A method for preparing copper nanowire clusters based on a bubble template method

Abstract

The application discloses a copper nanowire cluster preparation method based on a bubble template method. Nitrogen and hydrogen generated by the thermal decomposition reaction of hydrazine hydrate are used as templates to construct a porous nanowire cluster with a self-supporting structure in the process of preparing the copper nanowire cluster by a hydrothermal method. The hydrothermal reaction provides reaction conditions for the thermal decomposition of hydrazine hydrate, and the generated copper nanowire plays a catalytic role in the thermal decomposition of hydrazine hydrate. Compared with other liquid or solid template agents, the method does not need to introduce an additional catalyst, the bubble template automatically escapes in the process of removing the copper nanowire cluster from the solution, and the preparation process is simple and green. Finally, the porous copper nanowire cluster with the self-supporting structure is formed, and a feasible scheme is provided for the industrial application of the copper-based catalyst in various fields such as photocatalysis, electrocatalysis, electrolytic water catalysis and the like.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterial preparation, specifically relating to the preparation and application of copper nanowire clusters based on the bubble template method. Background Technology

[0002] With the development and needs of high technology, nanomaterials have attracted widespread attention due to their excellent optical, electrical, and electrocatalytic properties. Compared to traditional high-activity noble metal catalysts such as gold, silver, platinum, and palladium, copper-based nanomaterials have advantages such as low cost, wide availability, and simple preparation methods, making them an excellent alternative catalyst in the field of catalysis. To further improve the catalytic activity of copper nanomaterials, they are usually designed as porous spherical materials with high specific surface area. However, in use, they usually need to be dispersed and bonded onto a substrate, thus reducing the effective usable area. Nanowires are one-dimensional materials with high orientation and designable size, possessing high aspect ratio and specific surface area, as well as self-supporting mechanical properties. They are easily prepared by directly loading them onto a substrate in cluster form to prepare catalytic products. Currently, the main synthesis methods for copper nanowires include physical vapor deposition, hydrothermal methods, liquid phase deposition, and electrodeposition. Among these, the hydrothermal method, with its simple steps and ease of large-scale preparation, has been extensively studied. In hydrothermal methods, in order to obtain oriented and regularly distributed copper nanowires, it is usually necessary to use regularly distributed porous substrates such as copper foam or porous alumina as the initial growth source for directional growth of nanowires, which is costly and involves complicated steps.

[0003] To reduce the difficulty of growing copper nanowires, researchers used a template method to construct porous nanowire clusters with self-supporting structures. However, template residues often clog the pores, reducing the catalytic transport effect. Furthermore, this method of introducing and then removing the template increases the complexity of the process and the difficulty of large-scale preparation.

[0004] As can be seen from the above explanations and examples, the preparation of self-supporting and porous copper nanowire clusters is crucial for the use of copper-based nanocatalysts. Secondly, the current preparation steps for nanowire clusters based on template methods are complex, and template blockage reduces catalytic efficiency. Currently, self-supporting porous copper nanowires are prepared using template methods, and these templates are typically based on silica or other metal oxides. Removing these templates is a cumbersome process, and methods using bubbles as templates for copper nanowire cluster growth are rarely reported. Summary of the Invention

[0005] In view of the above problems, this invention proposes a method for using nitrogen and hydrogen gases decomposed from hydrazine hydrate as bubble templates to participate in the growth of copper nanowire clusters. Hydrazine hydrate (N₂H₄H₂O) can decompose at high temperatures to generate nitrogen and hydrogen gases, and the reaction equation is shown in the following formula:

[0006]

[0007] In the process of preparing copper nanowires by hydrothermal method, the hydrothermal reaction provides the reaction temperature for the thermal decomposition of hydrazine hydrate, and the product copper nanowires can act as a catalyst to catalyze the reaction of hydrazine hydrate. Under the combined effect of the two, a large amount of nitrogen and hydrogen will accumulate near the copper nanowire cluster, thereby forming a bubble template and further constructing a hierarchical porous structure.

[0008] The technical solution of the present invention:

[0009] A method for preparing copper nanowire clusters based on a bubble template method, characterized by comprising the following steps:

[0010] Step 1: Prepare copper nanowire pre-reaction solution

[0011] First, weigh a certain amount of sodium hydroxide and copper nitrate according to the mass fraction, and dissolve them in deionized water to prepare sodium hydroxide solution and copper nitrate solution respectively. Measure 100-500 parts of the prepared sodium hydroxide solution and transfer it to a blue-capped screw-top bottle, and keep it magnetically stirred. Then, according to the set volume ratio of copper nitrate solution to sodium hydroxide solution, add copper nitrate solution dropwise to sodium hydroxide solution, and stir magnetically for 10-30 minutes. Further, add the mixed solution of ethylenediamine and copper nitrate dropwise to the solution, and stir magnetically for 0.2-2 hours. Then add a dispersant accounting for 1-4% of the mass percentage of ethylenediamine. Then, sonicate for 5-20 minutes to prepare a uniformly dispersed copper nanowire pre-reaction solution.

[0012] Step 2: Growth of copper nanowire clusters using the bubble template method

[0013] A hydrazine hydrate solution with a mass fraction of 70-90% was prepared. The hydrazine hydrate solution was added dropwise to the pre-prepared copper nanowire pre-reaction solution at a set volume ratio of hydrazine hydrate solution to copper nitrate solution. The mixture was magnetically stirred at 22-25℃ for 10-30 min, followed by sonication at room temperature for 20-45 min. The blue-capped screw-top bottle was then transferred to a water bath and heated at 50-75℃ for 2-6 h to obtain a brick-red foamy copper nanowire structure. Subsequently, the prepared copper nanowire clusters were filtered, dried, and then transferred to a desiccator for storage.

[0014] Furthermore, the sodium hydroxide mentioned in step 1 can be replaced with potassium hydroxide, barium hydroxide, or calcium hydroxide.

[0015] Furthermore, the concentration of the sodium hydroxide solution in step 1 is 5-15 mol / L.

[0016] Furthermore, the copper nitrate mentioned in step 1 can be replaced with copper sulfate or copper chloride.

[0017] Furthermore, the volume ratio of copper nitrate solution to sodium hydroxide solution in step 1 is 1:20-30.

[0018] Furthermore, the volume ratio of ethylenediamine to copper nitrate solution in step 1 is 1:5-15.

[0019] Furthermore, the magnetic stirring speed in step 1 is 1000-2000 r / min.

[0020] Furthermore, the preparation method of the dispersing agent mentioned in step 1 is as follows:

[0021] H1: Weigh 0.12-0.24 parts by weight of boron nitrate, 0.3-0.6 parts by weight of 2-aminonaphthalene-4,8-disulfonic acid, and 0.01-0.05 parts by weight of acetic acid, place them in 100-200 parts by weight of water, stir at 30-40°C for 20-50 minutes, and remove the water by distillation;

[0022] H2: Continue to add 5-11 parts of dioctadecylamine, 5-8 parts of dilithium mercaptosuccinate, and 130-150 parts of DMF. React at 70-80℃ for 20-50 minutes, then remove DMF by distillation to obtain the dispersing agent.

[0023] Furthermore, the volume ratio of hydrazine hydrate solution to copper nitrate solution in step 2 is 1:100-500.

[0024] The preparation principle of the dispersing agent in this scheme is as follows:

[0025] Boron nitrate reacts with 2-aminonaphthalene-4,8-disulfonic acid to form a boron 2-aminonaphthalene-4,8-disulfonic acid complex; it then undergoes a mercapto-amino addition reaction with lithium mercaptosuccinate; bis(octadecylamine) reacts with lithium mercaptosuccinate (CAS: 58164-93-5); a mercapto-amino addition reaction is then carried out; a dispersing agent is obtained.

[0026] The 2-aminonaphthalene-4,8-disulfonate boron complex, a dispersant synthesized by lithium-grafted octadecylamine, can prevent secondary agglomeration of copper nanowires after initial dispersion, thereby stabilizing the dispersion, inhibiting the migration and agglomeration of nano-metals, and improving the dispersion effect.

[0027] The beneficial effects achieved by the present invention using the above technical solution are as follows: This solution:

[0028] 1. This invention utilizes nitrogen and hydrogen generated from the self-decomposition of hydrazine hydrate as bubble templates to construct a self-supporting hierarchical porous structure during the preparation of copper nanowires. Compared to traditional template agents, the bubble template method has advantages such as simple synthesis and easy removal. The decomposition of hydrazine hydrate produces nitrogen and hydrogen gases that do not pollute the atmosphere, and the decomposition process utilizes copper nanowires as a self-catalyst, requiring no additional catalysts or reaction conditions. Compared to other methods, the bubble template method has advantages such as simple synthesis, a green synthesis process, and no introduction of other catalysts, making it suitable for the large-scale industrialization of self-supporting copper nanowire clusters.

[0029] 2. The 2-aminonaphthalene-4,8-disulfonic acid boron complex binds to the surface of copper nanowires through coordination bonds, forming a stable interfacial layer that prevents secondary aggregation of the copper nanowires. Lithium-grafted octadecylamine acts as a steric hindrance, occupying active sites on the copper nanowire surface or creating a physical barrier, further preventing nanowire aggregation. The two compounds produce a synergistic effect, forming a stronger interfacial interaction, thus more effectively preventing copper nanowire aggregation. The copper nanowires remain stable after initial dispersion and do not undergo secondary aggregation. This not only improves the dispersion effect but also facilitates subsequent processing and applications. Attached Figure Description

[0030] Figure 1 The porous copper nanowire clusters synthesized in a blue-capped flask according to Example 1 of this invention are shown.

[0031] Figure 2 The porous copper nanowire clusters are obtained by vacuum filtration and drying on filter paper in Example 1 of this invention.

[0032] Figure 3 This is a SEM image of Embodiment 1 of the present invention at a magnification of 100x.

[0033] Figure 4 This is an SEM image of Embodiment 1 of the present invention at a magnification of 10,000x.

[0034] Figure 5 This is a SEM image of Embodiment 2 of the present invention at a magnification of 10,000x.

[0035] Figure 6 This is a SEM image of Embodiment 3 of the present invention at a magnification of 10,000x.

[0036] Figure 7 The copper nanowire clusters obtained by vacuum filtration on filter paper are a comparative example of the present invention.

[0037] Figure 8 This is a SEM image of the comparative example of this invention at a magnification of 1000x.

[0038] Figure 9These are the XRD patterns of copper nanowire clusters prepared in the embodiments and comparative examples of this invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with embodiments. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] Example 1

[0042] Preparation of dispersing agents:

[0043] H1: Weigh 1.8g boron nitrate, 4.5g 2-aminonaphthalene-4,8-disulfonic acid, and 0.3g acetic acid and place them in 1500g water. Stir at 35℃ for 45 minutes and remove water by distillation.

[0044] H2: Continue to add 80g of dioctadecylamine, 65g of dilithium mercaptosuccinate, and 1400g of DMF. React at 75°C for 35 minutes. Remove DMF by distillation to obtain the dispersing agent.

[0045] Preparation method of copper nanowire clusters based on bubble template method:

[0046] Weigh 240g of NaOH granules and dissolve them in 500mL of deionized water to prepare a 12mol / L NaOH solution. Transfer 250mL of the prepared NaOH solution to a blue-capped screw-top bottle and stir magnetically at 1500rpm. Weigh 2.42g of copper nitrate powder and disperse it evenly in 100mL of deionized water. Then, add 10mL of the prepared copper nitrate solution dropwise to the blue-capped screw-top bottle and continue stirring magnetically at 1500rpm for 20min. Further, add 1mL of ethylenediamine dropwise to the blue-capped screw-top bottle and stir magnetically at 1500rpm for 1h. Then, add a dispersant at 2.5% of the ethylenediamine mass percentage and sonicate for 10min.

[0047] 50 μL of hydrazine hydrate was added dropwise to a blue-capped screw-top bottle. The solution was magnetically stirred at 1500 rpm for 20 min at room temperature, followed by sonication at room temperature for 30 min. At this point, the solution turned blue-white. The bottle was then transferred to a water bath and incubated at 65°C for 4 h to obtain brick-red, foamy copper nanowire clusters. Figure 1 As shown. Further, the prepared copper nanowire clusters were filtered, dried, and then transferred to a desiccator for storage.

[0048] The morphology of the prepared copper nanowire clusters is as follows Figure 2 As shown, the copper nanowire clusters filtered onto the filter paper retain a multi-level porous structure while exhibiting self-supporting properties, such as... Figure 3 These are SEM images of the prepared copper nanowire clusters, clearly showing the pore structure distributed between 50-500 μm left by the bubble template. Increasing the magnification reveals, for example... Figure 4 The copper nanowire cluster shown is made up of copper nanowires with a length of about 10 μm and a diameter of about 0.2 μm.

[0049] Example 2

[0050] Preparation of dispersing agents:

[0051] H1: Weigh 1.8g boron nitrate, 4.5g 2-aminonaphthalene-4,8-disulfonic acid, and 0.3g acetic acid and place them in 1500g water. Stir at 35℃ for 45 minutes and remove water by distillation.

[0052] H2: Continue to add 80g of dioctadecylamine, 65g of dilithium mercaptosuccinate, and 1400g of DMF. React at 75°C for 35 minutes. Remove DMF by distillation to obtain the dispersing agent.

[0053] Preparation method of copper nanowire clusters based on bubble template method:

[0054] Weigh 370g of Ca(OH)₂ and dissolve it in 500mL of deionized water to prepare a 5mol / L Ca(OH)₂ solution. Transfer 250mL of the prepared sodium hydroxide solution to a blue-capped screw-top bottle and stir magnetically at 2000 rpm. Weigh 1.60g of copper sulfate powder and disperse it evenly in 100mL of deionized water. Then, add 10mL of the prepared copper sulfate solution dropwise to the blue-capped screw-top bottle and continue stirring magnetically at 1500 rpm for 20 minutes. Further, add 1mL of ethylenediamine dropwise to the blue-capped screw-top bottle and stir magnetically at 1500 rpm for 1 hour. Then, add a dispersant at 2.5% of the ethylenediamine mass percentage and sonicate for 10 minutes.

[0055] 50 μL of hydrazine hydrate was added dropwise to a blue-capped screw-top bottle. The solution was magnetically stirred at 1500 rpm for 20 min at room temperature, followed by sonication at room temperature for 30 min. At this point, the solution turned blue-white. The bottle was then transferred to a water bath and incubated at 65°C for 4 h to obtain brick-red, foamy copper nanowire clusters. Further, the prepared copper nanowire clusters were filtered, dried, and stored in a desiccator. Figure 5 These are SEM images of the prepared copper nanowire clusters.

[0056] Example 3

[0057] Preparation of dispersing agents:

[0058] H1: Weigh 1.8g boron nitrate, 4.5g 2-aminonaphthalene-4,8-disulfonic acid, and 0.3g acetic acid and place them in 1500g water. Stir at 35℃ for 45 minutes and remove water by distillation.

[0059] H2: Continue to add 80g of dioctadecylamine, 65g of dilithium mercaptosuccinate, and 1400g of DMF. React at 75°C for 35 minutes. Remove DMF by distillation to obtain the dispersing agent.

[0060] Preparation method of copper nanowire clusters based on bubble template method:

[0061] Weigh 300g of NaOH granules and dissolve them in 500mL of deionized water to prepare a 15mol / L NaOH solution. Transfer 250mL of the prepared NaOH solution to a blue-capped screw-top bottle and stir magnetically at 1500 rpm. Weigh 1.35g of copper chloride powder and disperse it evenly in 100mL of deionized water. Then, add 10mL of the prepared copper chloride solution dropwise to the blue-capped screw-top bottle and continue stirring magnetically at 1000 rpm for 20 minutes. Further, add 1mL of ethylenediamine dropwise to the blue-capped screw-top bottle and stir magnetically at 1500 rpm for 1 hour. Then, add a dispersant at 2.5% of the ethylenediamine mass percentage and sonicate for 10 minutes.

[0062] 50 μL of hydrazine hydrate was added dropwise to a blue-capped screw-top bottle. The solution was magnetically stirred at 1500 rpm for 20 min at room temperature, followed by sonication at room temperature for 30 min. At this point, the solution turned blue-white. The bottle was then transferred to a water bath and incubated at 65°C for 4 h to obtain brick-red, foamy copper nanowire clusters. Further, the prepared copper nanowire clusters were filtered, dried, and stored in a desiccator. Figure 6 These are SEM images of the prepared copper nanowire clusters.

[0063] Comparative Example

[0064] Copper nanowire clusters not grown using the bubble template method were used as a comparative example.

[0065] Weigh 240g of NaOH granules and dissolve them in 500mL of deionized water to prepare a 12mol / L NaOH solution. Transfer 250mL of the prepared NaOH solution to a blue-capped screw-top bottle and stir magnetically at 1500r / min. Weigh 2.42g of copper nitrate powder and disperse it evenly in 100mL of deionized water. Then, add 10mL of the prepared copper nitrate solution dropwise to the blue-capped screw-top bottle and continue stirring magnetically at 1500r / min for 20min. Further, add 1mL of ethylenediamine dropwise to the blue-capped screw-top bottle and stir magnetically at 1500r / min for 1h, followed by sonication for 10min. Transfer the blue-capped screw-top bottle to a water bath and incubate at 65℃ for 4h to obtain brick-red, foamy copper nanowire clusters. Further, filter and dry the prepared copper nanowire clusters and store them in a desiccator.

[0066] The morphology of the prepared copper nanowire clusters is as follows Figure 5 As shown, the copper nanowire clusters on the filter paper are tightly bound together, with no obvious porous structure on the surface, such as... Figure 6 These are SEM images of the prepared copper nanowire clusters. The tightly packed nanowire clusters show no obvious pore structure. Increasing the magnification reveals... Figure 7 Copper nanowire clusters are made up of copper nanowires with a length of about 10 μm and a diameter of about 0.2 μm.

[0067] Figure 8 The XRD characterization comparison between the examples and the comparative examples demonstrates that the examples and the comparative examples produce copper nanowires with regular morphology.

[0068] The present invention has been described above through specific embodiments and examples. However, these descriptions are merely illustrative and should not be construed as limiting the scope of protection of the present invention. Without departing from the spirit and scope of the present invention, those skilled in the art can make various improvements, modifications, or equivalent substitutions to the technical solutions and implementation methods of the present invention, and all such modifications and substitutions should fall within the scope of protection of the present invention.

Claims

1. A method for preparing copper nanowire clusters based on a bubble template method, characterized in that, Includes the following steps: Step 1: Prepare the copper nanowire pre-reaction solution. First, weigh a certain amount of sodium hydroxide and copper nitrate according to the mass ratio, and dissolve them in deionized water to prepare sodium hydroxide solution and copper nitrate solution respectively. Measure 100-500 parts of the prepared sodium hydroxide solution and transfer it to a blue-capped screw-top bottle, and keep it magnetically stirred. Then, according to the set volume ratio of copper nitrate solution to sodium hydroxide solution, add copper nitrate solution dropwise to sodium hydroxide solution, and stir magnetically for 10-30 minutes. Further, add ethylenediamine dropwise to the solution, and stir magnetically for 0.2-2 hours. Then add a dispersant accounting for 1-4% of the mass percentage of ethylenediamine, and then sonicate for 5-20 minutes to prepare a uniformly dispersed copper nanowire pre-reaction solution. Step 2: Growth of copper nanowire clusters using the bubble template method. Prepare a 70-90% hydrazine hydrate solution by adding the hydrazine hydrate solution dropwise to the pre-prepared copper nanowire pre-reaction solution at a set volume ratio of hydrazine hydrate solution to copper nitrate solution. After magnetic stirring at 22-25℃ for 10-30 min, sonicate at room temperature for 20-45 min. Transfer the blue-capped screw-top bottle to a water bath and incubate at 50-75℃ for 2-6 h to obtain a brick-red foamy copper nanowire structure. Subsequently, filter and dry the prepared copper nanowire clusters and transfer them to a desiccator for storage. The preparation method of the dispersing agent mentioned in step 1 is as follows: H1: Weigh 0.12-0.24 parts by weight of boron nitrate, 0.3-0.6 parts by weight of 2-aminonaphthalene-4,8-disulfonic acid, and 0.01-0.05 parts by weight of acetic acid, place them in 100-200 parts by weight of water, stir at 30-40°C for 20-50 minutes, and remove the water by distillation; H2: Continue to add 5-11 parts of dioctadecylamine, 5-8 parts of dilithium mercaptosuccinate, and 130-150 parts of DMF. React at 70-80℃ for 20-50 minutes, then remove DMF by distillation to obtain the dispersing agent.

2. The preparation method according to claim 1, characterized in that, The sodium hydroxide mentioned in step 1 is replaced with potassium hydroxide, barium hydroxide, or calcium hydroxide.

3. The preparation method according to claim 1, characterized in that, The sodium hydroxide solution in step 1 has a concentration of 5-15 mol / L.

4. The preparation method according to claim 1, characterized in that, The copper nitrate mentioned in step 1 is replaced with copper sulfate or copper chloride.

5. The preparation method according to claim 1, characterized in that, The volume ratio of copper nitrate solution to sodium hydroxide solution in step 1 is 1:20-30.

6. The preparation method according to claim 1, characterized in that, The volume ratio of ethylenediamine to copper nitrate solution in step 1 is 1:5-15.

7. The preparation method according to claim 1, characterized in that, The magnetic stirring speed in step 1 is 1000-2000 r / min.

8. The preparation method according to claim 1, characterized in that, The volume ratio of hydrazine hydrate solution to copper nitrate solution in step 2 is 1:100-500.

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