Silver superstructure material and preparation method and application thereof
By synthesizing silver superstructure materials in a one-pot, template-free process, the problems of low carbon monoxide selectivity and low current density in electrocatalytic carbon dioxide reduction reactions have been solved, achieving highly efficient carbon dioxide reduction that is suitable for industrial production.
Patent Information
- Application Number
- CN202410578088.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-10
- Publication Date
- 2025-11-11
AI Technical Summary
Existing electrocatalytic carbon dioxide reduction reactions suffer from low carbon monoxide selectivity and low current density. Furthermore, the catalyst preparation process is complex and costly, making large-scale application difficult.
A one-pot, template-free method was used to synthesize silver superstructure materials. By controlling the type of silver salt, solvent, and reducing agent, the size of the silver nanoparticles and their self-assembly into superstructures were controlled, thus solving the problems of complex catalyst preparation processes and insufficient performance.
It achieves carbon dioxide reduction with high selectivity (≥90%) and high current density (≥0.5A·cm-2), and the catalyst preparation is simple and low cost, making it suitable for industrial production.
Smart Images
Figure CN120920735A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrocatalysis, and more particularly to a silver superstructure material, its preparation method, and its application. Background Technology
[0002] Electrocatalytic carbon dioxide reduction can reduce the greenhouse gas carbon dioxide to high-value-added products such as carbon monoxide under mild conditions, which has significant environmental and economic implications. Although some progress has been made in the electrocatalytic carbon dioxide reduction to carbon monoxide production, bottlenecks such as low selectivity and low formation rate (current density) still exist. Furthermore, the complex preparation process and small production volume of electrocatalysts seriously hinder the application of electrocatalytic carbon dioxide reduction.
[0003] Metal nanoparticle superstructures are formed by the autonomous packing of metal nanoparticles under certain conditions. The coupling effect between neighboring particles can lead to changes in the optical and electrical properties of the nanoparticles, showing potential in promoting the activation and conversion of carbon dioxide molecules. However, nanoparticle superstructures are usually synthesized stepwise or template-induced, which presents challenges such as difficulty in quantifying the synthesis and high preparation costs. Summary of the Invention
[0004] In view of the shortcomings of the above-mentioned technologies, the present invention provides a method for preparing silver superstructure materials to solve the technical problems of complex catalyst preparation process and insufficient catalyst performance in existing electrocatalytic carbon dioxide reduction reactions.
[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0006] A method for preparing a silver superstructure material, wherein the preparation method employs a one-pot, template-free synthesis, and specifically includes the following steps:
[0007] S1: Dissolve soluble silver salts in a certain solvent to obtain a silver salt solution of a certain concentration;
[0008] S2: Add alkali to the silver salt solution obtained in step S1 to adjust the pH value of the silver salt solution;
[0009] S3: Add a reducing agent to the silver salt solution obtained in step S2, and react at a certain temperature for a period of time to obtain the silver superstructure material.
[0010] This invention provides a template-free, one-pot method for the quantitative preparation of silver superstructures. The size of the silver nanoparticles is controlled by the type of silver salt, solvent, and reducing agent. Furthermore, the solvent and reducing agent induce the silver nanoparticles to autonomously assemble into superparticles, and the amount of silver superstructure synthesized is controlled by the amount of silver salt solution. Grain boundaries are beneficial for the electrocatalytic reduction of carbon dioxide to carbon monoxide. This invention utilizes the abundant grain boundaries of the prepared silver superstructures to solve the problems of low selectivity and low current density in the electrocatalytic reduction of carbon dioxide.
[0011] As a preferred technical solution, the soluble silver salt is at least one of silver nitrate, silver tetrafluoroborate, and silver fluoride.
[0012] As a preferred technical solution, the solvent is at least one selected from water, N,N-dimethylacetamide, dimethyl sulfoxide, N-pyrrolidone, acetonitrile, ethanol, dioxane, and cyclohexane.
[0013] As a preferred technical solution, the alkali is at least one selected from ammonia, methylamine, dimethylamine, and triethylamine.
[0014] As a preferred technical solution, the pH value of the solution is 8 to 14.
[0015] As a preferred technical solution, the reducing agent is at least one selected from ethylene glycol, glucose, ascorbic acid, ascorbate, citric acid, citrate, and sodium borohydride acetate.
[0016] As a preferred technical solution, in step S3, the reaction temperature is 25℃~100℃; the reaction time is 10min~1440min.
[0017] As a preferred technical solution, in step S3, a dispersant is added to the silver salt solution obtained in step S2; the dispersant is polyvinylpyrrolidone.
[0018] Another aspect of the present invention is to provide a silver superstructure material, which is prepared by the silver superstructure material preparation method described above.
[0019] A third aspect of the present invention is to provide an application of the silver superstructure material as described above in the electrocatalytic carbon dioxide reduction reaction, wherein the silver superstructure material is used as a catalyst, and the electrolytic cell used is one of a membrane electrode electrolyzer, a solid electrolyte cell, and a flow electrolyzer, and the carbon dioxide reduction current density is greater than or equal to 0.5 A·cm⁻¹. -2 The selection of carbon monoxide is greater than or equal to 90%.
[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0021] The present invention discloses a method for preparing silver superstructure materials, which adopts a one-pot, template-free synthesis method. The preparation process is simple, convenient, and low in cost, making it suitable for large-scale industrial production.
[0022] The silver superparticle material prepared by this invention has the advantage of numerous grain boundaries and, when used in the electrocatalytic carbon dioxide reduction reaction, exhibits a carbon dioxide reduction current density greater than or equal to 0.5 A·cm⁻¹. -2 Its advantages, such as a selectivity of carbon monoxide greater than or equal to 90% and strong catalytic stability, enable it to meet the performance requirements of industrial production.
[0023] This invention provides a method for controlling the size of silver superstructures, the particle size of silver nanoparticles, and the distribution of crystal planes, which can prepare silver superstructures with different optical, electrical, and thermal properties for use in different fields such as photocatalysis and electrocatalysis. Attached Figure Description
[0024] Figure 1 These are photographs of the appearance of the silver superstructure materials prepared in Examples 1 to 4 of this invention.
[0025] Figure 2 The cyclic voltammetric performance curves of the silver superstructure materials prepared in Examples 1 to 4 of this invention are shown.
[0026] Figure 3 a to Figure 3 d is an electron microscope image of the silver superstructure material prepared in Example 1 of this invention.
[0027] Figure 4 a to Figure 4 Image d is an electron microscope image of the silver superstructure material prepared in Example 2 of this invention.
[0028] Figure 5 a and Figure 5 b is an electron microscope image of the silver superstructure material prepared in Example 3 of this invention.
[0029] Figure 6 a to Figure 6 Image d is an electron microscope image of the silver superstructure material prepared in Example 4 of this invention.
[0030] Figure 7 a to Figure 7 d is an electron microscope image of the product prepared in Comparative Example 1 of this invention.
[0031] Figure 8 This is a product distribution diagram of the electrocatalytic carbon dioxide reduction reaction after using silver superstructure material as a catalyst in Example 1 of this invention. Detailed Implementation
[0032] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.
[0033] Example 1
[0034] The preparation method of the silver superstructure material in this embodiment adopts a one-pot, template-free synthesis method, and specifically includes the following steps:
[0035] S1: Accurately weigh 0.5g of silver nitrate, add it to 60mL of ethanol, and heat it at 60℃ with an open container for 5 minutes under magnetic stirring to obtain a silver salt solution;
[0036] S2: Add ammonia water dropwise to the silver salt solution obtained in step S1, and use the ammonia water to adjust the pH value of the silver salt solution to 10;
[0037] S3: After stirring for another 10 minutes, add 2g of potassium ascorbate to the silver salt solution obtained in step S2, heat to 80℃ and continue the reaction for 3 hours; after the reaction is completed and cooled to room temperature, add the reaction solution to 200mL of deionized water, filter, and wash the filter residue with deionized water (3 times, 20mL each time) and ethanol (3 times, 20mL each time) in sequence. Dry the obtained solid under vacuum at 100℃ to obtain the silver superstructure material product, which is abbreviated as Ag-1.
[0038] Example 2
[0039] The preparation method of the silver superstructure material in this embodiment adopts a one-pot, template-free synthesis method, and specifically includes the following steps:
[0040] S1: Accurately weigh 0.5g of silver tetrafluoroborate, add it to 60mL of dimethyl sulfoxide, and heat it at 80℃ with an open container for 5 minutes under magnetic stirring to obtain a silver salt solution;
[0041] S2: Add ammonia water dropwise to the silver salt solution obtained in step S1, and use the ammonia water to adjust the pH value of the silver salt solution to 10;
[0042] S3: After stirring for another 10 minutes, add 2g of sodium citrate to the silver salt solution obtained in step S2, heat to 80℃ and continue the reaction for 1 hour; after the reaction is completed and cooled to room temperature, add the reaction solution to 200mL of deionized water, filter, and wash the filter residue with deionized water (3 times, 20mL each time) and ethanol (3 times, 20mL each time) in sequence. Dry the obtained solid under vacuum at 100℃ to obtain the silver superstructure material product, which is abbreviated as Ag-2.
[0043] Example 3
[0044] The preparation method of the silver superstructure material in this embodiment adopts a one-pot, template-free synthesis method, and specifically includes the following steps:
[0045] S1: Accurately weigh 0.5g of silver nitrate and 2g of polyvinylpyrrolidone, add them sequentially to 60mL of dioxane, heat at 70℃ with an open container for 5 minutes under magnetic stirring to obtain a silver salt solution;
[0046] S2: Add ammonia water dropwise to the silver salt solution obtained in step S1, and use the ammonia water to adjust the pH value of the silver salt solution to 11;
[0047] S3: After stirring for another 10 minutes, add 2g of ascorbic acid to the silver salt solution obtained in step S2, heat to 80℃ and continue the reaction for 2 hours; after the reaction is completed and cooled to room temperature, add the reaction solution to 200mL of deionized water, filter, and wash the filter residue with deionized water (3 times, 20mL each time) and ethanol (3 times, 20mL each time) in sequence. Dry the obtained solid under vacuum at 100℃ to obtain the silver superstructure material product, which is abbreviated as Ag-3.
[0048] Example 4
[0049] The preparation method of the silver superstructure material in this embodiment adopts a one-pot, template-free synthesis method, and specifically includes the following steps:
[0050] S1: Accurately weigh 0.5g of silver tetrafluoroborate, add it to 60mL of acetonitrile, and heat it at 70℃ with an open container for 5 minutes under magnetic stirring to obtain a silver salt solution;
[0051] S2: Add ammonia water dropwise to the silver salt solution obtained in step S1, and use the ammonia water to adjust the pH value of the silver salt solution to 11;
[0052] S3: After stirring for another 10 minutes, add 1.5g ascorbic acid and 0.5g glucose to the silver salt solution obtained in step S2, heat to 80℃ and continue the reaction for 2 hours; after the reaction is completed and cooled to room temperature, add the reaction solution to 200mL of deionized water, filter, and wash the filter residue with deionized water (3 times, 20mL each time) and ethanol (3 times, 20mL each time) in sequence. Dry the obtained solid under vacuum at 100℃ to obtain the silver superstructure material product, which is abbreviated as Ag-4.
[0053] Comparative Example 1
[0054] The preparation method of the comparative silver superstructure material adopts a one-pot, template-free synthesis, and specifically includes the following steps:
[0055] S1: Accurately weigh 0.5g of silver nitrate and 2g of polyvinylpyrrolidone, add them sequentially to 60mL of acetonitrile, and heat at 80℃ with an open container for 5 minutes under magnetic stirring to obtain a silver salt solution.
[0056] S2: Add ammonia water dropwise to the silver salt solution obtained in step S1, and use the ammonia water to adjust the pH value of the silver salt solution to 11;
[0057] S3: After stirring for another 10 minutes, add 5g of glucose to the silver salt solution obtained in step S2, heat to 80℃ and continue the reaction for 3 hours; after the reaction is completed and cooled to room temperature, add the reaction solution to 200mL of deionized water, filter, and wash the filter residue with deionized water (3 times, 20mL each time) and ethanol (3 times, 20mL each time) in sequence. Dry the obtained solid under vacuum at 100℃ to obtain the reaction product, abbreviated as Ag-5.
[0058] The results show that the appearance photographs of the silver superstructure materials prepared in Examples 1 to 4 are as follows: Figure 1 As shown in the figure, it can be observed that the silver superstructures synthesized under different conditions have different colors, indicating that the silver superstructures have different optical characteristics. Cyclic voltammetry tests were performed on the silver superstructure materials prepared in Examples 1 to 4, and the results are as follows: Figure 2 As shown, this demonstrates that the oxidation potentials of silver superstructures synthesized under different conditions are different, indicating that the silver superstructures have different electrochemical properties. Furthermore, electron microscopy analysis was performed on the silver superstructure materials prepared in Examples 1 to 4 and the product prepared in Comparative Example 1, and the results are as follows: Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown, this demonstrates that under the reaction conditions of Examples 1 to 4, the silver nanoparticles autonomously assembled into a silver superstructure material, and the morphology of the silver superstructure material was affected by the reaction conditions. However, under the reaction conditions of Comparative Example 1, the silver nanoparticles could not autonomously assemble into a silver superstructure.
[0059] Application Example 1
[0060] This application example demonstrates the use of silver superstructure materials as catalysts in the electrocatalytic carbon dioxide reduction reaction. The specific preparation of the working electrode for the electrocatalytic carbon dioxide reduction reaction includes the following steps: First, accurately weigh 30 mg of the product Ag-3 obtained in Example 3, add 1.95 mL of ethanol and 0.05 mL of Nafion solution (5 wt.%), and ultrasonically disperse in an ultrasonic instrument for 2 hours to obtain a dispersion; second, drop-coat the dispersion onto carbon paper (20% PTFE treated), controlling the Ag-3 concentration to 1 mg / cm³. 2 Finally, the working electrode is obtained.
[0061] This application example uses a flow electrolyzer to test the electrocatalytic carbon dioxide reduction characteristics of a silver superstructure material as a catalyst, employing a three-electrode system. Specifically, the anode and cathode chambers of the flow electrolyzer are separated by a Nafion 115 proton exchange membrane. Ag / AgCl is used as the reference electrode, and carbon paper coated with the catalyst is used as the working electrode. Carbon dioxide is uniformly introduced into the gas chamber using a mass flow meter at a flow rate of 20 sccm. The outlet of the gas chamber is connected to an online gas chromatograph for analyzing the composition of the gaseous products. 0.5 M K₂SO₄ is used as the electrolyte, and the liquid flow in both chambers is controlled by a peristaltic pump at a flow rate of 5 ml / min. -1 Constant current testing was performed to analyze the composition of the gaseous products in the gas chamber.
[0062] The test results for this application example are as follows: Figure 8 As shown, the experimental results indicate that using Ag-3 as a catalyst at a carbon dioxide reduction current density of 0.8 A·cm⁻¹ is effective. -2 At that time, the selectivity of carbon monoxide was 93%.
[0063] The products Ag-1, Ag-2, Ag-4, and Ag-5 prepared in Examples 1, 2, and 4, and Comparative Example 1, respectively, were subjected to performance testing using the same electrode preparation method and experimental testing method as in Application Example 1. The experimental results show that Ag-1, Ag-2, and Ag-4 can all achieve a carbon dioxide reduction current density greater than or equal to 0.5 A·cm⁻¹. -2 At a carbon monoxide selectivity of ≥90%, Ag-5 achieves a carbon dioxide reduction current density ≥0.5 A·cm⁻¹. -2 The selectivity of carbon monoxide is less than 85%.
[0064] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.
Claims
1. A method for preparing a silver superstructure material, characterized in that, The preparation method employs a one-pot, template-free synthesis and specifically includes the following steps: S1: Dissolve soluble silver salts in a certain solvent to obtain a silver salt solution of a certain concentration; S2: Add alkali to the silver salt solution obtained in step S1 to adjust the pH value of the silver salt solution; S3: Add a reducing agent to the silver salt solution obtained in step S2, and react at a certain temperature for a period of time to obtain the silver superstructure material.
2. The method for preparing the silver superstructure material as described in claim 1, characterized in that, The soluble silver salt is at least one of silver nitrate, silver tetrafluoroborate, and silver fluoride.
3. The method for preparing the silver superstructure material as described in claim 1, characterized in that, The solvent is at least one selected from water, N,N-dimethylacetamide, dimethyl sulfoxide, N-pyrrolidone, acetonitrile, ethanol, dioxane, and cyclohexane.
4. The method for preparing the silver superstructure material as described in claim 1, characterized in that, The alkali is at least one of ammonia, methylamine, dimethylamine, and triethylamine.
5. The method for preparing the silver superstructure material as described in claim 1, characterized in that, The reducing agent is at least one of ethylene glycol, glucose, ascorbic acid, ascorbate, citric acid, citrate, and sodium borohydride acetate.
6. The method for preparing the silver superstructure material as described in claim 1, characterized in that, In step S3, the reaction temperature is 25℃~100℃; the reaction time is 10min~1440min.
7. The method for preparing the silver superstructure material as described in claim 1, characterized in that, In step S3, a dispersant is added to the silver salt solution obtained in step S2; the dispersant is polyvinylpyrrolidone.
8. A silver superstructure material, characterized in that, The silver superstructure material is prepared using the preparation method of silver superstructure material as described in any one of claims 1 to 7.
9. An application of the silver superstructure material as described in claim 8 in the electrocatalytic carbon dioxide reduction reaction, characterized in that, The silver superstructure material is used as a catalyst, and the electrolytic cell employed is one of the following: membrane electrode electrolyzer, solid electrolyte cell, or flow electrolyzer, with a carbon dioxide reduction current density greater than or equal to 0.5 A·cm⁻¹. -2 The selection of carbon monoxide is greater than or equal to 90%.