Carbon dot nanoprotrusion carbon line and preparation method thereof

Abstract

The application discloses a preparation method of carbon dot nano-protruding carbon wire and belongs to the technical field of nano-carbon material preparation. A silicon substrate is subjected to oxidation and nitridation pretreatment, polyacrylonitrile fibers are deposited on the surface of the silicon substrate after the pretreatment through an electro-hydraulic power jetting mode, and then heat stabilization treatment and carbonization treatment are sequentially performed, so that the carbon dot nano-protruding carbon wire is obtained. The method can generate carbon dots on the surface of the carbon wire in situ, can obviously improve the optical performance of the carbon wire, and has a wider application prospect.

Description

Technical Field

[0001] This invention relates to carbon nanodots, and more particularly to carbon nanodot nano-protrusion carbon wires formed by in-situ growth of carbon nanodots on the surface of carbon nanowires, and also to their preparation method, belonging to the field of carbon nanomaterials technology. Background Technology

[0002] Nanostructuring carbon wires using techniques such as carbon spheres, conformal TiO2, photonic crystal structures, photonic architectures, and hollow-core photonic crystal microjunctions can enhance their optical properties. Typically, carbon dots (CDs) are dispersed in solution rather than on the surface of carbon wires (e.g., Carbon 173, 433-447 (2021); J. Appl. Phys. 127, 231101 (2020); ACS Sens. 8, 3812-3823 (2023); Nature Communications, 12: 812 (2021); Carbon 186, 91-127 (2022); ACS Nano 14, 6127-6137 (2020), etc.), exhibiting superior optical properties in applications such as cancer therapy, photocatalysis, bioimaging, and optical sensing. Growing carbon dots on the surface of carbon wires is expected to unlock unique new photonic mechanisms and devices.

[0003] Current methods for growing carbon dots (CDs) include microwave-assisted pyrolysis, chemical oxidation, hydrothermal / solvothermal reactions, and laser ablation, which produce carbon dots with conjugated sp... 2 The core and surface of the structure are rich in nitrogen and oxide chemical groups, which are closely related to photophysical properties. Raman spectroscopy can reveal the sp(s) surrounding these CD chemical groups. 2 Structure. In the Raman spectra of CDs, they are located at 1350 cm⁻¹. -1 and 1590cm -1 The D and G peaks respectively reflect the sp 3 and sp 2 The graphitic properties of carbon. The high dependence of emission wavelength on energy migration from the initial graphite nucleus to surface defects is elucidated, and this high dependence is used to excite extended spectra of carbon chromatographs (CDs). Due to the formation of indistinguishable impurity products resulting from hydrothermal and solvothermal synthesis, the relative proportions of graphite particle size and oxide surface defects on the optical properties of CDs are difficult to differentiate. Since both graphite particle size and oxide surface defects simultaneously affect CDs, highlighting the optical properties of carbon lines by extending the CD spectrum becomes extremely difficult. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the first objective of this invention is to provide a carbon dot nano-protrusion carbon wire, which can significantly improve the optical properties of carbon wire by forming carbon dots on the surface of carbon wire and has a wider range of application prospects.

[0005] The second objective of this invention is to provide a method for preparing carbon dot nano-bump carbon wires. This method involves pretreating a silicon substrate by oxidation and nitridation, depositing nano-bump PAN wires onto the pretreated silicon substrate using electro-hydrodynamic jetting, and subsequently performing thermal stabilization and carbonization to obtain carbon dot nano-bump carbon wires. This method not only enables the formation of carbon dots on the nano-bump carbon wires but also allows control over the number and dispersion of the carbon dots.

[0006] To achieve the above-mentioned technical objectives, the present invention provides a method for preparing carbon dot nano-protrusion carbon wires. The method involves pre-treating a silicon substrate by oxidation and nitridation, depositing polyacrylonitrile fibers on the surface of the pre-treated silicon substrate by electro-hydraulic jetting, and then sequentially performing thermal stabilization treatment and carbonization treatment to obtain carbon dot nano-protrusion carbon wires.

[0007] To achieve the above-mentioned technical objectives, the present invention provides a method for preparing carbon dot nano-protrusion carbon wires. The method involves pre-treating a silicon substrate by oxidation and nitridation, depositing polyacrylonitrile fibers on the surface of the pre-treated silicon substrate by electro-hydraulic jetting, and then sequentially performing thermal stabilization treatment and carbonization treatment to obtain carbon dot nano-protrusion carbon wires.

[0008] The key to the preparation method of carbon dot nano-protrusion carbon wires provided by this invention lies in the following aspects: On the one hand, by oxidizing and nitriding a silicon substrate, a nitrogen-doped silicon dioxide layer is generated on the silicon substrate. This substrate can induce the carbonization process of polyacrylonitrile fibers, transforming them into carbon nanowires grown in situ on the surface. On the other hand, the deposition of polyacrylonitrile fibers by spraying is beneficial for controlling the morphology of the polyacrylonitrile fibers, such as obtaining polyacrylonitrile fibers with a semi-circular cross-section, which is a key factor in realizing the growth of carbon dots on the surface of carbon wires. At the same time, the size of PAN fibers can be easily controlled by spraying. By controlling the diameter of the polyacrylonitrile fibers, the pore size of the porous microstructures contained therein is reduced to 0, thus transforming them into hidden nodes. These hidden node microstructures can be transformed into carbon dots grown in situ on carbon wires after thermal stabilization and carbonization treatment.

[0009] As a preferred embodiment, the oxidation pretreatment conditions are: oxidation in air atmosphere at 900–1000°C for 3–5 hours. The purpose of the oxidation treatment is to generate a layer of silicon dioxide in situ on the silicon substrate. By controlling the appropriate temperature and time, the thickness of the silicon dioxide layer can be controlled to be approximately 1 micrometer.

[0010] As a preferred embodiment, the nitriding pretreatment conditions are as follows: nitriding at 950–1050°C for 1–4 hours under a nitrogen atmosphere. Appropriate nitriding treatment can dope a suitable amount of nitrogen into the silica layer, and the doping of nitrogen atoms can alter the surface properties of the silica layer, significantly affecting the morphology of the deposited polyacrylonitrile fibers and the carbonization process.

[0011] As a preferred embodiment, the process of depositing polyacrylonitrile fibers is as follows: using a PAN solution as the jetting liquid, the temperature of the PAN solution is 106–115°C, using a treated silicon substrate as the receiving substrate, the distance between the nozzle and the receiving substrate is 1.8–1.95 mm, the jetting voltage is 500V–800V, the moving speed of the nozzle is 500–2400 m / s, and the moving speed of the receiving substrate is 0.6–10 m / s. Under high voltage, the PAN DMF solution droplet at the nozzle tip is driven to transform into a continuous PAN-based jet. During the movement of the PAN-based jet towards the receiving substrate, the solvent evaporates, thus transforming the PAN-based jet into PAN fibers. By controlling the movement of the receiving substrate, the PAN fibers deposited on the silicon substrate surface exhibit a patterned appearance. The jetting voltage is a crucial factor affecting the morphology and size of the polyacrylonitrile fibers. The closer the jetting voltage is to 800V, the closer the cross-section of the polyacrylonitrile fibers is to a semi-circular shape, and the larger its diameter is, the more favorable it is for the formation of carbon lines and carbon dots on the surface. The preferred injection voltage is 600-800V, and more preferably 700-800V.

[0012] As a preferred embodiment, the PAN solution has a mass concentration of 8-9%; the PAN solution is a PAN / DMF solution. Concentrations that are too high or too low will not meet the electrohydraulic spraying requirements for the preparation of carbon dot nanofibers.

[0013] As a preferred embodiment, the heat stabilization treatment is performed under air atmosphere at a temperature of 110–115°C for 8–13 hours. This heat stabilization process completely evaporates excess solvent from the polypropylene fibers, stabilizing them for molding.

[0014] As a preferred embodiment, the carbonization treatment conditions are as follows: under a protective atmosphere, the temperature is increased to 1000–1050°C at a heating rate of 10–20°C / min, and held at this temperature for 1.0–1.5 hours. During the carbonization process, the polypropylene fibers undergo H2O removal. 2、 CO, HCN, H2O, O 2、 NH 3、 Small molecules such as CH4 are carbonized and graphitized. The heating rate mainly affects the removal rate of small molecules in polyacrylonitrile, thus affecting the morphology of the carbon wire material.

[0015] The PAN / DMF solution of the present invention is formed by dissolving polyacrylonitrile (PAN) particles in N,N-dimethylformamide (DMF) under heating and magnetic stirring.

[0016] When the PAN / DMF solution of the present invention is heated to 106°C, its properties such as shear strength, loss modulus and conductivity become excellent. These outstanding properties ensure electro-hydrodynamic jetting under high local electric fields.

[0017] The present invention also provides carbon dot nano-protrusion carbon wires, which are obtained by the preparation method described above.

[0018] Compared with existing technologies, the beneficial technical effects of the present invention are as follows:

[0019] The carbon dot nano-protrusion carbon wire of the present invention can significantly improve the optical performance of carbon wire by forming carbon dots in situ on the surface of carbon wire. For example, forming carbon dots on continuous carbon wire can enhance the intensity of the G peak and D+G peak in photoelectron spectroscopy and Raman spectroscopy.

[0020] The method for preparing carbon dot nano-bump carbon wires of the present invention involves pre-treating a silicon substrate by oxidation and nitridation, depositing nano-bump PAN wires onto the pre-treated silicon substrate using electro-hydrodynamic jetting, and subsequently stabilizing and carbonizing. This method can form carbon dots on the nano-bump carbon wires and can control the number and dispersion of carbon dots.

[0021] The method for preparing carbon dot nano-protrusion carbon wires of the present invention is simple, low-cost, and conducive to large-scale production. Attached Figure Description

[0022] Figure 1 The synthesis process of carbon dot nano-protrusion carbon wires is as follows: a) the manufacturing process of carbon wires with carbon dot surfaces; b) scanning electron microscope image and outline of trapezoidal PAN fibers; d) scanning electron microscope image and outline of semi-circular PAN fibers; c) carbon wire image and outline without carbon dots; e) carbon wire image and outline with carbon dots. Figure 2 To control carbon dots based on PAN microstructure: a represents the manufacturing process from PAN fiber to carbon dots; b and e represent scanning electron microscope (SEM) images and outlines of PAN fiber; c and f represent SEM images and outlines of carbon wire; where b and c represent porous microstructure; e and f represent carbon dot microstructure; d represents the correlation between the pore structure and diameter of carbon wire; and d represents the functional relationship between the ratio of carbon dot size to diameter and the diameter of carbon wire. Figure 3The effects of carbon wire diameter and oxidation reaction on the nanostructuring of carbon dots in the absence of nitrogen pretreatment are shown in Figure 1. a represents the transformation from PAN conformation to carbon dots; b represents the scanning electron microscope (SEM) image and outline of PAN fibers with hidden node microstructure; c, d, and e represent the atomic force microscope (AFM) images and outlines of nanoconvex carbon wires with diameters of 191 nm, 177 nm, and 268 nm, respectively; f represents the SEM image, AFM image, and outline of the broken carbon wires after oxidation treatment; g represents the X-ray photoelectron spectroscopy (XPS) spectrum of the carbon wires in Figure f; h represents the dependence of axial carbon dot spacing on carbon wire diameter and carbon dot density.

[0023] Figure 4 The influence of carbon wire contact surface on the nanostructuring of carbon dots; a is the evolution of carbon dots on different substrates; b is the silica surface; c is the silicon surface; d is the nitrogen surface (nitrided silica surface); e is the carbon wire suspended between carbon supports; F is the shrinkage rate of PAN fiber to carbon wire on different contact surfaces; g is the correlation between the number of carbon dots per unit area and the shrinkage rate.

[0024] Figure 5 Characterization of carbon dots on carbon lines; a is a carbon line on a carbon surface, b is a broken carbon line on a silica surface; c is a scanning electron microscope and atomic force microscope of carbon dot-based carbon lines. d~f are X-ray photoelectron spectra of carbon lines in a, b and c, respectively; g~i are Raman spectra of carbon lines in a, b and c, respectively. Detailed Implementation

[0025] The following specific embodiments are intended to further illustrate the content of the present invention, rather than to limit the scope of protection of the claims of the present invention.

[0026] Example 1

[0027] 1. Place the silicon wafer in an oxidation furnace and perform an oxidation treatment at 1000°C for 4 hours in an air atmosphere to form an oxide layer of 1000nm on the surface of the silicon wafer.

[0028] 2. The oxidized silicon wafer is placed in a pyrolysis furnace under nitrogen atmosphere for nitriding at 1000°C for 1 hour, forming a structure like... Figure 1 The silicon substrate shown has a silicon dioxide layer and a nitrogen layer.

[0029] 3. Polyacrylonitrile (0.27g) and dimethylformamide (3g) were mixed, heated (at 106℃) and stirred to prepare a polyacrylonitrile solution;

[0030] IV. Using a polyacrylonitrile solution and its electro-hydraulic fluid jetting process (jetting voltage 800V, distance between the jetting needle and the silicon wafer surface 1.95mm, jetting needle moving speed 2400m / s, and the substrate on which the silicon wafer is located moving at a speed of 0.6m / s), polyacrylonitrile fibers are deposited onto the silicon wafer surface that has been pretreated with oxidation and nitrogen, forming a structure such as... Figure 1 The diagram shows a polyacrylonitrile fiber pattern. In the electrohydraulic jetting process of the polyacrylonitrile solution: 1) A voltage of 500V is applied between the silicon wafer and the nozzle; 2) The flow rate of the polyacrylonitrile solution in the nozzle is controlled to be 0–1 nL / min using an injection pump; 3) The distance between the nozzle and the silicon wafer is reduced until the polyacrylonitrile droplets on the nozzle contact the substrate where the silicon wafer is located, deform, and return to 1.95 mm, thereby activating electrohydraulic jetting and forming polyacrylonitrile jet fibers; 4) The voltage between the silicon wafer and the nozzle is increased to 800V by controlling the power supply; 5) The nozzle is further moved at a speed of 2400 m / s, and the substrate where the silicon wafer is located is moved at a speed of 0.6 m / s to ensure continuous deposition of polyacrylonitrile fibers onto the surface of the silicon wafer treated with oxidation and nitrogen.

[0031] 5. Polyacrylonitrile fibers and their silicon wafers are subjected to heat stabilization treatment at 115℃ (air environment, constant temperature of 115℃, heating time of 13 hours) and carbonization treatment at 1000℃ (heating rate from 115℃ to 1000℃ is 14.5℃ / min). The carbonization treatment time is 1 hour. Polyacrylonitrile fibers are transformed into nano-convex carbon wires and carbon dots are formed on the nano-convex carbon wires.

[0032] from Figure 1 As can be seen, at a spray voltage of 500V, the cross-section of the PAN fibers received by the silicon substrate is trapezoidal. As the spray voltage increases to 800V, the cross-sectional shape of the PAN fibers changes from trapezoidal to semi-circular. When the spray voltage reaches 600V or higher, up to 800V, the cross-section of the PAN fibers received by the silicon substrate after oxidation and nitriding treatment is semi-circular (see...). Figure 1 (a) The PAN fibers received on the silicon substrate undergo air thermal stabilization and carbonization in a nitrogen atmosphere at 1000°C. The trapezoidal cross-section of the PAN fibers is transformed into a graphite-like carbon structure, but no carbon dots grow on the carbon lines (see [reference]). Figure 1 (b and c) As the jetting voltage decreased to 800V, the diameter of the PAN fiber decreased from 3.05μm to 0.81μm, and the cross-section of the PAN fiber changed from trapezoidal to semi-circular. This cross-sectional change is a key factor in the growth of carbon dots onto the carbon wire surface. The PAN fibers received by the silicon substrate after oxidation and nitriding pretreatment were transformed into nano-convex carbon wires, and carbon dots grew on the surface of the nano-convex carbon wires.

[0033] Figure 2The carbon dot nanostructure based on the microstructure of PAN fibers was demonstrated. Using electrohydraulic fluid jetting, a PAN / DMF solution was transformed into PAN fibers, and the molecular chains within the PAN fibers assembled into a porous microstructure in a helical conformation. Figure 2 (a) By decreasing the injection voltage, the corresponding PAN fiber diameter decreases, and the pore size of the porous microstructure within the PAN fiber decreases to zero. This ensures that the hidden nodes of the PAN grow on the semi-circular PAN fiber, but cannot be effectively highlighted on the semi-circular cross-section (see [reference]). Figure 2 (a) The PAN fibers undergo thermal stabilization and carbonization pretreatment, transforming these hidden PAN nodes into carbon dots, which are clearly visible in the semi-circular cross-section (see [reference]). Figure 2 (a) When the transition from a lack of porous microstructure to a hidden-point microstructure in PAN occurs, the porous microstructure is reflected from the PAN fibers onto the carbon lines through thermal stabilization and carbonization treatment (see [link]). Figure 2 (bc). However, during the thermal stabilization and carbonization pretreatment, cyclization, dehydrogenation, denitrification, and decyanation reactions occur. These reactions release gases such as H2, CO, HCN, H2O, O2, NH3, and CH4. This gas release occurs in the porous microstructure, where the pore size increases from 15 nm to 78 nm (see [link to relevant documentation]). Figure 2 (bc). By reducing the diameter of the carbon wire to 620 nm, the ratio of aperture size to carbon wire diameter decreased from 4.047% to 0 (see [reference]). Figure 2 (bc). When PAN hidden points appear on the surface of PAN fibers, carbon dots can grow on the corresponding carbon lines (see bc). Figure 2 (b, e, and f). When the carbon wire diameter decreases from 620 nm to 100 nm, the carbon dot size on the carbon wire increases from 24 nm to 100 nm. This reveals a trend where the ratio of carbon dot size to carbon wire diameter increases to 100%. This trend indicates that the growth of carbon dots on carbon wires requires controlling the carbon wire diameter between 100 nm and 620 nm to avoid the ratio of carbon dot size to carbon wire diameter reaching 100%. Furthermore, the relationship between carbon dots and the PAN microstructure reveals that the growth of carbon dots depends on the PAN-based hidden nodes rather than the porous microstructure.

[0034] Comparative Example 1

[0035] Compared to Example 1, the difference is that after oxidizing the silicon substrate, no nitriding treatment is performed. The PAN hidden nodes are transformed into carbon nodes, which have a relatively low density (see Example 1). Figure 3 a). Control the diameter of the carbon wire and use oxidation treatment (see a). Figure 3 In the middle (a, c~g), the density of carbon dots increases and the distance between carbon dots decreases to near 0 (see a). Figure 3(f) The corresponding carbon wire breaks into carbon dots, which ensures the formation of carbon dots within the broken carbon wire. The above carbon dot nanostructuring based on carbon wire diameter and oxidation treatment can increase the carbon dot density on the carbon wire surface to a high level.

[0036] During the nanostructuring of carbon dots, removing the nitriding pretreatment step and reducing the diameter of PAN fibers to ~100 nm made the hidden nodes of PAN extremely inconspicuous. However, after carbonization of the hidden nodes of PAN, a large number of carbon dots were formed. The XPS O1s spectra of these carbon dots showed oxygen intensities of 46.14% and 53.86%, respectively. The 46.14% oxygen intensity originated from silica; the 53.86% oxygen intensity originated from acridinone-type carbonyl, carbonyl, and alcohol groups. These determined the oxidation of the carbon dots. The carbon lines composed of these oxidized carbon dots exhibited complete fragmentation and did not show a flat, semi-circular cross-sectional shape (see...). Figure 1 China and Figure 3 (f). This indicates that the oxidation reaction on the silicon substrate without nitrogen pretreatment can break down carbon lines into carbon dots.

[0037] During oxidation, when the carbon wire diameter increases from 191 nm to 270 nm, the carbon wire breaks into carbon dots, which then aggregate and their number increases significantly. Without oxidation, when the carbon wire diameter decreases from 191 nm to 177 nm, and increases from 177 nm to 268 nm, the number of carbon dots can increase from 4 to 8 and even up to 32 (see [link to relevant documentation]). Figure 3 (c~e). The axial distance between the corresponding carbon dots shows a periodic decreasing trend towards 0. The diameter of the carbon wire was controlled between 480 nm and 100 nm. This indicates that adjusting the carbon wire diameter can increase the density of carbon dots. In the region where the carbon dot spacing approaches 0, controlling the carbon wire diameter between 315 nm and 325 nm increases the carbon dot density from a relatively low level to a relatively high level; these findings suggest that changing the carbon wire diameter using the injection voltage can nanostructure these carbon dots.

[0038] Comparative Example 2

[0039] The difference compared to Example 1 is that carbon wires were prepared on different substrates (see Example 1). Figure 4 (b-e). In this process, carbon lines on the silica surface break into numerous carbon dots, which aggregate and make close contact with the silica surface. When the contact surface is replaced with a nitrided silica surface, the carbon dots can grow on the carbon line surface instead of the silica surface (see [reference]). Figure 4 (a-c) When the contact surface is replaced with carbon and air, no carbon dots grow on the carbon wire surface (see...). Figure 4 (a, 4d, and 4e). This indicates that the growth of carbon dots depends on the contact surfaces of the carbon wires, such as silica and nitrogen.

[0040] The material that the PAN fibers come into contact with during the thermal stabilization and carbonization process of PAN fibers to carbon wires is a major influencing factor in the nanostructuring of carbon dots on the carbon wires. Changing the material of the contacting component reduces the diameter of the carbon fibers from 465 nm to 244 nm, then to 25 nm, and finally to 12 nm. (See also...) Figure 4 In the middle f, the shrinkage rate of the corresponding PAN fiber to carbon thread increases from 9% (contact material is silicon dioxide) to 12.5% ​​(contact material is silicon dioxide nitride), then to 80% (contact material is carbon), and finally to 93% (contact material is air). See also Figure 4 The greater the shrinkage, the fewer carbon dots per unit area. When the carbon dot size decreases from the nanoscale to 0, the number of carbon dots per unit area decreases to 0.

[0041] Using the manufacturing method described above, carbon wires are grown on the carbon surface (see...). Figure 5 a) Silica surface without nitrogen pretreatment (see Figure 5 (b) and nitrided pretreated silica surfaces (see...) Figure 5 (c) These carbon lines exhibit the absence of carbon dots (see c). Figure 5 a) Broken carbon points (see Figure 5 (b) and continuous carbon points (see Figure 5 Features of c). Carbon lines without carbon dots (see c) Figure 5 In section a), signal A, with an intensity of 28.46%, and signal B, with an intensity of 71.54%, are observed in the N1s XPS energy spectrum (see [reference]). Figure 5 (d). Signal A responds to nitrogen atoms on the naphthidine and hydronaphthidine rings; signal B responds to nitrogen atoms in the acrylone ring. When the carbon line changes from having no carbon dots to having broken carbon dots, the intensity of signal A increases from 28.46% to 65.66%, while the intensity of signal B decreases from 71.54% to 34.34%. This indicates that broken carbon dots can enhance the intensity of signal A. When broken carbon dots transform into aggregated carbon dots on the carbon line surface, the intensity of signal A increases from 65.66% to 80.11%. Clearly, growing continuous carbon dots on the carbon line surface exhibits an advantage in enhancing signal A.

[0042] Carbon lines without carbon dots appear at 1350 cm⁻¹ in Raman spectra. -1 D peak signal, 1590cm -1 G peak signal, 2700cm -1 2D peak signal, 2950cm -1 D+G peak signal, 3180cm -1 2G peak signal (see Figure 5 (g). Therefore, the intensity ratio of peak D to peak G (I) can be obtained. D / IG The intensity ratio of the D peak to the D+G peak (I) is 0.996; D / I D+G The value is 3.01. When the carbon wire breaks into a large number of carbon dots, I D / I G From 0.996 to 1.411, I D / I D+G Increased from 3.01 to 5.45 ( Figure 5 (gh). I D / I G and I D / I D+G The increase in I indicates that the broken carbon dots exhibit a higher D peak intensity. When the broken carbon dots connect together and grow onto the surface of the carbon wire, I... D / I G From 0.996 or 1.411 to 0.768, I D / I D+G Reduced from 3.01 or 5.45 to 2.66 (see...) Figure 5 gi). I D / I G and I D / I D+G The decrease indicates that continuous carbon dots have stronger D-peak and D+G-peak signals.

Claims

1. A method for preparing carbon dot nano-protrusion carbon wires, characterized in that: The silicon substrate is pretreated by oxidation and nitridation. After pretreatment, polyacrylonitrile fibers are deposited on the surface of the silicon substrate by electro-hydraulic jetting. Then, thermal stabilization and carbonization are performed in sequence to obtain carbon dot nano-protrusion carbon wires. The nitriding pretreatment conditions are as follows: nitriding at 950–1050 °C for 1–4 h in a nitrogen atmosphere; The carbonization treatment conditions are as follows: under a protective atmosphere, the temperature is increased to 1000-1050°C at a heating rate of 10-20°C / min, and held for 1.0-1.5 hours. The process of depositing polyacrylonitrile fibers is as follows: using PAN solution as the spray liquid, the temperature of the PAN solution is 106-115℃, using the treated silicon substrate as the receiving substrate, the distance between the spray needle and the receiving substrate is 1.8-1.95mm, the spray voltage is 600V-800V, the moving speed of the spray needle is 500-2400m / s, and the moving speed of the receiving substrate is 0.6-10m / s.

2. The method for preparing carbon dot nano-protrusion carbon wires according to claim 1, characterized in that: The conditions for the oxidation pretreatment are: oxidation in air atmosphere at a temperature of 900–1000°C for 3–5 hours.

3. The method for preparing carbon dot nano-protrusion carbon wires according to claim 1, characterized in that: The PAN solution has a mass concentration of 8-9%; the PAN solution is a PAN / DMF solution.

4. The method for preparing carbon dot nano-protrusion carbon wires according to claim 1, characterized in that: The conditions for the heat stabilization treatment are: to maintain the temperature at 110–115°C for 8–13 hours in an air atmosphere.

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