Featured Research

from universities, journals, and other organizations

Effects of hydrogen on growing carbon nanotubes

Date:
October 9, 2010
Source:
American Institute of Physics
Summary:
Carbon nanotubes have many potential uses in nanotechnology, optics, electronics, and many other fields. Their exact properties depend on their structure, but controlling that structure, which is determined during their initial formation, is difficult, and scientists do not know precisely how they grow. Researchers now shed new light on the process.

Carbon nanotubes -- long, hollow cylinders of carbon billionths of a meter in diameter -- have many potential uses in nanotechnology, optics, electronics, and many other fields. The exact properties of nanotubes depend on their structure, and scientists as yet have little control over that structure, which is determined during the initial formation -- or growth -- of the nanotubes. In fact, says chemical engineer and materials scientist Eray Aydil of the University of Minnesota, "we do not know precisely how the nanotubes grow."

Related Articles


In a paper in the American Institute of Physics' Journal of Applied Physics, Aydil, professor of chemical engineering and materials science and the Ronald L. and Janet A. Christenson Chair in Renewable Energy, and his colleagues shed new light on the process. In particular, the researchers examined the influence of hydrogen gas.

"Carbon nanotubes grow from a metal catalyst particle that is immersed in a gas like methane," Aydil explains. "Sometimes hydrogen gas is also added and it was found that a little bit of hydrogen helps to grow carbon nanotubes with nice straight walls and with few defects. However, too much hydrogen addition gives fibers with thick walls, instead of nanotubes, or no growth at all."

To understand why, Aydil and colleagues used transmission electron microscopy and other methods to systematically image and characterize the effects of increasing concentrations of hydrogen. "It turns out that the iron metal catalysts turn to iron carbide by reacting with the carbon in methane. Iron carbide is a hard material that is not easily deformed, and carbon nanotubes grown from such catalysts tend to have nice straight walls," he says.

Adding more hydrogen to the mix causes iron carbide to turn into iron -- which is more malleable and ductile, and "deforms into shapes that give rise to more fiber-like structures rather than hollow carbon nanotubes," he says. At higher concentrations, hydrogen etches the forming carbon nanotubes, "and growth stops all together. It is the interaction of the hydrogen with the catalysts and its effect on the catalyst's structure that controls the carbon nanotube structure."


Story Source:

The above story is based on materials provided by American Institute of Physics. Note: Materials may be edited for content and length.


Journal Reference:

  1. Eray S. Aydil, Michael J. Behr, Elizabeth A. Gaulding and K. Andre Mkhoyan. Effect of Hydrogen on Catalyst Nanoparticles in Carbon Nanotube Growth. Journal of Applied Physics, 108, 053303 (2010) DOI: 10.1063/1.3467971

Cite This Page:

American Institute of Physics. "Effects of hydrogen on growing carbon nanotubes." ScienceDaily. ScienceDaily, 9 October 2010. <www.sciencedaily.com/releases/2010/10/101005104440.htm>.
American Institute of Physics. (2010, October 9). Effects of hydrogen on growing carbon nanotubes. ScienceDaily. Retrieved November 25, 2014 from www.sciencedaily.com/releases/2010/10/101005104440.htm
American Institute of Physics. "Effects of hydrogen on growing carbon nanotubes." ScienceDaily. www.sciencedaily.com/releases/2010/10/101005104440.htm (accessed November 25, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Tuesday, November 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Who Will Failed Nuclear Talks Hurt Most?

Who Will Failed Nuclear Talks Hurt Most?

Reuters - Business Video Online (Nov. 25, 2014) With no immediate prospect of sanctions relief for Iran, and no solid progress in negotiations with the West over the country's nuclear programme, Ciara Lee asks why talks have still not produced results and what a resolution would mean for both parties. Video provided by Reuters
Powered by NewsLook.com
Flying Enthusiast Converts Real-Life Aircraft Cockpit Into Simulator

Flying Enthusiast Converts Real-Life Aircraft Cockpit Into Simulator

Reuters - Innovations Video Online (Nov. 25, 2014) A virtual flying enthusiast converts parts of a written-off Airbus aircraft into a working flight simulator in his northern Slovenian home. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
Car Park Solution for Flexible Green Energy

Car Park Solution for Flexible Green Energy

Reuters - Innovations Video Online (Nov. 24, 2014) A British solar power start-up says that by covering millions of existing car park spaces around the UK with flexible solar panels, the country's power problems could be solved. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Newsy (Nov. 23, 2014) Microsoft has robotic security guards working at its Silicon Valley Campus. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins