Preparation method of cuprous oxide hollow nanometer microspheres and application thereof

Abstract

The application relates to a preparation method of cuprous oxide hollow nanospheres and application thereof, and belongs to the technical field of nanometer material preparation. The cuprous oxide hollow nanospheres are assembled by small cuprous oxide nanoparticles induced by a soft template method and are used for electrocatalytic carbon dioxide reduction reaction. The method is as follows: after sodium bis (2-ethylhexyl) sulfosuccinate and sodium dodecylbenzenesulfonate are dissolved in water, anion vesicles are constructed, a copper 4-ethylpyridine complex is added, and a reducing agent is added to generate cuprous oxide. The material is a hollow nanosphere assembled by extremely small nanoparticles, is favorable for increasing the specific surface area of the material and can expose more active sites, and the restriction effect of the hollow structure also makes the material exhibit relatively excellent performance in electrocatalytic carbon dioxide reduction for preparing multi-carbon products. In addition, the simple preparation method and the special structure of the material make the material possibly have a larger application prospect in other fields.

Description

Technical Field

[0001] This invention pertains to nanomaterials with multiple potential applications, specifically relating to a method for preparing cuprous oxide hollow nanospheres and their application in electrocatalytic carbon dioxide reduction. Background Technology

[0002] It is well known that the size, morphology, and structure of nanomaterials significantly affect their physical and chemical properties, leading to enhanced performance and potential applications that have attracted increasing attention, particularly in areas such as drug delivery, artificial cells, lightweight fillers, catalysis, and chemical storage. Hollow-structured nanomaterials possess immense application potential. Over the past few decades, extensive research has been conducted on the controlled synthesis of nanocrystals, and various methods have been developed to realize these unique nanostructures. For example, template synthesis is a typical and effective approach, and various hollow-structured nanomaterials have been synthesized using hard or soft template methods. However, existing mature template synthesis methods also have several drawbacks. For instance, most methods are cumbersome or require large amounts of template agents. The electrostatic interaction between metal ions and surfactants also hinders the application of soft template methods in preparing hollow metal oxides, and the resulting hollow spherical shells are generally smooth and uniform, which could further increase the number of active sites.

[0003] With the acceleration of global industrialization and the continuous increase in atmospheric carbon dioxide concentration, people are therefore committed to the reuse of carbon dioxide. Among these efforts, electrocatalytic carbon dioxide reduction technology has attracted widespread attention due to its numerous advantages. Research has found that copper-based catalysts can promote the formation of various hydrocarbons and oxygen-containing compounds such as alcohols, and catalysts with hollow structures can improve their performance by enriching reaction intermediates. However, current copper-based catalysts still suffer from many problems such as low selectivity and low current density. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing cuprous oxide hollow microsphere nanomaterials that may have multiple applications, and to use them for electrocatalytic carbon dioxide reduction reactions, in an attempt to solve the problem of low catalytic activity in the prior art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for preparing cuprous oxide hollow nanospheres, comprising the following steps: S1. Add sodium bis(2-ethylhexyl)sulfosuccinate and sodium dodecylbenzenesulfonate to deionized water and stir until dissolved; the molar ratio of sodium bis(2-ethylhexyl)sulfosuccinate to sodium dodecylbenzenesulfonate is 2.8:2.4; the concentration of sodium bis(2-ethylhexyl)sulfosuccinate is 6.22 – 12.44 g / L; S2. Add 4-ethylpyridine to a copper acetate solution to form a deep blue solution; the concentrations of copper ions and 4-ethylpyridine are equal. S3. Add the solution from step S2 to the solution from step S1 and continue stirring; wherein the molar ratio of copper ions to sodium bis(2-ethylhexyl)sulfosuccinate is (0.4-0.6):(1.4-2.8). S4. Prepare a reducing agent solution by dissolving ascorbic acid and sodium hydroxide in deionized water; wherein the molar ratio of ascorbic acid to copper ions is (1-5):1, and the molar ratio of sodium hydroxide to copper ions is (0-30):1. S5. Add the solution prepared in step S4 to the mixed solution obtained in step S3, and react for 10 min-30 min. S6. After the reaction is complete, centrifuge, wash, and dry to obtain cuprous oxide hollow nanospheres.

[0006] In step S2, the concentrations of copper ions and 4-ethylpyridine are both 0.1 mol / L.

[0007] The reducing agent solution contains 0.3 mol / L of ascorbic acid and 1.2 mol / L of sodium hydroxide.

[0008] A hollow cuprous oxide nanosphere was prepared using the method described above.

[0009] The cuprous oxide hollow nanospheres are used in the electrocatalytic carbon dioxide reduction reaction.

[0010] An electrode is prepared using the aforementioned hollow cuprous oxide nanospheres.

[0011] A method for preparing an electrode, wherein hollow cuprous oxide nanospheres are loaded onto carbon paper via a drop-coating method, with a loading amount of 0.2-1 mg / cm³. 2 .

[0012] The electrode is used in the electrocatalytic carbon dioxide reduction reaction.

[0013] Specifically, a method for preparing hollow cuprous oxide nanospheres includes the following steps: (S1) Take 100 mL of deionized water into a round-bottom flask, add 0.622-1.244 g of sodium bis(2-ethylhexyl)sulfosuccinate and 0.418-0.836 g of sodium dodecylbenzenesulfonate, and stir thoroughly in an oil bath at 30-50 °C until dissolved.

[0014] (S2) Dissolve 0.2g of copper acetate in 10mL of deionized water, then add 115μL of 4-ethylpyridine to form a dark blue solution.

[0015] (S3) Take 6 mL of the solution in S2 and add it to the solution in S1, and continue stirring to stabilize for 0.5 h.

[0016] (S4) Take 0.106-0.540g of ascorbic acid and 0-0.480g of sodium hydroxide in a beaker and dissolve them with 10mL of deionized water.

[0017] (S5) Add the solution prepared in S4 to the mixed solution obtained in S3 at an appropriate rate and react for 10 min.

[0018] (S6) The yellow turbid liquid obtained in S5 is centrifuged and washed multiple times with deionized water. Finally, it is washed once with ethanol and then dried in a vacuum drying oven at 50°C for later use.

[0019] The control group consisted of materials prepared without the addition of any surfactants.

[0020] The nanomaterials are loaded onto carbon paper using a drop-coating method and applied to the electrocatalytic carbon dioxide reduction reaction.

[0021] Compared with the prior art, the present invention has the following advantages: Hollow cuprous oxide nanospheres were assembled from small cuprous oxide nanoparticles using an optimized soft template method and were then used for the electrocatalytic reduction of carbon dioxide. This method involved dissolving sodium bis(2-ethylhexyl)sulfosuccinate and sodium dodecylbenzenesulfonate in water to construct anionic vesicles, adding a copper-4-ethylpyridine complex, and then adding a reducing agent to generate cuprous oxide.

[0022] (1) Hollow nanospheres are assembled from extremely small nanoparticles, which is beneficial to increasing the specific surface area of ​​the material and exposing more active sites. Compared with the uniform solid shells in other hollow nanomaterials, the present invention can expose more active sites.

[0023] (2) The optimized method uses fewer surfactants (such as the CTAB method) compared with other methods, but can still maintain the material with good morphology, uniform size and obvious hollow structure.

[0024] (3) The hollow structure helps to enrich intermediates in the electrocatalytic carbon dioxide reduction reaction, thereby promoting the formation of multi-carbon products such as ethylene and ethanol. In other words, the confinement effect of the hollow structure also makes it exhibit superior performance in the study of electrocatalytic carbon dioxide reduction to prepare multi-carbon products.

[0025] In summary, hollow copper-based nanomaterials not only possess a larger specific surface area and more active sites, but can also effectively enrich reaction intermediates through spatial confinement effects, promoting the occurrence of C-C coupling reactions to facilitate the generation of multi-carbon products such as ethylene and ethanol. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating Embodiment 1 of the present invention.

[0027] Figure 2 These are scanning electron microscope images of Examples 1-6 and Comparative Examples 1-2 of the present invention.

[0028] Figure 3 The X-ray diffraction patterns are those of Embodiment 1 and Comparative Example 1 of the present invention.

[0029] Figure 4 These are transmission electron microscope images of Embodiment 1 and Comparative Examples 1-2 of the present invention.

[0030] Figure 5 This is a Faraday efficiency diagram of the catalytic performance of the electrocatalytic carbon dioxide reduction reaction in Example 1 of the present invention. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and examples. The embodiments of the present invention include, but are not limited to, implementation examples.

[0032] A method for preparing hollow cuprous oxide nanospheres, comprising the following steps, involves the optimized soft template method to induce the assembly of small cuprous oxide nanoparticles: (S1) Take 100 mL of deionized water into a round-bottom flask, add 0.622 - 1.244 g of sodium bis(2-ethylhexyl)sulfosuccinate and 0.418 - 0.836 g of sodium dodecylbenzenesulfonate, and stir thoroughly in an oil bath at 30 - 50 °C until dissolved.

[0033] (S2) Dissolve 0.2g of copper acetate in 10mL of deionized water, then add 115μL of 4-ethylpyridine to form a dark blue solution.

[0034] (S3) Take 6 mL of the solution in S2 and add it to the solution in S1, and continue stirring to stabilize for 0.5 h.

[0035] (S4) Take 0.106 - 0.540 g ascorbic acid and 0 - 0.480 g sodium hydroxide in a beaker and dissolve them with 10 mL of deionized water.

[0036] (S5) Add the solution prepared in S4 to the mixed solution obtained in S3 at an appropriate rate and react for 10 min.

[0037] (S6) The yellow turbid liquid obtained in S5 is centrifuged and washed multiple times with deionized water. Finally, it is washed once with ethanol and then dried in a vacuum drying oven at 50°C for later use.

[0038] The control group consisted of materials prepared without the addition of any surfactants.

[0039] The nanomaterials are loaded onto carbon paper using a drop-coating method and applied to the electrocatalytic carbon dioxide reduction reaction.

[0040] Specific implementation examples are as follows: Example 1

[0041] A method for preparing hollow cuprous oxide nanospheres, comprising the following steps, involves the optimized soft template method to induce the assembly of small cuprous oxide nanoparticles: Take 100 mL of deionized water in a round-bottom flask, add 0.622 g of sodium bis(2-ethylhexyl)sulfosuccinate and 0.418 g of sodium dodecylbenzenesulfonate, and stir thoroughly in an oil bath at 30 °C until dissolved. Take 0.2 g of copper acetate and dissolve it completely in 10 mL of deionized water, then add 115 μL of 4-ethylpyridine to form a deep blue solution. Take 6 mL of the above solution and add it to the surfactant solution, and continue stirring to stabilize for 0.5 h. Take 0.54 g of ascorbic acid and 0.48 g of sodium hydroxide in a beaker and dissolve them in 10 mL of deionized water to prepare a reducing agent solution. Add the reducing agent solution to the mixed solution of surfactant and copper ions and react for 10 min. Centrifuge the resulting yellow turbid liquid, wash it several times with deionized water, and finally wash it twice with ethanol. Then dry it in a vacuum drying oven at 50 °C for later use. Example 2

[0042] Take 100 mL of deionized water in a round-bottom flask, add 1.244 g of sodium bis(2-ethylhexyl)sulfosuccinate and 0.836 g of sodium dodecylbenzenesulfonate, and stir thoroughly in an oil bath at 30 °C until dissolved. Take 0.2 g of copper acetate and dissolve it thoroughly in 10 mL of deionized water, then add 115 μL of 4-ethylpyridine to form a deep blue solution. Take 6 mL of the above solution and add it to the surfactant solution, and continue stirring to stabilize for 0.5 h. Take 0.54 g of ascorbic acid and 0.48 g of sodium hydroxide in a beaker and dissolve them in 10 mL of deionized water to prepare a reducing agent solution. Add the reducing agent solution to the mixed solution of surfactant and copper ions and react for 10 min. Centrifuge the resulting yellow turbid liquid, wash it several times with deionized water, and finally wash it twice with ethanol. Then dry it in a vacuum drying oven at 50 °C for later use. Example 3

[0043] Take 100 mL of deionized water in a round-bottom flask, add 1.244 g of sodium bis(2-ethylhexyl)sulfosuccinate and 0.836 g of sodium dodecylbenzenesulfonate, and stir thoroughly in an oil bath at 30 °C until dissolved. Take 0.2 g of copper acetate and dissolve it completely in 10 mL of deionized water, then add 115 μL of 4-ethylpyridine to form a deep blue solution. Take 6 mL of the above solution and add it to the surfactant solution, and continue stirring to stabilize for 0.5 h. Take 0.54 g of ascorbic acid and 0.48 g of sodium hydroxide in a beaker and dissolve them in 10 mL of deionized water to prepare a reducing agent solution. Add the reducing agent solution to the mixed solution of surfactant and copper ions and react for 30 min. Centrifuge the resulting yellow turbid liquid, wash it several times with deionized water, and finally wash it twice with ethanol. Then dry it in a vacuum drying oven at 50 °C for later use. Example 4

[0044] Take 100 mL of deionized water in a round-bottom flask, add 1.244 g of sodium bis(2-ethylhexyl)sulfosuccinate and 0.836 g of sodium dodecylbenzenesulfonate, and stir thoroughly in an oil bath at 50 °C until dissolved. Take 0.2 g of copper acetate and dissolve it thoroughly in 10 mL of deionized water, then add 115 μL of 4-ethylpyridine to form a deep blue solution. Take 6 mL of the above solution and add it to the surfactant solution, and continue stirring to stabilize for 0.5 h. Take 0.54 g of ascorbic acid and 0.48 g of sodium hydroxide in a beaker and dissolve them in 10 mL of deionized water to prepare a reducing agent solution. Add the reducing agent solution to the mixed solution of surfactant and copper ions and react for 10 min. Centrifuge the resulting yellow turbid liquid, wash it several times with deionized water, and finally wash it twice with ethanol. Then dry it in a vacuum drying oven at 50 °C for later use. Example 5

[0045] Take 100 mL of deionized water in a round-bottom flask, add 1.244 g of sodium bis(2-ethylhexyl)sulfosuccinate and 0.836 g of sodium dodecylbenzenesulfonate, and stir thoroughly in an oil bath at 30 °C until dissolved. Take 0.2 g of copper acetate and dissolve it thoroughly in 10 mL of deionized water, then add 115 μL of 4-ethylpyridine to form a deep blue solution. Take 6 mL of the above solution and add it to the surfactant solution, and continue stirring to stabilize for 0.5 h. Take 0.106 g of ascorbic acid in a beaker and dissolve it in 10 mL of deionized water to prepare a reducing agent solution. Add the reducing agent solution to the mixed solution of surfactant and copper ions and react for 30 min. Centrifuge the resulting yellow turbid liquid, wash it several times with deionized water, and finally wash it twice with ethanol. Then dry it in a vacuum drying oven at 50 °C for later use. Example 6

[0046] Take 100 mL of deionized water in a round-bottom flask, add 1.244 g of sodium bis(2-ethylhexyl)sulfosuccinate and 0.836 g of sodium dodecylbenzenesulfonate, and stir thoroughly in an oil bath at 30 °C until dissolved. Take 0.2 g of copper acetate and dissolve it thoroughly in 10 mL of deionized water, then add 115 μL of 4-ethylpyridine to form a deep blue solution. Take 4 mL of the above solution and add it to the surfactant solution, and continue stirring to stabilize for 0.5 h. Take 0.070 g of ascorbic acid in a beaker and dissolve it in 10 mL of deionized water to prepare a reducing agent solution. Add the reducing agent solution to the mixed solution of surfactant and copper ions and react for 30 min. Centrifuge the resulting yellow turbid liquid, wash it several times with deionized water, and finally wash it twice with ethanol. Then dry it in a vacuum drying oven at 50 °C for later use.

[0047] Comparative Example 1

[0048] Dissolve 0.2 g of copper acetate in 10 mL of deionized water, then add 115 μL of 4-ethylpyridine to form a deep blue solution. Add 6 mL of this solution to a round-bottom flask and 100 mL of deionized water. Stir and stabilize in an oil bath at 30 °C for 0.5 h. Dissolve 0.54 g of ascorbic acid and 0.48 g of sodium hydroxide in 10 mL of deionized water to prepare a reducing agent solution. Add the reducing agent solution to the copper complex solution and react for 10 min. Centrifuge the resulting yellow turbid liquid, wash repeatedly with deionized water, and finally wash twice with ethanol. Dry the liquid in a vacuum drying oven at 50 °C for later use.

[0049] Comparative Example 2

[0050] Dissolve 0.2 g of copper acetate in 10 mL of deionized water, then add 115 μL of 4-ethylpyridine to form a deep blue solution. Add 6 mL of this solution to a round-bottom flask and 100 mL of deionized water. Stir and stabilize in an oil bath at 30 °C for 0.5 h. Dissolve 0.106 g of ascorbic acid in 10 mL of deionized water to prepare a reducing agent solution. Add the reducing agent solution to the copper complex solution and react for 10 min. Centrifuge the resulting yellow turbid liquid, wash repeatedly with deionized water, and finally wash twice with ethanol. Dry the liquid in a vacuum drying oven at 50 °C for later use.

[0051] Figure 2These are scanning electron microscope images of the materials obtained in Examples 1, 2, 3, 4, 5, and 6 of the present invention, and Comparative Examples 1 and 2. As can be seen, the nanomaterials obtained in Example 1 (Figure a) have good morphology and uniform size, and a hollow structure can be observed. When the surfactant concentration is doubled (Example 2 (Figure b), the material morphology remains good. When the reaction time is extended to 30 minutes (Example 3, Figure c), some nanospheres break down and revert to dispersed nanoparticles, similar to the morphology of the material obtained by increasing the temperature to 50°C while keeping the reaction time constant (Example 4, Figure d). It can be inferred that the assembly of anionic vesicles will be disrupted after the reaction reaches a certain extent. When the reducing agent solution is changed (Example 5, Figure e), crystal nucleation is hindered, so that the nanospheres are not assembled from nanoparticles, and the morphology of the microspheres is irregular. Moreover, the morphology remains basically unchanged when the copper ion concentration is changed (Example 6, Figure f). When no surfactant is added (Comparative Example 1, Figure g), the nanoparticles do not assemble into hollow microspheres and will aggregate irregularly. When no surfactant is added and the reducing agent solution is changed (Comparative Example 2, Figure h), the nanomaterials exhibit a regular solid spherical structure.

[0052] Figure 3 The X-ray diffraction patterns of the materials obtained in Example 1 and Comparative Example 1 of the present invention show that both are cuprous oxide materials with obvious crystal lattices. In Comparative Example 1, the material is extremely small and dispersed, and its surface is more easily oxidized by oxygen, thus exhibiting extremely low-intensity copper oxide lattice peaks.

[0053] Figure 4 The images shown are transmission electron microscope (TEM) images of the nanomaterials obtained in Example 1, Comparative Example 1, and Comparative Example 2 of this invention. They reveal that extremely small nanoparticles assemble into hollow nanospheres under the action of a surfactant (Figure a). Without a surfactant, the dispersed nanoparticles exhibit irregular aggregation (Figure b). By changing and reducing the amount of reducing agent, the spherical nanomaterials display a distinct solid structure (Figure c).

[0054] Example 1 was used in the application study of electrocatalytic carbon dioxide reduction. The sample was loaded onto carbon paper using a common drop-coating method, with a loading concentration of 0.4 mg / cm³. 2 The catalytic performance of the material was tested using an electrochemical workstation (CHI1140E), and the products were analyzed using gas chromatography and liquid chromatography. Figure 5 It is evident that the Faraday efficiency of multi-carbon products can remain above 50% over a wide range, while the yield of single-carbon products such as carbon monoxide is relatively low. This is attributed to the enrichment of reaction intermediates by the hollow structure, which promotes the synthesis of multi-carbon products. The relatively high amount of hydrogen byproduct may be due to the adsorption of small amounts of 4-ethylpyridine or surfactant molecules on the material surface, enhancing its hydrogen evolution capacity.

[0055] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any changes made based on the design principles of the present invention, or any non-creative modifications made thereon, shall fall within the scope of protection of the present invention.

Claims

1. A method for preparing hollow cuprous oxide nanospheres, characterized in that, Includes the following steps: S1. Sodium bis(2-ethylhexyl)sulfosuccinate and sodium dodecylbenzenesulfonate are added to deionized water and stirred in an oil bath at 30°C until dissolved; the molar ratio of sodium bis(2-ethylhexyl)sulfosuccinate to sodium dodecylbenzenesulfonate is 2.8:2.4; the concentration of sodium bis(2-ethylhexyl)sulfosuccinate is 6.22-12.44 g / L; S2. Add 4-ethylpyridine to a copper acetate solution to form a dark blue mixed solution; the concentrations of copper ions and 4-ethylpyridine in the mixed solution are equal. S3. Add the solution from step S2 to the solution from step S1 and continue stirring; wherein the molar ratio of copper ions to sodium bis(2-ethylhexyl)sulfosuccinate is (0.4-0.6):(1.4-2.8). S4. Prepare a reducing agent solution by dissolving ascorbic acid and sodium hydroxide in deionized water; wherein the molar ratio of ascorbic acid to copper ions is (1-5):1, and the molar ratio of sodium hydroxide to copper ions is (20-30):

1. S5. Add the solution prepared in step S4 to the mixed solution obtained in step S3 and react for 10 min. S6. After the reaction is complete, centrifuge, wash, and dry. Hollow cuprous oxide nanospheres were obtained; In step S2, the concentrations of copper ions and 4-ethylpyridine are both 0.1 mol / L; The reducing agent solution contains 0.3 mol / L of ascorbic acid and 1.2 mol / L of sodium hydroxide.

2. A hollow cuprous oxide nanosphere, characterized in that: It is prepared by the method described in claim 1.

3. The application of the cuprous oxide hollow nanospheres according to claim 2, characterized in that: The cuprous oxide hollow nanospheres are used in the electrocatalytic carbon dioxide reduction reaction.

4. An electrode, characterized in that: The electrode is prepared using cuprous oxide hollow nanospheres as described in claim 2.

5. The method for preparing an electrode according to claim 4, characterized in that: The cuprous oxide hollow nanospheres were loaded onto carbon paper using a drop-coating method, with a loading amount of 0.2-1 mg / cm³. 2 .

6. The application of the electrode according to claim 4, characterized in that: The electrode is used in the electrocatalytic carbon dioxide reduction reaction.

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