An Ag-doped InSe nanosheet structure material, its preparation method and application

Abstract

This invention provides an Ag-doped InSe nanosheet structure, its preparation method, and its applications. The InSe nanosheets are prepared by hydrothermal reaction in an aqueous solution containing a silver source. Compared with existing technologies, this invention incorporates Ag into the InSe nanosheet structure. + Subsequently, the electronic structure of In, Se, and Ag atoms is effectively modulated, increasing the exposure of active sites, forming multiple active sites, improving the conductivity of the catalyst, optimizing intermediate species and their adsorption behavior, and accelerating catalytic kinetics. Doped Ag + Can be with In 2+ Site co-stability * CO * OH intermediates promote their conversion to enhanced adsorption. * CO L and * CO B Intermediate, promote * CO L Protonization * CHO * This process triggers a C-C coupling reaction, ultimately reducing CO2 to ethanol. In a membrane battery electrolyzer, it can electroreduce carbon dioxide to a single liquid ethanol product, exhibiting superior activity, selectivity, stability, and high energy efficiency.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterial preparation methods and electrocatalytic applications, specifically relating to an Ag-doped InSe nanosheet structure material, its preparation method, and its application. Background Technology

[0002] Electrocatalytic carbon dioxide reduction (CO2ER) utilizes electrical energy to convert carbon dioxide into value-added fuels and chemicals, potentially alleviating the current energy crisis and greenhouse gas emissions. Among CO2ER products, ethanol, as a multi-carbon liquid, offers advantages such as safe and convenient storage and transportation, and is widely used as a solvent, raw material for chemical synthesis, and gasoline additive. However, due to the low controllability of C / C coupling and the limited solubility of CO2 in aqueous solutions, achieving high selectivity in the electroreduction of CO2 to ethanol at high current densities remains a significant challenge.

[0003] Currently, high-selectivity ethanol production has been achieved in H-type electrolyzers by controlling the adsorption behavior of reaction intermediates through the design of active sites on catalysts. The current challenge is to achieve high selectivity and low energy consumption in the electroreduction of CO2 to ethanol at high current densities on an industrial scale. Flow cells equipped with gas diffusion electrodes (GDEs) alleviate the mass transfer limitations caused by the low solubility of CO2, enabling ethanol production at industrial-scale current densities. However, the large cathode-anode gap causes ohmic drop, leading to significant energy loss and limiting its practical application. Zero-gap membrane electrolyzers (MEA) significantly shorten the distance between electrodes, reduce the device resistance, and avoid the mass transfer limitations of CO2 by eliminating the use of cathode liquid, thus significantly improving energy efficiency. Currently, catalysts for the electroreduction of CO2 to ethanol in MEA electrolyzers primarily rely on Cu-based materials. However, the competing C2 gaseous product ethylene and various liquid products result in low selectivity for ethanol products and increase downstream separation costs. Furthermore, in most cases, the active Cu in Cu-based materials... δ+ The site undergoes in-situ electroreduction to generate Cu during the CO2ER process. 0 This lack of site structure results in poor durability of CO2ERs. Therefore, it is essential to design structurally stable non-copper-based electrocatalysts for the efficient electroreduction of CO2 to the single liquid-phase product ethanol in MEA electrolyzers.

[0004] Indium-based chalcogenides are a typical class of two-dimensional layered compounds with advantages such as large surface area, high electron mobility, good mechanical strength, and strong chemical stability. They exhibit strong adsorption capacity for CO2 molecules and can reduce CO2 levels during electrocatalytic carbon dioxide reduction (CO2ER). * CO2 ·- The binding energy of the intermediate. However, due to the influence of indium-based chalcogenides... *The strong binding affinity of the OCHO intermediate inhibited its further reduction, or... * The weak adsorption of CO limits its further coupling, resulting in formate or CO as the usual product, which limits its further application in CO2ER. Summary of the Invention

[0005] The purpose of this invention is to provide an Ag-doped InSe nanosheet structure material and its preparation method. The Ag-doped InSe nanosheet structure material is synthesized on a copper foam substrate by a two-step liquid phase method, and the preparation method is simple.

[0006] Another objective of this invention is to provide an application of Ag-doped InSe nanosheet structure material as a CO2ER electrocatalyst, achieving the characteristics of low potential, high selectivity, and good stability under high current density.

[0007] The specific technical solution of this invention is as follows:

[0008] A method for preparing Ag-doped InSe nanosheet structure material includes the following steps:

[0009] 1) Preparation of InSe nanosheets;

[0010] 2) Copper foam containing InSe nanosheets was placed in an aqueous solution containing a silver source and subjected to a hydrothermal reaction to obtain Ag-doped InSe nanosheet structure material.

[0011] In step 1), the InSe nanosheets are prepared by placing copper foam in a mixed solvent containing a selenium source, a reducing agent and an indium source, and carrying out a solvothermal reaction to obtain InSe nanosheet structural materials.

[0012] In step 1), the foamed copper needs to be cleaned before use. The specific cleaning method is as follows: first soak it in 6M hydrochloric acid for 15 minutes to remove the surface oxides, and then wash it with deionized water and anhydrous ethanol. When using it, the foamed copper is cut into 2×3cm pieces.

[0013] In the preparation method of the InSe nanosheets:

[0014] The molar ratio of the selenium source, indium source and reducing agent is 1-3:1-3:50-70, preferably 2:2:61.8.

[0015] The mixed solvent is a mixed solution of ethanol, ethylenediamine and water, and the volume ratio of ethanol, ethylenediamine and water is 1-3:1-3:0.5-1.5, preferably 2:2:1.

[0016] The concentration of the reducing agent in the mixed solvent is 0.9–1.23 M;

[0017] The selenium source is selected from Se powder;

[0018] The indium source is selected from soluble indium salts, preferably InCl3·4H2O;

[0019] The reducing agent is hydrazine hydrate with a mass fraction of 50 wt.%.

[0020] The solvothermal reaction is carried out at 160-200℃ for 8-16 hours, preferably at 170-190℃ for 10-15 hours, and more preferably at 180℃ for 12 hours. The solvothermal reaction is carried out in a reaction vessel lined with polytetrafluoroethylene. During the preparation process, the copper foam is placed at an angle so that the sample can grow evenly on both sides of the copper foam.

[0021] Furthermore, after the solvothermal reaction, the material was naturally cooled to room temperature, washed, and dried to obtain InSe nanosheet structured material;

[0022] The washing process involves washing with deionized water 3 to 5 times, followed by washing with anhydrous ethanol 3 to 5 times.

[0023] The drying process involves drying in a vacuum drying oven at 55–70°C for 6–12 hours.

[0024] In step 2), the copper foam covered with InSe nanosheets obtained in step 1) is placed obliquely in a reaction vessel containing an aqueous solution of silver source to carry out a hydrothermal reaction.

[0025] In step 2), the concentration of the aqueous solution of the silver source is 0.33–1.67 mM, preferably 1.0 mM;

[0026] In step 2), the molar ratio of the silver source to the indium source in step 1) is 0.005 to 0.025:1, preferably 0.015:1;

[0027] The silver source is a soluble silver salt, preferably AgNO3;

[0028] In step 2), the hydrothermal reaction specifically involves reacting at 140–180°C for 6–10 hours, preferably at 150–170°C for 7–9 hours, and more preferably at 160°C for 8 hours.

[0029] In step 2), after the reaction is complete, wash with deionized water and anhydrous ethanol 2 to 4 times each, and dry in an oven at 60 to 70°C for 8 to 12 hours to obtain Ag-doped InSe nanosheet structure material.

[0030] The present invention provides an Ag-doped InSe nanosheet structure material, which is obtained by the above preparation method; the morphology of the Ag-doped InSe nanosheet structure material is a nanosheet structure material with a lateral size of 300-1000 nm.

[0031] This invention provides an application of Ag-doped InSe nanosheet structure material as a CO2ER electrocatalyst.

[0032] When the Ag-doped InSe nanosheet structure material is used as a CO2ER electrocatalyst, the specific application method is as follows: the Ag-doped InSe nanosheet structure material is cut into 0.5×0.5cm pieces to serve as the working electrode, and a carbon rod and an Ag / AgCl electrode are used as the counter electrode and reference electrode, respectively. The electrolyte is a 0.1M KHCO3 solution. The assembly is carried out in an H-type electrolytic cell, and electrochemical tests are performed using a CHI760E electrochemical workstation.

[0033] The powder obtained by ultrasonic exfoliation of Ag-doped InSe nanosheets was ultrasonically mixed with Nafion solution and isopropanol reagent and loaded onto a 1.0 × 1.0 cm hydrophilic carbon paper as the cathode. A 1.0 × 1.0 cm nickel foam loaded with NiFe2O4 / NiFe LDH was used as the anode. The anolyte was a 1.0 M KOH solution. The assembly was carried out in a membrane cell electrolyzer, and electrochemical tests were performed using a CHI 760E electrochemical workstation and a CHI 680C high-current amplifier.

[0034] The inventors discovered that by doping with heterogeneous cations Ag... + This can modulate the electronic structure of InSe and diversify the active sites. During electrolysis, In... 2+ and Ag + The sites were jointly stabilized * CO * OH intermediate, promoting * CO L and * CO B Adsorption and * CO L The protonation of InSe significantly improves CO2ER performance, enabling the highly selective production of the single liquid product ethanol. CO2ER in a membrane cell electrolyzer effectively alleviates the problems of mass transfer limitation, flooding, and high energy consumption during electrocatalysis, achieving CO2ER applications at high current densities and low energy consumption. Therefore, constructing an Ag-doped InSe nanosheet catalyst, optimizing the adsorption behavior of intermediates by controlling its electronic structure and building multiple active sites, is of great significance for achieving high selectivity, high activity, and low energy consumption in the electrocatalytic reduction of CO2 to the single liquid product ethanol at high current densities in a membrane cell electrolyzer.

[0035] In the preparation method of this invention, Ag is synthesized through a two-step chemical liquid-phase method. + InSe nanosheet structured materials. Firstly, in the first step, ethylenediamine molecules readily react with In... 3+Combine to form [In(en)2] 3+ Complex. Simultaneously, Se powder is reduced to Se by N₂H₄·H₂O under alkaline conditions provided by ethylenediamine. 2- And with [In(en)2] 3+ The reaction generates In2Se3 seed crystals. As the reaction proceeds, the In2Se3 seed crystals are further reduced to InSe seed crystals by excess N2H4·H2O. The amine groups in the ethylenediamine molecule are preferentially chemically adsorbed by the In atoms on the surface of the InSe seed crystals, reducing the growth rate of the attached crystal facets, causing the InSe seed crystals to gradually grow into InSe nanosheets with exposed (015) crystal faces. The role of water is to dissolve InCl3, and the role of ethanol is to adjust the size of the nanosheet morphology; its specific effects are shown in (5) of Comparative Example 1. Figure 32 and Figure 38 In the second step, the unpaired electrons of the amine groups in the ethylenediamine molecules adsorbed on the InSe surface can interact with Ag. + Ions form coordinate bonds, therefore, Ag + Ions can be adsorbed onto the InSe surface. Subsequently, Ag... + With some In 2+ Cation exchange occurs, generating Se vacancies to maintain the overall electroneutrality of the material, ultimately forming Ag grown on the copper foam. + InSe nanosheet structure material.

[0036] In this invention, Ag + Doping induces the formation of Se vacancies and facilitates electron transfer from Ag to Se, diversifying the active sites. During the electroreduction of CO2, electrons accumulate at In sites near the Se vacancies, adsorbing CO2 molecules. Electrons then flow to the empty orbitals of the CO2 molecules, resulting in bending. * CO2 ·- Intermediate. Subsequently... * CO2 ·- intermediate protonation generation * CO * The OH intermediate has its C-terminus adsorbed at the Ag site and its O-terminus adsorbed at the In site. * CO * The OH intermediate is further hydrogenated to produce * CO L and * CO B intermediate, in which * CO L Located at the Ag site, * CO B Located at the Ag-Ag bridge site. Subsequently... * CO L Hydrogenation forms C-terminal adsorption sites on Ag sites and O-terminal adsorption sites on In sites.* CHO * intermediate, and with * CO B Coupled generation * COCHO * The intermediate has its C-terminus adsorbed at the Ag site and its O-terminus bound to the In site. * COCHO * The intermediate is further hydrogenated to produce * OHCCHO * The intermediate has one O-terminus adsorbed at an Ag site and the other O-terminus adsorbed at an In site. It undergoes multiple proton-coupled electron transfer steps. * OHCCHO * The intermediate is converted into CH3CHO adsorbed at the O-terminus of the Ag site. * The intermediate is further protonated into CH3CH2O adsorbed at the O-terminus of the In-Ag bridging site. * Intermediate. Finally, CH3CH2O * Hydrogenation produces ethanol. Simultaneously, H₂O molecules adsorb onto Se sites and dissociate to form protons, which can provide protons for the protonation of carbonaceous intermediates. Electron transfer from Ag to Se stabilizes In. 2+ The site ensures a continuous electrocatalytic CO2 reduction reaction. Simultaneously, Ag doping... + Ions can increase the electrochemical active surface area of ​​a catalyst, exposing more catalytic active sites. Furthermore, Ag... + Ion doping enhances the catalyst's conductivity and significantly increases the interfacial charge transfer rate. This material can electroreduce CO2 to the single liquid product ethanol in a membrane cell electrolyzer, achieving a Faradaic efficiency of 68.7% and a bias current density of 186.6 mA·cm⁻¹ at 3.0 V. –2 Meanwhile, the overall energy efficiency of the cell reached 26.1%. In addition, after 22 hours of continuous electrolysis at 3.0V, the Faraday efficiency of ethanol was 61.4%, and the current density remained at 94.6% of the initial value, demonstrating excellent activity, selectivity, stability and high energy efficiency, which is very valuable for practical applications of electrocatalytic CO2 reduction.

[0037] Compared with existing technologies, this invention incorporates Ag into the InSe nanosheet structure. + Ionization can effectively modulate the electronic structure of In, Se, and Ag atoms, increase the exposure of active sites, form multiple active sites, improve the conductivity of the catalyst, optimize intermediate species and their adsorption behavior, and accelerate catalytic kinetics. Doped Ag + Can be with In 2+ Site co-stability * CO *OH intermediates promote their conversion to enhanced adsorption. * CO L and * CO B Intermediate, promote * CO L Protonization * CHO * The intermediate triggers a C-C coupling reaction, ultimately reducing CO2 to ethanol. This material can electroreduced CO2 to a single liquid ethanol product in a membrane battery electrolyzer, exhibiting superior activity, selectivity, stability, and high energy efficiency. Furthermore, it features a simple preparation process, environmental friendliness, and low cost. Attached Figure Description

[0038] Figure 1 The image shows the X-ray powder diffraction (XRD) pattern of the Ag-doped InSe nanosheet structure material prepared in Example 1.

[0039] Figure 2 The energy dispersive X-ray (EDX) spectrum of the Ag-doped InSe nanosheet structure material prepared in Example 1;

[0040] Figure 3 The image shows a scanning electron microscope (SEM) image of the Ag-doped InSe nanosheet structure material prepared in Example 1.

[0041] Figure 4 Transmission electron microscope (TEM) image of the Ag-doped InSe nanosheet structure material prepared in Example 1;

[0042] Figure 5 High-resolution lattice fringe (HRTEM) image of the Ag-doped InSe nanosheet structure material prepared in Example 1;

[0043] Figure 6 Scanning electron microscope (SEM) image and corresponding elemental distribution map of the Ag-doped InSe nanosheet structure material prepared in Example 1;

[0044] Figure 7 X-ray powder diffraction (XRD) patterns of Ag-doped InSe nanosheet structures with Ag doping concentrations of 0.5% and 2.4% prepared in Example 2;

[0045] Figure 8 Energy dispersive X-ray (EDX) spectra of Ag-doped InSe nanosheet structures with Ag doping levels of 0.5% and 2.4% prepared in Example 2;

[0046] Figure 9The image shows a scanning electron microscope (SEM) image of the Ag-doped InSe nanosheet structure material with an Ag doping concentration of 0.5% prepared in Example 2.

[0047] Figure 10 The image is a scanning electron microscope (SEM) image of the Ag-doped InSe nanosheet structure material with an Ag doping concentration of 2.4% prepared in Example 2.

[0048] Figure 11 LSV curves of Ag-doped InSe nanosheet structures and InSe nanosheet structures with different Ag doping amounts prepared in Examples 1, 2 and 3 in an H-type electrolytic cell;

[0049] Figure 12 The image shows the Faraday efficiency of the Ag-doped InSe nanosheet structure prepared in Examples 1 and 3 at different potentials in an H-type electrolytic cell.

[0050] Figure 13 The Faraday efficiency diagrams for Ag-doped InSe nanosheet structures with Ag doping levels of 0.5% and 2.4% in Example 2 are shown at different potentials in an H-type electrolytic cell.

[0051] Figure 14 The image shows the stability test results of the Ag-doped InSe nanosheet structure in Example 1 at a potential of -0.6V in an H-type electrolytic cell after 15 hours.

[0052] Figure 15 LSV curves of Ag-doped InSe nanosheet structures prepared in Examples 1 and 3 in a membrane cell electrolyzer;

[0053] Figure 16 The diagrams show the Faradaic efficiency and energy efficiency of the Ag-doped InSe nanosheet structures prepared in Examples 1 and 3 at different voltages in a membrane cell electrolyzer. The solid line I represents the Faradaic efficiency (FE) of the C2H5OH product, while the dashed line I represents the energy efficiency (EE) of C2H5OH.

[0054] Figure 17 The image shows the stability test results of the Ag-doped InSe nanosheet structure material in Example 1 at a voltage of 3.0V for 22 hours in a membrane cell electrolyzer.

[0055] Figure 18 The images show Ag-doped InSe nanosheet structures with different Ag doping amounts prepared in Examples 1, 2 and 3, and the capacitance current diagrams of InSe nanosheet structures at different scan rates under CO2ER conditions.

[0056] Figure 19Impedance diagrams of Ag-doped InSe nanosheet structures with different Ag doping amounts and InSe nanosheet structures prepared in Examples 1, 2 and 3 under CO2ER conditions;

[0057] Figure 20 Ag-doped InSe nanosheet structures with different Ag doping levels prepared in Examples 1, 2, and 3, and the hydroxyl (OH) groups of InSe nanosheet structures under CO2ER conditions. - Adsorption diagram;

[0058] Figure 21 The in-situ infrared spectrum of the InSe nanosheet structure material prepared in Example 1 as a function of time under CO2ER conditions with a potential of -0.6V;

[0059] Figure 22 The in-situ infrared spectrum of the Ag-doped InSe nanosheet structure prepared in Example 1 as a function of time under CO2ER conditions with a potential of -0.6V;

[0060] Figure 23 X-ray powder diffraction (XRD) patterns of the sample prepared in Comparative Example 1 (1) after 8 h and 16 h of solvothermal reaction in step 1);

[0061] Figure 24 The scanning electron microscope (SEM) image of the sample prepared in Comparative Example 1 (1) after a solvothermal reaction for 8 hours in step 1);

[0062] Figure 25 The scanning electron microscope (SEM) image of the sample prepared in Comparative Example 1 (1) after a solvothermal reaction for 16 h in step 1);

[0063] Figure 26 The scanning electron microscope (SEM) image of the sample prepared in Comparative Example 1 (2) at a solvothermal reaction temperature of 160°C in step 1);

[0064] Figure 27 The scanning electron microscope (SEM) image of the sample prepared in Comparative Example 1 (2) at a solvothermal reaction temperature of 200°C in step 1);

[0065] Figure 28 The image is a scanning electron microscope (SEM) image of (3) in Comparative Example 1 after hydrothermal reaction for 6 hours in step 2);

[0066] Figure 29 The image is a scanning electron microscope (SEM) image of (3) in Comparative Example 1 after hydrothermal reaction for 10 h in step 2);

[0067] Figure 30The image is a scanning electron microscope (SEM) image of Comparative Example 1 (4) at a hydrothermal reaction temperature of 140°C in step 2);

[0068] Figure 31 The image is a scanning electron microscope (SEM) image of Comparative Example 1 (4) at a hydrothermal reaction temperature of 180°C in step 2);

[0069] Figure 32 The image is a scanning electron microscope (SEM) image of Comparative Example 1 (5) in step 1) with 40 mL of ethanol (C2H5OH) and 10 mL of H2O as solvent;

[0070] Figure 33 The image is a scanning electron microscope (SEM) image of Comparative Example 1 (5) in step 1) with 40 mL ethylenediamine (EDA) and 10 mL H2O as solvent;

[0071] Figure 34 The LSV curve of the sample prepared in Comparative Example 1 (1) with a solvothermal reaction time of 8h or 16h in step 1) in an H-type electrolytic cell;

[0072] Figure 35 The LSV curve of the sample prepared in Comparative Example 1 (2) at a solvothermal temperature of 160°C or 200°C in step 1) in an H-type electrolytic cell;

[0073] Figure 36 The LSV curve of the sample prepared in Comparative Example 1 (3) with a hydrothermal reaction time of 6h or 10h in step 2) in an H-type electrolytic cell;

[0074] Figure 37 The LSV curve of the sample prepared in Comparative Example 1 (4) at a hydrothermal temperature of 140°C or 180°C in step 2) in an H-type electrolytic cell;

[0075] Figure 38 The LSV curve of the sample prepared in step 1) of Comparative Example 1 (5) with solvent of 40 mL ethanol (C2H5OH) and 10 mL H2O or 40 mL ethylenediamine (EDA) and 10 mL H2O in an H-type electrolytic cell. Detailed Implementation

[0076] The present invention will now be described in detail with reference to the embodiments and accompanying drawings.

[0077] The copper foam used in this invention is treated as follows before use: first, a piece of copper foam (CF) with an area of ​​2×3cm is soaked in 6M hydrochloric acid for 15 minutes, and then washed 3 times each with deionized water and anhydrous ethanol.

[0078] Example 1

[0079] A method for preparing Ag-doped InSe nanosheet structure material includes the following steps:

[0080] 1) Preparation of InSe nanosheet structure materials:

[0081] Accurately measure 20 mL of anhydrous ethanol, 20 mL of ethylenediamine, and 10 mL of deionized water into a clean small beaker. Accurately weigh 2 mmol of Se powder and add it to the beaker, followed by 6 mL of hydrazine hydrate (N2H4·H2O, 50 wt.%). Sonicate the mixture for 30 min to form a reddish-brown solution. Then, add 2 mmol of indium chloride tetrahydrate (InCl3·4H2O) to the solution and stir magnetically for 10 min. Transfer the mixture to a polytetrafluoroethylene-lined reactor. Place the pre-treated copper foam into the reactor at an angle and react in an oven at 180 °C for 12 h. After the reaction is complete, allow it to cool naturally to room temperature. Wash the copper foam covering the sample three times with deionized water and three times with anhydrous ethanol. Dry the resulting sample in a vacuum drying oven at 70 °C for 12 h to obtain the InSe nanosheet structure material.

[0082] 2) Preparation of Ag-doped InSe nanosheet structure: Accurately measure 30 mL of H2O into a clean small beaker, accurately weigh 0.03 mmol of silver nitrate (AgNO3), and add it to the beaker to form a 1.0 mM AgNO3 aqueous solution. Then transfer it to a reaction vessel lined with polytetrafluoroethylene, and obliquely place the copper foam covering the InSe nanosheet structure obtained in step 1) into the reaction vessel. React in an oven at 160℃ for 8 h. After the reaction is complete, allow it to cool naturally to room temperature. Wash the copper foam covering the sample three times each with deionized water and anhydrous ethanol. Place the obtained sample in a vacuum drying oven at 70℃ for 12 h to obtain the Ag-doped InSe nanosheet structure.

[0083] Structural and morphological characterization of the product in Example 1:

[0084] The final product obtained in Example 1 was characterized using X-ray powder diffraction (XRD). Figure 1 As shown, the diffraction peaks of the final product are consistent with the orthorhombic hexahedral InSe structure (JCPDS no. 42-919).

[0085] The composition of the final product was analyzed using energy-dispersive X-ray spectroscopy. For example... Figure 2 As shown, the atomic percentages of Ag, In, and Se are 0.015:0.985:0.734. Based on the atomic ratio of Ag and In in the EDX spectrum, the atomic percentage of Ag is calculated to be 1.5% using the formula: x% = Ag / (Ag+In) × 100%. The product is defined as Ag. 1.5％-InSe.

[0086] The morphology of the final product obtained in Example 1 was analyzed using scanning electron microscopy (SEM). Figure 3 As shown, the sample is a uniformly distributed nanosheet structure with a lateral dimension of 300–1000 nm.

[0087] Transmission electron microscopy (TEM) image of the final product as shown below Figure 4 As shown, the sample is a flexible nanosheet structure.

[0088] High-resolution transmission electron microscopy (HRTEM) image of the final product as shown below Figure 5 As shown, the nanosheets are polycrystalline structures with clear grain boundaries, and the lattice fringes with different orientations all correspond to the (015) plane of the orthorhombic hexahedral InSe structure.

[0089] The elemental distribution map of the final product using scanning electron microscopy is shown below. Figure 6 As shown, In, Se, and Ag elements are evenly distributed, with Ag having a relatively low distribution density.

[0090] Example 2

[0091] A method for preparing Ag-doped InSe nanosheet structure material includes the following steps:

[0092] Accurately measure 30 mL of deionized water into a clean small beaker, and accurately weigh 0.01 or 0.05 mmol of silver nitrate (AgNO3), adding it to the beaker to form an AgNO3 aqueous solution with a concentration of 0.33 or 1.67 mM. Then transfer the solution to a polytetrafluoroethylene-lined reactor. Place the copper foam covering the InSe nanosheet structure material, prepared according to step 1) of Example 1, obliquely into the reactor and react in a 160°C oven for 8 hours. After the reaction is complete and the solution has cooled naturally to room temperature, wash the copper foam covering the sample three times each with deionized water and anhydrous ethanol. Dry the resulting sample in a vacuum drying oven at 70°C for 12 hours to obtain the Ag-doped InSe nanosheet structure material. When the concentration of AgNO3 aqueous solution is 0.33 mM, Ag-doped InSe nanosheet structure material with Ag doping amount of 0.5% is obtained; when the concentration of AgNO3 aqueous solution is 1.67 mM, Ag-doped InSe nanosheet structure material with Ag doping amount of 2.4% is obtained.

[0093] The phase characterization of the product obtained in Example 2 was performed using X-ray powder diffraction, such as... Figure 7 As shown, all diffraction peaks are consistent with the orthorhombic hexahedral InSe structure (JCPDS no. 42-919).

[0094] The composition of the product of Example 2 was analyzed using energy-dispersive X-ray spectroscopy (EDX), such as... Figure 8 As shown, the atomic percentages of Ag, In, and Se are 0.005:0.995:0.766 and 0.024:0.976:0.695, respectively. Therefore, the atomic percentages of Ag are calculated to be 0.5% and 2.4%, and the product is defined as Ag. 0.5％ -InSe and Ag 2.4％ -InSe.

[0095] The morphology of the samples prepared in Example 2 was analyzed using scanning electron microscopy (SEM). Figure 9 and Figure 10 The images are scanning electron microscope (SEM) images of Ag-doped InSe samples with Ag doping concentrations of 0.5% and 2.4%, respectively, showing that the samples are all nanosheet structures.

[0096] Example 3

[0097] An application of Ag-doped InSe nanosheet structure as a CO2ER electrocatalyst is described. The specific application method is as follows: an Ag-doped InSe nanosheet structure with an area of ​​0.5 × 0.5 cm is used as the working electrode, and a carbon rod and an Ag / AgCl electrode are used as the counter electrode and reference electrode, respectively. The test is conducted in an H-type electrolytic cell containing 0.1 M KHCO3 electrolyte using a CHI760E electrochemical workstation.

[0098] This invention uses InSe nanosheet structures prepared on copper foam and Ag-doped InSe nanosheet structures as working electrodes, and measures and compares their CO2ER performance in an H-type electrolytic cell. The InSe nanosheet structures prepared on copper foam are obtained through step 1) of Example 1.

[0099] 10 mg of Ag-doped InSe nanosheet material was ultrasonically exfoliated and dispersed in a mixture of 200 μL Nafion solution (5 wt.%) and 800 μL anhydrous isopropanol. The resulting powder was then loaded onto a 1.0 × 1.0 cm carbon paper sheet as the working electrode (loading 0.8 mg·cm⁻¹). -2 A 1.0×1.0cm nickel foam loaded with NiFe2O4 / NiFe LDH was used as the anode, and a 1.0M KOH solution was used as the anode electrolyte. The cells were assembled in a membrane cell electrolyzer and electrochemical tests were performed using a CHI 760E electrochemical workstation equipped with a CHI 680C high-current amplifier.

[0100] The method for preparing the NiFe2O4 / NiFe LDH-supported nickel foam is as follows: A piece of nickel foam (2×2 cm) was immersed in 6M HCl solution for 15 min, and washed twice with deionized water and anhydrous ethanol. 0.5 mmol of Ni(NO3)2, 0.75 mmol of FeCl2, and 1.5 mmol of NaHCO3 were dissolved in a mixed solvent of 20 mL deionized water and 15 mL methanol, and stirred for 0.5 h. The solution was then transferred to a 40 mL reaction vessel, and the pre-cleaned nickel foam was placed obliquely inside. The reaction was carried out at 120 °C for 2 h. After the reaction, the foam was washed three times with deionized water and anhydrous ethanol, and then vacuum dried at 50 °C for 6 h.

[0101] In electrochemical testing, the linear sweep polarization curve (LSV) was observed at 5.0 mV·s. -1 The scan rate was obtained. The Faradaic efficiency of the CO2ER gas phase products was calculated from the products obtained by gas chromatography (GC2030), and the Faradaic efficiency of the liquid phase products was obtained by nuclear magnetic resonance spectroscopy (NMR 1H). 1 The product was calculated using a Bruker (ASCEnd™) 400MHz ¹H NMR spectrometer. Stability was determined by measuring the current density-time curve at a constant potential. Hydroxyl (OH) - Adsorbed in argon-saturated 0.1M NaOH electrolyte and 5.0 mV·s -1 The electrochemical active area (ECSA) was obtained at scan rates of 20, 40, 60, 80, 100, and 120 mV·s without a significant Faraday region. -1 ) Using cyclic voltammetry to measure electrochemical double-layer capacitance (C dl The evaluation was conducted at potentials ranging from -0.1V to -0.2V (relative to the reversible hydrogen electrode); electrochemical impedance spectroscopy (EIS) was performed at -0.3V (relative to the reversible hydrogen electrode) over a frequency range of 100kHz to 0.01Hz.

[0102] Figure 11 The figures show the LSV polarization curves of Ag-doped InSe nanosheet structures with different Ag doping levels prepared in Examples 1, 2, and 3, and the InSe nanosheet structures under CO2 or Ar saturation in an H-type electrolytic cell. As can be seen from the figures, the current density of the LSV polarization curves under CO2 saturation is higher than that under Ar saturation, indicating that the samples are more inclined to catalyze the CO2 reduction reaction rather than the competing hydrogen evolution reaction. Within a potential range of -0.4 to -1.2 V, the current density of the sample with 1.5% Ag doping in CO2-saturated electrolyte ranges from 6.9 to 54.9 mA·cm⁻¹. -2 The value was higher than that of samples with an Ag doping concentration of 0.5% (4.9–46.5 mA·cm⁻¹). -2Samples with Ag doping of 2.4% (6.3–50.5 mA·cm⁻¹) -2 ) and undoped Ag samples (1.8–20.5 mA·cm) -2 The results indicate that Ag doping significantly enhances the electrocatalytic CO2 reduction reaction activity, and the Ag doping content significantly affects the electrocatalytic CO2 reduction reaction activity. The sample with an Ag doping content of 1.5% exhibits better activity than the samples with doping contents of 0.5% and 2.4%.

[0103] Figure 12 The figures show the Faradaic efficiency (FE) of the Ag-doped InSe nanosheet materials and the InSe nanosheet materials prepared in Examples 1 and 3 at different potentials in an H-type electrolytic cell. As can be seen from the figures, the Ag-doped InSe nanosheet material achieves a Faradaic efficiency of 75.2% for the liquid product ethanol at -0.6V, and the Faradaic efficiency of ethanol exceeds 50% in the potential range of -0.5 to -1.2V. In contrast, the InSe nanosheet material does not produce any liquid product ethanol.

[0104] Figure 13 The figure shows the Faradaic efficiency (FE) of the Ag-doped InSe nanosheet structure prepared in Example 2 at different potentials. As can be seen from the figure, the sample with 0.5% Ag doping achieves the highest Faradaic efficiency (52.3%) at -0.7V. The sample with 2.4% Ag doping achieves the highest Faradaic efficiency (40.3%) at -0.7V.

[0105] Figure 14 The figure shows the current density-time curve of the Ag-doped InSe nanosheet structure prepared in Example 1 at a potential of -0.6V in an H-type electrolytic cell. As can be seen from the figure, after continuous electrolysis of the Ag-doped InSe nanosheet structure at -0.6V for 15 hours, the current density and the Faraday efficiency of ethanol showed a decrease of less than 2% and 4%, respectively, indicating that the catalyst has good catalytic stability.

[0106] Figure 15 The image shows the LSV curve of the Ag-doped InSe nanosheet structure prepared in Example 1 in a membrane battery electrolyzer. The graph shows that as the voltage increases from 2.0V to 4.5V, the current density increases from 89.1 mA·cm⁻¹. -2 Significantly increased to 710.0 mA·cm -2 .

[0107] Figure 16The graphs show the Faradaic efficiency (FE) and energy efficiency (EE) of the Ag-doped InSe nanosheet electrode materials prepared in Examples 1 and 3 at different voltages in a membrane cell electrolyzer. As can be seen from the graphs, the Faradaic efficiency of ethanol reaches its maximum of 68.7% at 3.0 V for Ag-doped InSe, while the energy efficiency reaches its maximum of 26.1% at this voltage. Furthermore, liquid ethanol can be produced within the voltage range of 2.0–4.5 V.

[0108] Figure 17 The figure shows the current density-time curve of the Ag-doped InSe nanosheet structure prepared in Example 1 at a voltage of 3.0 V in a membrane cell electrolyzer. As can be seen from the figure, after continuous electrolysis at 3.0 V for 22 h, the current density remained at 94.6% of the initial value, while the Faraday efficiency of ethanol still reached 61.4%, indicating that the material has good catalytic stability in the membrane cell electrolyzer.

[0109] Figure 18 The images show the capacitance-current diagrams of Ag-doped InSe nanosheet structures with different Ag doping levels prepared in Examples 1, 2, and 3, and the InSe nanosheet structures under different scan rates and CO2ER conditions. The double-layer capacitance of the sample with 1.5% Ag doping is 4.3 mF·cm. -2 The sample with a doping concentration greater than 0.5% (3.0 mF·cm⁻¹) -2 The sample with an Ag doping concentration of 2.4% (3.7 mF·cm⁻¹) -2 ) and undoped Ag sample (2.4 mF·cm) -2 This indicates that Ag doping increases the electrochemical active area of ​​the samples, with the sample having the largest electrochemical active area being the one with 1.5% Ag doping.

[0110] Figure 19 The images show Ag-doped InSe nanosheet structures with different Ag doping levels prepared in Examples 1, 2, and 3, and their electrochemical impedance spectroscopy (EIS) under CO2ER conditions. The charge transfer resistance (R) of the sample with 1.5% Ag doping is also shown. ct The charge transfer resistance (CTR) is 26.9 Ω, which is lower than that of the sample with 0.5% Ag doping (107.4 Ω) and the sample with 2.4% Ag doping (62.2 Ω), while the undoped sample has the highest CTR (128.7 Ω). This indicates that the Ag-doped InSe nanosheets with 1.5% Ag doping have the lowest CTR and the fastest catalytic kinetics.

[0111] Figure 20Ag-doped InSe nanosheet structures with different Ag doping levels prepared in Examples 1, 2, and 3, and the hydroxyl groups (OH) of the InSe nanosheet structures. - Adsorption diagram. Based on... * CO2 ·- The bonding strength on the catalyst surface and OH - The positive correlation between adsorption and OH, using OH - To evaluate the adsorption strength * CO2 ·- The binding strength on the catalyst surface. As shown in the figure, the OH groups of samples with Ag doping levels of 0.5%, 1.5%, and 2.4% have different binding strengths. - The adsorption potentials were -0.97V, -1.01V, and -0.99V, respectively, while the OH- of the undoped Ag sample... - The adsorption potential is -0.91V. This indicates that the OH groups on the Ag-doped InSe nanosheet structure are... - The adsorption potential is lower than that of the undoped Ag sample, with the Ag doping level of 1.5% being lower than that of the OH- sample. - It has the most negative adsorption potential, therefore it is effective against OH-. - It has the strongest affinity and can effectively stabilize... * CO2 ·- Intermediates that accelerate the CO2ER process.

[0112] Figure 21 The in-situ diffuse reflectance infrared Fourier transform spectrum of the undoped InSe nanosheet structure prepared in Example 3 was obtained by measuring the potential at -0.6V every 1 minute under CO2ER conditions. As shown in the figure, with the increase of electrolysis time, * The gradual increase in CO2 peak intensity indicates increased coverage on the catalyst, providing more reactants for subsequent reactions. HCO * The peak position of the O intermediate gradually red-shifts with increasing time, accompanied by an increase in peak intensity, indicating that its coverage on the catalyst surface increases and adsorption weakens, thereby promoting the formation of formate. Furthermore, with increasing electrolysis time... * CO * OH and * CO L The increased peak intensity indicates that their coverage on the catalyst surface has increased, but * CO L The gradual red shift of the peak position indicates that its adsorption on the catalyst is weakened, thus... * CO L It readily desorbs from active sites to form CO, preventing CC coupling. Furthermore, with increasing electrolysis time... * The position of the OH peak gradually shifts to the red and is accompanied by an increase in peak intensity, indicating that the adsorption of water molecules on the catalyst surface is weakened.

[0113] Figure 22 The in-situ diffuse reflectance infrared Fourier transform spectra of the Ag-doped InSe nanosheet structure prepared in Example 1 were obtained by measuring the potential at -0.6V every 1 minute under CO2ER conditions. As shown in the figure, with increasing electrolysis time... * The gradual increase in CO2 peak intensity indicates increased coverage on the catalyst, which can provide more reactants for subsequent reactions and improve the mass transfer efficiency of the reaction process. * CO * The gradual blue shift of the OH intermediate peak position indicates an increased binding strength of the catalyst, which facilitates its further conversion into an adsorption-enhanced form. * CO L and * CO B An intermediate used in subsequent C / C coupling reactions. Simultaneously, HCO3-... * The absence of the O intermediate indicates that the formate formation pathway is inhibited. With increasing electrolysis time, * CO L intermediates and * CO B The peak positions of the intermediates gradually shift to blue, indicating enhanced adsorption on the catalyst surface, which is beneficial for... * CO L The intermediate is further protonated * CHO * intermediate and * CO B Intermediate coupling generation * COCHO * The intermediate, which is then further protonated into * OHCCHO * Intermediate. It undergoes multiple proton-coupled electron transfer steps. * OHCCHO * The intermediate is protonated to CH3CHO * The intermediate is further hydrogenated to produce CH3CH2O. * The intermediate eventually forms ethanol. Furthermore, * The gradual blue shift of the OH peak, accompanied by an increase in peak intensity, indicates that more water molecules are adsorbed on the catalyst surface, suggesting that more protons can be dissociated for the protonation of carbonaceous intermediates.

[0114] This invention utilizes a two-step liquid-phase synthesis method to synthesize Ag. + Ion doping into InSe nanosheets can effectively optimize the electronic structure of the catalyst, forming multiple active sites. Doped Ag + Can be with In 2+ Site co-stability* CO * OH intermediates promote their conversion to enhanced adsorption. * CO L and * CO B Intermediate, promote * CO L Protonization * CHO * The intermediate triggers the C-C coupling reaction, ultimately reducing CO2 to ethanol. It is also doped with Ag. + Ions can increase the electrochemical active surface area of ​​the catalyst, exposing more catalytic active sites. Furthermore, doping with Ag... + Ions enhance the conductivity of the catalyst, significantly promote interfacial charge transfer, and accelerate catalytic kinetics. The Ag-doped InSe nanosheet structure material exhibits advantages such as low overpotential at high current densities, high selectivity, good stability, simple preparation process, and environmental friendliness in the application of electrocatalysts for the electrocatalytic reduction of CO2 to the single liquid product ethanol. These characteristics make it highly valuable for practical applications in electrocatalytic CO2 reduction.

[0115] Comparative Example 1

[0116] The following are some comparative results with the Ag-doped InSe nanosheet structure material prepared in Example 1:

[0117] (1) The preparation method is the same as in Example 1, except that the reaction time in step 1) is different: the solvothermal reaction time is kept at 8h or 16h respectively, and all other variables are kept the same.

[0118] (2) The preparation method is the same as in Example 1, except that the reaction temperature in step 1) is different: the reaction temperature is maintained at 160℃.

[0119] Or 200℃, with all other variables remaining the same.

[0120] (3) The preparation method is the same as in Example 1, except that the reaction time in step 2) is different: the hydrothermal reaction time is kept at 6h or 10h respectively, and all other variables are kept the same.

[0121] (4) The preparation method is the same as in Example 1, except that the reaction temperature in step 2) is different: the reaction temperature is maintained at 140℃.

[0122] Or 180℃, with all other variables remaining the same.

[0123] (5) The preparation method is the same as in Example 1, except that the solvent in step 1) is adjusted to 40 mL of ethanol (C2H5OH) and 10 mL of H2O or 40 mL of ethylenediamine (EDA) and 10 mL of H2O, while all other variables remain the same.

[0124] Figure 23 The images show the X-ray powder diffraction (XRD) patterns of the solvothermal reaction for 8 h and 16 h in Comparative Example 1(1). The sample obtained after 8 h of solvothermal reaction in step (1) consisted of a mixture of hexagonal In₂Se₃ (JCPDS no. 45-1041) and orthorhombic InSe (JCPDS no. 42-919), while the sample obtained after 16 h of solvothermal reaction in step (1) consisted of orthorhombic InSe (JCPDS no. 42-919). This indicates that the sample obtained after 8 h of solvothermal reaction in step (1) was not completely converted.

[0125] Figure 24 The image shows a scanning electron microscope (SEM) image of the sample prepared by the solvothermal reaction for 8 hours in Comparative Example 1 (1). As can be seen from the image, the sample has a nanosheet structure with a lateral dimension of 240–350 nm.

[0126] Figure 25 Scanning electron microscope (SEM) image of the sample prepared by solvothermal reaction for 16 h in Comparative Example 1 (1). The product after 16 h of reaction formed nanosheets with large lateral dimensions. Due to the large lateral dimensions of the generated nanosheets, the number of exposed active sites is reduced, thus affecting... * The generation of CO affects the CC coupling process and reduces the performance of CO2ER.

[0127] Figure 26 The image shows a scanning electron microscope (SEM) image of the sample prepared in Comparative Example 1 (2) with a solvothermal reaction temperature of 160℃. It shows that the sample is composed of non-uniform, rough nanocubes and nanosheets.

[0128] Figure 27 The image shows a scanning electron microscope (SEM) image of the sample prepared in Comparative Example 1 (2) with a solvothermal reaction temperature of 200℃. The image shows that the sample consists of nanosheets with serrated edges, and the average lateral size of the nanosheets is approximately 1.5 μm.

[0129] Figure 28 The image shows a scanning electron microscope (SEM) image of the sample prepared by hydrothermal reaction for 6 hours in Comparative Example 1 (3). As can be seen from the image, the sample has a nanosheet structure, with the lateral dimensions of the nanosheets ranging from 240 to 350 nm.

[0130] Figure 29 The image shows a scanning electron microscope (SEM) image of the sample prepared by hydrothermal reaction (3) for 10 h in Comparative Example 1. It indicates that the sample has a relatively sparse mixed structure of nanosheets and nanoparticles. The excessively long ion exchange reaction time led to the degradation and reconstruction of the nanosheet structure.

[0131] Figure 30The image shows a scanning electron microscope (SEM) image of the sample prepared at a hydrothermal reaction temperature of 140℃ in Comparative Example 1 (4). It shows that the sample has a nanosheet structure with an average lateral size of about 600 nm.

[0132] Figure 31 The image shows a scanning electron microscope (SEM) image of the sample prepared at a hydrothermal reaction temperature of 180℃ in Comparative Example 1 (4). The image shows that the sample has a large nanosheet structure with an average lateral size of approximately 1.3 μm.

[0133] Figure 32 The image shows a scanning electron microscope (SEM) image of the sample prepared in Comparative Example 1 (5) using 40 mL of ethanol (C2H5OH) and 10 mL of H2O as solvents. It shows that the sample is a nanoplate structure with a thickness of about 15 nm and an average lateral size of about 520 nm.

[0134] Figure 33 The image shows a scanning electron microscope (SEM) image of the sample prepared in Comparative Example 1 (5) using 40 mL of ethylenediamine (EDA) and 10 mL of H2O as solvents. The image indicates that the sample has a nanosheet structure with a lateral dimension of 1–3 μm.

[0135] Figure 34 The LSV curves of the samples prepared in Comparative Example 1 (1) with solvothermal reaction times of 8 h or 16 h are shown in an H-type electrolytic cell. The samples prepared with solvothermal reaction times of 8 h or 16 h had current densities of 3.3–33.4 mA·cm⁻¹ under carbon dioxide saturation in a potential range of -0.4 to -1.2 V. -2 Or 5.6~43.8mA·cm -2 However, the current density differentiation with the sample prepared under argon saturation at the same potential range is less than that of the sample prepared by solvothermal reaction for 12 hours in step (1). This indicates that the CO2ER performance of the sample is lower than that of the sample prepared by solvothermal reaction for 12 hours in step (1).

[0136] Figure 35 The LSV curves of the samples prepared at solvothermal temperatures of 160℃ or 200℃ in Comparative Example 1 (2) are shown in an H-type electrolytic cell. The samples prepared at solvothermal reaction temperatures of 160℃ or 200℃ had current densities of 2.8–25.3 mA·cm⁻¹ under carbon dioxide saturation in a potential range of -0.4 to -1.2 V. -2 Or 5.6~45.1mA·cm -2 This indicates that the CO2ER performance of the sample is lower than that of the sample prepared in step (1) with a solvothermal reaction temperature of 180℃.

[0137] Figure 36The LSV curves of the samples prepared in Comparative Example 1 (3) with hydrothermal reaction times of 6 h or 10 h are shown in an H-type electrolytic cell. The samples prepared in step (2) with hydrothermal reaction times of 6 h or 10 h had current densities of 3.3–34.3 mA·cm⁻¹ at a potential range of -0.4 to -1.2 V under carbon dioxide saturation. -2 Or 1.1~31.1mA·cm -2 However, the current density differentiation between the sample and the sample under argon saturation at the same potential range is less than that of the sample that underwent hydrothermal reaction for 8 hours. This indicates that the CO2ER performance of the sample is lower than that of the sample that underwent hydrothermal reaction for 8 hours in step (2).

[0138] Figure 37 The LSV curves of the samples prepared at hydrothermal temperatures of 140℃ or 180℃ in Comparative Example 1 (4) are shown in an H-type electrolytic cell. The samples prepared at hydrothermal reaction temperatures of 140℃ or 180℃ in step (2) have current densities of 0.9 to 26.1 mA·cm⁻¹ in the potential range of -0.4 to -1.2V under carbon dioxide saturation. -2 Or 4.8~40.3mA·cm -2 This indicates that the CO2ER performance of the sample is lower than that of the sample prepared in step (2) at a hydrothermal reaction temperature of 160℃.

[0139] Figure 38 The LSV curves of samples prepared in step (1) of Comparative Example 1 (5) using 40 mL ethanol (C2H5OH) and 10 mL H2O or 40 mL ethylenediamine (EDA) and 10 mL H2O as solvents are shown in an H-type electrolytic cell. Under carbon dioxide saturation and a potential range of -0.4 to -1.2 V, the current density of samples prepared using 40 mL ethanol (C2H5OH) and 10 mL H2O as solvents ranges from 1.1 to 25.7 mA·cm⁻¹. -2 Samples prepared using 40 mL of ethylenediamine (EDA) and 10 mL of H₂O as solvents exhibited current densities ranging from 2.2 to 30.9 mA·cm⁻¹. -2 This indicates that the CO2ER performance of the sample is lower than that of the sample prepared in step (1) using 20 mL of ethanol (C2H5OH), 20 mL of ethylenediamine (EDA), and 10 mL of H2O as solvents.

[0140] The above detailed description of an Ag-doped InSe nanosheet structure material, its preparation method, and its application, with reference to the embodiments, is illustrative rather than limiting. Several embodiments may be listed within the defined scope. Therefore, variations and modifications that do not depart from the overall concept of the present invention should be within the protection scope of the present invention.

Claims

1. A method for preparing Ag-doped InSe nanosheet structured materials, characterized in that, The preparation method includes the following steps: 1) Preparation of InSe nanosheets; 2) Copper foam containing InSe nanosheets was placed in an aqueous solution containing a silver source and subjected to a hydrothermal reaction to obtain Ag-doped InSe nanosheet structure material. In step 1), the InSe nanosheets are prepared by placing copper foam in a mixed solvent containing a selenium source, a reducing agent, and an indium source, and performing a solvothermal reaction to obtain InSe nanosheet structural materials; the mixed solvent is a mixed solution of ethanol, ethylenediamine, and water, and the volume ratio of ethanol, ethylenediamine, and water is 1~3 : 1~3 : 0.5~1.5; the solvothermal reaction is carried out at 160~200℃ for 8~16 h. In step 2), the hydrothermal reaction specifically involves reacting at 140~180℃ for 6~10 h.

2. The preparation method according to claim 1, characterized in that, The molar ratio of the selenium source, indium source, and reducing agent is 1~3 : 1~3 : 50~70.

3. The preparation method according to claim 1, characterized in that, In step 2), the concentration of the aqueous solution containing the silver source is 0.33~1.67 mM.

4. The preparation method according to claim 1 or 3, characterized in that, In step 2), the molar ratio of the silver source to the indium source in step 1) is 0.005~0.025:

1.

5. An Ag-doped InSe nanosheet structure material prepared by the preparation method according to any one of claims 1-4.

6. An application of the Ag-doped InSe nanosheet structure material according to claim 5, characterized in that, The application of the Ag-doped InSe nanosheet structure material as a CO2ER electrocatalyst.

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