A one-step method for preparing antioxidant and highly conductive copper nanoparticles

Abstract

This invention belongs to the field of surface functionalization of metal materials and manufacturing of metal powders. It provides a one-step method for preparing antioxidant and highly conductive copper nanoparticles, comprising: adding a multifunctional organic ligand containing at least two functional groups (amino, thiol, and carboxyl) to a copper ion solution, performing a coordination reaction to obtain an organically ligand-modified copper ion solution; adding a reducing agent and a crosslinking agent to the organically ligand-modified copper ion solution, and performing a reaction to obtain copper nanoparticles coated with a nanoscale film. This invention improves the antioxidant and corrosion-resistant properties of copper-based nanomaterials by forming a dense nanoscale film on the surface of copper particles, thus preventing contact between the copper nanoparticles and oxidizing or corrosive media. Furthermore, the surface-modified film of the copper-based nanomaterials prepared using this one-step method is very thin, only a few nanometers thick, maintaining the excellent electrical conductivity of the copper-based nanomaterials.

Description

Technical Field

[0001] This invention belongs to the field of surface functionalization of metal materials and manufacturing of metal powders, and relates to a one-step method for preparing antioxidant and highly conductive copper nanoparticles. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Conductive powder materials, as key basic materials for the manufacture of electronic components, have wide applications in solar photovoltaic modules, chip packaging, printed circuits, sensors, and radio frequency identification. Copper, as a commonly used conductive metal, has conductivity comparable to silver, but costs only 1% of silver, making it considered the most promising alternative to silver-based conductive materials. However, copper materials face significant challenges in practical applications: its high chemical reactivity makes it prone to oxidation in air, and it is also susceptible to corrosion in humid environments, leading to a sharp decline or even failure in its conductivity. How to effectively improve copper's oxidation and corrosion resistance while maintaining its excellent conductivity has become a critical issue that urgently needs to be addressed in the field of materials science.

[0004] Some studies have explored the use of self-assembled films to passivate metal surfaces, but the preparation methods are complex, and there is an urgent need to develop more efficient methods for preparing antioxidant and highly conductive copper nanoparticles. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a one-step method for preparing copper-based nanoparticles with excellent oxidation and corrosion resistance and conductivity. This invention protects copper ions by adding organic ligands with specific coordination interactions during the preparation of copper-based nanomaterials. Subsequently, a reducing agent is added to initiate a reduction reaction, resulting in the in-situ modification of the copper-based nanoparticles with a certain amount of organic ligands. Simultaneously, the functional groups in the organic ligands further cross-link with a cross-linking agent, forming a dense nanoscale film on the surface of the copper particles. This film prevents the copper nanoparticles from contacting oxidizing and corrosive media, thus improving the oxidation and corrosion resistance of the copper-based nanomaterials. Furthermore, the film modified on the surface of the copper nanoparticles prepared by this invention is extremely thin, only a few nanometers thick, maintaining the excellent conductivity of the copper-based material.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a one-step method for preparing antioxidant and highly conductive copper nanoparticles, comprising:

[0008] An organic ligand containing at least two functional groups (amino, thiol, and carboxyl) is added to a copper ion solution to carry out a coordination reaction, thereby obtaining an organic ligand-modified copper ion solution.

[0009] A reducing agent and a crosslinking agent were added to the copper ion solution modified with the organic ligand, and a reaction was carried out to obtain copper nanoparticles coated with a nano-scale film.

[0010] The crosslinking agent is selected from at least one of propylene oxide, pentaerythritol glycidyl ether, and 4-hydroxy-3-methoxybenzaldehyde.

[0011] In this invention, the ligand needs to coordinate with copper ions while ensuring uniform particle size dispersion of the copper particles formed during the reduction process. To this end, this invention has discovered that if the ligand possesses one of the three functional groups—amino, carboxyl, or thiol—it can coordinate with copper ions. Furthermore, after the copper ions are reduced to elemental copper, these three functional groups can continue to react with elemental copper to form Cu-S, Cu-O, or Cu-N coordination bonds, allowing the ligand to continue adsorbing onto the surface of the synthesized copper particles, resulting in copper nanoparticles with uniform particle size dispersion.

[0012] Beneficial effects of the present invention

[0013] (1) In this invention, an organic ligand with excellent coordination ability with copper ions is used to pre-coordinate copper ions, and then a reducing agent is used to reduce the coordinated copper ions to zero valence. While zero-valent copper nanoparticles are being generated, the coordinated ligand can be in situ modified on the surface of the copper particles, and further react with a crosslinking agent to generate a thin film with a nanometer-thickness. The nanometer-thick film generated in situ can protect the surface of the generated zero-valent copper from oxidation by oxidizing substances such as oxygen, and the film is very thin, which can ensure the conductivity of copper.

[0014] (2) The present invention modifies the surface of zero-valent copper particles with an organic film, which improves the compatibility between copper nanoparticles and organic carriers in conductive paste and improves the stability of copper-containing conductive paste.

[0015] (3) The present invention modifies the surface of zero-valent copper particles with a dense thin film, which can improve the oxidation resistance of copper-based materials;

[0016] (4) The present invention prepares an antioxidant and corrosion resistant copper-based material in one step. The preparation method is simple, practical and easy to promote. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. Exemplary embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0018] Figure 1 The images show SEM images (a), TEM images (b), X-ray photoelectron spectroscopy (c), and Auger spectrum (d) of the copper nanoparticles prepared in Example 1 of this invention.

[0019] Figure 2 The Cu Auger spectra of the samples prepared in this invention after baking at 200 degrees Celsius for 30 minutes are shown in the figures: (a) the sample prepared in Example 1, (b) the sample prepared in Comparative Example 1, (c) the sample prepared in Comparative Example 2, and (d) the sample prepared in Comparative Example 3. Detailed Implementation

[0020] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. The reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they are used in accordance with conventional methods in the art or product instructions. Similarly, unless otherwise specified, the test methods of this invention are performed in accordance with conventional methods in the art or industry-standard methods or practices. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described herein are for illustrative purposes only.

[0022] A one-step method for preparing antioxidant and highly conductive copper nanoparticles includes:

[0023] An organic ligand containing at least two functional groups (amino, thiol, and carboxyl) is added to a copper ion solution to carry out a coordination reaction, thereby obtaining an organic ligand-modified copper ion solution.

[0024] A reducing agent and a crosslinking agent were added to the copper ion solution modified with the organic ligand, and a reaction was carried out to obtain copper nanoparticles coated with a nano-scale film.

[0025] The crosslinking agent is selected from at least one of propylene oxide, pentaerythritol glycidyl ether, and 4-hydroxy-3-methoxybenzaldehyde.

[0026] The concentration of copper ions affects the size and aggregation degree of copper nanoparticles. In order to control the particle size of copper nanoparticles to within 50 nm, this invention studies the concentration of copper ions. Preferably, the concentration of copper ions is 0.01 M-0.1 M. This invention utilizes organic ligands that have specific adsorption properties with copper to coordinate copper ions, so that the surface of the reduced zero-valent copper particles is modified with an appropriate amount of organic ligands, and then undergoes appropriate cross-linking with the added cross-linking agent to form a nanoscale film on the surface of the copper particles, thereby improving their antioxidant and corrosion resistance properties.

[0027] To improve the modification effect of organic ligands on the surface of copper particles, this invention studies the types and concentrations of organic ligands. Preferably, the organic ligands containing at least one functional group (amino, thiol, or carboxyl) and having two or more functional groups are selected from at least one of diethylenetriaminepentaacetic acid, 2,2'-(1,2-ethylenedioxy)diethylthiol, dimercaptoethylene glycol, glutathione, and lysine.

[0028] Preferably, the molar ratio of copper ions to organic ligands containing at least two functional groups (amino, thiol, or carboxyl) is (1-10):(1-2). When the ligands have two or more functional groups, it ensures that the ligands adsorbed on the copper surface still have available functional groups and crosslinking agents to carry out crosslinking reactions.

[0029] This invention does not impose any specific limitations on the type of copper ion solution, as long as it can dissolve in a solvent and coordinate with the ligand. Preferably, the copper ion solution is a copper sulfate solution to better form copper nanoparticles.

[0030] This invention does not impose any specific limitation on the type of reducing agent, as long as it reduces copper ions in a solvent. Preferably, the reducing agent is sodium borohydride, to reduce copper ions to elemental copper.

[0031] Preferably, the pH of the organic ligand-modified copper ion solution is adjusted to 8.5-10, and then a reducing agent and a cross-linking agent are added to promote the reduction and cross-linking reactions under alkaline conditions.

[0032] The selection of crosslinking agents needs to match the empty functional groups in the organic ligands. Therefore, based on the screening of the types of crosslinking agents, the present invention has also studied their dosage. Preferably, the molar ratio of the multifunctional organic ligand containing at least one functional group of amino, thiol, or carboxyl and having more than two functional groups to the crosslinking agent is (5-10):(1-3).

[0033] The reaction temperature affects the coordination effect between the organic ligand and the copper ion. Therefore, the present invention has studied the reaction temperature. Preferably, the temperature of the coordination reaction is 50-60 degrees Celsius.

[0034] More specifically, the process includes: first, dissolving a copper source in pure water; placing the resulting solution in a water bath at 50-60 degrees Celsius; adding a multifunctional organic ligand containing at least two functional groups (amino, thiol, or carboxyl) under magnetic stirring; adjusting the pH of the solution to 8-10; and stirring continuously for 2 hours. Then, adding sufficient reducing agent and crosslinking agent, and stirring continuously for 1-2 hours. Cooling the product to room temperature and centrifuging at 10,000 rpm for 3 minutes yields a brick-red solid. The solid is then ultrasonically washed with ultrapure water and centrifuged three times. The resulting solid product is dried in a vacuum drying oven at 80 degrees Celsius to obtain antioxidant, corrosion-resistant, and highly conductive copper nanoparticles.

[0035] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0036] The raw materials described in the examples and comparative examples are all conventional raw materials and commercially available products.

[0037] The conductivity test method is as follows: Copper nanomaterials are pressed into thin sheets with a thickness of about 2 mm using a tablet press (Tianjin Zhongtuo Technology) (pressure of about 20 MPa). The conductivity of the samples under different conditions is tested using the standard four-probe method.

[0038] Example 1

[0039] Add 2.5g CuSO₄ to 100mL of ultrapure water. 4˙ A 0.1 M copper ion solution was prepared using 5H₂O and placed in a 50°C water bath. Then, 0.292 g of lysine was added to bring the lysine concentration to 0.02 M. The solution was stirred at 50°C for 2 hours. The pH of the solution was adjusted to 9 using sodium hydroxide. Then, excess sodium borohydride and 0.06 g of 4-hydroxy-3-methoxybenzaldehyde were added to bring the 4-hydroxy-3-methoxybenzaldehyde concentration to 0.004 M. The solution was stirred continuously for 1 hour. After centrifugation, washing with water, and drying, copper nanoparticles with an organic film coating on their surface were obtained.

[0040] Example 2

[0041] Add 1.25g CuSO₄ to 100mL of ultrapure water. 4˙A 0.05 M copper ion solution was prepared using 5H₂O and placed in a 60°C water bath. Then, 0.912 g of 2,2'-(1,2-ethylenedioxydioxo)diethanethiol was added to bring the concentration of 2,2'-(1,2-ethylenedioxydioxo)diethanethiol to 0.05 M. The solution was stirred at 60°C for 2 hours. The pH of the solution was adjusted to 10 with sodium hydroxide. Then, excess sodium borohydride and 0.06 g of propylene oxide were added to bring the concentration of propylene oxide to 0.01 M, and the mixture was stirred continuously for 2 hours. The solution was then centrifuged, washed with water, and dried to obtain copper nanoparticles with an organic film coating on their surface.

[0042] Example 3

[0043] Add 0.25g CuSO₄ to 100mL of ultrapure water. 4˙ A 0.01M copper ion solution was prepared using 5H₂O and placed in a 50°C water bath. Then, 0.420g of dimercaptoethylene glycol was added to bring the dimercaptoethylene glycol concentration to 0.02M. The solution was stirred at 50°C for 2 hours. The pH of the solution was adjusted to 8.5 with sodium hydroxide. Then, excess sodium borohydride and 0.216g of pentaerythritol glycidyl ether were added to bring the pentaerythritol glycidyl ether concentration to 0.006M. The solution was stirred continuously for 1 hour. After centrifugation, washing with water, and drying, copper nanoparticles with an organic film coating on their surface were obtained.

[0044] Example 4

[0045] Add 2.5g CuSO₄ to 100mL of ultrapure water. 4˙ A 0.1M copper ion solution was prepared using 5H₂O and placed in a 50°C water bath. Then, 0.393g of diethylenetriaminepentaacetic acid (DTA) was added to bring the DTA concentration to 0.01M, followed by 0.307g of glutathione to bring the glutathione concentration to 0.01M. The solution was stirred at 50°C for 2 hours. The pH of the solution was adjusted to 9 using sodium hydroxide. Then, excess sodium borohydride and 0.03g of 4-hydroxy-3-methoxybenzaldehyde were added to bring the 4-hydroxy-3-methoxybenzaldehyde concentration to 0.002M, along with 0.072g of pentaerythritol glycidyl ether to bring the concentration to 0.002M. The solution was stirred continuously for 1 hour. After centrifugation, washing with water, and drying, copper nanoparticles with an organic film coating on their surface were obtained.

[0046] Comparative Example 1

[0047] The difference from Example 1 is that no organic ligands and crosslinking agents were added. Specifically, it includes:

[0048] Add 2.5g CuSO₄ to 100mL of ultrapure water. 4˙A 0.1 M copper ion solution was prepared using 5H₂O and placed in a 50°C water bath. The solution was stirred at 50°C for 2 hours. The pH was adjusted to 9 with sodium hydroxide, and then excess sodium borohydride was added. Stirring continued for 1 hour. The solution was then centrifuged, washed with water, and dried to obtain copper nanoparticles.

[0049] Comparative Example 2

[0050] The difference from Example 1 is that no organic ligands were added. Specifically, it includes:

[0051] Add 2.5g CuSO₄ to 100mL of ultrapure water. 4˙ A 0.1 M copper ion solution was prepared using 5H₂O and placed in a 50°C water bath. The solution was stirred at 50°C for 2 hours. The pH was adjusted to 9 using sodium hydroxide. Then, excess sodium borohydride and 0.06 g of 4-hydroxy-3-methoxybenzaldehyde were added to bring the concentration of 4-hydroxy-3-methoxybenzaldehyde to 0.004 M. The mixture was stirred continuously for 1 hour. After centrifugation, washing with water, and drying, copper nanoparticles were obtained.

[0052] Comparative Example 3

[0053] The difference from Example 1 is that no crosslinking agent was added. Specifically, it includes:

[0054] Add 2.5g CuSO₄ to 100mL of ultrapure water. 4˙ A 0.1 M copper ion solution was prepared using 5H₂O and placed in a 50°C water bath. Then, 0.292 g of lysine was added to bring the lysine concentration to 0.02 M. The solution was stirred at 50°C for 2 hours. The pH of the solution was adjusted to 9 using sodium hydroxide, and then excess sodium borohydride was added. The mixture was stirred continuously for 1 hour. The solution was then centrifuged, washed with water, and dried to obtain copper nanoparticles.

[0055] Comparative Example 4

[0056] The difference from Example 1 is that the ligand used is triethanolamine. Specifically, it includes:

[0057] Add 2.5g CuSO₄ to 100mL of ultrapure water. 4˙ A 0.1 M copper ion solution was prepared using 5H₂O and placed in a 50°C water bath. Then, 0.298 g of triethanolamine was added to bring the triethanolamine concentration to 0.02 M. The solution was stirred at 50°C for 2 hours. The pH of the solution was adjusted to 9 with sodium hydroxide. Then, excess sodium borohydride and 0.06 g of 4-hydroxy-3-methoxybenzaldehyde were added to bring the 4-hydroxy-3-methoxybenzaldehyde concentration to 0.004 M. The solution was stirred continuously for 1 hour. After centrifugation, washing with water, and drying, copper nanoparticles were obtained.

[0058] Comparative Example 5

[0059] The difference from Example 1 is that the ligand used is acetylacetone. Specifically, it includes:

[0060] Add 2.5g CuSO₄ to 100mL of ultrapure water. 4˙ A 0.1 M copper ion solution was prepared using 5H₂O and placed in a 50°C water bath. Then, 0.200 g of acetylacetone was added to bring the acetylacetone concentration to 0.02 M. The solution was stirred at 50°C for 2 hours. The pH of the solution was adjusted to 9 using sodium hydroxide. Then, excess sodium borohydride and 0.06 g of 4-hydroxy-3-methoxybenzaldehyde were added to bring the 4-hydroxy-3-methoxybenzaldehyde concentration to 0.004 M. The solution was stirred continuously for 1 hour. After centrifugation, washing with water, and drying, copper nanoparticles were obtained.

[0061] Comparative Example 6

[0062] The difference from Example 1 is that acetaldehyde is used as the crosslinking agent. Specifically, it includes:

[0063] Add 2.5g CuSO₄ to 100mL of ultrapure water. 4˙ A 0.1 M copper ion solution was prepared using 5H₂O and placed in a 50°C water bath. Then, 0.292 g of lysine was added to bring the lysine concentration to 0.02 M. The solution was stirred at 50°C for 2 hours. The pH of the solution was adjusted to 9 using sodium hydroxide. Then, excess sodium borohydride and 0.018 g of acetaldehyde were added to bring the concentration to 0.004 M, and the mixture was stirred continuously for 1 hour. The solution was then centrifuged, washed with water, and dried to obtain copper nanoparticles.

[0064] Comparative Example 7

[0065] The difference from Example 1 is that glutaraldehyde is used as the crosslinking agent. Specifically, it includes:

[0066] Add 2.5g CuSO₄ to 100mL of ultrapure water. 4˙ A 0.1 M copper ion solution was prepared using 5H₂O and placed in a 50°C water bath. Then, 0.292 g of lysine was added to bring the concentration to 0.02 M. The solution was stirred at 50°C for 2 hours. The pH of the solution was adjusted to 9 with sodium hydroxide. Then, excess sodium borohydride and 0.04 g of glutaraldehyde were added to bring the concentration to 0.004 M, and the mixture was stirred continuously for 1 hour. The solution was then centrifuged, washed with water, and dried to obtain copper nanoparticles.

[0067] The copper nanomaterials prepared in Example 1 were characterized by SEM, and the results are as follows: Figure 1 As shown in (a). The copper nanomaterials prepared in Example 1 were characterized by TEM, and the results are shown in the appendix. Figure 1As shown in (b). The copper nanoparticles prepared in Example 1 were characterized by XPS, and the results are as follows. Figure 1 As shown in (c) and (d), copper nanoparticles were successfully prepared using the method in Example 1, wherein the copper valence state is zero and the particle surface is modified with a nanofilm.

[0068] Table 1. Room temperature conductivity of fresh copper samples and copper nanoparticles prepared in Examples 1-4

[0069]

[0070] Table 2. Conductivity of fresh copper samples, copper nanoparticles prepared in Examples 1-4 and Comparative Examples 1-7 after baking at 200°C for 30 minutes.

[0071]

[0072] The room temperature conductivity of fresh copper samples and copper nanoparticles prepared in Examples 1-4 (Table 1) and the conductivity of fresh copper samples, copper nanoparticles prepared in Examples 1-4, and Comparative Examples 1-7 after baking at 200 degrees Celsius for 30 minutes (Table 2) were tested. The results showed that the conductivity of the copper nanoparticles prepared in Examples 1-4 could reach more than 95% of that of pure copper, and they maintained good conductivity even after baking at 200 degrees Celsius for 30 minutes, indicating that the samples prepared in Examples 1-4 have excellent antioxidant properties. The copper nanoparticles prepared by using a mixture of ligands and crosslinking agents exhibited the best conductivity after baking at 200 degrees Celsius for 30 minutes, indicating that the combined use of ligands and crosslinking agents can improve the antioxidant properties of the material.

[0073] Figure 2 (a) shows the XPS test results of the sample prepared in Example 1 after baking at 200 degrees Celsius for 30 minutes. Figure 2 (b) shows the XPS test results of the sample prepared in Example 1 after baking at 200 degrees Celsius for 30 minutes. Figure 2 Image (c) shows the XPS test results of the sample prepared in Example 1 after baking at 200 degrees Celsius for 30 minutes. Figure 2 (d) shows the XPS test results of the sample prepared in Example 1 after baking at 200 degrees Celsius for 30 minutes. This indicates that the sample prepared in Example 1 remained in a zero valence state after high-temperature baking, showing no oxidation, while the samples in Comparative Examples 1-3, after baking, mainly exhibited mono- and di-valence states, indicating oxidation. This demonstrates that the sample prepared in Example 1 possesses excellent antioxidant properties.

[0074] As can be seen from the comparison of Example 1 and Comparative Examples 1 and 2, without ligands, it is impossible to form a film on the surface of the copper nanoparticles. Therefore, the antioxidant performance is poor and it is rapidly oxidized at high temperature.

[0075] As can be seen from the comparison between Example 1 and Comparative Example 3, in the absence of crosslinking agent, although ligands are adsorbed on the surface of the copper nanoparticles, a dense oxide film cannot be formed, and therefore, its antioxidant performance is also poor.

[0076] As can be seen from the comparison of Example 1 and Comparative Examples 4 and 5, if the ligand and crosslinking agent are not compatible, a dense film layer cannot be formed, resulting in weak antioxidant properties.

[0077] As can be seen from the comparison of Example 1 and Comparative Examples 6 and 7, if the molecular chain of the crosslinking agent is relatively short and the crosslinking is not sufficient, the film layer will not have sufficient density and antioxidant properties.

[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A one-step method for preparing antioxidant and highly conductive copper nanoparticles, characterized in that, include: A multifunctional organic ligand containing at least two functional groups (amino, thiol, and carboxyl) is added to a copper ion solution to carry out a coordination reaction, thereby obtaining an organic ligand-modified copper ion solution. A reducing agent and a crosslinking agent were added to the copper ion solution modified with the organic ligand, and a reaction was carried out to obtain copper nanoparticles coated with a nano-scale film. The crosslinking agent is selected from at least one of propylene oxide, pentaerythritol glycidyl ether, and 4-hydroxy-3-methoxybenzaldehyde; The multifunctional organic ligand containing at least two functional groups, including amino, thiol, and carboxyl groups, is selected from at least one of diethylenetriaminepentaacetic acid, 2,2'-(1,2-ethylenedioxy)diethylthiol, dimercaptoethylene glycol, glutathione, adenine, and lysine. The molar ratio of copper ions to a multifunctional organic ligand containing at least two functional groups (amino, thiol, or carboxyl) is (1-10):(1-2). The molar ratio of the multifunctional organic ligand containing at least two functional groups (amino, thiol, and carboxyl) to the crosslinking agent is (5-10):(1-3).

2. The method for preparing antioxidant and highly conductive copper nanoparticles in one step as described in claim 1, characterized in that, The concentration of the copper ion solution is 0.01M-0.1M.

3. The method for preparing antioxidant and highly conductive copper nanoparticles in one step as described in claim 1, characterized in that, The copper ion solution is a copper sulfate solution.

4. The method for preparing antioxidant and highly conductive copper nanoparticles in one step as described in claim 1, characterized in that, The pH of the organic ligand-modified copper ion solution was adjusted to 8.5-10, and then a reducing agent and a cross-linking agent were added.

5. The method for preparing antioxidant and highly conductive copper nanoparticles in one step as described in claim 1, characterized in that, The reducing agent is sodium borohydride.

6. The method for preparing antioxidant and highly conductive copper nanoparticles in one step as described in claim 1, characterized in that, The coordination reaction is carried out at a temperature of 50-60 degrees Celsius.

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