CN108101024B

CN108101024B - Method for preparing carbon nano tube by mixed gas source

Info

Publication number: CN108101024B
Application number: CN201711394933.3A
Authority: CN
Inventors: 谢宝东; 徐壮; 阮玉凤; 朱玉莲; 张美杰; 郑涛
Original assignee: Jiangsu Cnano Technology Ltd
Current assignee: Jiangsu Cnano Technology Ltd
Priority date: 2017-12-21
Filing date: 2017-12-21
Publication date: 2020-07-10
Anticipated expiration: 2037-12-21
Also published as: CN108101024A

Abstract

The invention discloses a method for preparing a carbon nano tube by using a mixed gas source, belonging to the technical field of preparation of materials for batteries. The method uses propylene and an organic solvent as a mixed carbon source, the volume ratio of propylene gas to organic solvent gas is 0.5:1-5:1, and the organic solvent comprises aldehyde and alcohol organic matters such as formaldehyde, methanol, acetaldehyde, ethanol, propanol, isopropanol, butanol, butanediol and the like; the total volume ratio of nitrogen to organic gas is 1:2-2:1, the reaction temperature is 690-750 ℃, and 8-16 liters of propylene is consumed per gram of catalyst. The yield of the carbon nano tube prepared by the method can reach 40g/g catalyst-60 g/g catalyst, and the purity of the carbon nano tube can reach 97.5-98.3%.

Description

Method for preparing carbon nano tube by mixed gas source

Technical Field

The invention belongs to the technical field of preparation of materials for batteries, and particularly relates to a method for preparing a carbon nano tube by using a mixed gas source.

Background

The carbon nano tube has very good conductive performance and extremely high length-diameter ratio, and the carbon nano tube is added into an electrode material of the lithium ion battery to effectively form a conductive network, so that the conductive performance of the electrode is improved, and the lithium ion battery has excellent performance, particularly shows large battery capacity and long cycle life, and is suitable for high-end-number batteries and new energy automobile batteries. The carbon nano tube is prepared by using a fixed bed process, the catalyst cannot be fluidized due to process limitation, the catalyst cannot be in full contact with reaction gas, the yield of the carbon nano tube is only 10g/g of catalyst-20 g/g of catalyst, and the highest purity of the carbon nano tube can only reach 95%. There is therefore a great need to develop a fixed bed process with high carbon nanotube yields.

Disclosure of Invention

The invention aims to provide a method for preparing carbon nanotubes by using a mixed gas source.

A method for preparing carbon nano tube by mixed gas source comprises uniformly scattering catalyst on graphite crucible, introducing nitrogen, propylene and organic solvent, reacting at 690-750 deg.C for 60-90min, ending reaction, introducing nitrogen, cooling to obtain carbon nano tube; 8-16 liters of propylene are consumed per gram of catalyst.

The volume ratio of the propylene to the organic solvent is in the range of 0.5:1-5: 1.

The total volume ratio of the nitrogen to the propylene and the organic solvent is in the range of 1:2 to 2: 1.

The organic solvent is one or more selected from formaldehyde, methanol, acetaldehyde, ethanol, propanol, isopropanol, butanol and butanediol.

The volume ratio of the nitrogen to the propylene is in the range of 1:2 to 2: 1.

The yield of the carbon nano tube can reach 40g/g catalyst-60 g/g catalyst, and the purity of the carbon nano tube can reach 97.5-98.3%.

The invention has the beneficial effects that: the normal propylene process reaction temperature is limited to 650-680 ℃, the temperature rise is easy to generate byproduct tar, the yield of the carbon nano tube is only 10g/g catalyst-20 g/g catalyst, the highest purity of the carbon nano tube can only reach 95%, the reaction temperature can be increased to 690-750 ℃, the yield of the carbon nano tube can reach 40g/g catalyst-60 g/g catalyst by adopting propylene and an organic solvent as a mixed carbon source, and the purity of the carbon nano tube can reach 97.5-98.3%.

Drawings

FIG. 1 is TEM and SEM images of carbon nanotubes prepared in a fixed bed.

Fig. 2 is a raman diagram of the carbon nanotube prepared in example 1.

Fig. 3 is a raman diagram of the carbon nanotube prepared in example 2.

Fig. 4 is a raman diagram of the carbon nanotube prepared in example 3.

Fig. 5 is a raman diagram of the carbon nanotube prepared in comparative example 1.

FIG. 6 is a diagram illustrating an exemplary method for testing the diameter and thickness of a carbon nanotube.

Detailed Description

The invention is further described with reference to the following figures and specific embodiments.

Example 1

The method comprises the steps of enabling a tube furnace with the diameter of 200mm to be a heat preservation area with the length of 800mm, enabling a quartz tube with the total length of 1600mm, precisely controlling the mass and the volume of formaldehyde through a peristaltic pump, uniformly scattering 1.5 g of catalyst in a graphite crucible, introducing nitrogen gas 1L/min, heating to 730 ℃, introducing nitrogen gas 1.5L/min, propylene 0.8L/min and formaldehyde 0.8L/min, finishing the reaction after reacting for 75min, continuously introducing nitrogen gas 1L/min and 5min, cooling, and then collecting 78 g of carbon nano tubes, wherein the yield of the carbon nano tubes can reach 52g/g of catalyst.

Example 2

The method comprises the steps of enabling a tube furnace with the diameter of 200mm to be a heat preservation area with the length of 800mm, enabling a quartz tube with the total length of 1600mm, enabling methanol to be precisely controlled in quality and volume through a peristaltic pump, enabling 1.5 g of catalyst to be uniformly scattered in a graphite crucible, enabling nitrogen to flow in 1L/min, enabling nitrogen to flow in 1.5L/min, enabling propylene to flow in 1.0L/min and methanol to flow in 0.5L/min, ending the reaction after 50min, cooling, and then obtaining 60g of carbon nano tubes, wherein the yield of the carbon nano tubes can reach 40g/g of catalyst.

Example 3

The method comprises the steps of enabling a tube furnace with the diameter of 200mm to be a heat preservation area with the length of 800mm, enabling a quartz tube with the total length of 1600mm, precisely controlling the mass and the volume of isopropanol through a peristaltic pump, uniformly scattering 3 g of catalyst in a graphite crucible, introducing 1L/min of nitrogen, heating to 750 ℃, introducing 1.5L/min of nitrogen, 0.5L/min of propylene and 1.5L/min of isopropanol, ending the reaction after 85min of reaction, continuously introducing 1L/min of nitrogen for 5min, cooling, and then collecting 90 g of carbon nanotubes, wherein the yield of the carbon nanotubes can reach 60g/g of catalyst.

Example 4

The method comprises the steps of a tubular furnace with the diameter of 200mm, the length of a heat preservation area of 800mm, the total length of a quartz tube of 1600mm, formaldehyde and 4-hydroxy-1-indanone, precisely controlling the mass and the volume by a peristaltic pump, uniformly scattering 1.5 g of catalyst in a graphite crucible, introducing nitrogen gas of 1L/min, heating to 730 ℃, introducing nitrogen gas of 1.5L/min, introducing propylene of 0.8L/min, 4-hydroxy-1-indanone of 0.1L/min, and formaldehyde of 0.8L/min, finishing the reaction after the reaction is carried out for 75min, continuously introducing nitrogen gas of 1L/min, carrying out 5min, cooling, and then collecting 99 g of carbon nanotubes, wherein the yield of the carbon nanotubes can reach 66g/g of catalyst.

Example 5

The method comprises the steps of a tubular furnace with the diameter of 200mm, the length of a heat preservation area of 800mm, the total length of a quartz tube of 1600mm, precisely controlling the mass and the volume of formaldehyde and 4-amino-2-methoxypyridine by a peristaltic pump, uniformly scattering 1.5 g of catalyst in a graphite crucible, introducing nitrogen of 1L/min, heating to 730 ℃, introducing nitrogen of 1.5L/min, introducing propylene of 0.8L/min, formaldehyde of 0.8L/min, introducing 4-amino-2-methoxypyridine of 0.1L/min, finishing the reaction after the reaction is carried out for 75min, continuously introducing nitrogen of 1L/min, carrying out 5min, cooling, and then collecting 88 g of carbon nanotubes, wherein the yield of the carbon nanotubes can reach 65g/g of catalyst.

Comparative example 1

The method comprises the steps of introducing nitrogen 1L/min, heating to 660 ℃, introducing nitrogen 2L/min and propylene 2L/min, reacting for 30min, generating yellow tar behind the quartz tube, introducing nitrogen 1L/min, cooling, and collecting 42 g of carbon nanotubes, wherein the diameter of a tube furnace is 200mm, the length of a heat preservation area is 800mm, the total length of the quartz tube is 1600mm, 2g of catalyst is uniformly scattered in a graphite crucible, introducing nitrogen 1L/min, heating to 660 ℃, introducing nitrogen 2L/min and propylene 2L/min, reacting for 30min, continuing to introduce nitrogen 1L/min.

Raman spectroscopy analysis was performed on the carbon nanotubes prepared in examples 1, 2, 3 and comparative example 1, and the raman spectra are shown in fig. 2, 3, 4 and 5. The D peak and the G peak in the Raman spectrum are analyzed, and the results are shown in the table I. From the table one, it can be seen that the defect degree of the carbon nanotube prepared by using the mixed gas source of propylene and organic solvent is lower than that of the carbon nanotube prepared by using propylene alone as the gas source.

Epi-carbon nanotube Raman I_D/I_GComparison of

TEM analysis was performed on the carbon nanotubes prepared in examples 1, 2, 3 and comparative example 1, and the tube diameter and the wall thickness of the carbon nanotube were measured using gatan digital micrograph software, as shown in fig. 6. The tube diameters and the tube wall thicknesses of the carbon nanotubes prepared in examples 1, 2 and 3 were smaller than those of comparative example 1.

Comparison of pipe diameter and pipe wall thickness of the carbon nanotubes

Carbon nanotube	Diameter of carbon nanotube is nm	Thickness of the tube wall is nm
			Example 1 carbon nanotubes	10.6-12.0	3.3-3.8
Example 2 carbon nanotubes	10.9-12.3	3.4-3.9
			Example 3 carbon nanotubes	10.1-11.2	3.0-3.4
Example 4 carbon nanotubes	9.8-10.9	2.9-3.1
			Example 5 carbon nanotubes	9.7-10.7	2.8-3.2
Comparative example 1 carbon nanotube	11.2-12.6	4.5-5.1

Claims

1. A method for preparing carbon nano tubes by a mixed gas source is characterized in that a tube furnace with the diameter of 200mm, a heat preservation area with the length of 800mm, a quartz tube with the total length of 1600mm, formaldehyde and 4-hydroxy-1-indanone are precisely controlled in quality and volume by a peristaltic pump, 1.5 g of catalyst is uniformly scattered in a graphite crucible, after nitrogen is introduced for 1L/min and the temperature is raised to 730 ℃, nitrogen is introduced for 1.5L/min, propylene is introduced for 0.8L/min, 4-hydroxy-1-indanone is introduced for 0.1L/min, formaldehyde is introduced for 0.8L/min, the reaction is finished after 75min, nitrogen is continuously introduced for 1L/min and 5min, 99 g of carbon nano tubes are collected after cooling, and the yield of the carbon nano tubes reaches 66g/g of catalyst.