A method and application for preparing single-walled carbon nanotube powder using ferrocene suspension.
Single-walled carbon nanotube powder was prepared by ferrocene suspension and FCCVD method, which solved the problem of uneven tube diameter caused by uneven catalyst particle size, and achieved high-quality and continuous production. The product has high crystallinity and is suitable for applications such as conductive paste, functionalized composite materials and sensors.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Wenzhou University Carbon Materials and Hydrogen Energy Industry Technology Research Institute
- Filing Date
- 2026-04-21
- Publication Date
- 2026-06-02
AI Technical Summary
In existing single-walled carbon nanotube production, it is difficult to achieve uniform catalyst particle size distribution, resulting in uneven tube diameter, which affects product quality and makes continuous production impossible.
Single-walled carbon nanotube powder was prepared using ferrocene suspension and produced in large-scale continuous manner by floating catalyst chemical vapor deposition (FCCVD). Ferrocene in the supersaturated suspension was uniformly dispersed in the form of micro- and nano-sized aggregates and simultaneously pyrolyzed at high temperature to control the collision of Fe atoms/small clusters, forming uniform Fe catalyst particles and achieving the matching growth of carbon source and catalyst.
This method achieves uniform diameter distribution, high crystallinity, and minimal catalyst adhesion in single-walled carbon nanotube powder, enabling continuous production and producing high-quality products.
Smart Images
Figure CN122126836A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of single-walled carbon nanotube technology, and relates to a method and application for preparing single-walled carbon nanotube powder using ferrocene suspension. Background Technology
[0002] Single-walled carbon nanotube powders are currently mostly produced using conventional CVD (Continuous Chemical Vapor Deposition) growth methods, utilizing metal compounds containing Fe, Co, and Ni. A key advantage of CVD is the stability of the reaction, allowing for easy control and optimization of factors such as temperature and atmosphere flow rate during nanotube growth. However, this method also has significant drawbacks. For instance, conventional CVD growth of single-walled carbon nanotubes requires the preparation of solid catalysts with matching diameter ranges. Direct screening using particle size analysis typically results in significant errors, making it difficult to maintain uniform catalyst particle size. This can easily lead to products with excessively large diameters, affecting the quality of the final product. Furthermore, conventional CVD-grown carbon nanotubes are often produced using a single-feed loading method, which does not allow for continuous production.
[0003] Existing methods for growing single-walled carbon nanotubes suffer from difficulties in achieving uniform particle size distribution during catalyst preparation, resulting in inconsistent tube diameters and impacting product quality. Furthermore, continuous production is not feasible, limiting production efficiency. Therefore, the primary challenges are improving the uniformity of catalyst particle size and enabling continuous production to increase yield.
[0004] In view of the above problems, this invention is proposed. Summary of the Invention
[0005] To address the shortcomings of existing technologies, this invention provides a method and application for preparing single-walled carbon nanotube powder using ferrocene suspension, and utilizes floating catalyst chemical vapor deposition (FCCVD) for the large-scale continuous preparation of single-walled carbon nanotubes.
[0006] The first objective of this invention is to provide a method for preparing single-walled carbon nanotube powder using ferrocene suspension, comprising the following steps: S1: Preparation of catalyst solution At room temperature, ferrocene was added to xylene solvent, and a growth promoter was introduced. The mixture was then ultrasonically dispersed to prepare a homogeneous supersaturated ferrocene turbidity. S2: Growth Regulation Under inert gas protection, the mixture is treated at high temperature; a mixture of inert gas, hydrogen and gaseous carbon-containing organic matter is continuously introduced into the reaction chamber, and the catalyst solution prepared in step S1 is injected into the reaction chamber at the same time. The reaction time is ≥2h to obtain single-walled carbon nanotube powder.
[0007] Preferably, the mass-to-volume ratio of ferrocene to xylene solution in step S1 is 2-5:8-12 (g / ml).
[0008] Preferably, the mass ratio of ferrocene to growth promoter in step S1 is 1500-4500:1.
[0009] Preferably, the growth promoter in step S1 is sublimed sulfur or thiophene.
[0010] Preferably, the high-temperature treatment in step S2 specifically involves heating the reaction chamber to 900-1200°C at a heating rate of 15-30°C / min and holding it at that temperature for 10-30 minutes.
[0011] Preferably, the mixed gas in step S2 is a mixture of inert gas, hydrogen, and gaseous carbonaceous organic matter.
[0012] Preferably, the flow ratio of inert gas, hydrogen, and gaseous carbonaceous organic matter in the mixed gas is 1-3:3-10:1.
[0013] Preferably, the carbon-containing organic gas is one or more of methane, ethylene, and propylene.
[0014] Using the above technical solution, conventional FCCVD often employs a dilute ferrocene solution / pure gas phase feed. Ferrocene molecules are unevenly dispersed in the carrier gas, and after pyrolysis, iron atoms collide and agglomerate randomly, easily forming Fe nanoparticles with a wide particle size distribution (1-5 nm, or even larger). This invention uses a supersaturated suspension feed, where ferrocene is uniformly dispersed in the solvent as micro-nano-scale aggregates. After vaporization, it forms a uniformly sized aerosol precursor. Upon entering the high-temperature zone, simultaneous and uniform pyrolysis results in a more controllable collision probability between released Fe atoms and small clusters, significantly reducing the polarization between "large particles" and "overly small clusters." The in-situ generated Fe catalyst particles have an extremely narrow particle size distribution (typically concentrated in 1.0-2.0 nm), laying the foundation for uniform tube diameter. The uniform Fe particles are liquid at high temperatures; after the C atoms from the carbon source decomposition dissolve and become supersaturated, they uniformly precipitate from the particle surface and curl into tubes.
[0015] Ferrocene (catalyst) and carbon source (xylene) are premixed at the molecular level in the suspension and decompose simultaneously upon entering the reaction zone, ensuring a high degree of match between C supply and Fe catalytic activity. This avoids amorphous carbon / multi-walled carbon (MWCNT) impurities caused by "carbon source cracking first, catalyst forming later," and also reduces short / defective tubes caused by "excessive catalyst agglomeration and insufficient carbon source." The stable C supply allows SWCNTs to grow continuously and uniformly, reducing structural defects and resulting in higher crystallinity and a larger IG / ID ratio.
[0016] This invention utilizes floating catalyst chemical vapor deposition (FCCVD) to prepare single-walled carbon nanotubes in large-scale continuous processes. During the high-temperature treatment stage, solid ferrocene can be directly vaporized into catalyst particles, providing a sufficient iron source. These particles are then introduced into the high-temperature zone of a tubular furnace with the carrier gas for the continuous preparation and collection of single-walled carbon nanotube powder. This method can achieve an IG / ID ratio of over 60 times, uniform tube diameter distribution of approximately 1.34 nm, clean surface, and minimal residual catalyst particles.
[0017] A second objective of this invention is to provide applications of the single-walled carbon nanotube powder prepared by the above method.
[0018] Preferably, it is used in the preparation of conductive pastes, functionalized composite materials, highly sensitive chemical sensors, biosensors, strain sensors, and as a lithium battery material to improve the conductivity and cycle characteristics of electrodes.
[0019] The beneficial effects of this invention are: This invention employs a supersaturated suspension as feedstock, where ferrocene is uniformly dispersed in the solvent as micro-nano-scale aggregates. After vaporization, it forms a uniformly sized aerosol precursor. Upon entering the high-temperature zone, it undergoes simultaneous and uniform pyrolysis, resulting in a more controllable collision probability between the released Fe atoms / small clusters and significantly reducing the polarization between "large particles" and "overly small clusters." Attached Figure Description
[0020] Figure 1 A schematic diagram of the preparation process of this invention.
[0021] Figure 2 An optical photograph of the single-walled carbon nanotube powder obtained for the invention.
[0022] Figure 3 Raman spectrum of single-walled carbon nanotube powder prepared for invention under 532 nm laser conditions.
[0023] Figure 4 SEM image of the single-walled carbon nanotube powder prepared for the invention, magnified 10k times.
[0024] Figure 5 SEM image of the single-walled carbon nanotube powder prepared for the invention, magnified 20k times.
[0025] Figure 6 SEM image of the single-walled carbon nanotube powder prepared for the invention, magnified 50k times.
[0026] Figure 7 The single-walled carbon nanotube powder prepared for the invention was at 500,000. Transmission electron microscopy image under 200 kV conditions.
[0027] Figure 8The single-walled carbon nanotube powder prepared for the invention was at 250,000. Transmission electron microscopy image under 200 kV conditions.
[0028] Figure 9 The single-walled carbon nanotube powder prepared for the invention was at 150,000. Transmission electron microscopy image under 200 kV conditions. Detailed Implementation
[0029] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.
[0030] This invention employs the following technology: A method for preparing single-walled carbon nanotube powder using ferrocene suspension includes the following steps: S1: Preparation of catalyst solution At room temperature, ferrocene was added to xylene solvent, and a growth promoter was introduced. The mixture was then ultrasonically dispersed to prepare a homogeneous supersaturated ferrocene turbidity. S2: Growth Regulation Under inert gas protection, the mixture is treated at high temperature; a mixture of inert gas, hydrogen and gaseous carbon-containing organic matter is continuously introduced into the reaction chamber, and the catalyst solution prepared in step S1 is injected into the reaction chamber at the same time. The reaction time is ≥2h to obtain single-walled carbon nanotube powder.
[0031] In some embodiments, the mass-to-volume ratio of ferrocene to xylene solution in step S1 is 2-5:8-12 (non-limiting examples, such as 2:9, 1:5, 5:12, 3:8, 4:9, etc.).
[0032] In some embodiments, the mass ratio of ferrocene to growth promoter in step S1 is 1500-4500:1 (non-limiting examples, such as 1500:1, 2500:1, 3500:1, 4500:1, etc.).
[0033] In some embodiments, the growth promoter in step S1 is sublimed sulfur or thiophene.
[0034] In some embodiments, the high-temperature treatment in step S2 specifically involves heating the reaction chamber to 900-1200°C at a heating rate of 15-30°C / min and holding it at that temperature for 10-30 minutes.
[0035] In some embodiments, the mixed gas in step S2 is a mixture of inert gas, hydrogen, and gaseous carbonaceous organic matter.
[0036] In some embodiments, the flow ratio of inert gas, hydrogen and gaseous carbonaceous organic matter in the mixed gas is 1-3:3-10:1 (non-limiting examples, such as 1:3:1, 1:5:1, 2:7:1, 3:10:1, 1:8:1, 1:9:1, etc.).
[0037] In some embodiments, the carbon-containing organic gas is one or more of methane, ethylene, and propylene.
[0038] Applications of single-walled carbon nanotube powder prepared by the above method.
[0039] In some embodiments, applications include the preparation of conductive pastes, functionalized composite materials, highly sensitive chemical sensors, biosensors, strain sensors, and the use of lithium battery materials to enhance the conductivity and cycle characteristics of electrodes.
[0040] The materials for this invention are synthesized using an OTF-1200X tubular furnace manufactured by Hefei Kejing Materials Technology Co., Ltd., and the gases used—argon, hydrogen, ethylene, propylene, and methane—are all 99.99% high-purity gases.
[0041] Example 1 30g of ferrocene was dissolved in 100ml of xylene solvent, and 0.01g of sublimed sulfur was added as a growth promoter. The mixture was sonicated for 30min to ensure uniform mixing of the catalyst solution. The temperature was increased to 1000℃ in a tube furnace at a rate of 20℃ / min, with argon gas continuously introduced at a rate of 100sccm during the heating process. After reaching the set temperature of 1000℃, 300sccm of hydrogen gas was introduced and continued for 10min. Then, 100sccm of propylene carbon source was introduced, and the catalyst delivery device was immediately turned on to feed at a rate of 0.25ml / min. Subsequently, single-walled carbon nanotube powder was continuously collected at the tube opening. For detailed preparation procedures, please refer to [reference needed]. Figure 1 .
[0042] Example 2 20g of ferrocene was dissolved in 100ml of xylene solvent, and 0.01g of sublimed sulfur was added as a growth promoter. The mixture was sonicated for 30min to ensure uniform mixing of the catalyst solution. The temperature of the tube furnace was increased to 1200℃ at a rate of 15℃ / min. During the heating process, argon gas was continuously introduced at a rate of 200sccm. After reaching the set temperature of 1200℃, 500sccm of hydrogen gas was introduced and continued for 10min. Then, 100sccm of propylene carbon source was introduced, and the catalyst delivery device was immediately turned on to feed at a rate of 0.25ml / min. Subsequently, the single-walled carbon nanotube powder was continuously collected at the tube opening.
[0043] Example 3 40g of ferrocene was dissolved in 120ml of xylene solvent, and 0.01g of sublimed sulfur was added as a growth promoter. The mixture was sonicated for 30min to ensure uniform mixing of the catalyst solution. The temperature of the catalyst solution was increased to 900℃ in a tube furnace at a rate of 30℃ / min. During the heating process, argon gas was continuously introduced at a rate of 200sccm. After reaching the set temperature of 900℃, hydrogen gas was introduced at a rate of 700sccm for 10min. Then, methane carbon source was introduced at a rate of 100sccm, and the catalyst delivery device was immediately turned on to feed the catalyst at a rate of 0.25ml / min. Subsequently, the single-walled carbon nanotube powder was continuously collected at the tube opening.
[0044] Example 4 50g of ferrocene was dissolved in 120ml of xylene solvent, and 0.01g of thiophene was added as a growth promoter. The mixture was sonicated for 30min to ensure uniform mixing of the catalyst solution. The temperature of the tube furnace was increased to 1000℃ at a rate of 25℃ / min. During the heating process, argon gas was continuously introduced at a rate of 300sccm. After reaching the set temperature of 1000℃, hydrogen gas was introduced at a rate of 1000sccm and continued for 10min. Then, ethylene carbon source was introduced at a rate of 100sccm, and the catalyst delivery device was immediately turned on to feed the catalyst at a rate of 0.25ml / min. Subsequently, the single-walled carbon nanotube powder was continuously collected at the tube opening.
[0045] Example 5 30g of ferrocene was dissolved in 120ml of xylene solvent, and 0.01g of thiophene was added as a growth promoter. The mixture was sonicated for 30min to ensure uniform mixing of the catalyst solution. The temperature of the catalyst solution was increased to 1000℃ in a tube furnace at a rate of 15℃ / min. During the heating process, argon gas was continuously introduced at a rate of 300sccm. After reaching the set temperature of 1000℃, 900sccm of hydrogen gas was introduced and continued for 10min. Then, 100sccm of ethylene carbon source was introduced, and the catalyst delivery device was immediately turned on to feed the catalyst at a rate of 0.25ml / min. Subsequently, the single-walled carbon nanotube powder was continuously collected at the tube opening.
[0046] Example 6 35g of ferrocene was dissolved in 100ml of xylene solvent, and 0.01g of thiophene was added as a growth promoter. The mixture was sonicated for 30min to ensure uniform mixing of the catalyst solution. The temperature of the tube furnace was increased to 1100℃ at a rate of 20℃ / min. During the heating process, argon gas was continuously introduced at a rate of 300sccm. After reaching the set temperature of 1100℃, 900sccm of hydrogen gas was introduced and continued for 10min. Then, 100sccm of ethylene carbon source was introduced, and the catalyst delivery device was immediately turned on to feed at a rate of 0.25ml / min. Subsequently, the single-walled carbon nanotube powder was continuously collected at the tube opening.
[0047] Example 7 45g of ferrocene was dissolved in 80ml of xylene solvent, and 0.01g of thiophene was added as a growth promoter. The mixture was sonicated for 30min to ensure uniform mixing of the catalyst solution. The temperature of the tube furnace was increased to 900℃ at a rate of 20℃ / min. During the heating process, argon gas was continuously introduced at a rate of 300sccm. After reaching the set temperature of 900℃, 300sccm of hydrogen gas was introduced and continued for 10min. Then, 100sccm of ethylene carbon source was introduced, and the catalyst delivery device was immediately turned on to feed at a rate of 0.25ml / min. Subsequently, the single-walled carbon nanotube powder was continuously collected at the tube opening.
[0048] Example 8 30g of ferrocene was dissolved in 80ml of xylene solvent, and 0.01g of thiophene was added as a growth promoter. The mixture was sonicated for 30min to ensure uniform mixing of the catalyst solution. The temperature of the tube furnace was increased to 900℃ at a rate of 25℃ / min. During the heating process, argon gas was continuously introduced at a rate of 300sccm. After reaching the set temperature of 900℃, 300sccm of hydrogen gas was introduced and continued for 10min. Then, 100sccm of ethylene carbon source was introduced, and the catalyst delivery device was immediately turned on to feed at a rate of 0.25ml / min. Subsequently, the single-walled carbon nanotube powder was continuously collected at the tube opening.
[0049] Example 9 30g of ferrocene was dissolved in 120ml of xylene solvent, and 0.01g of thiophene was added as a growth promoter. The mixture was sonicated for 30min to ensure uniform mixing of the catalyst solution. The temperature of the catalyst solution was increased to 1100℃ in a tube furnace at a rate of 25℃ / min. During the heating process, argon gas was continuously introduced at a rate of 200sccm. After reaching the set temperature of 1100℃, 300sccm of hydrogen gas was introduced and continued for 10min. Then, 100sccm of ethylene carbon source was introduced, and the catalyst delivery device was immediately turned on to feed the catalyst at a rate of 0.25ml / min. Subsequently, the single-walled carbon nanotube powder was continuously collected at the tube opening.
[0050] Example 10 50g of ferrocene was dissolved in 120ml of xylene solvent, and 0.01g of thiophene was added as a growth promoter. The mixture was sonicated for 30min to ensure uniform mixing of the catalyst solution. The temperature of the tube furnace was increased to 1100℃ at a rate of 15℃ / min. During the heating process, argon gas was continuously introduced at a rate of 200sccm. After reaching the set temperature of 1100℃, 800sccm of hydrogen gas was introduced and continued for 10min. Then, 100sccm of ethylene carbon source was introduced, and the catalyst delivery device was immediately turned on to feed at a rate of 0.25ml / min. Subsequently, the single-walled carbon nanotube powder was continuously collected at the tube opening.
[0051] The single-walled carbon nanotube powder obtained in Example 1 was subjected to the following experiments: Experimental Example 1 The single-walled carbon nanotube powder prepared in Example 1 was subjected to Raman spectroscopy testing, such as... Figure 3 As shown, in Raman spectroscopy, the radial breathing mode (RBM) is a characteristic Raman peak of single-walled carbon nanotubes (SWCNTs). Its peak position is directly related to the tube diameter, and the peak width reflects the uniformity of the tube diameter, making it the core basis for identifying SWCNTs and analyzing their diameter distribution. Multi-walled carbon nanotubes (MWCNTs) have virtually no RBM peak due to significantly suppressed radial vibrations. Graphene, fullerenes, and amorphous carbon do not possess tubular radial breathing vibration modes and therefore do not exhibit characteristic RBM peaks. The G and D peaks are key indicators for evaluating the quality of SWCNTs. The D peak corresponds to the defect-induced vibration of the sp² carbon lattice; a higher peak intensity indicates higher levels of material defects, disorder, and amorphous carbon impurities, resulting in poorer material quality. The G peak reflects the degree of graphitization and crystal integrity of carbon materials. The G peak of SWCNTs exhibits G⁺ and G⁻ characteristic splitting, which can be used to distinguish between SWCNTs and MWCNTs. A sharp peak shape indicates superior crystal quality. The intensity ratio of the D peak to the G peak, ID / IG, is typically used to quantitatively characterize the defect level of materials. A smaller ratio indicates a more complete single-walled carbon nanotube structure and higher quality. Raman characterization of the sample showed that its radial breathing mode (RBM) peaks were located at a single position, with a relatively concentrated tube diameter distribution; the calculated tube diameter was approximately 1.42 nm. Simultaneously, the G peak exhibited obvious G⁻ characteristic splitting, a typical feature of single-walled carbon nanotubes. The intensity ratio of the D peak to the G peak, ID / IG, was more than 60 times, indicating low material defect content and excellent crystallinity quality.
[0052] Experimental Example 2 The single-walled carbon nanotube powder obtained in Example 1 was subjected to SEM at 1 μm, 500 nm, and 200 nm, respectively. Figure 2-6 It can be seen from this that Figure 2 The single-walled carbon nanotube powder prepared by ferrocene suspension was shown to have a black film-like structure. Figure 3 Raman characterization revealed that the material's IG / ID ratio could reach over 60 times, with fewer defects and higher crystallinity. Figure 4-6 SEM characterization of the material at different magnifications allows for a preliminary observation of the tubular structure of single-walled carbon nanotubes. Figure 7-9 The single-walled carbon nanotube powder obtained in Example 1 was subjected to a process at 500,000... 200kV, 250000 200kV and at 150000 Transmission electron microscopy was performed at 200 kV.
[0053] Experimental Example 3 Excessive addition of ferrocene can lead to poor catalyst flowability, causing blockages in the feeding device and posing a safety hazard. Conversely, insufficient addition of ferrocene will prevent the formation of a supersaturated turbid solution. Therefore, the optimal mass-to-volume ratio of ferrocene to xylene solution (g / ml) of 2-5:8-12 is chosen in this invention.
[0054] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.
[0055] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A method for preparing single-walled carbon nanotube powder using ferrocene suspension, characterized in that, Includes the following steps: S1: Preparation of catalyst solution At room temperature, ferrocene was added to xylene solvent, and a growth promoter was introduced. The mixture was then ultrasonically dispersed to prepare a homogeneous supersaturated ferrocene turbidity. S2: Growth Regulation Under inert gas protection, the mixture is treated at high temperature; a mixture of inert gas, hydrogen and gaseous carbon-containing organic matter is continuously introduced into the reaction chamber, and the catalyst solution prepared in step S1 is injected into the reaction chamber at the same time. The reaction time is ≥2h to obtain single-walled carbon nanotube powder.
2. The method for preparing single-walled carbon nanotube powder using ferrocene suspension as described in claim 1, characterized in that, The mass-to-volume ratio of ferrocene to xylene solution in step S1 is 2-5:8-12 (g / ml).
3. The method for preparing single-walled carbon nanotube powder using ferrocene suspension as described in claim 2, characterized in that, In step S1, the mass ratio of ferrocene to growth promoter is 1500-4500:
1.
4. The method for preparing single-walled carbon nanotube powder using ferrocene suspension as described in claim 3, characterized in that, The growth promoter in step S1 is sublimed sulfur or thiophene.
5. The method for preparing single-walled carbon nanotube powder using ferrocene suspension as described in claim 1, characterized in that, In step S2, the high-temperature treatment specifically involves heating the reaction chamber to 900-1200℃ at a heating rate of 15-30℃ / min and holding it at that temperature for 10-30min.
6. The method for preparing single-walled carbon nanotube powder using ferrocene suspension as described in claim 5, characterized in that, The mixed gas in step S2 is a mixture of inert gas, hydrogen, and gaseous carbonaceous organic matter.
7. The method for preparing single-walled carbon nanotube powder using ferrocene suspension as described in claim 6, characterized in that, The flow ratio of inert gas, hydrogen, and gaseous carbonaceous organic matter in the mixed gas is 1-3:3-10:
1.
8. The method for preparing single-walled carbon nanotube powder using ferrocene suspension as described in claim 7, characterized in that, The carbon-containing organic gas is one or more of methane, ethylene, and propylene.
9. Application of the single-walled carbon nanotube powder prepared by the method according to any one of claims 1-8.
10. The application of the single-walled carbon nanotube powder as described in claim 9, characterized in that, Applications include the preparation of conductive pastes, functionalized composite materials, highly sensitive chemical sensors, biosensors, strain sensors, and as materials for lithium batteries to improve the conductivity and cycle performance of electrodes.