Ever dreamed of a fuel cell that is more compact, efficient and cheaper than the existing ones? Recent research has uncovered a new type of fuel cell based on carbon nanotubes that is just this and much more. Forget the old platinum catalysts which make electrochemical conversion a very expensive process.

Liming Dai of the University of Dayton and his team grew tightly packed vertically aligned carbon nanotubes that were doped with nitrogen atoms using a process called chemical vapour deposition^{[See footnote]}.These aligned nanotubes, when used as cathodes in highly alkaline solution, can catalyse the reduction of oxygen more efficiently than platinum.

The research by Dai and his team has made the iron containing carbon nanotube catalysts obsolete. The research revealed that efficient catalysts can be made from carbon nanotube scaffold without the need for metals.

This catalytic mechanism finds application in other materials too, such as cars and phones of the future, where the reduction of oxygen is required but its real operating environment has to be tested first.

Vertically aligned nitrogen-doped carbon nanotubes used in fuel cells. © Science

Mechanism for electrochemical reduction of oxygen:

Create carbon nanotubes, doped with nitrogen, from a base of iron nanoparticles. Remove the iron from it. The small amount of nitrogen (around four or six atoms of nitrogen for every 100 of carbon) present in the walls of the nanotube has the effect of drawing electrons away from neighbouring carbons giving them a net positive charge. When an electrochemical potential is applied to the electrode, these carbons become reduced, becoming negative or neutral. When oxygen is presented to the electrode’s surface, the carbons readily donate electrons to revert to their preferred positive status.

The cost of carbon nanotubes has fallen since its inception and is expected to reduce further. On the other hand, platinum is a finite resource and there are limited reserves of it. Also, its properties degrade over time. Carbon monoxide can stick to platinum’s surface making it less effective. All these drawbacks of platinum could be overcome by using carbon nanotubes which are electrically and mechanically robust, have long-term operational stability and do not suffer from carbon-monoxide poisoning.

However, the fuel cell experts disagree with Dai regarding making alkaline fuel cells viable. Commenting on this matter, Nafion said that the biggest problem in practically using fuel cells is the development of alkaline version of the solid polymer electrolyte employed in acidic fuel cells, rather than the electrode.

*Chemical vapour deposition is a process in which a compound containing carbon, nitrogen and iron is taken. It is placed on a quartz substrate and heated in the presence of ammonia, resulting in nitrogen doped carbon nanotubes growing straight up from the surface.

Bookmark and Share

Close Bookmark and Share This Page

Save to Browser Favorites / Bookmarks

Ask backflip blinklist BlogBookmark Bloglines BlogMarks Blogsvine BuddyMarks BUMPzee! CiteULike co.mments Connotea del.icio.us

Digg diigo DotNetKicks DropJack dzone Facebook Fark Faves Feed Me Links Friendsite folkd.com Furl Google

Hugg Jamespot Jeqq Kaboodle kirtsy linkaGoGo LinkedIn LinksMarker Ma.gnolia Mister Wong Mixx MySpace MyWeb

Netvouz Newsvine oneview OnlyWire PlugIM Propeller Reddit Rojo Segnalo Shoutwire Simpy Slashdot Sphere

Sphinn Spurl Squidoo StumbleUpon Technorati ThisNext Twitter Webride Windows Live Worlds Movies Yahoo!

Email This to a Friend

Copy HTML: 

 If you like this then please subscribe to the RSS Feed.

Powered by Bookmarkify™

More »