by Graeme » Tue 06 Oct 2009, 04:22:10
I'm certainly not a fuel-cell engineer and I'm not aware of all the latest research on fuel cells. However, I did a quick google search and found this:
Smaller Isn't Always Better: Catalyst Simulations Could Lower Fuel Cell Cost
$this->bbcode_second_pass_quote('', 'T')o maximize platinum use, researchers use catalysts made with platinum particles as small as two nanometers, which are approximately 10 atoms across. These tiny structures have a large surface area on which the fuel cell reaction occurs. However, platinum catalysts this small degrade very quickly.
Morgan and Holby, who are working in collaboration with Professor Yang Shao-Horn from the Massachusetts Institute of Technology, have found a possible solution to the rapid degradation problem: When it comes to catalyst particle size, sometimes smaller isn't better.
Their modeling work, which is funded by 3M and the U.S. Department of Energy, shows that if the particle size of a platinum catalyst is increased to four or five nanometers, which is approximately 20 atoms across, the level of degradation significantly decreases. This means the catalyst and the fuel cell as a whole can continue to function for much longer than if the particle size was only two or three nanometers.
sciencedailyI'm sure Toyota are aware of this and they will continue to do further research on this and other problems themselves. There is still 5 years available for research before commercial production.
Here is a possible substitute for platinum:
A Catalyst for Cheaper Fuel Cells$this->bbcode_second_pass_quote('', 'F')uel cell researchers have been looking for cheaper, more abundant alternatives to platinum, which costs between $1,000 and $2,000 an ounce and is mined almost exclusively in just two countries: South Africa and Russia. One promising catalyst that uses far less expensive materials--iron, nitrogen, and carbon--has long been known to promote the necessary reactions, but at rates that are far too slow to be practical.
Now researchers at the Institut National de la Recherche Scientifique (INRS) in Quebec have dramatically increased the performance of this type of iron-based catalyst. Their material produces 99 amps per cubic centimeter at 0.8 volts, a key measurement of catalytic activity. That is 35 times better than the best nonprecious metal catalyst so far, and close to the Department of Energy's goal for fuel-cell catalysts: 130 amps per cubic centimeter. It also matches the performance of typical platinum catalysts, says Jean-Pol Dodelet, a professor of energy, materials, and telecommunications at INRS who led the work.