Novel method for realizing helical carbon growth by utilizing electrodeposition nickel catalyst

Abstract

The invention relates to a novel method for realizing helical carbon growth by using an electro-deposition nickel catalyst, which comprises the following steps: (1) cutting a copper foil into a required size, and sequentially carrying out ultrasonic cleaning in ethanol and acetone to obtain a sample; (2) carrying out electro-deposition on the sample in a nickel plating electrolyte; (3) placing the Cu foil sample plated with the Ni film on a quartz boat, placing the quartz boat at the central position of a horizontal tube furnace, and introducing argon before heating; and (4) raising the furnace temperature, after the temperature is stable, introducing acetylene as a carbon source, maintaining the argon flow, reacting for several minutes, generating a carbon micro / nano coil on the surface of the Ni catalyst, stopping supply of acetylene after deposition is finished, and naturally cooling the sample to room temperature under the condition of continuously introducing Ar atmosphere so as to avoid oxidation. According to the method disclosed by the invention, extensible, repeatable and high-yield synthesis of the carbon micro / nano coil is realized, and a new technical approach is provided for high-performance electromagnetic wave absorption and preparation of a multifunctional composite material.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electrodeposition, and particularly relates to a new method for realizing growth of spiral carbon by using electrodeposited nickel catalyst. BACKGROUND

[0002] Common catalysts such as Ni, Fe or Co films prepared by sputtering, hydrothermal or thermal evaporation methods usually have problems such as poor adhesion to the substrate, uneven particle distribution and unstable catalytic activity at high temperatures. These defects result in low product yield, irregular coil morphology and poor repeatability.

[0003] Spiral carbon has a unique three-dimensional spiral structure and excellent mechanical and electrical properties, and therefore has broad application prospects in the fields of electromagnetic wave absorbing materials, supercapacitors and sensors. Among various preparation methods, chemical vapor deposition (CVD) is considered to be the most effective method for preparing high-quality carbon micro / nanocoils (CMNCs) due to its high efficiency and controllability, and can realize adjustable morphology and good structural uniformity.

[0004] Catalysts play a key role in the nucleation and growth process of spiral carbon. Transition metals such as Ni, Fe and Co are widely used due to their high catalytic activity for the decomposition of hydrocarbons. Among them, nickel (Ni) is particularly concerned due to its good carbon solubility and thermal stability. However, traditional Ni catalyst preparation methods (such as sputtering, thermal evaporation, hydrothermal method, etc.) usually result in uneven distribution of catalytic particles, poor adhesion to the substrate and unstable catalytic performance at high temperatures, thereby causing low yield, uneven structure and poor repeatability of spiral carbon.

[0005] Existing carbon micro / nanocoil (CMNCs) synthesis technologies, such as catalysts prepared by sputtering, thermal evaporation or hydrothermal method, have several limitations. These traditional catalyst preparation methods usually result in poor adhesion between the catalyst and the substrate, uneven distribution of catalytic particles, and unstable catalytic performance at high temperatures. Therefore, the growth of spiral carbon is irregular, the yield is low, the morphology is inconsistent, and the repeatability is poor. In addition, these methods have limited scalability and cost-effectiveness, and are not suitable for large-scale or industrial production. SUMMARY

[0006] The present application overcomes the deficiencies of traditional catalysts and their preparation processes in the synthesis of carbon micro / nanocoils (CMNCs).

[0007] To overcome the above-mentioned defects, the present application uses electrodeposition technology to prepare uniform and firmly bonded Ni films. This method has the advantages of low cost and strong controllability, and can accurately control the film thickness and particle size, thereby ensuring high catalytic activity during the CVD process.

[0008] A new method for realizing spiral carbon growth by using electro-deposited nickel catalyst, comprising the following steps: (1) After cutting the copper foil into the desired size, sequentially performing ultrasonic cleaning in ethanol and acetone to obtain a sample.

[0009] (2) Electrodepositing the sample in a nickel plating electrolyte.

[0010] (3) Placing the Cu foil sample plated with a Ni film on a quartz boat and placing it in the center position of a horizontal tube furnace, before heating, introducing argon, and purging the system to remove residual air and form an inert atmosphere.

[0011] (4) Increasing the furnace temperature, after the temperature is stable, introducing acetylene as a carbon source while maintaining the argon flow, and the reaction continues for several minutes to generate carbon micro / nanocoils on the surface of the Ni catalyst. After the deposition is completed, stop the acetylene supply, and the sample is naturally cooled to room temperature under continuous argon atmosphere to avoid oxidation.

[0012] Preferably, in step (1), after cutting the copper foil into the desired size, the ultrasonic cleaning in ethanol and acetone is performed for 3 minutes, respectively.

[0013] Preferably, in step (2), the electro-deposition in the nickel plating electrolyte is performed at a current density of 1.5 A / dm 2 .

[0014] Preferably, in step (2), the electroplating solution comprises nickel sulfate hexahydrate, boric acid, trisodium citrate dihydrate, and sodium chloride.

[0015] Preferably, the composition of the electroplating solution comprises 150 g / L of nickel sulfate hexahydrate, 35 g / L of boric acid, 120 g / L of trisodium citrate dihydrate, and 12 g / L of sodium chloride.

[0016] 6. The new method for realizing spiral carbon growth by using electro-deposited nickel catalyst according to claim 1, wherein during the electroplating process of step (2), the solution pH is maintained at 5.0-5.6, and the temperature is maintained at 35°C.

[0017] Preferably, in step (3), the flow rate of the argon gas is 80 mL / min.

[0018] Preferably, in step (4), the furnace temperature is increased to 500°C or 600°C.

[0019] Preferably, in step (4), the gas flow rate of the acetylene is 20 mL / min.

[0020] Preferably, in step (4), the argon flow rate is maintained, and the reaction continues for 30 minutes.

[0021] Compared with the prior art, the present application has the following technical advantages: 1. Enhanced catalytic stability The present application covers the nickel (Ni) film on the copper foil, with strong adhesion and uniform Ni particle distribution, which can maintain stable catalytic activity even at high temperatures of about 600°C.

[0022] 2. High yield and structural uniformity Compared with traditional sputtering or evaporation methods, the present application can realize the growth of carbon micro / nanocoil (CMNCs) with good morphology and uniform structure, and significantly improve the repeatability and scalability.

[0023] 3. Low-cost and scalable process The present application is a low-cost, controllable and scalable process for the preparation of spiral carbon.

[0024] 4. Excellent structural and functional performance The carbon micro / nanocoil obtained by the present application has excellent structural uniformity and excellent microwave absorption performance, and is very suitable for advanced functional materials.

[0025] 5. Controllable coil morphology The present application can accurately control the diameter, length and morphology of the coil by adjusting the CVD parameters, thereby improving its flexibility in different application fields.

[0026] 6. The present application uses electrodeposited nickel (Ni) film covering the copper (Cu) substrate as a catalyst for the decomposition of acetylene, and is synthesized during the chemical vapor deposition (CVD) process. Electrodeposition technology can ensure firm bonding between the catalyst and the substrate, uniform distribution of Ni particles, and accurate control of the thickness of the catalyst, thereby improving the catalytic stability and promoting the uniform growth of the coil. Therefore, the present application realizes the high yield, high repeatability and scalable synthesis of carbon micro / nanocoil, and obtains products with more uniform structure and more excellent microwave absorption performance.

[0027] 7. The present application uses electrodeposited nickel (Ni) film covering the copper (Cu) substrate as a catalyst for the decomposition of acetylene during the chemical vapor deposition (CVD) process. Electrodeposition technology can realize firm interface bonding, uniform Ni particle distribution and accurate control of the thickness of the catalytic layer, thereby significantly improving the catalytic stability and enhancing the generation efficiency of spiral carbon.

[0028] 8. The present application regulates the diameter of carbon micro / nanocoil and invents its growth mechanism, which helps to optimize the preparation process and expand its application field. Therefore, the present application effectively solves the problems of low yield, non-uniform structure and insufficient microwave absorption performance in traditional spiral carbon synthesis. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 Figure 1 is a schematic diagram of a Ni thin film on a copper foil and a schematic diagram of the synthesis of carbon micro / nano-helixes by CVD on a Ni catalyst.

[0030] Figure 2 Figure 2 is a growth diagram of carbon micro / nano-coils, wherein, Figure 2 (a) is a pure copper substrate; Figure 2 (b) and Figure 2 (c) are grown in a CVD system on a copper foil coated with a Ni catalytic film at 500°C and 600°C, respectively.

[0031] Figure 3 Figure 3 is a TEM image of the growth of helical carbon on a Ni thin film, wherein, Figure 3 (a) and Figure 3 (b) are the results obtained by growing at 500°C for 30 minutes, Figure 3 (c) and Figure 3 (d) are the results obtained by growing at 600°C for 30 minutes, both prepared using a CVD system.

[0032] Figure 4 Figure 4 is a SEM image and a TEM image of helical carbon, wherein, Figure 4 (a) is a SEM image of helical carbon grown at 600°C, Figure 4 (b) is the corresponding TEM image, and its corresponding SEM / EDS and TEM elemental mapping.

[0033] Figure 5 Figure 5 is a Raman spectrum of carbon fibers grown by CVD on a Ni catalyst at 600°C. DETAILED DESCRIPTION

[0034] 1. Experimental Section 1.1 Materials The copper (Cu) foil used as a substrate in the present application was cut to the desired size for nickel plating. The chemical reagents used included nickel sulfate hexahydrate (NiS04-6H20), boric acid (H3B03), trisodium citrate dihydrate (C6H5Na307-2H20), sodium chloride (NaCl) and ethanol, all purchased from Sigma-Aldrich and used without further purification.

[0035] 1.2. Synthesis of carbon micro / nano-coils on a Ni catalyst After cutting the copper foil to the desired size, it was ultrasonically cleaned in ethanol and acetone for 3 minutes each. Subsequently, the sample was immersed in a nickel plating electrolyte at 1.5 A / dm2for 30 minutes. The copper foil was then removed from the electrolyte and rinsed with distilled water. The copper foil was then dried in a vacuum oven at 60°C for 30 minutes. 2The current density for electrodeposition was 1.5 A / dm2. The composition of the plating solution included 150 g / L nickel sulfate hexahydrate (NiS04-6H20), 35 g / L boric acid (H3B03), 120 g / L trisodium citrate dihydrate (C6H5Na307-2H20), and 12 g / L sodium chloride (NaCl). During plating, the pH of the solution was maintained at 5.0-5.6, and the temperature was maintained at 35 °C.

[0036] In the second step, the Cu foil sample with Ni thin film was placed on a quartz boat and positioned in the center of a horizontal tube furnace. Prior to heating, high-purity argon (Ar) was introduced at a flow rate of 80 mL / min to purge the system of residual air and create an inert atmosphere. Subsequently, the furnace temperature was raised to 500 °C or 600 °C. When the temperature was stable, acetylene (C2H2) was introduced as the carbon source at a flow rate of 20 mL / min, while maintaining the argon flow rate (80 mL / min). The reaction continued for 30 minutes, resulting in the formation of carbon micro / nanocoils on the surface of the Ni catalyst, as shown in the SEM images. After the deposition was complete, the C2H2supply was stopped, and the sample was allowed to cool to room temperature under a continuous Ar atmosphere to avoid oxidation. The above process successfully formed carbon micro / nanocoils with clear structures on the Ni thin film / Cu substrate at both 500 °C and 600 °C. A schematic diagram of the process is shown in FIG. 2. Figure 1

[0037] 1.3. Material Characterization Field emission scanning electron microscopy (FE-SEM, Inspect F50, FEI Co., Hillsboro, OR, USA) with an energy dispersive X-ray spectrometer (EDS) was used to analyze the surface morphology and elemental composition of the electrodeposited Ni thin film catalyst and the synthesized carbon micro / nanocoils. Raman spectroscopy was used to characterize the D and G peaks of the carbon material to confirm the formation of carbon structures.

[0038] Transmission electron microscopy (TEM, JEOL JEM-210, filament, 200 kV) was used to observe the nanostructure of the electrodeposited Ni thin film and the carbon micro / nanocoils. High-resolution transmission electron microscopy (HR-TEM), EDS, and elemental mapping were also used to further analyze the microstructure and elemental distribution. The TEM sample was prepared by ultrasonically dispersing a small amount of carbon powder in ethanol for 30 minutes, then adding one drop of the dispersion to a copper grid (TEM grid) and allowing it to dry naturally.

[0039] 2.1 Scanning Electron Microscopy (SEM) Figure 2 (a)- Figure 2 (c) shows the formation of carbon micro / nanocoils on the surface of the Ni thin film / Cu substrate in a CVD system. Figure 2 (a) pure Cu foil and Figure 2 (b)- Figure 2 ​(c) Growth of carbon nanowires on the surface of Ni-coated Cu foils, experiments were carried out at 500 °C and 600 °C for 30 min. The results show that pure Cu is not an effective catalyst for carbon nanowire formation, as Figure 2 (a) shows. Only a small amount of carbon growth was observed on the Cu substrate at 500 °C, accompanied by cracks and voids, which can be caused by thermal stress during the CVD process. In contrast, when a thin Ni film was used as the catalytic layer, as shown in Figure 2 (b), short carbon nanowires / micro-wires started to form on the surface after 30 min at 500 °C. As the temperature was increased to 600 °C, the surface morphology clearly shows that longer and more regular carbon micro / nano-wires were formed on the Ni-coated surface (c). Figure 2 (c). In addition, SEM observations show the presence of Ni catalytic particles, which contribute to the nucleation and growth of the wires, as shown in Figure 3 (d).

[0040] 2.2 Transmission Electron Microscopy (TEM) Figure 3 (a)- Figure 3 (d) shows TEM results of the growth behavior and structural evolution of carbon micro / nano-helices on Ni thin films under CVD conditions at 500 °C and 600 °C. At low magnification Figure 3 (a) and Figure 3 (c), it can be seen that the carbon deposited at 500 °C forms short, irregular, and partially entangled helices, while at 600 °C well-structured, continuous, and longer carbon helices are observed, due to enhanced catalytic activity and carbon diffusion. HRTEM images, such as Figure 3 (b) and Figure 3 (d), further confirm the catalyst-assisted growth by showing clear interfaces between the Ni particles and the deposited carbon. At 500 °C, Figure 3 (b), the carbon layer around the Ni particles is partially graphitized, showing lattice fringes of about 0.34 nm corresponding to the (002) plane of graphite carbon, while the Ni catalytic particles show fringes of about 0.20-0.21 nm corresponding to the (111) plane of Ni. At 600 °C, Figure 4 (d), the carbon layer surrounding the Ni particles is more ordered and continuous, indicating higher crystallinity and improved graphitization. The clear interface between Ni and carbon at this temperature proves that the increased temperature facilitates efficient carbon deposition and the formation of well-structured helices. These observations show that Ni is an effective catalyst for the growth of carbon helices, and increasing the temperature from 500 °C to 600 °C significantly improves the morphology and crystallinity of the carbon structure.

[0041] 2.3 SEM / EDS and TEM mapping Figure 4The morphology and elemental composition of carbon helices grown at 600 °C are shown. Figure 4 (a) shows SEM results revealing the surface microstructure of carbon helices, with SEM / EDS elemental mapping showing uniform distribution of carbon on the sample surface (see middle two images of Figure 4 Figure 5 (b) shows TEM images highlighting the internal structure of carbon helices and their fine structure at the nanoscale. Corresponding TEM elemental mapping shows high concentration of carbon within the helices, while nickel is embedded or attached to the carbon structure in the form of discrete nanoparticles, indicating that nickel plays a catalytic role in the growth of helices. The results confirm the successful formation of carbon helices and demonstrate the spatial distribution of carbon and nickel at the micro- and nanoscale.

[0042] 2.4 Raman spectroscopy The Raman spectrum of the synthesized helical carbon is shown in ​ Raman spectroscopy is used to analyze the structural quality and degree of graphitization of carbon materials. In the Raman spectrum of carbon-based samples, the D peak (around 1350 cm -1 ) represents disordered carbon or structural defects, while the G peak (around 1580 cm -1 ) corresponds to graphitized sp 2 bonded carbon structures. The intensity ratio (ID / IG) is an important indicator of the degree of structural order: the lower the ID / IG value, the higher the degree of crystallinity; while the higher the ID / IG value, the more defects or amorphous characteristics present in the material. This analysis helps to assess the effectiveness of the synthesis conditions and the quality of the resulting carbon structure.​

Claims

1. A novel method for spiral carbon growth using electrodeposition nickel catalyst, characterized in that, Includes the following steps: (1) After cutting the copper foil into the required size, it is ultrasonically cleaned in ethanol and acetone in sequence to obtain the sample; (2) The sample is electrodeposited in a nickel plating electrolyte; (3) Place the Cu foil sample coated with Ni film on a quartz boat and place it in the center of a horizontal tube furnace. Before heating, argon gas is introduced to purge the system to remove residual air and form an inert atmosphere. (4) Increase the furnace temperature. When the temperature stabilizes, introduce acetylene as a carbon source while maintaining the argon flow rate. The reaction continues for several minutes to generate carbon micro / nano coils on the surface of the Ni catalyst. After the deposition is completed, stop the acetylene supply and allow the sample to cool naturally to room temperature under a continuous Ar atmosphere to avoid oxidation.

2. The novel method for spiral carbon growth using electrodeposited nickel catalyst according to claim 1, characterized in that, In step (1), after the copper foil is cut to the required size, it is ultrasonically cleaned in ethanol and acetone for 3 minutes respectively.

3. The novel method for spiral carbon growth using electrodeposited nickel catalyst according to claim 1, characterized in that, In step (2), the nickel plating electrolyte contains 1.5 A / dm 2 Electrodeposition is performed using a current density.

4. The novel method for spiral carbon growth using electrodeposited nickel catalyst according to claim 1, characterized in that, The electroplating solution mentioned in step (2) includes: nickel sulfate hexahydrate, boric acid, trisodium citrate dihydrate and sodium chloride.

5. The novel method for spiral carbon growth using an electrodeposited nickel catalyst according to claim 4, characterized in that, The electroplating solution comprises: 150 g / L nickel sulfate hexahydrate, 35 g / L boric acid, 120 g / L trisodium citrate dihydrate, and 12 g / L sodium chloride.

6. The novel method for spiral carbon growth using an electrodeposited nickel catalyst according to claim 1, characterized in that, During the electroplating process in step (2), the solution pH is maintained at 5.0-5.6 and the temperature is maintained at 35℃.

7. The novel method for achieving helical carbon growth using an electrodeposited nickel catalyst according to claim 1, characterized in that, The flow rate of argon gas in step (3) is 80 mL / min.

8. The novel method for spiral carbon growth using electrodeposited nickel catalyst according to claim 1, characterized in that, In step (4), the furnace temperature is raised to 500°C or 600°C.

9. The novel method for spiral carbon growth using an electrodeposited nickel catalyst according to claim 1, characterized in that, The gas flow rate of acetylene in step (4) is 20 mL / min.

10. The novel method for achieving helical carbon growth using an electrodeposited nickel catalyst according to claim 1, characterized in that, In step (4), maintain the argon flow rate and the reaction lasts for 30 minutes.

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