Most fuel cells being developed for portable use are based on direct-methanol technology, which requires an expensive platinum catalyst.

Then comes the cost of hydrogen-based vehicles. Just the platinum for the catalyst inside a fuel cell costs as much as an internal-combustion engine of equivalent power, according to a recent study.

The other key to the operation of a PEM membrane is the thin layer of platinum-based catalyst that coats both of its sides and that represents 40 percent of the stack cost.