A Sn-doped Co 0.85 Se@Ti3C2 oxygen evolution electrocatalyst, its preparation method and application

Abstract

The application belongs to the technical field of electrolytic water and new energy, and relates to preparation of an oxygen evolution electrocatalyst, in particular to a Sn-doped Co 0.85 The Se@Ti3C2 oxygen evolution electrocatalyst, a preparation method and application thereof are used to solve the technical problems of poor catalytic activity, small current density and poor catalytic stability of the oxygen evolution reaction catalyst. Firstly, Ti3C2-MXene powder is obtained by etching titanium aluminum carbide; then a mixed aqueous solution of a tin source and a cobalt source, a selenium source solution and an ultrasonic treated MXene dispersion liquid are uniformly mixed and stirred, reacted, centrifuged (suction filtration), washed, dried after cooling to obtain a catalyst powder. The catalytic activity is improved by preparing a composite material, and the preparation process is simple, the yield is high, the cost is low and the catalytic performance is excellent. In the oxygen evolution reaction, a large current can be realized at a lower overpotential, and in the stability test, it can be maintained for 300 h, showing excellent electrochemical stability.

Description

Technical Field

[0001] This invention belongs to the field of oxygen evolution reaction and new energy technology, and relates to the preparation of oxygen evolution electrocatalysts, specifically to a Sn-doped Co catalyst. 0.85 Se@Ti3C2 oxygen evolution electrocatalyst, its preparation method, and its application. Background Technology

[0002] Hydrogen possesses advantages such as high energy density and environmental friendliness, making it a crucial energy carrier for future sustainable energy systems. Hydrogen production through water electrolysis, which utilizes abundant water resources to produce high-purity hydrogen on a large scale, is known as "green hydrogen." However, the slow four-electron kinetics of the oxygen evolution reaction (OER) in water electrolysis limits the overall efficiency of the process. Furthermore, Ru,Ir-based noble metal catalysts, while exhibiting excellent OER catalytic performance, still face challenges such as high cost and difficulty in large-scale deployment.

[0003] Currently, the academic community has studied a variety of low-cost, alternative, non-precious metal-based high-efficiency OER catalysts. In particular, transition metal selenide OER catalysts have exhibited low overpotentials. However, these catalysts are often only effective at low current densities (10-50 mA / cm²). 2 It exhibits excellent electrocatalytic activity for water splitting at low current densities, but still faces challenges in terms of poor activity and durability at high current densities.

[0004] For example, patent CN116876025A discloses "a Mo-doped Ni". 0.85 "Se Electrocatalysts, Their Preparation Methods, and Applications" describes the preparation of an electrocatalyst by in-situ growth of Mo-MOF material on the surface of nickel foam, using selenium powder as the selenium source and treated nickel foam as the nickel source, followed by selenization. This catalyst operates at a current density of 10 mA / cm². 2 At that time, the OER overpotential was 249.42 mV. Although the overpotential at this small current is acceptable, it is far from meeting the requirements of industrial applications, namely, the ability to sustainably generate large current densities (≥500 mA / cm²) at small overpotentials (≤300 mV). 2 Therefore, there is an urgent need to develop non-noble metal-based OER catalysts with high activity, high current, and long-term cycling stability to promote their practical industrial application. Summary of the Invention

[0005] To address the problems of poor catalytic activity, low current density, and poor catalytic stability of existing oxygen evolution reaction catalysts, this invention proposes a Sn-doped Co catalyst. 0.85Se@Ti3C2 oxygen evolution electrocatalyst, its preparation method, and its application: The oxygen evolution electrocatalyst prepared by a simple and efficient method exhibits excellent electrocatalytic activity and stability for the oxygen evolution reaction under alkaline conditions, thus meeting the requirements of related applications and development.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows: A Sn-doped Co 0.85 The preparation method of Se@Ti3C2 oxygen evolution electrocatalyst is as follows: (1) Titanium aluminum carbide was added to a mixed solution of hydrochloric acid and lithium fluoride I for etching, and after cleaning and drying, multilayer Ti3C2-MXene powder was obtained; (2) Dissolve the MXene powder prepared in step (1) in a mixed solvent, and obtain an MXene dispersion after ultrasonic treatment. Then mix and stir the mixed aqueous solution of tin source and cobalt source, selenium source solution and MXene dispersion to obtain mixed solution II. (3) The mixed solution II obtained in step (2) is reacted, centrifuged, filtered, washed, and dried to obtain Sn-doped Co. 0.85 Se@Ti3C2 oxygen evolution electrocatalyst.

[0007] In step (1), the mass-to-volume ratio of titanium aluminum carbide, lithium fluoride, and hydrochloric acid is 2.0 g: (0.2-4.0) g: (20-40) mL, the concentration of the hydrochloric acid solution is 6-12 mol / L, the etching temperature is 30-90℃, and the etching time is 3-7 days.

[0008] In step (2), the mixed solvent consists of deionized water and organic solvent in a volume ratio of (1-5):1, and the mass concentration of MXene dispersion is 2.5-10 g / L; the ultrasonic treatment time is 20-60 min.

[0009] The organic solvent is any one of ethylene glycol, ethanolamine, diethanolamine, triethanolamine, and N,N-dimethylformamide.

[0010] In step (2), the tin source is any one of stannous acetate, stannous oxalate, stannous chloride, and stannous sulfate; the cobalt source is any one of cobalt sulfate, cobalt oxalate, cobalt nitrate, cobalt chloride, cobalt acetate, and cobalt acetylacetonate.

[0011] In step (2), the selenium source solution uses selenium powder as the selenium source and hydrazine hydrate as the solvent.

[0012] In step (2), the molar ratio of tin source, cobalt source and selenium source in the mixed aqueous solution II is (0.25-1.25):(0.75-1.5):1; the volume ratio of mixed aqueous solution, selenium source solution and MXene dispersion is 1:1:(1-3); and the stirring time is 20-60 min.

[0013] The reaction temperature in step (3) is 160-200℃ and the time is 10-24 h.

[0014] Sn-doped Co prepared by the above method 0.85 Se@Ti3C2 oxygen evolution electrocatalyst.

[0015] The above-mentioned Sn-doped Co 0.85 Application of Se@Ti3C2 oxygen evolution electrocatalyst in oxygen evolution reaction.

[0016] Furthermore, the application steps are as follows: the catalyst is prepared into a slurry and coated on a glassy carbon electrode as the working electrode, while a carbon rod serves as the counter electrode and a calomel electrode serves as the reference electrode, together forming a three-electrode system to carry out the oxygen evolution reaction.

[0017] Furthermore, the preparation method of the slurry is as follows: Sn-doped Co 0.85 Se@Ti3C2 powder was mixed with 1 mL of anhydrous ethanol and 30 μL of Nafion solution, and then sonicated at 40-100 W power for 30 min.

[0018] Furthermore, the coating method is drop coating, and the loading of the slurry on the glassy carbon electrode after coating is 0.5 mg / cm³. 2 The oxygen evolution reaction takes place in a strongly alkaline electrolysis environment, with the electrolyte being 200 mL of 1 M NaOH or KOH solution.

[0019] The beneficial effects of this invention are: 1. This invention employs a simple and efficient hydrothermal synthesis method to synthesize Sn-doped Co. 0.85 Se@Ti3C2 oxygen evolution electrocatalyst with roughened Sn-doped Co surface 0.85 Se nanospheres are uniformly grown on the surface of Ti3C2, which increases the electrochemical active area of ​​the catalyst, provides more active sites, facilitates the contact between the catalyst and water molecules in the electrolyte, further promotes the electrolysis reaction of water molecules to produce oxygen, thereby enhancing the catalytic performance of the catalyst, improving the stability of the catalyst, and enhancing the commercial application value of the catalyst.

[0020] 2. In this invention, Sn-doped Co was synthesized under hydrothermal conditions in the next step. 0.85Se@Ti3C2 catalyst powder has a simple preparation method, short reaction time, low cost, and is easy to industrialize. Therefore, it has the advantages of being relatively green and economical.

[0021] 3. The Sn-doped Co of the present invention 0.85 Se@Ti3C2 exhibits good catalytic performance in the oxygen evolution reaction. At room temperature, the catalyst in 1M KOH solution at a current density of 1000 mA cm⁻¹... -2 and 1500 mA cm -2 When Sn is doped with Co 0.85 The overpotentials of the Se@Ti3C2 oxygen evolution electrocatalyst are only 241 mV and 268 mV, which is attributed to the abundant MXene-based heterostructures generated on the electrode surface, the high electrochemical active area, the fully exposed active sites, and the promotion of charge transfer. Furthermore, the Sn-doped Co prepared in this invention... 0.85 Se@Ti3C2 at a current density of 500 mA cm⁻¹ -2 When measured by an electrochemical workstation, it was found to maintain its stability for 300 hours, demonstrating excellent electrochemical stability. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 Sn-doped Co prepared in Example 1 of this invention 0.85 Scanning electron microscope (SEM) image of Se@Ti3C2 oxygen evolution electrocatalyst.

[0024] Figure 2 Sn-doped Co prepared in Example 1 of this invention 0.85 High-magnification transmission electron microscope (HRTEM) image of Se@Ti3C2 oxygen evolution electrocatalyst.

[0025] Figure 3 XRD patterns (a) of the catalysts prepared in Example 1 and Comparative Examples 1-3 of this invention, and Sn-doped Co prepared in Example 1. 0.85 (b) High-resolution XPS spectrum of Co 2p and (c) High-resolution XPS spectrum of Sn 3d of Se@Ti3C2.

[0026] Figure 4The following are the LSV curves, Tafel curves, and electrochemical impedance spectroscopy of the catalysts prepared in Example 1 and Comparative Examples 1-3 of this invention and the RuO2 catalyst in a three-electrode system: (a) LSV curves, (b) Tafel curves, and (c) electrochemical impedance spectroscopy.

[0027] Figure 5 Sn-doped Co prepared in Examples 2-8 of this invention 0.85 LSV curve of Se@Ti3C2 oxygen evolution electrocatalyst.

[0028] Figure 6 The graph shows the double-layer capacitance electrochemical performance of the catalysts prepared in Example 1 and Comparative Examples 1-3 of this invention in a three-electrode system.

[0029] Figure 7 Sn-doped Co prepared in Example 1 of this invention 0.85 Stability curve of Se@Ti3C2 oxygen evolution electrocatalyst. Detailed Implementation

[0030] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1 This embodiment features Sn-doped Co 0.85 The preparation method of Se@Ti3C2 oxygen evolution electrocatalyst is as follows: (1) Titanium aluminum carbide was added to a mixed solution of concentrated hydrochloric acid and lithium fluoride for etching. The mass-volume ratio of titanium aluminum carbide, lithium fluoride and hydrochloric acid was 2.0 g: 2.0 g: 20 mL, and the concentration of hydrochloric acid solution was 12 mol / L. The etching temperature was 55℃ and the time was 5 days. After cleaning and drying, accordion-shaped multilayer Ti3C2-MXene powder was obtained.

[0032] (2) Weigh 50 mg of Ti3C2-MXene powder and dissolve it in a mixed solvent of 20 mL deionized water and ethylene glycol at a volume ratio of 1:1. After sonication for 20 min, obtain an MXene dispersion. Dissolve 3 mmol Co(NO3)2•6H2O and 1 mmol SnCl2•2H2O in 10 mL of deionized water and stir for 20 min to obtain solution A. Weigh 4 mmol of selenium powder and dissolve it in 10 mL of hydrazine hydrate and stir thoroughly for 20 min to obtain solution B.

[0033] (3) Use a peristaltic pump to transfer the MXene dispersion and solution B to solution A at a speed of 30 r / min, and stir magnetically for 20 min; transfer the solution to a 50 mL reactor and react at 160℃ for 10 h. After cooling to room temperature, wash the solution three times with deionized water and anhydrous ethanol, and then dry it under vacuum at 60℃ for 12 h to obtain catalyst powder.

[0034] Figure 1 Sn-doped Co prepared in this embodiment 0.85 Scanning electron microscope (SEM) image of Se@Ti3C2 oxygen evolution electrocatalyst, by Figure 1 It can be seen that the catalyst has a regular morphology, with a rough spherical shape, which can maximize the specific surface area of ​​the catalyst.

[0035] Figure 2 Sn-doped Co prepared in this embodiment 0.85 High-resolution transmission electron microscopy (HRTEM) image of the Se@Ti3C2 oxygen evolution electrocatalyst. The HRTEM image shows that a 0.269 nm interlayer spacing corresponds to Co... 0.85 The Se(110) crystal plane, with a 1.24 nm interlayer spacing, corresponds to the Ti3C2(002) crystal plane. No tin selenide crystal planes are present in this plane, indicating that tin ions have been successfully doped into Co. 0.85 The simultaneous appearance of two crystal planes in the Se lattice demonstrates the heterogeneous interface structure formed by this composite material.

[0036] Figure 3 Sn-doped Co prepared in this embodiment 0.85 XRD and XPS spectra of the Se@Ti3C2 oxygen evolution electrocatalyst, by Figure 3 (a) It can be seen that Sn is doped with Co 0.85 Characteristic peaks of Se@Ti3C2 material and the relationship between Ti3C2 and Co 0.85 The standard card of SE is basically consistent (PDF#52-1008), combined with Figure 2 This indicates that an MXene-based heterostructure has been synthesized. Figure 3 (b) is Sn-doped Co 0.85 High-resolution XPS spectra of Co 2p in Se@Ti3C2 composites, Co 2p 3 / 2 Corresponding to two characteristic peaks at 776.9 and 792.2 eV, while Co2p 1 / 2 The two corresponding characteristic peaks are at 780.1.7 and 795.9 eV, while the peaks at 785.1 and 802.1 eV are satellite peaks, indicating that the surface of the material is partially oxidized in air. Figure 3 (c) is Sn-doped Co 0.85High-resolution XPS spectra of Sn 3d in Se@Ti3C2 composite materials, Sn 2+ and Sn 4+ The corresponding characteristic peaks are at 485.2 eV, 493.5 eV and 486.4 eV, 494.4 eV.

[0037] Example 2 This embodiment features Sn-doped Co 0.85 The preparation method of Se@Ti3C2 oxygen evolution electrocatalyst is as follows: (1) Titanium aluminum carbide was added to a mixed solution of concentrated hydrochloric acid and lithium fluoride for etching. The mass-volume ratio of titanium aluminum carbide, lithium fluoride and hydrochloric acid was 2 g: 0.2 g: 20 mL, and the concentration of hydrochloric acid solution was 6 mol / L. The etching temperature was 30℃ and the time was 7 days. After cleaning and drying, accordion-shaped multilayer Ti3C2-MXene powder was obtained.

[0038] (2) Weigh 50 mg of Ti3C2-MXene powder and dissolve it in a mixed solvent of 20 mL deionized water and ethanolamine at a volume ratio of 1:1. After sonication for 30 min, obtain an MXene dispersion. Dissolve 3.4 mmol CoSO4•6H2O and 5 mmol SnCl2•2H2O in 10 mL of deionized water and stir for 30 min to obtain solution A. Weigh 4 mmol of selenium powder and dissolve it in 10 mL of hydrazine hydrate and stir thoroughly for 30 min to obtain solution B.

[0039] (3) Use a peristaltic pump to transfer the MXene dispersion and solution B to solution A at a speed of 30 r / min, and stir magnetically for 30 min; transfer the solution to a 50 mL reactor and react at 170℃ for 12 h. After cooling to room temperature, wash the solution three times with deionized water and anhydrous ethanol, and then dry it under vacuum at 60℃ for 12 h to obtain catalyst powder.

[0040] Example 3 This embodiment features Sn-doped Co 0.85 The preparation method of Se@Ti3C2 oxygen evolution electrocatalyst is as follows: (1) Titanium aluminum carbide was added to a mixed solution of concentrated hydrochloric acid and lithium fluoride for etching. The mass-volume ratio of titanium aluminum carbide, lithium fluoride and hydrochloric acid was 2 g: 4 g: 40 mL, and the concentration of hydrochloric acid solution was 8 mol / L. The etching temperature was 90℃ and the time was 3 days. After cleaning and drying, accordion-shaped multilayer Ti3C2-MXene powder was obtained.

[0041] (2) Weigh 50 mg of Ti3C2-MXene powder and dissolve it in a mixed solvent of 20 mL deionized water and diethanolamine at a volume ratio of 1:1. After sonication for 30 min, obtain an MXene dispersion. Dissolve 6 mmol CoC2O4·4H2O and 5 mmol SnCl2•2H2O in 10 mL of deionized water and stir for 30 min to obtain solution A. Weigh 4 mmol of selenium powder and dissolve it in 10 mL of hydrazine hydrate and stir thoroughly for 30 min to obtain solution B.

[0042] (3) Use a peristaltic pump to transfer the MXene dispersion and solution B to solution A at a speed of 30 r / min, and stir magnetically for 40 min; transfer the solution to a 50 mL reactor and react at 180℃ for 14 h. After cooling to room temperature, wash the solution three times with deionized water and anhydrous ethanol, and then dry it under vacuum at 60℃ for 12 h to obtain catalyst powder.

[0043] Example 4 This embodiment features Sn-doped Co 0.85 The preparation method of Se@Ti3C2 oxygen evolution electrocatalyst is as follows: (1) Titanium aluminum carbide was added to a mixed solution of concentrated hydrochloric acid and lithium fluoride for etching. The mass-volume ratio of titanium aluminum carbide, lithium fluoride and hydrochloric acid was 2 g: 2.0 g: 30 mL, and the concentration of hydrochloric acid solution was 12 mol / L. The etching temperature was 60℃ and the time was 5 days. After cleaning and drying, accordion-shaped multilayer Ti3C2-MXene powder was obtained.

[0044] (2) Weigh 50 mg of Ti3C2-MXene powder and dissolve it in a mixed solvent of 20 mL deionized water and triethanolamine at a volume ratio of 1:1. After sonication for 60 min, obtain an MXene dispersion. Dissolve 3.4 mmol CoCl2•6H2O and 2 mmol SnCl2•2H2O in 10 mL of deionized water and stir for 50 min to obtain solution A. Weigh 4 mmol of selenium powder and dissolve it in 10 mL of hydrazine hydrate and stir thoroughly for 50 min to obtain solution B.

[0045] (3) Use a peristaltic pump to transfer the MXene dispersion and solution B to solution A at a speed of 30 r / min, and stir magnetically for 50 min; transfer the solution to a 50 mL reactor and react at 190℃ for 16 h. After cooling to room temperature, wash the solution three times with deionized water and anhydrous ethanol, and then dry it under vacuum at 60℃ for 12 h to obtain catalyst powder.

[0046] Example 5 This embodiment features Sn-doped Co 0.85The preparation method of Se@Ti3C2 oxygen evolution electrocatalyst is as follows: (1) Titanium aluminum carbide was added to a mixed solution of concentrated hydrochloric acid and lithium fluoride for etching. The mass-volume ratio of titanium aluminum carbide, lithium fluoride and hydrochloric acid was 2 g: 2.0 g: 20 mL, and the concentration of hydrochloric acid solution was 12 mol / L. The etching temperature was 55℃ and the time was 5 days. After cleaning and drying, accordion-shaped multilayer Ti3C2-MXene powder was obtained.

[0047] (2) Weigh 50 mg of Ti3C2-MXene powder and dissolve it in a mixed solvent of 20 mL deionized water and N,N-dimethylformamide (DMF) at a volume ratio of 1:1. After sonication for 60 min, obtain an MXene dispersion. Dissolve 3.4 mmol of (CH3COO)2Co•4H2O and 1 mmol of SnCl2•2H2O in 10 mL of deionized water and stir for 60 min to obtain solution A. Weigh 4 mmol of selenium powder and dissolve it in 10 mL of hydrazine hydrate and stir thoroughly for 60 min to obtain solution B.

[0048] (3) Use a peristaltic pump to transfer the MXene dispersion and solution B to solution A at a speed of 30 r / min, and stir magnetically for 60 min; transfer the solution to a 50 mL reactor and react at 200℃ for 18 h. After cooling to room temperature, wash the solution three times with deionized water and anhydrous ethanol, and then dry it under vacuum at 60℃ for 12 h to obtain catalyst powder.

[0049] Example 6 This embodiment features Sn-doped Co 0.85 The preparation method of Se@Ti3C2 oxygen evolution electrocatalyst is as follows: (1) Titanium aluminum carbide was added to a mixed solution of concentrated hydrochloric acid and lithium fluoride for etching. The mass-volume ratio of titanium aluminum carbide, lithium fluoride and hydrochloric acid was 2 g: 2.0 g: 20 mL, and the concentration of hydrochloric acid solution was 12 mol / L. The etching temperature was 55℃ and the time was 5 days. After cleaning and drying, accordion-shaped multilayer Ti3C2-MXene powder was obtained.

[0050] (2) Weigh 50 mg of Ti3C2-MXene powder and dissolve it in a mixed solvent of 20 mL deionized water and N,N-dimethylformamide (DMF) at a volume ratio of 1:1. After sonication for 60 min, an MXene dispersion is obtained. Add 3 mmol C 10 H 14CoO4 and 5 mmol SnCl2•2H2O were dissolved in 10 mL of deionized water and stirred for 60 min to obtain solution A. 4 mmol of selenium powder was weighed and dissolved in 10 mL of hydrazine hydrate and stirred thoroughly for 60 min to obtain solution B.

[0051] (3) Use a peristaltic pump to transfer the MXene dispersion and solution B to solution A at a speed of 30 r / min, and stir magnetically for 60 min; transfer the solution to a 50 mL reactor and react at 200℃ for 24 h. After cooling to room temperature, wash the solution three times with deionized water and anhydrous ethanol, and then dry it under vacuum at 60℃ for 12 h to obtain catalyst powder.

[0052] Example 7 This embodiment features Sn-doped Co 0.85 The preparation method of Se@Ti3C2 oxygen evolution electrocatalyst is as follows: (1) Titanium aluminum carbide was added to a mixed solution of concentrated hydrochloric acid and lithium fluoride for etching. The mass-volume ratio of titanium aluminum carbide, lithium fluoride and hydrochloric acid was 2 g: 2.0 g: 20 mL, and the concentration of hydrochloric acid solution was 12 mol / L. The etching temperature was 55℃ and the time was 5 days. After cleaning and drying, accordion-shaped multilayer Ti3C2-MXene powder was obtained.

[0053] (2) Weigh 50 mg of Ti3C2-MXene powder and dissolve it in a mixed solvent of 10 mL deionized water and ethylene glycol at a volume ratio of 3:1. After sonication for 20 min, obtain an MXene dispersion. Dissolve 3 mmol Co(NO3)2•6H2O and 3 mmol SnCl2•2H2O in 10 mL of deionized water and stir for 20 min to obtain solution A. Weigh 4 mmol of selenium powder and dissolve it in 10 mL of hydrazine hydrate and stir thoroughly for 20 min to obtain solution B.

[0054] (3) Use a peristaltic pump to transfer the MXene dispersion and solution B to solution A at a speed of 30 r / min, and stir magnetically for 20 min; transfer the solution to a 50 mL reactor and react at 160℃ for 10 h. After cooling to room temperature, wash the solution three times with deionized water and anhydrous ethanol, and then dry it under vacuum at 60℃ for 12 h to obtain catalyst powder.

[0055] Example 8 This embodiment features Sn-doped Co 0.85 The preparation method of Se@Ti3C2 oxygen evolution electrocatalyst is as follows: (1) Titanium aluminum carbide was added to a mixed solution of concentrated hydrochloric acid and lithium fluoride for etching. The mass-volume ratio of titanium aluminum carbide, lithium fluoride and hydrochloric acid was 2 g: 0.2 g: 20 mL, and the concentration of hydrochloric acid solution was 12 mol / L. The etching temperature was 55℃ and the time was 5 days. After cleaning and drying, accordion-shaped multilayer Ti3C2-MXene powder was obtained. (2) Weigh 150 mg of Ti3C2-MXene powder and dissolve it in a mixed solvent of 15 mL deionized water and ethylene glycol at a volume ratio of 5:1. After sonication for 20 min, obtain an MXene dispersion. Dissolve 1.5 mmol Co(NO3)2•6H2O and 2.5 mmol SnCl2•2H2O in 5 mL of deionized water and stir for 20 min to obtain solution A. Weigh 2 mmol of selenium powder and dissolve it in 5 mL of hydrazine hydrate and stir thoroughly for 20 min to obtain solution B.

[0056] (3) Use a peristaltic pump to transfer the MXene dispersion and solution B to solution A at a speed of 30 r / min, and stir magnetically for 20 min; transfer the solution to a 50 mL reactor and react at 160℃ for 10 h. After cooling to room temperature, wash the solution three times with deionized water and anhydrous ethanol, and then dry it under vacuum at 60℃ for 12 h to obtain catalyst powder.

[0057] Comparative Example 1 Co in this comparative example 0.85 The preparation method of Se@Ti3C2 catalyst powder is as follows: (1) Titanium aluminum carbide was added to a mixed solution of concentrated hydrochloric acid and lithium fluoride for etching. The mass-volume ratio of titanium aluminum carbide, lithium fluoride and hydrochloric acid was 2 g: 2.0 g: 20 mL, and the concentration of hydrochloric acid solution was 12 mol / L. The etching temperature was 55℃ and the time was 5 days. After cleaning and drying, accordion-shaped multilayer Ti3C2-MXene powder was obtained.

[0058] (2) Weigh 50 mg of Ti3C2-MXene powder and dissolve it in a 1:1 mixture of 20 mL of deionized water and ethylene glycol. After sonication for 20 min, obtain an MXene dispersion. Dissolve 3 mmol of Co(NO3)2•6H2O in 10 mL of deionized water and stir for 20 min to obtain solution A. Weigh 4 mmol of selenium powder and dissolve it in 10 mL of hydrazine hydrate. Stir thoroughly for 20 min to obtain solution B.

[0059] (3) Use a peristaltic pump to transfer the MXene dispersion and solution B to solution A at a speed of 30 r / min, and stir magnetically for 20 min; transfer the solution to a 50 mL reactor and react at 160℃ for 10 h. After cooling to room temperature, wash the solution three times with deionized water and anhydrous ethanol, and then dry it under vacuum at 60℃ for 12 h to obtain catalyst powder.

[0060] Comparative Example 2 This comparative example shows Sn-doped Co. 0.85 The preparation method of Se catalyst powder includes the following steps: (1) Dissolve 3 mmol Co(NO3)2•6H2O and 1 mmol SnCl2•2H2O in a mixed solution of 30 mL deionized water and ethylene glycol at a volume ratio of 2:1, and stir for 15 min to obtain solution A. Weigh 4 mmol of selenium powder and dissolve it in 10 mL of hydrazine hydrate, and stir thoroughly for 20 min to obtain solution B.

[0061] (3) Use a peristaltic pump to transfer solution B to solution A at a speed of 30 r / min and stir magnetically for 20 min; transfer the solution to a 50 mL reactor and react at 160℃ for 10 h. After cooling to room temperature, wash the solution three times with deionized water and anhydrous ethanol, and then dry it under vacuum at 60℃ for 12 h to obtain catalyst powder.

[0062] Comparative Example 3 The preparation method of the Ti3C2-MXene catalyst powder in this comparative example is as follows: Titanium aluminum carbide was added to a mixed solution of concentrated hydrochloric acid and lithium fluoride for etching. The mass-volume ratio of titanium aluminum carbide, lithium fluoride and hydrochloric acid was 2 g: 2.0 g: 20 mL, and the concentration of hydrochloric acid solution was 12 mol / L. The etching temperature was 55℃ and the etching time was 5 days. After cleaning and drying, accordion-shaped multilayer Ti3C2-MXene powder was obtained.

[0063] Implementation Results Example The oxygen evolution reaction performance of the catalysts prepared in Examples 1-8, Comparative Examples 1, 2, and 3 of this invention, as well as a commercial RuO2 catalyst, was tested. The specific test process is as follows: 5 mg of the above-mentioned catalyst powder was mixed with 1 mL of anhydrous ethanol and 30 μL of Nafion solution, and ultrasonicated at 20 W for 20 min to obtain a slurry. The slurry was then drop-coated onto a glassy carbon electrode as the working electrode, while a carbon rod was used as the counter electrode and a saturated calomel electrode was used as the reference electrode to form a three-electrode system for the oxygen evolution reaction. The electrolyte was 200 mL of 1 M KOH solution.

[0064] Figure 4 This image shows the electrocatalytic oxygen evolution reaction (OER) performance of the catalysts prepared in Examples 1, 1, 2, and 3 of this invention, and a commercial RuO2 catalyst in a three-electrode system. Figure 4 As seen from the LSV curve in a, at a current density of 1000 mA cm⁻¹ -2 and 1500 mA cm -2 At the same time, the Sn-doped Co prepared in Example 1 0.85 The overpotentials of the Se@Ti3C2 catalyst were only 241 mV and 268 mV, which are much lower than those of Comparative Example 1 (376 and 417 mV) and Comparative Example 2 (603 and 729 mV), while Comparative Example 3 showed a higher overpotential at a current density of 10 mA cm⁻¹. -2 At that time, the overpotential reached 410 mV, while that of commercial RuO2 was 320 mV. Furthermore... Figure 4 The Tafel curve of b indicates that the Sn-doped Co prepared in Example 1... 0.85 The Se@Ti3C2 catalyst exhibits a 56 mV dec... -1 The slope is much lower than that of RuO2 (109 mV dec). -1 This indicates that Sn is doped with Co. 0.85 Se@Ti3C2 catalyst exhibits excellent oxygen evolution catalytic performance; Figure 4 c represents the impedance spectrum. Compared with Comparative Example 3 (20.67 Ω), Comparative Example 1 (3.61 Ω), and Comparative Example 2 (6.12 Ω), Example 1 has the smallest charge transfer impedance Rct (3.54 Ω).

[0065] Figure 5 Sn-doped Co prepared in Examples 2-8 of this invention 0.85 The LSV curve of the Se@Ti3C2 oxygen evolution electrocatalyst, as shown in the figure, indicates that at a current density of 1000 mA cm⁻¹... -2 and 1500 mA cm -2 At that time, the overpotentials of Examples 2-8 were Example 2 (257 mV, 279 mV), Example 3 (260 mV, 280 mV), Example 4 (261 mV, 294 mV), Example 5 (260 mV, 320 mV), Example 6 (264 mV, 337 mV), Example 7 (250 mV, 290 mV), and Example 8 (259 mV, 332 mV).

[0066] Figure 6 The diagram shows the double-layer capacitance of the catalysts prepared in Examples 1, 1, 2, and 3 of this invention in a three-electrode system, reflecting the electrochemical active area of ​​the catalysts. Figure 6It can be seen that Example 1 exhibits a large double-layer capacitance (41.36 mF cm⁻¹). -2 This indicates a large electrochemical active area, providing more active sites for catalytic reactions. These results demonstrate the formation of abundant MXene-based heterostructures and fully exposed active sites on the electrode surface, promoting charge transfer.

[0067] Sn-doped Co prepared in Example 1 0.85 Se@Ti3C2 water electrolysis catalyst in 1M KOH electrolyte at a current density of 500 mA / cm² -2 The stability of the electrocatalytic oxygen evolution reaction was tested, and the results are as follows: Figure 7 As shown in the figure. It can be seen from the figure that the catalyst operates at a current density of 500 mA cm⁻¹. -2 It remained stable even after a stability test lasting up to 300 hours, demonstrating excellent electrocatalytic oxygen evolution stability.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A Sn-doped Co 0.85 The preparation method of Se@Ti3C2 oxygen evolution electrocatalyst is characterized by, The steps are as follows: (1) Titanium aluminum carbide was added to a mixed solution of hydrochloric acid and lithium fluoride I for etching, and after cleaning and drying, multilayer Ti3C2-MXene powder was obtained; (2) Dissolve the MXene powder prepared in step (1) in a mixed solvent, and obtain an MXene dispersion after ultrasonic treatment. Then, mix and stir the mixed aqueous solution of tin source and cobalt source, the selenium source solution and the MXene dispersion to obtain mixed solution II. The mass concentration of the MXene dispersion is 2.5-10 g / L, and the mixed solvent is composed of deionized water and organic solvent in a volume ratio of (1-5):

1. The tin source is stannous chloride. The molar ratio of tin source, cobalt source and selenium source in mixed solution II is (0.25-1.25):(0.75-1.5):

1. (3) The mixed solution II obtained in step (2) was subjected to hydrothermal reaction, centrifuged, filtered, washed and dried to obtain Sn-doped Co. 0.85 Se@Ti3C2 oxygen evolution electrocatalyst.

2. The Sn-doped Co according to claim 1 0.85 The preparation method of Se@Ti3C2 oxygen evolution electrocatalyst is characterized by, In step (1), the mass-to-volume ratio of titanium aluminum carbide, lithium fluoride, and hydrochloric acid is 2.0 g: (0.2-4.0) g: (20-40) mL, the concentration of the hydrochloric acid solution is 6-12 mol / L, the etching temperature is 30-90℃, and the etching time is 3-7 days.

3. The Sn-doped Co according to claim 2 0.85 The preparation method of Se@Ti3C2 oxygen evolution electrocatalyst is characterized by, The ultrasonic treatment time in step (2) is 20-60 min.

4. The Sn-doped Co according to claim 3 0.85 The preparation method of Se@Ti3C2 oxygen evolution electrocatalyst is characterized by, The organic solvent is any one of ethylene glycol, ethanolamine, diethanolamine, triethanolamine, and N,N-dimethylformamide.

5. The Sn-doped Co according to claim 4 0.85 The preparation method of Se@Ti3C2 oxygen evolution electrocatalyst is characterized by, In step (2), the cobalt source is any one of cobalt sulfate, cobalt oxalate, cobalt nitrate, cobalt chloride, cobalt acetate, and cobalt acetylacetonate.

6. The Sn-doped Co according to claim 5 0.85 The preparation method of Se@Ti3C2 oxygen evolution electrocatalyst is characterized by, In step (2), the selenium source in the selenium source solution is selenium powder, and the solvent is hydrazine hydrate.

7. The Sn-doped Co according to claim 6 0.85 The preparation method of Se@Ti3C2 oxygen evolution electrocatalyst is characterized by, In step (2), the volume ratio of the mixed aqueous solution, selenium source solution and MXene dispersion is 1:1:(1-3); the stirring time is 20-60 min.

8. The Sn-doped Co according to claim 7 0.85 The preparation method of Se@Ti3C2 oxygen evolution electrocatalyst is characterized by, The hydrothermal reaction in step (3) is carried out at a temperature of 160-200℃ for 10-24 hours.

9. Sn-doped Co prepared by the preparation method according to claim 1 0.85 Se@Ti3C2 oxygen evolution electrocatalyst.

10. The Sn-doped Co according to claim 9 0.85 Application of Se@Ti3C2 oxygen evolution electrocatalyst in oxygen evolution reaction.

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