Method for preparing carbon-coated copper by in-situ reduction of copper oxide with homodopamine, carbon-coated copper and application

Abstract

The embodiment of the present application discloses a method for preparing carbon-coated copper by in-situ reduction of copper oxide with dopa-like polymer, which comprises the following steps: adding copper oxide into an aqueous solution of catechol compound and aniline compound, and reacting under the condition of oxidizing gas to obtain copper oxide coated with dopa-like polymer; and calcining the copper oxide coated with dopa-like polymer under the atmosphere of inert gas to obtain carbon-coated copper. The method for preparing carbon-coated copper is simple in process, and the prepared carbon-coated copper has good conductivity, oxidation resistance and corrosion resistance. The embodiment of the present application further provides carbon-coated copper prepared by the method and application of the carbon-coated copper in conductive material, catalytic material or electromagnetic shielding material.

Description

Technical Field

[0001] This invention relates to the field of materials technology, and in particular to a method for preparing carbon-coated copper by in-situ reduction of copper oxide with polydopamine, as well as the application of carbon-coated copper. Background Technology

[0002] Copper powder is widely used in the power, electrical, and engineering industries due to its high electrical and thermal conductivity, as well as its corrosion resistance. It is a promising material in electronics, circuits, conductive inks, internal electrodes, and catalysts. Traditionally, copper can be produced through pyrometallurgy or hydrometallurgy. The former requires significant energy and produces furnace gas with low sulfur dioxide concentrations, while the latter heavily relies on sulfuric acid as a leaching agent, organic solvents as extractants, and toxic reducing agents (e.g., ammonia, heavy oil, and petroleum gas). Neither method is environmentally friendly. Currently, there are reports of preparing copper by reducing copper oxide, but this process is typically complex, costly, and produces copper powder with a relatively low oxidation potential. This makes it prone to reacting with oxygen in the air, leading to decreased conductivity. Further protection methods such as molecular passivation, core / shell passivation, and polymer encapsulation are needed. Therefore, it is necessary to improve and optimize the process for preparing copper by reducing copper oxide. Summary of the Invention

[0003] Based on this, embodiments of the present invention provide a method for preparing carbon-coated copper. This method utilizes the chemical reaction between catechol compounds and aniline compounds to grow a polydopamine-like coating in situ on the surface of copper oxide. Then, through high-temperature calcination, the copper oxide is reduced to metallic copper in situ during the carbonization process of the polydopamine-like coating, forming a dense carbon layer on the surface of the metallic copper. The reduction of copper oxide to copper and the passivation of the copper surface occur simultaneously, resulting in a relatively simple preparation process. The carbon-coated copper prepared by this method exhibits good electrical conductivity, oxidation resistance, and corrosion resistance.

[0004] In a first aspect, embodiments of the present invention provide a method for preparing carbon-coated copper, comprising:

[0005] Copper oxide was added to an aqueous solution of catechol and aniline compounds and reacted under conditions containing oxidizing gas to obtain copper oxide coated with polydopamine-like compounds.

[0006] The copper oxide coated with the polydopamine-like substance was calcined in an inert gas atmosphere to obtain carbon-coated copper.

[0007] In this embodiment of the invention, the calcination includes heating to 200℃-400℃ at a heating rate of 1℃ / min-10℃ / min and holding at that temperature for 0min-240min, and then heating to 600℃-1200℃ at a heating rate of 1℃ / min-10℃ / min and holding at that temperature for 60min-480min.

[0008] In this embodiment of the invention, the copper oxide includes at least one of granular copper oxide, linear copper oxide, and irregular copper oxide; the particle size D50 of the granular copper oxide is 20nm-10μm; the length of the linear copper oxide is 40nm-10mm; and the concentration of the copper oxide in the aqueous solution is 1mg / ml-20mg / ml.

[0009] In this embodiment of the invention, the concentration of the catechol compound in the aqueous solution is 1 mmol / L-50 mmol / L; the concentration of the aniline compound in the aqueous solution is 1 mmol / L-50 mmol / L; and the molar ratio of the catechol compound to the aniline compound is (0.7-1.3):(0.7-1.3).

[0010] In this embodiment of the invention, the reaction temperature is 15℃-55℃, and the reaction time is 10min-24h.

[0011] In this embodiment of the invention, the oxidizing gas includes at least one of air, oxygen, and ozone; the inert gas includes at least one of argon and nitrogen.

[0012] The carbon-coated copper preparation method provided in this invention utilizes the spontaneous polymerization reaction of dopamine on various material surfaces. Dopamine molecules, including catechol and aniline compounds, react with copper oxide in the same environment, causing polydopamine to coat the copper oxide surface, thus modifying the copper oxide. Subsequently, high-temperature calcination decomposes the polydopamine on the copper oxide surface into small-molecule carbon monoxide and nitric oxide, which have reducing properties, reducing the coated copper oxide. At high temperature, the remaining carbon from calcination forms a carbon coating layer on the reduced copper surface, giving it better oxidation and corrosion resistance. This method for preparing carbon-coated copper is relatively simple, simultaneously reducing copper oxide to copper and passivating the copper surface. The carbon-coated copper prepared by this method exhibits good conductivity, oxidation resistance, and corrosion resistance.

[0013] Secondly, embodiments of the present invention provide a carbon-coated copper, which is prepared by the method for preparing carbon-coated copper by in-situ reduction of copper oxide with polydopamine as described in the first aspect. The carbon-coated copper includes a copper core and a carbon layer that surrounds the copper core.

[0014] In this embodiment of the invention, the molar ratio of copper to carbon in the carbon-coated copper is (10-50):1.

[0015] In this embodiment of the invention, the thickness of the carbon layer is 5nm-400nm; the material of the carbon layer includes graphene.

[0016] The carbon-coated copper provided in this invention retains the high conductivity of copper while exhibiting better oxidation and corrosion resistance than copper itself. The carbon layer in the carbon-coated copper has excellent corrosion resistance, reducing oxidation and corrosion of the copper surface in humid environments, thereby extending its service life and performance. Simultaneously, copper, as the core, provides good mechanical strength, while the carbon layer increases hardness and wear resistance, making the carbon-coated copper more durable.

[0017] Thirdly, embodiments of the present invention provide the application of the carbon-coated copper described in the second aspect in conductive materials, catalytic materials, or electromagnetic shielding materials.

[0018] The carbon-coated copper provided in this invention has good conductivity, oxidation resistance and corrosion resistance, and can be used in conductive materials, catalytic materials or electromagnetic shielding materials, such as conductive connections of integrated circuit components, conductive or antistatic coatings, electromagnetic shielding shells, catalysts, electrodes, etc. Especially in applications requiring high conductivity and corrosion resistance, it can effectively improve the conductivity and service life of conductive components. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the background art, the accompanying drawings used in the embodiments of the present invention or the background art will be described below.

[0020] Figure 1 This is a process flow diagram of carbon-coated copper preparation in one embodiment of the present invention;

[0021] Figure 2 These are transmission electron microscope images of CuO, PDL@CuO, and C@Cu provided in Embodiment 1 of the present invention;

[0022] Figure 3 These are the XRD spectra of CuO, PDL@CuO, and C@Cu provided in Embodiment 1 of the present invention;

[0023] Figure 4 These are the XPS spectra of CuO, PDL@CuO, and C@Cu provided in Embodiment 1 of the present invention, wherein... Figure 4 In the image, (a) is the full spectrum of CuO, (b) is the Cu2p spectrum of CuO, (c) is the full spectrum of PDL@CuO, (d) is the Cu2p spectrum of PDL@CuO, (e) is the full spectrum of C@Cu, and (f) is the Cu2p spectrum of C@Cu.

[0024] Figure 5 These are the Raman spectra of CuO, PDL@CuO, and C@Cu provided in Embodiment 1 of the present invention;

[0025] Figure 6 This is the XRD pattern of C@Cu after being placed at 150°C for 5 hours, as provided in Example 1 of this invention;

[0026] Figure 7 The XRD patterns of C@Cu provided in Example 1 of this invention after being placed in saturated NaCl solution, 0.1M NaOH solution and 0.5M H2SO4 solution for 5 hours respectively;

[0027] Figure 8 These are scanning electron microscope images of CuO, PDL@CuO, and C@Cu provided in Embodiment 10 of the present invention;

[0028] Figure 9 This is the XRD pattern of the carbon-coated material provided in Comparative Example 1 of this invention;

[0029] Figure 10 This is a thermogravimetric analysis curve of PDL@CuO provided in Comparative Example 1 of this invention. Detailed Implementation

[0030] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0031] Copper powder is widely used in the power, electronics, and engineering industries due to its excellent electrical and thermal conductivity and corrosion resistance. Related technologies include the reduction of copper oxide to produce copper, such as thermal reduction, which involves treating copper oxide at high temperatures and reducing it in a hydrogen atmosphere; suitable for copper oxide powder but requiring high-purity hydrogen; chemical reduction, which uses reducing agents to reduce copper oxide to metallic copper (common reducing agents include monoethanolamine, sodium borohydride, ascorbic acid, sodium hydroxide, and hydrogen sulfide); electrochemical reduction, which reduces copper oxide to metallic copper through electrolysis, requiring specific equipment and current; and microbial reduction, which utilizes the metabolic activity of microorganisms such as sulfur-reducing and iron-reducing bacteria to reduce copper oxide, but is relatively complex. While these methods are more environmentally friendly than traditional methods, they are complex, have high production costs, and the resulting copper powder lacks a passivation layer, making it easily oxidized. Therefore, it is necessary to continue improving and optimizing the copper preparation process.

[0032] Based on this, embodiments of the present invention provide a method for preparing carbon-coated copper, such as... Figure 1 As shown, it includes:

[0033] S101. Copper oxide is added to an aqueous solution of catechol and aniline compounds and reacted under conditions containing oxidizing gas to obtain copper oxide coated with polydopamine-like compounds.

[0034] S102. The copper oxide coated with the polydopamine-like substance is calcined in an inert gas atmosphere to obtain carbon-coated copper.

[0035] The method for preparing carbon-coated copper provided in this invention utilizes a dopamine-like polymerization reaction between catechol and aniline compounds to grow a polydopamine-like coating in situ on the surface of copper oxide. Then, through high-temperature calcination, the copper oxide is reduced to metallic copper in situ during the carbonization process of the polydopamine, forming a dense carbon layer on the surface of the metallic copper. Dopamine polymerization is a spontaneous chemical reaction that can occur at room temperature. The reaction product, polydopamine, has good adhesion and can be used to modify the surfaces of various materials, including metals, ceramics, and polymers. Similarly, catechol and aniline compounds can also spontaneously polymerize on the surface of copper oxide. The reaction mechanism is similar to that of dopamine polymerization and is called dopamine-like polymerization. Dopamine-like polymerization shares the same advantages as dopamine polymerization, but it can use lower-cost raw materials and polydopamine-like compounds have superior adhesion. Polydopamine-like compounds are coated onto the surface of copper oxide. High-temperature calcination decomposes these compounds to generate small-molecule carbon monoxide and nitric oxide, which have reducing properties and reduce the coated copper oxide. At high temperatures, the remaining carbon from calcination forms a carbon coating on the reduced copper surface, giving it better oxidation and corrosion resistance. This method for preparing carbon-coated copper is relatively simple, simultaneously reducing copper oxide to copper and passivating the copper surface. The carbon-coated copper prepared by this method exhibits good conductivity, oxidation resistance, and corrosion resistance.

[0036] In this embodiment of the invention, the concentration of copper oxide in the aqueous solution is 1 mg / ml to 20 mg / ml. Controlling the concentration of copper oxide in the aqueous solution within the range of 1 mg / ml to 20 mg / ml ensures good dispersion uniformity, which is beneficial for the uniform deposition of polydopamine on the copper oxide surface. Specifically, the concentration of copper oxide in the aqueous solution can be, but is not limited to, 1 mg / ml, 2 mg / ml, 4 mg / ml, 5 mg / ml, 7 mg / ml, 9 mg / ml, 10 mg / ml, 12 mg / ml, 15 mg / ml, 18 mg / ml, or 20 mg / ml. In some embodiments, the concentration of copper oxide in the reaction solution can be 5 mg / ml to 10 mg / ml.

[0037] In this embodiment of the invention, the copper oxide includes at least one of granular copper oxide, linear copper oxide, and irregular copper oxide; the particle size D50 of the granular copper oxide is 20 nm-10 μm; the length of the linear copper oxide is 40 nm-10 mm. The carbon-coated copper preparation method provided in this embodiment of the invention can be used for the reduction of various forms of copper oxide and has a wide range of applications. In some embodiments, the particle size of the granular copper oxide can be, but is not limited to, 20 nm, 50 nm, 100 nm, 200 nm, 300 nm, 500 nm, 700 nm, 900 nm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm. In some embodiments, the length of the linear copper oxide may be, but is not limited to, 40 nm, 100 nm, 500 nm, 800 nm, 1 μm, 10 μm, 100 μm, 300 μm, 500 μm, 700 μm, 900 μm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm.

[0038] In this invention, catechol compounds are compounds containing two adjacent phenolic hydroxyl groups and two or more reaction sites on the benzene ring. Specifically, catechol compounds may include, but are not limited to, catechol, 3-methylcatechol, 4-chlorocatechol, 3,4-dihydroxybenzaldehyde, catechol purple, 4,5-dichlorocatechol, 4-ethylphosphodiesterol, 2,3-dihydroxynaphthalene, 4-nitrocatechol, pyrogallol, 3-methoxycatechol, 4-(chloroacetyl)catechol, 4-tert-butylcatechol, (E)-4-[2-(3,5-dihydroxyphenyl)vinyl]-1, At least one of 2-benzenediol, 3-(8Z-pentenyl)-1,2-benzenediol, 1,4-bis(3,4-dihydroxyphenyl)-2,3-dimethylbutane, 3,4-dihydroxycinnamool, 3-(8Z,11Z-pentadecanediol)-1,2-benzenediol, 3-(8Z,11Z,14-pentadecanediol)-1,2-benzenediol, salvianolic acid A, gossypol, and 4-(1-hydroxy-2-[methylamino]ethyl)-1,2-benzenediol.

[0039] In this embodiment of the invention, the concentration of catechol compounds in the aqueous solution is 1 mmol / L-50 mmol / L. Controlling the concentration of catechol compounds within the range of 1 mmol / L-50 mmol / L results in a faster dopamine polymerization rate, a higher degree of polymerization of the resulting polydopamine, and better adhesion properties. In some embodiments, the concentration of catechol compounds in the aqueous solution may be, but is not limited to, 1 mmol / L, 3 mmol / L, 5 mmol / L, 8 mmol / L, 10 mmol / L, 12 mmol / L, 15 mmol / L, 20 mmol / L, 30 mmol / L, 40 mmol / L, or 50 mmol / L. In some embodiments, the concentration of catechol compounds may be 10 mmol / L-12.5 mmol / L.

[0040] In this invention, aniline compounds are compounds having an aniline group. Specifically, aniline compounds may include, but are not limited to, aniline, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, m-toluidine, 2,4-dichloroaniline, o-methylaniline, p-toluidine, 2-bromoaniline, 2-iodoaniline, 2-chloroaniline, 3-iodoaniline, 3-chloroaniline, 3-fluoroaniline, 3-bromoaniline, 2,6-difluoroaniline, 2,4,6-trimethylaniline, 2-isopropenylphenylaniline, 4-octylaniline, 4-bromoaniline, 4-iodoaniline, 4-chloroaniline, and 4-fluoroaniline. Amines, 4-aminobiphenyl, diphenylamine, N-methylaniline, acetaniline, 4,4′-dimethyldiphenylamine, N-ethylaniline, 2-chloro-5-methylaniline, 4-ethoxyaniline, 3-ethoxyaniline, 3-ethynylaniline, 3,4,5-trichloroaniline, 4-butylaniline, 4-decylaniline, 4-octadecylaniline, 4-tetradecylaniline, 4-nitrodiphenylamine, 2-propylaniline, 2-ethynylaniline, 3-benzylaniline, 3-benzyloxyaniline, 3-ethyl 3,4-Difluoroaniline, 3,4-Dichloroaniline, 4-Hexyloxyaniline, 4-Benzylaniline, 4-Butoxyaniline, 2,3-Dichloroaniline, 4-Hexylaniline, 3,5-Dichloroaniline, 2-Ethylaniline, 4-Ethylaniline, 3-(Heptadecylfluorooctyl)aniline, 2-Isopropylaniline, 4-Ethynylaniline, 3,3′-Methylenediphenylamine, 4-Vinylaniline, 4-Bromo-3-methylaniline, 2-Fluoro-5-methylaniline, 4,5-Dimethyl-1, At least one of 2-phenylenediamine, 2,5-dichloro-p-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine, N-methyl-1,2-phenylenediamine, 2-nitro-1,4-phenylenediamine, 2-methyl-m-phenylenediamine, 6-amino-1,4-benzodioxane, 4-chloro-o-phenylenediamine, 5-(trifluoromethyl)-1,3-phenylene diamine, 2-(3,5-dimethylphenoxy)ethylamine, 4-bromo-5-methyl-1,2-phenylenediamine, and benzene-1,3-dithiocarboxamide.

[0041] In this embodiment of the invention, the concentration of aniline compounds in the aqueous solution is 1 mmol / L-50 mmol / L. Controlling the concentration of aniline compounds within this range results in a faster dopamine polymerization rate, a higher degree of polymerization of the resulting polydopamine, and better adhesion properties. In some embodiments, the concentration of aniline compounds in the aqueous solution may be, but is not limited to, 1 mmol / L, 3 mmol / L, 5 mmol / L, 8 mmol / L, 10 mmol / L, 12 mmol / L, 12.5 mmol / L, 15 mmol / L, 20 mmol / L, 30 mmol / L, 40 mmol / L, or 50 mmol / L. In some embodiments, the concentration of aniline compounds may be 10 mmol / L-12.5 mmol / L.

[0042] In this embodiment of the invention, the molar ratio of catechol compounds to aniline compounds can be (0.7-1.3):(0.7-1.3). Controlling the molar ratio of catechol compounds to aniline compounds at (0.7-1.3):(0.7-1.3) is beneficial for improving the conversion rate of the dopamine-like polymerization reaction, increasing the utilization rate of reactants, and thus reducing costs. In some embodiments, the molar ratio of catechol compounds to aniline compounds can be 1:(0.7-1) or 1:(1-1.3).

[0043] In this invention, the aqueous solution can dissolve or disperse copper oxide, catechol compounds, and aniline compounds, and the aqueous solution does not react with copper oxide, catechol compounds, and aniline compounds. Specifically, the aqueous solution can be, but is not limited to, a tris(hydroxymethyl)aminomethane hydrochloride (Tris-HCl) buffer solution.

[0044] In this invention, an oxidizing gas is a necessary condition for the oxidation of dopamine molecules, promoting the oxidation reaction to generate dopamine quinone and other oxidation products. These products further undergo polymerization and cross-linking reactions to form polydopamine. In embodiments of this invention, the oxidizing gas can be at least one of air, oxygen, and ozone, which is beneficial for better promoting the reaction.

[0045] In this embodiment of the invention, the reaction temperature is 15℃-55℃, and the reaction time is 10min-24h. Controlling the temperature of the dopamine polymerization reaction within the range of 15℃-55℃ and the reaction time within the range of 10min-24h results in a faster reaction rate, fewer side reactions, and a higher yield of polydopamine. In some embodiments, the reaction temperature may be, but is not limited to, 15℃, 18℃, 20℃, 23℃, 25℃, 28℃, 30℃, 35℃, 40℃, 45℃, 50℃, or 55℃; and the reaction time may be, but is not limited to, 10min, 15min, 30min, 1h, 2h, 4h, 6h, 8h, 10h, 12h, 15h, 18h, 20h, or 24h.

[0046] In this embodiment of the invention, the dopamine-like polymerization reaction is continuously stirred. After the reaction is completed, the mixture is centrifuged / filtered and repeatedly washed and dried with ethanol and water to obtain copper oxide coated with polydopamine-like substances.

[0047] In this invention, the calcination process is carried out under an inert gas atmosphere to avoid oxidation and ensure the formation of copper. In embodiments of this invention, the inert gas may include at least one of argon and nitrogen.

[0048] In this embodiment of the invention, calcination includes heating to 200℃-400℃ at a heating rate of 1.0℃ / min-10℃ / min and holding at that temperature for 0min-240min, and then heating to 600℃-1200℃ at a heating rate of 1.0℃ / min-10℃ / min and holding at that temperature for 60min-480min. In some embodiments, calcination can be carried out in a single-stage calcination method, that is, heating to 600℃-1200℃ at a heating rate of 1.0℃ / min-10℃ / min and holding at that temperature for 60min-480min; wherein the heating rate can be 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min or 10℃ / min; the calcination temperature can be 600℃, 700℃, 800℃, 900℃, 1000℃, 1100℃ or 1200℃; and the calcination time can be 60min, 120min, 180min, 240min, 300min, 360min, 420min or 480min. In other embodiments, calcination can be carried out in two stages. The heating rate of the first stage can be 1°C / min, 2°C / min, 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, or 10°C / min; the calcination temperature of the first stage can be 200°C, 300°C, 350°C, or 400°C; and the calcination time of the first stage can be 30 min, 60 min, 90 min, 120 min, 180 min, or 240 min. After the first stage of calcination is completed, the calcination is then... The second stage of calcination is then carried out. The heating rate of the second stage can be 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, or 10℃ / min; the calcination temperature of the second stage can be 600℃, 700℃, 800℃, 900℃, 1000℃, 1100℃, or 1200℃; and the calcination time of the second stage can be 60min, 120min, 180min, 240min, 300min, 360min, 420min, or 480min. Compared with the one-stage calcination method, the two-stage calcination can achieve a more thorough decomposition of the polydopamine-like layer and a higher reduction rate of copper oxide.

[0049] The carbon-coated copper preparation method provided in this invention utilizes the spontaneous polymerization reaction of dopamine on various material surfaces. Dopamine molecules react with copper oxide in the same environment, causing polydopamine to coat the copper oxide surface, thus modifying the copper oxide. Subsequently, high-temperature calcination decomposes the polydopamine on the copper oxide surface into small molecules with reducing properties, reducing the coated copper oxide. At high temperature, the remaining carbon from the calcination forms a carbon coating layer on the reduced copper surface, giving it better oxidation and corrosion resistance. This method introduces polydopamine as the sole reducing agent for copper oxide at high temperatures, resulting in a relatively simple process. It simultaneously reduces copper oxide to copper and passivates the copper surface. The carbon-coated copper prepared by this method exhibits good conductivity, oxidation resistance, and corrosion resistance.

[0050] This invention also provides a carbon-coated copper, prepared by the method described in any of the above embodiments for in-situ reduction of copper oxide with polydopamine. The carbon-coated copper comprises a copper core and a carbon layer encapsulating the copper core. The carbon-coated copper provided by this invention retains the high conductivity of copper while exhibiting better oxidation and corrosion resistance than copper itself. The carbon layer of the carbon-coated copper has excellent corrosion resistance, reducing oxidation and corrosion of the copper surface in humid environments, thereby extending its service life and performance. Simultaneously, the copper core provides good mechanical strength, while the carbon layer increases hardness and wear resistance, making the carbon-coated copper more durable.

[0051] In this embodiment of the invention, the molar ratio of copper to carbon in the carbon-coated copper is (10-50):1. This range of molar ratios ensures both the conductivity and stability of the carbon-coated copper, while also enhancing its corrosion resistance. In some embodiments, the molar ratio of copper to carbon in the carbon-coated copper may be, but is not limited to, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, or 50:1.

[0052] In this invention, the copper core in carbon-coated copper is surrounded by a dense carbon layer. This dense carbon layer protects the copper core and slows down its oxidation and corrosion rates in the environment. In one embodiment of this invention, as... Figure 8 As shown, the surface of carbon-coated copper has a dense layered structure.

[0053] In this embodiment of the invention, the thickness of the carbon layer is 5nm-400nm. The carbon-coated copper within the above-mentioned carbon layer range possesses both high conductivity and corrosion resistance. In some embodiments, the thickness of the carbon layer may be, but is not limited to, 5nm, 10nm, 20nm, 30nm, 50nm, 60nm, 80nm, 100nm, 200nm, 300nm, or 400nm.

[0054] In this embodiment of the invention, the carbon layer is made of graphene. Graphene can protect the copper surface from oxidation and corrosion, thereby extending the service life of the copper. Simultaneously, graphene has high thermal conductivity; therefore, graphene-coated copper can effectively improve the thermal conductivity of copper, making it more suitable for heat dissipation in high-power electronic devices. This embodiment of the invention also provides the application of carbon-coated copper in conductive components according to any of the above embodiments. The carbon-coated copper provided by this embodiment of the invention has good conductivity, oxidation resistance, and corrosion resistance, and can be used in conductive materials, catalytic materials, or electromagnetic shielding materials, such as conductive connections for integrated circuit components, conductive or antistatic coatings, electromagnetic shielding shells, catalysts, electrodes, etc., especially in applications requiring high conductivity and corrosion resistance, it can effectively improve the conductivity and service life of conductive components.

[0055] The effects of the technical solution of the present invention will be further illustrated below through several examples.

[0056] Example 1

[0057] Weigh 0.5407 g of o-phenylenediamine and 0.5505 g of catechol into a beaker, add 500 mL of Tris-HCl buffer solution, stir well, and then add 2.5 g of spherical copper oxide. React in air at 25 °C for 24 h. Centrifuge the reaction solution, wash repeatedly with ethanol and water, and then place the centrifuged substrate in a 65 °C oven for 5 h to obtain polydopamine-like coated copper oxide (PDL@CuO). After drying, grind the coated copper oxide in a mortar and pestle, place it in a crucible, and place the crucible in a tube furnace. Under an argon atmosphere, calcine the copper oxide by heating from 30 °C to 300 °C at a rate of 2 °C / min, holding at 300 °C for 120 min, and then heating from 300 °C to 700 °C at a rate of 2 °C / min, holding at 700 °C for 120 min. After calcination, cool to room temperature to obtain carbon-coated copper (C@Cu).

[0058] The raw materials copper oxide (CuO), polydopamine-coated copper oxide (PDL@CuO), and carbon-coated copper (C@Cu) from Example 1 were subjected to the following tests:

[0059] (1) Transmission electron microscopy (TEM) characterization

[0060] The morphology of copper oxide (CuO), polydopamine-coated copper oxide (PDL@CuO), and carbon-coated copper (C@Cu) was observed using TEM, and the results are as follows: Figure 2 As shown in the figure, from left to right are the TEM spectra of CuO, PDL@CuO and C@Cu. The TEM spectra show that the surface of the raw copper oxide has no coating. After modification with polydopamine, a layer of material was successfully coated on the surface of the copper oxide. The surface of the material obtained after calcination is also coated with a layer of material.

[0061] (2) Characterization by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS)

[0062] The copper oxide (CuO), polydopamine-coated copper oxide (PDL@CuO), and carbon-coated copper (C@Cu) were characterized by XRD and XPS, and the results are as follows: Figure 3 and Figure 4 As shown, the copper oxide material remained unchanged after being modified with polydopamine. After calcination, the copper oxide modified with polydopamine was completely reduced to metallic copper.

[0063] (3) Raman characterization

[0064] Raman characterization was performed on copper oxide (CuO), polydopamine-coated copper oxide (PDL@CuO), and carbon-coated copper (C@Cu). The results are as follows: Figure 5 As shown, after modification with polydopamine, the surface of copper oxide was successfully coated with polydopamine. After calcination, the polydopamine coated with copper oxide was converted into carbon, and the Raman peak of copper oxide disappeared, indicating that the copper oxide was completely reduced.

[0065] (4) Antioxidant test

[0066] Carbon-coated copper (C@Cu) was placed in a forced-air drying oven at 150℃ for 5 hours. The heat-treated carbon-coated copper (C@Cu - 150℃ 5h) was then characterized by XRD. The results are as follows: Figure 6 As shown, no obvious oxidation peak was observed in the carbon-coated copper (C@Cu-150℃5h) after heat treatment, indicating that the carbon-coated copper provided in Example 1 of this invention has antioxidant properties.

[0067] (5) Corrosion resistance test

[0068] Carbon-coated copper (C@Cu) was placed in saturated sodium chloride solution (NaCl), 0.1M sodium hydroxide solution (NaOH), and 0.5M sulfuric acid solution (H2SO4) for 5 h, respectively. Then, the NaCl-treated (C@Cu-NaCl-5h), NaOH-treated (C@Cu-0.1M NaOH-5h), and H2SO4-treated (C@Cu-0.5M H2SO4-5h) carbon-coated copper were characterized by XRD. The results are as follows: Figure 7 As shown, after treatment with NaCl, NaOH, and H2SO4, only a small number of oxidation peaks appeared in the carbon-coated copper, indicating that the carbon-coated copper provided in Example 1 of this invention has corrosion resistance.

[0069] (6) Conductivity comparison

[0070] Five samples each of copper oxide (CuO) and carbon-coated copper (C@Cu) were taken, and their sheet resistance, resistivity and conductivity were tested using the four-probe method. The data for each group and their average values ​​are listed in Table 1.

[0071] Table 1. Comparison of conductivity between CuO and C@Cu in Example 1

[0072]

[0073] As shown in Table 1, the conductivity of copper oxide (CuO) increased from 0.038 S / cm to 471.230 S / cm after being coated with polydopamine-like substance and calcined, which is beneficial for its use in conductive components.

[0074] Example 2

[0075] Weigh 0.5407 g of o-phenylenediamine and 0.5505 g of catechol into a beaker, add 500 mL of Tris-HCl buffer solution, stir well, and then add 2.5 g of irregular copper oxide. React in air at 25 °C for 24 h. Centrifuge the reaction solution, wash repeatedly with ethanol and water, and then place the centrifuged substrate in a 65 °C oven for 5 h to obtain polydopamine-modified copper oxide (PDL@CuO). After drying, grind the powder in a mortar and pestle, place it in a crucible, and place the crucible in a tube furnace. Under an argon atmosphere, calcine the copper oxide by heating from 30 °C to 300 °C at a rate of 2 °C / min, holding at 300 °C for 120 min, then heating from 300 °C to 700 °C at a rate of 2 °C / min, and holding at 700 °C for 120 min. After calcination, cool to room temperature to obtain carbon-coated copper (C@Cu).

[0076] Example 3

[0077] Weigh 0.5407 g of o-phenylenediamine and 0.5505 g of catechol into a beaker, add 500 mL of Tris-HCl buffer solution, stir well, and then add 5 g of spherical copper oxide. React in air at 25 °C for 24 h. Centrifuge the reaction solution, wash repeatedly with ethanol and water, and then place the centrifuged substrate in a 65 °C forced-air oven for 5 h to obtain polydopamine-modified copper oxide (PDL@CuO). After drying, grind the powder in a mortar and pestle, place it in a crucible, and place the crucible in a tube furnace. Under an argon atmosphere, calcine the copper oxide by heating from 30 °C to 300 °C at a rate of 2 °C / min, holding at 300 °C for 120 min, and then heating from 300 °C to 700 °C at a rate of 2 °C / min, holding at 700 °C for 120 min. After calcination, cool to room temperature to obtain carbon-coated copper (C@Cu).

[0078] Example 4

[0079] Weigh 0.4326 g of o-phenylenediamine and 0.5505 g of catechol into a beaker, add 400 mL of Tris-HCl buffer solution, stir well, and then add 2.0 g of spherical copper oxide. React in air at 25 °C for 24 h. Centrifuge the reaction solution, wash repeatedly with ethanol and water, and then place the centrifuged substrate in a 65 °C forced-air oven for 5 h to obtain polydopamine-modified copper oxide (PDL@CuO). After drying, grind the powder in a mortar and pestle, place it in a crucible, and place the crucible in a tube furnace. Under an argon atmosphere, calcine the copper oxide by heating from 30 °C to 300 °C at a rate of 2 °C / min, holding at 300 °C for 120 min, and then heating from 300 °C to 700 °C at a rate of 2 °C / min, holding at 700 °C for 120 min. After calcination, cool to room temperature to obtain carbon-coated copper (C@Cu).

[0080] Example 5

[0081] Weigh 0.5407 g of o-phenylenediamine and 0.4404 g of catechol into a beaker, add 400 mL of Tris-HCl buffer solution, stir well, and then add 2.0 g of spherical copper oxide. React in air at 25 °C for 24 h. Centrifuge the reaction solution, wash repeatedly with ethanol and water, and then place the centrifuged substrate in a 65 °C oven for 5 h to obtain polydopamine-modified copper oxide (PDL@CuO). After drying, grind the powder in a mortar and pestle, place it in a crucible, and place the crucible in a tube furnace. Under an argon atmosphere, calcine the copper oxide by heating from 30 °C to 300 °C at a rate of 2 °C / min, holding at 300 °C for 120 min, and then heating from 300 °C to 700 °C at a rate of 2 °C / min, holding at 700 °C for 120 min. After calcination, cool to room temperature to obtain carbon-coated copper (C@Cu).

[0082] Example 6

[0083] Weigh 0.4655 g of aniline and 0.6206 g of 3-methylcatechol into a beaker, add 500 mL of Tris-HCl buffer solution, stir well, and then add 2.5 g of spherical copper oxide. React in air at 25 °C for 24 h. Centrifuge the reaction solution, wash repeatedly with ethanol and water, and then place the centrifuged substrate in a 65 °C oven for 5 h to obtain polydopamine-modified copper oxide (PDL@CuO). After drying, grind the powder in a mortar and pestle, place it in a crucible, and place the crucible in a tube furnace. Under an argon atmosphere, calcine the copper oxide by heating from 30 °C to 300 °C at a rate of 2 °C / min, holding at 300 °C for 120 min, then heating from 300 °C to 700 °C at a rate of 2 °C / min, and holding at 700 °C for 120 min. After calcination, cool to room temperature to obtain carbon-coated copper (C@Cu).

[0084] Example 7

[0085] Weigh 0.5407 g of o-phenylenediamine and 0.5505 g of catechol into a beaker, add 500 mL of Tris-HCl buffer solution, stir well, and then add 2.5 g of spherical copper oxide. React at 25 °C in an oxygen atmosphere for 24 h. Centrifuge the reaction solution, wash repeatedly with ethanol and water, and then place the centrifuged substrate in a 65 °C forced-air drying oven for 5 h to obtain polydopamine-modified copper oxide (PDL@CuO). After drying, grind the powder in a mortar and pestle, place it in a crucible, and place the crucible in a tube furnace. Under an argon atmosphere, calcine the material by heating from 30 °C to 300 °C at a rate of 2 °C / min, holding at 300 °C for 120 min, and then heating from 300 °C to 700 °C at a rate of 2 °C / min, holding at 700 °C for 120 min. After calcination, cool to room temperature to obtain carbon-coated copper (C@Cu).

[0086] Example 8

[0087] Weigh 0.5407 g of o-phenylenediamine and 0.5505 g of catechol into a beaker, add 500 mL of Tris-HCl buffer solution, stir well, and then add 2.5 g of spherical copper oxide. React in air at 25 °C for 6 h. Centrifuge the reaction solution, wash repeatedly with ethanol and water, and then place the centrifuged substrate in a 65 °C forced-air oven for 5 h to obtain polydopamine-modified copper oxide (PDL@CuO). After drying, grind the powder in a mortar and pestle, place it in a crucible, and place the crucible in a tube furnace. Under an argon atmosphere, calcine the copper oxide by heating from 30 °C to 300 °C at a rate of 2 °C / min, holding at 300 °C for 120 min, and then heating from 300 °C to 700 °C at a rate of 2 °C / min, holding at 700 °C for 120 min. After calcination, cool to room temperature to obtain carbon-coated copper (C@Cu).

[0088] Example 9

[0089] Weigh 0.5407 g of o-phenylenediamine and 0.5505 g of catechol into a beaker, add 500 mL of Tris-HCl buffer solution, stir well, and then add 2.5 g of spherical copper oxide. React in air at 25 °C for 24 h. Centrifuge the reaction solution, wash repeatedly with ethanol and water, and then place the centrifuged substrate in a 65 °C forced-air oven for 5 h to obtain polydopamine-modified copper oxide (PDL@CuO). After drying, grind the powder in a mortar and pestle, place it in a crucible, and place the crucible in a tube furnace. Under a nitrogen atmosphere, calcine the copper oxide by heating from 30 °C to 300 °C at a rate of 4 °C / min, holding at 300 °C for 60 min, then heating from 300 °C to 700 °C at a rate of 4 °C / min, and holding at 700 °C for 120 min. After calcination, cool to room temperature to obtain carbon-coated copper (C@Cu).

[0090] Example 10

[0091] Weigh 0.5407 g of o-phenylenediamine and 0.5505 g of catechol into a beaker, add 500 mL of Tris-HCl buffer solution, stir well, and then add 2.5 g of spherical copper oxide. React in air at 25 °C for 24 h. Centrifuge the reaction solution, wash repeatedly with ethanol and water, and then place the centrifuged substrate in a 65 °C forced-air oven for 5 h to obtain polydopamine-modified copper oxide (PDL@CuO). After drying, grind the powder in a mortar and pestle, place it in a crucible, and place the crucible in a tube furnace. Under an argon atmosphere, calcine the copper oxide by heating from 30 °C to 300 °C at a rate of 4 °C / min, holding at 300 °C for 120 min, then heating from 300 °C to 900 °C at a rate of 4 °C / min, and holding at 900 °C for 180 min. After calcination, cool to room temperature to obtain carbon-coated copper (C@Cu).

[0092] The raw materials copper oxide (CuO), polydopamine-coated copper oxide (PDL@CuO), and carbon-coated copper (C@Cu) from Examples 2-10 were tested and analyzed using the same methods as in Example 1. The results showed that the copper oxide in Examples 2-10 was completely reduced to metallic copper after calcination, and the irregular copper oxide in Example 2 was completely reduced to spherical metallic copper after calcination. The carbon-coated copper (C@Cu) obtained in Examples 2-10 showed no obvious oxidation peaks after being placed in a 150°C forced-air oven for 5 hours. Only a small amount of oxidation peaks were observed after being placed in saturated sodium chloride solution (NaCl), 0.1M sodium hydroxide solution (NaOH), and 0.5M sulfuric acid solution (H2SO4) for 5 hours. These results indicate that the carbon-coated copper (C@Cu) provided in Examples 2-10 possesses antioxidant and corrosion-resistant properties.

[0093] Comparative Example 1

[0094] 0.6305 g of melamine and 0.5505 g of catechol were weighed and added to a beaker. 500 mL of Tris-HCl buffer solution was added, and the mixture was stirred until homogeneous. Then, 2.5 g of spherical copper oxide was added, and the mixture was reacted in air at 25 °C for 6 h. The reaction solution was centrifuged and repeatedly washed with ethanol and water. After washing, the centrifuged substrate was placed in a 65 °C oven for 5 h to obtain polydopamine-modified copper oxide (PDL@CuO). After drying, the oxide was ground in a mortar and pestle and placed in a crucible. The crucible was then placed in a tube furnace, and calcined under an argon atmosphere by increasing the temperature from 30 °C to 300 °C at a rate of 4 °C / min, holding at 300 °C for 120 min, and then increasing the temperature from 300 °C to 700 °C at a rate of 4 °C / min, holding at 700 °C for 180 min. After calcination, the mixture was cooled to room temperature to obtain a carbon-coated material.

[0095] The following tests were performed on the polydopamine-coated copper oxide (PDL@CuO) and carbon-coated material in Comparative Example 1:

[0096] (1) X-ray diffraction (XRD) characterization

[0097] The carbon-coated material was characterized by XRD, and the results are as follows: Figure 9 As shown, most of the copper oxide coated with polydopamine-like substances generated by the reaction of melamine and catechol was not reduced after calcination, and a small amount was reduced to cuprous oxide. This indicates that the type of polymer coating material is crucial to the reduction effect of copper oxide. Only by using polydopamine-like substances synthesized from aniline compounds and catechol compounds provided in the embodiments of the present invention to coat copper oxide can carbon-coated copper be obtained after calcination.

[0098] (2) Thermogravimetric analysis (TGA)

[0099] The thermogravimetric curve was obtained by measuring the solid residue rate of polydopamine-coated copper oxide (PDL@CuO) as a function of temperature. The results are as follows: Figure 10 As shown, within the TGA heating range of 25℃-800℃, PDL@CuO only lost 3.29% of its weight, which means that PDL@CuO in Comparative Example 1 could not achieve the reduction of copper oxide after high-temperature treatment.

[0100] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing carbon-coated copper by in-situ reduction of copper oxide with a polydopamine-like substance, characterized in that, include: Copper oxide was added to an aqueous solution of catechol and aniline compounds and reacted under conditions containing an oxidizing gas to obtain copper oxide coated with a polydopamine-like substance. In the aqueous solution, the concentration of the catechol compound was 1 mmol / L-50 mmol / L, the concentration of the aniline compound was 1 mmol / L-50 mmol / L, and the molar ratio of the catechol compound to the aniline compound was (0.7-1.3):(0.7-1.3). The copper oxide coated with the polydopamine-like substance was calcined in an inert gas atmosphere to obtain carbon-coated copper.

2. The method for preparing carbon-coated copper by in-situ reduction of copper oxide with polydopamine as described in claim 1, characterized in that, The calcination process includes heating to 200℃-400℃ at a heating rate of 1℃ / min-10℃ / min and holding at that temperature for 0min-240min, and then heating to 600℃-1200℃ at a heating rate of 1℃ / min-10℃ / min and holding at that temperature for 60min-480min.

3. The method for preparing carbon-coated copper by in-situ reduction of copper oxide with polydopamine as described in claim 1, characterized in that, The copper oxide includes at least one of granular copper oxide, linear copper oxide, and irregular copper oxide; the particle size D50 of the granular copper oxide is 20nm-10μm; the length of the linear copper oxide is 40nm-10mm; and the concentration of the copper oxide in the aqueous solution is 1mg / ml-20mg / ml.

4. The method for preparing carbon-coated copper by in-situ reduction of copper oxide with polydopamine as described in claim 1, characterized in that, The reaction temperature is 15℃-55℃, and the reaction time is 10min-24h.

5. The method for preparing carbon-coated copper by in-situ reduction of copper oxide with polydopamine as described in claim 1, characterized in that, The oxidizing gas includes at least one of air, oxygen, and ozone; the inert gas includes at least one of argon and nitrogen.

6. A carbon-coated copper, characterized in that, The carbon-coated copper is prepared by the method of in-situ reduction of copper oxide with polydopamine as described in any one of claims 1-5, wherein the carbon-coated copper comprises a copper core and a carbon layer encapsulating the copper core.

7. The carbon-coated copper as described in claim 6, characterized in that, The molar ratio of copper to carbon in the carbon-coated copper is (10-50):

1.

8. The carbon-coated copper as described in claim 6, characterized in that, The thickness of the carbon layer is 5nm-400nm; the material of the carbon layer includes graphene.

9. The application of carbon-coated copper as described in any one of claims 6-8 in conductive materials, catalytic materials or electromagnetic shielding materials.

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