One of the more expensive parts of a standard fuel cell is its platinum catalyst. Platinum is a metal that is good at splitting up the oxygen (O2) molecule into two oxygen ions (O+) at the cell’s cathode. Platinum is also pretty expensive. In a fuel cell for a typical passenger car, the platinum catalyst can cost about $4,000.
Researchers at the University of Dayton, however, have been able to use an array of carbon nanotubes to perform the same catalytic activity. The carbon nanotubes are doped with nitrogen (the full name is nitrogen-containing carbon nanotubes, or VA-NCNTs) – this is to prevent the carbon from reacting with oxygen to form CO, a process called “poisoning”. The CO builds up on the surface, and reduces the effectiveness of the catalyst over time. But these VA-NCNTs keep carbon unreactive, and thereby prolong the catalyst’s lifetime.
There’s no estimate yet on how much such a fuel cell would cost – no one has built a full prototype. There will certainly be costs involved in processing such precise and aligned nanotubes, but such costs would also certainly go down with economies of scale. The bottom line is that carbon is plentiful and cheap, while platinum is rare and expensive.
As fuel cells can be designed with fewer and fewer such rare metals and materials, the concept of a hydrogen economy gains more long-term credibility. Sure, some claim that hydrogen technology will always be 10 years away. But that statement is more a reflection of the practical hurdles that stand between us and a hydrogen economy, and less a reflection of technical flaws in the plan. That is, the hydrogen economy still looks really good on paper, and the replacement of platinum catalysts with carbon makes it look even better.
Via Green Car Congress
written by Martijn, February 07, 2009
written by Magnulus, February 07, 2009
written by Kenny Canuck, February 09, 2009
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