CN-121974335-A - Single-wall carbon nano tube and preparation method thereof

CN121974335ACN 121974335 ACN121974335 ACN 121974335ACN-121974335-A

Abstract

The invention belongs to the technical field of carbon nanotubes, and particularly relates to a single-walled carbon nanotube and a preparation method thereof. The preparation method of the single-walled carbon nanotube comprises the step of performing floating catalyst chemical vapor deposition to grow the single-walled carbon nanotube by taking an alcohol compound as a carbon source and taking a silicon source precursor as a morphology regulator, wherein the alcohol compound contains methanol and ethanol. The key of the invention is that a floating catalyst chemical vapor deposition method is adopted to prepare the single-wall carbon nano tube, methanol and ethanol are compounded to be used as carbon sources to realize synergy, and simultaneously, a silicon source precursor is added to be used as a morphology regulator to achieve high coordination of the carbon sources and the catalyst, thereby remarkably improving the yield and purity of the single-wall carbon nano tube and improving the uniformity of diameter distribution, and having wide application prospect.

Inventors

LIU CHAONONG
ZHAO LIPING
FANG CHONGQING
HONG JIANGBIN

Assignees

厦门凯纳石墨烯技术股份有限公司
永安市凯纳新材料科技有限公司

Dates

Publication Date: 20260505
Application Date: 20260407

Claims (9)

1. The preparation method of the single-walled carbon nanotube is characterized by comprising the step of performing floating catalyst chemical vapor deposition to grow the single-walled carbon nanotube by taking an alcohol compound as a carbon source and taking a silicon source precursor as a morphology regulator, wherein the alcohol compound consists of methanol and ethanol, and the silicon source precursor is at least one selected from hexamethyldisiloxane, polymethylsiloxane, trimethylsilane, tetramethylsilane, tetraethoxysilane and octamethyltetrasiloxane.
2. The method according to claim 1, wherein the floating catalyst chemical vapor deposition process comprises uniformly mixing a metal catalyst precursor, a silicon source precursor, an alcohol compound and an optional auxiliary agent, evaporating the obtained raw material liquid into a mixed gas stream, and performing high-temperature chemical vapor deposition on the obtained mixed gas stream, wherein the metal catalyst precursor is decomposed to form active catalyst nano particles and the alcohol compound is catalytically cracked in the high-temperature chemical vapor deposition process, so that the single-wall carbon nanotubes are grown.
3. The method for preparing single-walled carbon nanotubes according to claim 2, wherein the mass concentration of the metal catalyst precursor in the raw material liquid is 0.1% -2%, the mass concentration of the silicon source precursor is 0.03% -0.2%, the mass concentration of the auxiliary agent is 0.05% -1%, and the balance is an alcohol compound.
4. The method for preparing single-walled carbon nanotubes according to claim 2, wherein the volume ratio of methanol to ethanol in the alcohol compound is 20:80-80:20.
5. The method for preparing single-walled carbon nanotubes according to claim 2, wherein the metal catalyst precursor is at least one selected from the group consisting of ferrocene, cobaltocene, nickel-dicyclopentadienyl, iron acetylacetonate and iron carbonyl, and the auxiliary agent is a sulfur-containing compound.
6. The method for preparing the single-walled carbon nanotubes according to any one of claims 2 to 5, wherein the high-temperature chemical vapor deposition comprises the steps of introducing a first path of carrier gas into a mixed gas flow to accelerate the mixed gas flow, so as to obtain a raw material flow, introducing the raw material flow and a second path of carrier gas into a high-temperature tubular reactor together to complete chemical vapor deposition, wherein the first path of carrier gas is argon and/or nitrogen, and the second path of carrier gas is a mixed gas of argon, hydrogen and steam.
7. The method for preparing the single-walled carbon nanotube according to claim 6, wherein the flow rate of the raw material liquid is 0.1-0.8 mL/min, the flow rate of the first carrier gas is 200-500 sccm, the second carrier gas is obtained by bubbling argon and hydrogen through constant temperature water after mixing, the flow rate of argon is 2000-3000 sccm, the flow rate of hydrogen is 2000-600 sccm, the total flow rate of the mixed gas of argon and hydrogen is 4000-9000 sccm, or the argon and hydrogen are obtained by bubbling each through constant temperature water after mixing, the flow rate of argon bubbling through constant temperature water is 2000-3000 sccm, and the flow rate of hydrogen bubbling through constant temperature water is 2000-600 sccm.
8. The method for preparing single-walled carbon nanotubes according to claim 6, wherein the temperature of the mixed gas stream obtained by evaporation of the raw material liquid is 200-300 ℃, and the temperature of the high-temperature chemical vapor deposition is 1000-1100 ℃.
9. A single-walled carbon nanotube prepared by the method of any of claims 1-6.

Description

Single-wall carbon nano tube and preparation method thereof Technical Field The invention belongs to the technical field of carbon nanotubes, and particularly relates to a single-walled carbon nanotube and a preparation method thereof. Background Floating catalyst chemical vapor deposition is one of the mainstream methods for preparing single-walled carbon nanotubes. Unlike traditional method, the floating catalyst chemical vapor deposition process omits complicated catalyst preparation and loading steps, and the process is to gasify all the materials (carbon source, metal catalyst precursor, assistant, etc.) once into the reaction chamber for high temperature vapor deposition reaction. At high temperature, the metal catalyst instantaneously nucleates and grows in the gas phase, and immediately enters a reaction state to catalyze carbon atoms cracked from the same gas phase environment, so that continuous and direct growth of the single-walled carbon nanotube is realized. In the floating catalyst chemical vapor deposition process, the selection of the carbon source is critical, which directly affects the yield, quality and cost of single-walled carbon nanotubes. The alcohol carbon source obtains the best balance in the direct, continuous and safe synthesis of the high-purity and high-quality single-wall carbon nano tube by virtue of the high-efficiency carbon supply capability and the unique in-situ self-cleaning capability. The method greatly simplifies the production process, reduces the purification cost, and is one of key technologies for pushing single-wall carbon nanotubes to scale application from laboratories. Ethanol is the most widely used liquid carbon source for preparing single-walled carbon nanotubes by the current floating catalyst chemical vapor deposition method (reference The role of carbon precursor on carbon nanotube chirality in floating catalyst chemical vapour deposition[J].Nanoscale, 2016, 8(39):17262-17270. Barnard J S , Paukner C , Koziol K K.）. ethanol is a very good solvent because of low toxicity, low cost and easy vaporization, and can uniformly dissolve a plurality of organometallic catalyst precursors and can be cracked at a relatively low temperature: firstly, a large amount of oxygen-containing active species can be generated during high-temperature pyrolysis of ethanol, so that the oxygen potential of a reaction system is too high, metal catalytic nano particles are easy to oxidize, the catalytic activity of the metal catalytic nano particles is reduced, and even the catalyst is deactivated, thereby affecting the normal growth of single-wall carbon nanotubes; secondly, ethanol has higher molecular oxygen content, high-temperature cracking Jie Yi generates oxygen-containing byproducts such as CO, H 2 O and the like, and can inhibit amorphous carbon deposition to a certain extent, but excessively consume a carbon source, so that the growth efficiency and yield of the carbon nano tube are reduced, researches show that ethanol is adopted as the carbon source, the single-wall carbon nano tube is prepared by a floating catalyst chemical vapor deposition method, the G/D ratio of the collected single-wall carbon nano tube is only 4 at most, the integral mass is poor (the carbon nano tube fiber floating catalyst chemical vapor deposition method is prepared and the performance is optimized, the Harbin industrial university is Han Baoshuai.) wherein G/D is obtained according to Raman spectrum calculation, G peak (1580 cm -1) represents ordered and complete sp2 hybridized carbon structure in the single-wall carbon nano tube and is a mark of graphitization degree and crystallization quality, D peak (1350 cm -1) represents disordered, defective or 3 hybridized carbon structure in the single-wall carbon nano tube, which is a sign of defect density, and the G-peak to D-peak intensity ratio (G/D) can reflect the defect level, in general, the higher the quality of single-walled carbon nanotubes, the greater the G/D. Methanol is a cleaner carbon source, contains only one carbon atom in the molecule, generates little tar or other long-chain hydrocarbon byproducts after cracking, does not contain C-C bonds, and can theoretically effectively reduce the generation of amorphous carbon. However, when methanol is used alone as a carbon source, there are often problems of insufficient carbon supply, slow growth rate, and low yield. These challenges stem primarily from the mismatch between the molecular structure and chemical nature of methanol and the Floating Catalyst Chemical Vapor Deposition (FCCVD) process requirements. Specifically, the methanol molecule contains only one carbon atom and has high oxygen content, so that most of carbon atoms are converted into carbon monoxide or carbon dioxide and other gaseous byproducts to escape in the high-temperature cracking process, rather than being effectively deposited to form single-wall carbon nanotubes, thereby lowering the actual utilization rate o