The method eliminates the need to store or transport hydrogen — two major hurdles on the road to a hydrogen economy, says Jerry Woodall, professor of electrical and computer engineering at Purdue and inventor of the process.

"Hydrogen is generated on demand, so you only produce as much as you need, when you need it," says Woodall. The technology could drive small internal combustion engines in portable emergency generators, lawn mowers, and chain saws. In theory, however, the process could totally replace gasoline in cars and trucks, he says.

Hydrogen is generated when water is added to pellets of aluminum alloyed with gallium. The aluminum reacts because it has a strong attraction to oxygen in the water. The reaction splits the oxygen and hydrogen, releasing hydrogen in the process.

Gallium is critical because it prevents the skin that normally forms on the aluminum's surface after oxidation. Without the skin, the reaction continues until the aluminum is used up.

Jerry Woodall, center, and doctoral students Charles Allen (holding the test tube) and Jeffrey Ziebarth demonstrate their method for producing hydrogen by adding water to an alloy of aluminum and gallium.