The fuel cells I know of, and GM is testing in the Equinoxes run off hydrogen
The catalyst is Titanium, which causes a reverse hydrolysis. Meaning that instead of passing electricity through water to creat hydrogen and oxygen; it combines hydrogen and oxygen, to produce electricity and water. Really cool stuff.
I've never heard of a fuel cell that 'burns' aluminum, that's not to say they don't exist, though...
And currently, hydrogen fuel cells need a jumpstart in order to create the infrastructure to supply them. But after that, I agree it can't be a "be all and end all". But it can be a significant source of power and transportation. Hydrogen is in excess quantites in our world, and oxygen, nor hydrogen for that matter, are lost during the process. They are just converted into water: H
I think the future of automobiles is going to include many different sources of fuel. I believe that our muscle cars, and other high-power vehicles like trucks etc...will run for some time off of Ethanol. probably cellulosic ethanol, but electric motors that produce realistic enough power in such heavy vehicles(trucks) are just too big. and the batteries required to supply enough power to such motors, too would be too huge. but the vast majority of passenger cars, and small SUVs will probably be run off of some version of E-flex
:shrug: That's my take on it.