Method for preparing multi-wall carbon nanotubes using chemical vapor deposition with an atomization system

Patent metadata

Field	Value
Publication number	US-9878912-B2
Application number	US-201514877644-A
Country	US
Kind code	B2
Filing date	Oct 7, 2015
Priority date	Oct 7, 2015
Publication date	Jan 30, 2018
Grant date	Jan 30, 2018

Abstract

A method for preparing multi-wall carbon nanotubes comprising atomizing a precursor solution comprising an aromatic hydrocarbon and a carrier gas. The mixture is then injected through an ultrasonic atomization system to form atomized precursor droplets. Then by injecting the atomized precursor droplets from the top of a vertical chemical vapor deposition reactor, the droplets can then react with a reaction gas in the reactor vessel to form a film that adsorbs to a growth surface in the reactor vessel. Layer by layer multi-wall carbon nanotubes are formed. This method is repeated to form layers of the multi-wall carbon nanotubes. The nanotubes formed have an outer diameter of 10 nm-51 nm and a length to diameter aspect ratio of 7200-13200.

First claim

The invention claimed is:

1. A method for preparing multi-wall carbon nanotubes, comprising:
atomizing a precursor solution comprising an aromatic hydrocarbon and a carrier gas, wherein the precursor solution is injected through an ultrasonic atomization system to form ultrasonic atomized precursor droplets;
injecting the ultrasonic atomized precursor droplets from the top of a vertical chemical vapor deposition reactor into a preheating zone;
reacting a reaction gas with the ultrasonic atomized precursor droplets in the vertical chemical vapor deposition reactor to form a film precursor that adsorbs to a growth surface in the vertical chemical vapor deposition reactor to form a layer of multi-wall carbon nanotubes; and
repeating the atomizing, the injecting of the ultrasonic atomized precursor molecule, and the reacting until one or more layers of the multi-wall carbon nanotubes are formed and then removing the multi-wall carbon nanotubes from the growth surface;
wherein the multi-wall carbon nanotubes have an outer diameter of 10 nm-51 nm, a length to diameter aspect ratio of 7200-13200.

2. The method of claim 1 , wherein the precursor solution further comprises an organometallic catalyst.

3. The method of claim 2 , wherein the organometallic catalyst is an organometallocene catalyst, and the organometallocene catalyst is present in an amount from 0.3-2.0 wt % relative to the total weight of the precursor solution.

4. The method of claim 1 , wherein the carrier gas is a inert gas.

5. The method of claim 4 , wherein the inert gas is argon.

6. The method of claim 1 , wherein the ultrasonic atomizing system comprises an ultrasonic generating unit and an atomizing nozzle.

7. The method of claim 6 , wherein the ultrasonic atomization system produces an ultrasonic frequency of 15 kHz-25 kHz.

8. The method of claim 6 , wherein the atomizing nozzle has a 0.1-0.2 cm aperture and a radial spray angle of 125°-140°.

9. The method of claim 6 , wherein the precursor solution is injected through the atomizing nozzle with a flow rate of 80-110 mL/min.

10. The method of claim 1 , wherein the vertical chemical vapor deposition reactor has at least four sections: the preheating zone, a reaction zone, a cooling zone and a collector.

11. The method of claim 10 , wherein the reacting takes place in the reaction zone, which is heated by a furnace to a temperature of 750° C.-1100° C.

12. The method of claim 1 , wherein the atomizing comprises injecting the precursor solution at 75-105 mL/hour through the ultrasonic atomization system.

13. The method of claim 1 , wherein the atomizing forms ultrasonic atomized precursor droplets with a diameter of 0.9 μm-500 μm.

14. The method of claim 1 , wherein the reaction gas is comprised of a 5:1-3:2 ratio of reacting gas to carrier gas.

15. The method of claim 14 , wherein the reacting gas is a reducing gas.

16. The method of claim 15 , wherein the reducing gas is hydrogen gas.

17. The method of claim 1 , wherein the reacting takes place at a pressure less than 1.5 bar and a constant temperature.

18. The method of claim 1 , wherein the vertical chemical vapor deposition reactor is a hot-wall reactor.

19. The method of claim 1 , wherein the growth surface is comprised of quartz.

20. The method of claim 1 , wherein the multi-wall carbon nanotubes are formed in 70%-95% yield based on a 6%-10% conversion rate of the precursor solution.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Malaibari Zuhair Omar
• Atieh Muataz Ali
• RABBANI Fahad Ali

Classifications

• C01B2202/36

  Diameter · CPC title

• C23C16/26

  Deposition of carbon only · CPC title

• C01B2202/06

  Multi-walled nanotubes · CPC title

• C01B32/16 Primary

  Preparation · CPC title

• C23C16/4418

  Methods for making free-standing articles (C23C16/01 takes precedence) · CPC title