application belongs to the technical field of electrochemical water decomposition, and discloses carbon-coupled nickel-iron bimetallic hydroxide and an in-situ rapid preparation method and application thereof. The in-situ rapid preparation method comprises the following steps: 1) dispersing two-dimensional titanium carbide loaded with single atoms in a water-ethanol mixed solution to obtain a suspension A; and 2) spraying the suspension A to the surface of a clean iron-nickel alloy, and air-drying, so that carbon-coupled nickel-iron bimetallic hydroxide is generated on the surface of the iron-nickel alloy by in-situ construction. The single atoms include one or more than one of Mn, Fe, Co, Ni, Cu and Ru. The method is convenient and efficient, and can realize the in-situ construction of carbon-coupled nickel-iron bimetallic hydroxide on the surface of the iron-nickel alloy in one step within 30 minutes, and is easy to scale up. The nickel-iron bimetallic hydroxide is applied as an efficient catalyst for oxygen evolution reaction in the field of electrochemical water decomposition, effectively improves the electron transmission efficiency inside the catalyst under industrial large current density, and reduces the oxygen evolution overpotential.

Description

Technical Field

[0001] This invention relates to a nickel-iron bimetallic hydroxide material, specifically to a carbon-coupled nickel-iron bimetallic hydroxide and its in-situ rapid preparation method and application, belonging to the field of electrochemical water splitting technology. Background Technology

[0002] Electrochemical water splitting for hydrogen production consists of two half-reactions: the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). The OER on the anode side is a four-electron transfer reaction with slow kinetics, a key bottleneck limiting the efficiency of hydrogen production. Studies have shown that ruthenium or iridium-based noble metal compounds can effectively lower the OER energy barrier and improve electrolysis efficiency. However, ruthenium and iridium are expensive. Therefore, abundant and inexpensive transition metal-based OER catalysts have gained widespread attention from researchers. Among them, nickel-iron bimetallic hydroxides with excellent activity are considered the most promising alternative to noble metal catalysts for commercial application in the OER.

[0003] In industrial applications, the oxygen evolution reaction (OER) occurs at a complex gas-liquid-solid three-phase interface (oxygen-electrolyte-catalyst). The OER electrode needs to operate for tens of thousands of hours under extreme conditions of high-concentration potassium hydroxide solution and high current density. During this process, the catalyst coated on the conductive substrate is prone to detachment, leading to a continuous decrease in electrode catalytic activity and severely impacting the efficiency and lifespan of the electrolysis equipment. This places extremely high demands on the bonding strength between the conductive substrate and the catalyst. To address this, researchers have proposed methods such as hydrothermal synthesis and electrodeposition to construct nickel-iron bimetallic hydroxides in situ on conductive substrates, aiming to achieve stable operation of the OER electrode under harsh anodic electrolysis conditions. For example, Chinese invention patent 201810044072.4 discloses a method for preparing nickel-iron bimetallic hydroxide with a lamellar structure grown in situ on nickel foam: nickel foam is placed in an aqueous solution containing a certain amount of nickel nitrate hexahydrate, ferric nitrate nonahydrate, urea, and ammonium fluoride. The solution is then transferred to a high-pressure reactor and placed in an oven for a period of time. After the high-pressure reactor cools to room temperature, the nickel foam is removed, cleaned, and dried to obtain the nickel-iron bimetallic hydroxide with a lamellar structure grown in situ on nickel foam. While the hydrothermal method used in this invention is a common reaction synthesis technique under laboratory conditions, it requires high-temperature and high-pressure reaction vessels, which is not only time-consuming and energy-intensive but also poses certain safety hazards, making it difficult to scale up for mass production. To solve these problems, Chinese invention patent 202210845166.8 discloses a method for preparing a nickel-based oxygen evolution electrode based on electrodeposition technology: in a two-electrode system, a nickel-iron metal salt electroplating solution is used, with the composite material as the working electrode and a platinum sheet as the counter electrode, at an A / C ratio of 10–50 mA. -2Electrodeposition is performed on the composite material to obtain a nickel-iron hydroxide deposition layer, thereby obtaining a nickel-based oxygen evolution electrode. This invention significantly reduces the time and energy consumption for in-situ preparation of nickel-iron bimetallic hydroxides and has high safety. However, this invention still requires specific electrochemical deposition equipment and is not easy to manufacture.

[0004] Furthermore, nickel-iron bimetallic hydroxides (NiFeBiMHs) exhibit poor conductivity, and only their surface layer participates in the electrocatalytic oxygen evolution reaction (OER). Therefore, the electron transport efficiency from the core to the surface is limited, restricting their application at high current densities in industrial applications. To address these issues, researchers typically employ a two-step process: pre-constructing a highly efficient electron transport layer on a conductive substrate before in-situ growth of NiFeBiMHs. For example, Chinese invention patent 202110519822.0 uses electrochemical deposition to pre-construct a highly conductive ZnO nanostructure on the surface of nickel foam; Chinese invention patent 202110433457.1 utilizes chemical vapor deposition to pre-construct a graphene conductive layer on the surface of nickel foam. While similar two-step methods improve electron transport efficiency, the fabrication process is more time-consuming and complex. Currently available methods for preparing nickel-iron bimetallic hydroxides cannot achieve in-situ construction of highly conductive nickel-iron bimetallic hydroxides under the premise of simplicity and efficiency. This greatly limits the large-scale production and application of nickel-iron bimetallic hydroxide catalysts.

[0005] In summary, to better promote the practical application of nickel-iron bimetallic hydroxides in electrolytic hydrogen production, we urgently need to develop an in-situ rapid preparation method for nickel-iron bimetallic hydroxides with high conductivity. Summary of the Invention

[0006] To overcome the shortcomings and deficiencies of existing preparation techniques, this invention aims to provide a rapid in-situ preparation method for carbon-coupled nickel-iron bimetallic hydroxides on the surface of an iron-nickel alloy. This invention involves spraying a water-ethanol solution containing single-atom-loaded two-dimensional titanium carbides onto the surface of an iron-nickel alloy. Utilizing the highly efficient photocatalytic properties of the oxidation derivatives of the two-dimensional titanium carbides under visible light, the carbon-coupled nickel-iron bimetallic hydroxides can be rapidly constructed in situ at the interface between the two-dimensional titanium carbide oxidation derivatives and the iron-nickel alloy. The preparation method of this invention is convenient and efficient, and can be completed within a short time (30 minutes) without the need for large auxiliary equipment.

[0007] Another object of the present invention is to provide a carbon-coupled nickel-iron bimetallic hydroxide obtained by the above preparation method.

[0008] Another object of the present invention is to provide applications of the aforementioned carbon-coupled nickel-iron bimetallic hydroxide. This carbon-coupled nickel-iron bimetallic hydroxide is used in the field of electrocatalytic water splitting, particularly for the highly efficient catalysis of the oxygen evolution reaction. Carbon coupling improves the conductivity of the nickel-iron bimetallic hydroxide, effectively enhancing the electron transport efficiency within the catalyst under high current densities in industrial applications.

[0009] This invention is achieved through the following technical solution:

[0010] A rapid in-situ preparation method for carbon-coupled nickel-iron bimetallic hydroxides includes the following steps:

[0011] (1) Disperse the single-atom-loaded two-dimensional titanium carbide in a water-ethanol mixed solution to obtain suspension A;

[0012] (2) Spray the suspension A obtained in step (1) onto a clean iron-nickel alloy surface and let it dry. Carbon-coupled nickel-iron bimetallic hydroxides are generated on the iron-nickel alloy surface in situ.

[0013] In step (1), the two-dimensional titanium carbide includes Ti2CT. x (T = O, F, Cl), Ti3C2T x (T = O, F, Cl) etc.

[0014] In step (1), the loaded single atoms include, but are not limited to, Mn, Fe, Co, Ni, Cu, Ru, etc.

[0015] In step (1), the amount of single-atom loading in the single-atom-loaded two-dimensional titanium carbide is 0.1 to 20% of the mass of the two-dimensional titanium carbide.

[0016] In step (1), the mass ratio of the single-atom-loaded two-dimensional titanium carbide, water and ethanol in the suspension A is (1-10):(40-400):(40-400); the mass ratio of water to ethanol is preferably 1:(0.5-4), more preferably 1:(0.8-3).

[0017] In step (1), the single-atom-loaded two-dimensional titanium carbide in the suspension can be rapidly oxidized to carbon-coupled TiO2. 2-x-y F x Cl y .

[0018] In step (2), the iron-nickel alloy is mainly composed of two elements, Fe and Ni, with the mass fraction of Fe between 50% and 80% and the mass fraction of Ni between 20% and 50%.

[0019] The clean iron-nickel alloy mentioned in step (2) is obtained by thoroughly polishing the selected iron-nickel alloy to remove the oxide scale and cleaning it for later use.

[0020] The polishing process uses 180-360 grit SiC sandpaper and takes 5-15 minutes.

[0021] The cleaning process involves sequentially cleaning with acetone, water, and alcohol.

[0022] In step (2), the spraying amount of suspension A, calculated based on the mass ratio of the single-atom-loaded two-dimensional titanium carbide to the area of ​​the iron-nickel alloy, is 0.1–2.0 mg / cm². -2 .

[0023] In step (2), the drying time is 10 to 30 minutes. The drying process involves air drying.

[0024] A carbon-coupled nickel-iron bimetallic hydroxide in situ constructed on the surface of an iron-nickel alloy is prepared by the above method. The carbon-coupled nickel-iron bimetallic hydroxide exhibits a nanoarray structure with carbon elements uniformly distributed on the surface.

[0025] The carbon-coupled nickel-iron bimetallic hydroxide is used as a highly efficient catalyst for the oxygen evolution reaction in the field of electrochemical water splitting.

[0026] The principle of this invention is:

[0027] Firstly, the loaded metal single atoms can enhance the adsorption capacity of titanium sites in two-dimensional titanium carbides for oxygen, allowing the single-atom-loaded two-dimensional titanium carbides to oxidize rapidly after being dispersed in a water-ethanol solution, thus forming carbon-coupled TiO₂. 2-x- y F x Cl y Carbon-coupled TiO₂ 2-x-y F x Cl y As an excellent photocatalyst, the introduction of elements such as C, F, and Cl can achieve rapid separation and transport of photogenerated carriers, while simultaneously reducing the band gap of TiO2 and expanding its photoresponse range to the visible light range. Therefore, carbon-coupled TiO2 under visible light... 2-x-y F x Cl y At the interface between the iron-nickel alloy and the ethanol-nickel alloy, an oxidative coupling hydrogen evolution reaction can occur, producing a certain amount of hydroxide ions; simultaneously, a side reaction occurs on the iron-nickel alloy surface where iron-nickel ions are precipitated. Thus, the precipitated iron-nickel ions combine with hydroxide ions, forming a hydrogen evolution reaction on the carbon-coupled TiO₂. 2-x-y F x Cl y Carbon-coupled nickel-iron bimetallic hydroxides are obtained at the interface with the iron-nickel alloy, enabling rapid in-situ construction.

[0028] The present invention has the following advantages and beneficial effects compared with the prior art:

[0029] (1) This invention utilizes the efficient photocatalytic properties of two-dimensional titanium carbide oxidation derivatives to induce visible light-catalyzed ethanol oxidation coupled with hydrogen evolution reaction and iron-nickel ion precipitation side reaction at the interface between two-dimensional titanium carbide oxidation derivatives and iron-nickel alloy, thereby realizing the in-situ rapid construction of carbon-coupled nickel-iron bimetallic hydroxides on the surface of iron-nickel alloy.

[0030] (2) This invention uses a simple one-step spraying process to spray a water-ethanol solution containing single-atom-loaded two-dimensional titanium carbides onto the surface of an iron-nickel alloy, which is then naturally dried in the air to obtain an in-situ nickel-iron bimetallic hydroxide on the surface of the iron-nickel alloy. The entire process does not require additional large-scale equipment, the time can be controlled within 30 minutes, the operation is simple, the process flow is short, the efficiency and reliability are high, and it is easy to achieve large-scale production.

[0031] (3) This invention realizes one-step coupling of nickel-iron bimetallic hydroxide and carbon, which can improve the conductivity of nickel-iron bimetallic hydroxide. The resulting carbon-coupled nickel-iron bimetallic hydroxide is used for electrochemical water desorption oxygen reaction, which effectively improves the electron transport efficiency inside the catalyst under industrial high current density and reduces oxygen evolution overpotential. Attached Figure Description

[0032] Figure 1 Ti2CT loaded with Co single atoms in Example 1 x X-ray diffraction pattern of its diffraction products in water-ethanol solution;

[0033] Figure 2 Ti2CT loaded with Co single atoms in Example 1 x Scanning electron microscope images of the oxidation derivatives;

[0034] Figure 3 Ti2CT loaded with Co single atoms in Example 1 x Scanning electron microscope image;

[0035] Figure 4 The X-ray diffraction pattern of the nickel-iron bimetallic alloy with carbon coupling constructed in situ in Example 1.

[0036] Figure 5 The carbon-coupled TiO2 in Example 1 2-x-y F x Cl y Scanning electron microscope image of the interface with the iron-nickel alloy after the interfacial reaction;

[0037] Figure 6 The electrochemical oxygen evolution reaction activity test curve of the iron-nickel alloy with carbon-coupled nickel-iron bimetallic hydroxide constructed in situ in Example 1;

[0038] Figure 7 The carbon-coupled TiO in Example 2 2-x-y F x Cl y Scanning electron microscope image of the interface with the iron-nickel alloy after the interfacial reaction;

[0039] Figure 8 The carbon-coupled TiO in Example 3 2-x-y F x Cl y Scanning electron microscope image of the interface with the iron-nickel alloy after the interfacial reaction;

[0040] Figure 9 The carbon-coupled TiO in Example 4 2-x-y F x Cl y Scanning electron microscope image of the interface with the iron-nickel alloy after the interfacial reaction;

[0041] Figure 10 The carbon-coupled TiO in Example 5 2-x-y F x Cl y Scanning electron microscope image of the interface with the iron-nickel alloy after the interfacial reaction;

[0042] Figure 11 For carbon-coupled TiO in Comparative Example 1 2-x-y F x Cl y Scanning electron microscope image of the interface with the iron-nickel alloy after the interfacial reaction;

[0043] Figure 12 The electrochemical oxygen evolution reaction activity curves of the iron-nickel alloy with carbon-coupled nickel-iron bimetallic hydroxide constructed in situ in Comparative Example 1 are shown. Detailed Implementation

[0044] To better understand the present invention, the present invention will be further described below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0045] Single-atom loaded Ti2CT in the examples x (T = O, F, Cl)Mxene materials were prepared by a combination of traditional wet chemical etching and classical electrostatic adsorption precipitation. The preparation process is as follows:

[0046] S1: Ti2CT fabricated using the traditional wet chemical etching method xMxene material. LiF powder was dissolved in hydrochloric acid solution, and Ti2AlC precursor powder was slowly added under stirring to obtain mixed solution A; the mass concentration of the hydrochloric acid was 3-27%; the LiF powder accounted for 2-10% of the mass of the hydrochloric acid solution; the Ti2AlC precursor was a 200-400 mesh powder with a purity of 99%; and the Ti2AlC precursor powder accounted for 50%-200% of the mass of the LiF powder.

[0047] S2: Transfer the mixed solution A obtained in step (S1) to an oil bath, stir at 25-50°C, and continue etching for 18-72 hours to obtain mixed solution B;

[0048] S3: Centrifuge the mixed solution B to obtain Ti2CT. x Mxene suspension; the Ti2CT x The concentration of Mxene suspension is 5–10 mg / mL;

[0049] S4: Single-atom-loaded Ti2CT was prepared using the classic electrostatic adsorption precipitation method. x (T = O, F, Cl)Mxene: Dissolve the acetates of metals such as Co, Fe, Ni and Mn in water to obtain metal ion solution C; the concentration of the metal ion solution is 2-5 mg / mL based on the mass of the metal ions;

[0050] S5: Add the metal ion solution C obtained in step (S4) dropwise to Ti2CT. x In the Mxene suspension, after stirring for 2–10 minutes, a mixed solution D is obtained; the amount of metal ion solution C added is based on the metal ions and Ti2CT. x The mass fraction of Mxene is 1–15%;

[0051] S6: Centrifuge the mixed solution D, collect the solid, and dry it to obtain Ti2CT loaded with single metal atoms such as Co, Fe, Ni, and Mn with different loading amounts. x (T = O, F, Cl) Mxene material.

[0052] Example 1:

[0053] (1) By weight, 3 parts of Co single-atom-loaded Ti2CT x (T = O, F, Cl) was dispersed in a mixed solution of 250 parts water and 230 parts ethanol to obtain suspension A, in which the loading of Co single atoms was Ti2CT. x 3% of the mass;

[0054] (2) Select an iron-nickel alloy, in which the mass fraction of iron is about 40% and the mass fraction of nickel is about 60%. Use 180-mesh SiC sandpaper to polish its surface for 5 minutes to remove the surface oxide scale, and then clean it with acetone, water and alcohol in sequence before use.

[0055] (3) Based on the mass ratio of the single-atom-loaded two-dimensional titanium carbide to the area of ​​the iron-nickel alloy, the suspension A obtained in step (1) is sprayed onto the surface of the iron-nickel alloy obtained in step (2), with a spraying amount of 0.4 mg / cm². -2 ;

[0056] (4) The iron-nickel alloy coated with suspension A obtained in step (3) can be dried in the air for 15 minutes. At this time, carbon-coupled nickel-iron bimetallic hydroxides are generated on the surface of the iron-nickel alloy.

[0057] Suspension A was freeze-dried to collect Co single-atom-loaded Ti2CT. x X-ray diffraction analysis was performed on the diffraction products in the water-ethanol solution, and the results are as follows: Figure 1 As shown, this demonstrates the effect of Co single-atom-loaded Ti2CT x It has the property of being easily oxidized. When dispersed in a water-ethanol solution, it can be rapidly oxidized, and the oxidation derivative is anatase TiO2. Figure 2 Scanning electron microscopy (SEM) image of the oxidation derivative, compared with Ti2CT supported by Co single atoms. x compared to( Figure 3 The oxidation derivatives retained their plate-like structure. Elemental analysis using scanning electron microscopy (SEM) and its accompanying energy dispersive spectroscopy (EDS) revealed the presence of C, Ti, O, F, and Cl, with an O:Ti ratio of 2.47. Co single-atom-loaded Ti₂CT was also present. x The O:Ti ratio is only 1.59. These results indicate that Co-supported Ti₂CT... x The oxidation derivative in water-ethanol solution is carbon-coupled TiO₂. 2-x-y F x Cl y The introduction of elements such as C, F, and Cl enables rapid separation and transport of photogenerated carriers, while simultaneously reducing the bandgap of TiO2 and expanding its photoresponse range to the visible light range. Therefore, Co-supported Ti2CT... x It has excellent photocatalytic properties.

[0058] Figure 4 The X-ray diffraction pattern of the nickel-iron alloy with carbon-coupled nickel-iron bimetallic hydroxide in situ in this embodiment is shown. The characteristic diffraction peaks at 43.6°, 50.7° and 72.7° belong to the nickel-iron alloy, while the characteristic diffraction peak at 11.9° belongs to the nickel-iron bimetallic hydroxide. Figure 5In this embodiment, the carbon-coupled TiO₂ 2-x-y F x Cl y Scanning electron microscopy (SEM) images of the interface between the nickel-iron bimetallic hydroxide and the iron-nickel alloy clearly show the typical nanoarray structure of nickel-iron bimetallic hydroxide. Elemental analysis using energy dispersive spectroscopy (EDS) with the SEM revealed that carbon (C) is uniformly distributed on the surface of the nickel-iron bimetallic hydroxide nanoarray. These results indicate that carbon-coupled nickel-iron bimetallic hydroxide can be constructed in situ on the surface of an iron-nickel alloy within 15 minutes.

[0059] A three-electrode testing system was employed, using an iron-nickel alloy with carbon-coupled nickel-iron bimetallic hydroxide on its surface as the working electrode, a platinum sheet as the counter electrode, mercury oxide as the reference electrode, and 1 mol / L potassium hydroxide as the electrolyte. Linear sweep voltammetry was performed using a Gamry Interface 1000 electrochemical workstation to characterize the oxygen evolution reaction activity of the working electrode. Specific test parameters were as follows: scan rate 5 mV / s. -1 The scanning voltage range was 1.2–1.65 V (vs. RHE, relative to the reversible hydrogen electrode). The test results are as follows: Figure 6 As shown, when carbon-coupled nickel-iron bimetallic hydroxides are formed in situ on the surface of the iron-nickel alloy, the electrocatalytic activity is significantly improved, especially when the current density reaches 100 mA / cm². -2 The overpotential is only 293 mV, less than the 365 mV of the iron-nickel alloy. Furthermore, at an overpotential of 388 mV, the iron-nickel alloy with carbon-coupled nickel-iron bimetallic hydroxides on its surface prepared in this embodiment can also produce a 1000 mA / cm² overpotential required for industrial applications. -2 The current density indicates that carbon coupling can improve the conductivity of nickel-iron bimetallic hydroxide and effectively improve the electron transport efficiency inside the catalyst under industrial high current density.

[0060] Example 2:

[0061] (1) By weight, 1 part of Fe single-atom supported Ti2CT x (T = O, F, Cl) was dispersed in a mixed solution of 40 parts water and 56 parts ethanol to obtain suspension A, in which the loading of Fe single atoms was Ti2CT. x 5% of the mass;

[0062] (2) Select an iron-nickel alloy, in which the mass fraction of iron is about 40% and the mass fraction of nickel is about 60%. Use 360-mesh SiC sandpaper to polish its surface for 15 minutes to remove the surface oxide scale. Then clean it with acetone, water and alcohol in sequence before use.

[0063] (3) Based on the mass ratio of the single-atom-loaded two-dimensional titanium carbide to the area of ​​the iron-nickel alloy, the suspension A obtained in step (1) is sprayed onto the surface of the iron-nickel alloy obtained in step (2), with a spraying amount of 0.6 mg / cm². -2 ;

[0064] (4) The iron-nickel alloy sprayed with suspension A obtained in step (3) can be dried in the air for 20 minutes. At this time, carbon-coupled nickel-iron bimetallic hydroxides are generated on the surface of the iron-nickel alloy.

[0065] Figure 7 In this embodiment, the carbon-coupled TiO₂ 2-x-y F x Cl y Scanning electron microscopy (SEM) images of the interface reaction at the nickel-iron alloy interface clearly show the typical nanoarray structure of nickel-iron bimetallic hydroxide. Elemental analysis using energy dispersive spectroscopy (EDS) with the SEM shows that carbon (C) is uniformly distributed on the surface of the nickel-iron bimetallic hydroxide nanoarray, indicating that carbon-coupled nickel-iron bimetallic hydroxide can be constructed in situ on the surface of the nickel-iron alloy within 20 minutes.

[0066] The electrochemical oxygen evolution reaction activity test results of the iron-nickel alloy with carbon-coupled nickel-iron bimetallic hydroxide on its surface prepared in this embodiment are similar to those of Example 1, and its electrocatalytic activity is significantly improved when the current density reaches 100 mA / cm². -2 The overpotential is only 295mV, which is less than the 365mV of the iron-nickel alloy. It can generate a current density that meets the requirements of industrial applications at a low overpotential, indicating that carbon coupling can improve the conductivity of nickel-iron bimetallic hydroxide and effectively improve the electron transport efficiency inside the catalyst under high current density in industrial applications.

[0067] Example 3:

[0068] (1) By weight, 1 part of Ni single-atom supported Ti2CT x (T = O, F, Cl) was dispersed in a mixed solution of 50 parts water and 46 parts ethanol to obtain suspension A, in which the loading of Ni single atoms was Ti2CT. x 4% of the mass;

[0069] (2) Select an iron-nickel alloy, in which the mass fraction of iron is about 40% and the mass fraction of nickel is about 60%. Use 180-mesh SiC sandpaper to polish its surface for 10 minutes to remove the surface oxide scale. Then clean it with acetone, water and alcohol in sequence before use.

[0070] (3) Based on the mass ratio of the single-atom-loaded two-dimensional titanium carbide to the area of ​​the iron-nickel alloy, the suspension A obtained in step (1) is sprayed onto the surface of the iron-nickel alloy obtained in step (2), with a spraying amount of 0.8 mg / cm².-2 ;

[0071] (4) The iron-nickel alloy coated with suspension A obtained in step (3) can be dried in the air for 15 minutes. At this time, carbon-coupled nickel-iron bimetallic hydroxides are generated on the surface of the iron-nickel alloy.

[0072] Figure 8 In this embodiment, the carbon-coupled TiO₂ 2-x-y F x Cl y Scanning electron microscope (SEM) images of the interface reaction at the iron-nickel alloy interface clearly show the typical nanoarray structure of nickel-iron bimetallic hydroxide. Elemental analysis using energy dispersive spectroscopy (EDS) with the SEM shows that carbon (C) is uniformly distributed on the surface of the nickel-iron bimetallic hydroxide nanoarray, indicating that carbon-coupled nickel-iron bimetallic hydroxide can be constructed in situ on the iron-nickel alloy surface within 15 minutes.

[0073] The electrochemical oxygen evolution reaction activity test results of the iron-nickel alloy with carbon-coupled nickel-iron bimetallic hydroxide on its surface prepared in this embodiment are similar to those of Example 1, and its electrocatalytic activity is significantly improved when the current density reaches 100 mA / cm². -2 The overpotential is only 297mV, which is less than the 365mV of the iron-nickel alloy. It can generate a current density that meets the requirements of industrial applications at a low overpotential, indicating that carbon coupling can improve the conductivity of nickel-iron bimetallic hydroxide and effectively improve the electron transport efficiency inside the catalyst under high current density in industrial applications.

[0074] Example 4:

[0075] (1) By weight, 7 parts of Ti2CT supported on Mn single atoms were... x (T = O, F, Cl) was dispersed in a mixed solution of 125 parts water and 350 parts ethanol to obtain suspension A, in which the loading of Mn single atoms was Ti2CT. x 10% of the quality;

[0076] (2) Select an iron-nickel alloy, in which the mass fraction of iron is about 40% and the mass fraction of nickel is about 60%. Use 360-mesh SiC sandpaper to polish its surface for 10 minutes to remove the surface oxide scale. Then clean it with acetone, water and alcohol in sequence before use.

[0077] (3) Based on the mass ratio of the single-atom-loaded two-dimensional titanium carbide to the area of ​​the iron-nickel alloy, the suspension A obtained in step (1) is sprayed onto the surface of the iron-nickel alloy obtained in step (2), with a spraying amount of 1.2 mg / cm². -2 ;

[0078] (4) The iron-nickel alloy coated with suspension A obtained in step (3) can be dried in the air for 30 minutes. At this time, carbon-coupled nickel-iron bimetallic hydroxides are generated on the surface of the iron-nickel alloy.

[0079] Figure 9 In this embodiment, the carbon-coupled TiO₂ 2-x-y F x Cl y Scanning electron microscopy (SEM) images of the interface reaction at the iron-nickel alloy interface clearly show the typical nanoarray structure of nickel-iron bimetallic hydroxide. Elemental analysis using energy dispersive spectroscopy (EDS) with the SEM revealed that carbon (C) is uniformly distributed on the surface of the nickel-iron bimetallic hydroxide nanoarray, indicating that carbon-coupled nickel-iron bimetallic hydroxide can be constructed in situ on the iron-nickel alloy surface within 30 minutes.

[0080] The electrochemical oxygen evolution reaction activity test results of the iron-nickel alloy with carbon-coupled nickel-iron bimetallic hydroxide on its surface prepared in this embodiment are similar to those of Example 1, and its electrocatalytic activity is significantly improved when the current density reaches 100 mA / cm². -2 The overpotential is only 309mV, which is less than the 365mV of the iron-nickel alloy. It can generate a current density that meets the requirements of industrial applications at a low overpotential, indicating that carbon coupling can improve the conductivity of nickel-iron bimetallic hydroxide and effectively improve the electron transport efficiency inside the catalyst under high current density in industrial applications.

[0081] Example 5:

[0082] (1) By weight, 3 parts of Co single-atom-loaded Ti2CT x (T = O, F, Cl) was dispersed in a mixed solution of 250 parts water and 230 parts ethanol to obtain suspension A, in which the loading of Co single atoms was Ti2CT. x 5% of the quality.

[0083] (2) Select an iron-nickel alloy, in which the mass fraction of iron is about 40% and the mass fraction of nickel is about 60%. Use 180-mesh SiC sandpaper to polish its surface for 5 minutes to remove the surface oxide scale, and then clean it with acetone, water and alcohol in sequence before use.

[0084] (3) Based on the mass ratio of the single-atom-loaded two-dimensional titanium carbide to the area of ​​the iron-nickel alloy, the suspension A obtained in step (1) is sprayed onto the surface of the iron-nickel alloy obtained in step (2), with a spraying amount of 2.0 mg / cm². -2 ;

[0085] (4) The iron-nickel alloy coated with suspension A obtained in step (3) can be dried in the air for 30 minutes. At this time, carbon-coupled nickel-iron bimetallic hydroxides are generated on the surface of the iron-nickel alloy.

[0086] Figure 10 In this embodiment, the carbon-coupled TiO₂ 2-x-y F x Cl y Scanning electron microscopy (SEM) images of the interface reaction at the iron-nickel alloy interface clearly show the typical nanoarray structure of nickel-iron bimetallic hydroxide. Elemental analysis using energy dispersive spectroscopy (EDS) with the SEM revealed that carbon (C) is uniformly distributed on the surface of the nickel-iron bimetallic hydroxide nanoarray, indicating that carbon-coupled nickel-iron bimetallic hydroxide can be constructed in situ on the iron-nickel alloy surface within 30 minutes.

[0087] The electrochemical oxygen evolution reaction activity test results of the iron-nickel alloy with carbon-coupled nickel-iron bimetallic hydroxide on its surface prepared in this embodiment are similar to those of Example 1, and its electrocatalytic activity is significantly improved when the current density reaches 100 mA / cm². -2 The overpotential is only 289mV, which is less than the 365mV of the iron-nickel alloy. It can generate a current density that meets the requirements of industrial applications at a low overpotential, indicating that carbon coupling can improve the conductivity of nickel-iron bimetallic hydroxide and effectively improve the electron transport efficiency inside the catalyst under high current density in industrial applications.

[0088] Comparative Example 1:

[0089] (1) By weight, 3 parts of Co single-atom-loaded Ti2CT x (T = O, F, Cl) was dispersed in 480 parts of ethanol to obtain suspension A, in which the loading of Co single atoms was Ti2CT. x 3% of the mass;

[0090] (2) Select an iron-nickel alloy, in which the mass fraction of iron is about 40% and the mass fraction of nickel is about 60%. Use 180-mesh SiC sandpaper to polish its surface for 5 minutes to remove the surface oxide scale. Then clean it with acetone, water and alcohol in sequence before use.

[0091] (3) Based on the mass ratio of the single-atom-loaded two-dimensional titanium carbide to the area of ​​the iron-nickel alloy, the suspension A obtained in step (1) is sprayed onto the surface of the iron-nickel alloy obtained in step (2), with a spraying amount of 0.4 mg / cm². -2 ;

[0092] (4) The iron-nickel alloy coated with suspension A obtained in step (3) can be dried in the air for 15 minutes. At this time, carbon-coupled nickel-iron bimetallic hydroxides are generated on the surface of the iron-nickel alloy.

[0093] Thermogravimetric analysis showed that, by mass fraction, Co-supported Ti2CT xThe (T=O,F,Cl) material contains 5% adsorbed water. Therefore, when it is dispersed in an ethanol solution and sprayed onto the surface of an iron-nickel alloy, it can still induce a visible light-catalyzed ethanol oxidation coupled with hydrogen evolution and iron-nickel ion precipitation side reaction, thus realizing the in-situ construction of carbon-coupled nickel-iron bimetallic hydroxides on the surface of the iron-nickel alloy. Figure 11 In this comparative example, carbon-coupled TiO₂ 2-x-y F x Cl y The scanning electron microscope (SEM) images of the interface reaction at the iron-nickel alloy interface show the formation of carbon-coupled nickel-iron bimetallic hydroxide. However, compared to the carbon-coupled nickel-iron bimetallic hydroxide constructed with water-ethanol solution in Example 1, the carbon-coupled nickel-iron bimetallic hydroxide constructed with ethanol solution in this comparative example shows sparse growth and a relatively low content at the interface. This is due to the presence of Co single-atom-supported Ti2CT. x This is caused by the adsorbed water in the (T=O,F,Cl) material not providing enough water to participate in the reaction.

[0094] A three-electrode testing system was employed, using a carbon-coupled nickel-iron bimetallic hydroxide working electrode constructed with ethanol (as in this comparative example), a platinum sheet as the counter electrode, mercuric oxide as the reference electrode, and 1 mol / L potassium hydroxide as the electrolyte. Linear sweep voltammetry was performed using a GamryInterface 1000 electrochemical workstation to characterize the oxygen evolution reaction activity of the working electrode. Specific test parameters were as follows: scan rate 5 mV / s. -1 The scanning voltage range was 1.2–1.65 V (vs. RHE, relative to the reversible hydrogen electrode). The test results are as follows: Figure 12 As shown, when the overpotential is 388 mV, the carbon-coupled nickel-iron bimetallic hydroxide constructed with ethanol in this comparative example can only generate about 500 mA cm⁻¹. -2 The current density is much lower than the 1000 mA / cm² generated by the carbon-coupled nickel-iron bimetallic hydroxide constructed with water-ethanol solution in Example 1. -2 The current density.

[0095] Furthermore, if Ti2CT is loaded with Co single atoms x The (T=O,F,Cl) material, when directly dispersed in an aqueous solution and sprayed onto the surface of an iron-nickel alloy, cannot be dried within 15 minutes, and the surface coating is prone to detachment, making in-situ rapid construction of carbon-coupled nickel-iron bimetallic hydroxides impossible. Therefore, only by using Co single-atom-supported Ti2CT... x Only when the (T=O,F,Cl) material is dispersed in an appropriate proportion of water-ethanol solution can a stable and highly active carbon-coupled nickel-iron bimetallic hydroxide be rapidly constructed in situ on the surface of the iron-nickel alloy.

Claims

1. A rapid in-situ preparation method for carbon-coupled iron-nickel bimetallic hydroxides, characterized in that: Includes the following steps: (1) Disperse the single-atom-loaded two-dimensional titanium carbide in a water-ethanol mixed solution to obtain suspension A; (2) Spray the suspension A obtained in step (1) onto a clean iron-nickel alloy surface and let it dry. In situ carbon-coupled iron-nickel bimetallic hydroxides are generated on the iron-nickel alloy surface. In step (1), the loaded single atom includes one or more of Mn, Fe, Co, Ni, Cu, and Ru; In step (1), the amount of single-atom loading in the single-atom-supported two-dimensional titanium carbide is 0.1~20% of the mass of the two-dimensional titanium carbide; In step (1), the two-dimensional titanium carbide includes Ti2CT. x T = O, F, Cl or Ti3C2T x T = O, F, Cl; In step (1), the mass ratio of the single-atom-loaded two-dimensional titanium carbide, water, and ethanol in the suspension A is (1~10):(40~400):(40~400); In step (2), the drying time is 10 to 30 minutes.

2. The in-situ rapid preparation method of carbon-coupled iron-nickel bimetallic hydroxide according to claim 1, characterized in that: The mass ratio of water to ethanol in the suspension A is 1:(0.5~4).

3. The in-situ rapid preparation method of carbon-coupled iron-nickel bimetallic hydroxide according to claim 1, characterized in that: In step (2), the spraying amount of suspension A, calculated as the ratio of the mass of the single-atom-loaded two-dimensional titanium carbide to the area of ​​the iron-nickel alloy, is 0.1~2.0 mg cm⁻¹. -2 .

4. The in-situ rapid preparation method of carbon-coupled iron-nickel bimetallic hydroxide according to claim 1, characterized in that: In step (1), the single-atom-loaded two-dimensional titanium carbide in the suspension is rapidly oxidized to carbon-coupled TiO2. 2-x- y F x Cl y ; In step (2), the iron-nickel alloy is mainly composed of two elements, Fe and Ni, with Fe having a mass fraction of 50-80% and Ni having a mass fraction of 20-50%.

5. The in-situ rapid preparation method of carbon-coupled iron-nickel bimetallic hydroxide according to claim 1, characterized in that: The clean iron-nickel alloy mentioned in step (2) is obtained by thoroughly polishing the selected iron-nickel alloy to remove the oxide scale and cleaning it for later use.

6. The in-situ rapid preparation method of carbon-coupled iron-nickel bimetallic hydroxide according to claim 5, characterized in that: The polishing process uses 180-360 grit SiC sandpaper and takes 5-15 minutes. The cleaning process involves sequentially cleaning with acetone, water, and alcohol.

7. A carbon-coupled iron-nickel bimetallic hydroxide obtained by the preparation method according to any one of claims 1 to 6.

8. The carbon-coupled iron-nickel bimetallic hydroxide according to claim 7, characterized in that: The carbon-coupled iron-nickel bimetallic hydroxide exhibits a nanoarray structure with carbon elements uniformly distributed on the surface.

9. The application of the carbon-coupled iron-nickel bimetallic hydroxide according to claim 7 or 8, characterized in that: The carbon-coupled iron-nickel bimetallic hydroxide is used as a highly efficient catalyst for the oxygen evolution reaction in the field of electrochemical water splitting.

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