Pellets made out of aluminum and gallium can produce pure hydrogen when water is poured on them, offering a possible alternative to gasoline-powered engines, U.S. scientists say.
Hydrogen is seen as the ultimate in clean fuels, especially for powering cars, because it emits only water when burned. U.S. President George W. Bush has proclaimed hydrogen to be the fuel of the future, but researchers have not decided what is the most efficient way to produce and store hydrogen.
In the experiment conducted at Purdue University in Indiana, "The hydrogen is generated on demand, so you only produce as much as you need when you need it," said Jerry Woodall, an engineering professor at Purdue who invented the system.
Woodall said in a statement the hydrogen would not have to be stored or transported, taking care of two stumbling blocks to generating hydrogen.
For now, the Purdue scientists think the system could be used for smaller engines like lawn mowers and chain saws. But they think it would work for cars and trucks as well, either as a replacement for gasoline or as a means of powering hydrogen fuel cells.
"It is one of the more feasible ideas out there," Jay Gore, an engineering professor and interim director of the Energy Center at Purdue's Discovery Park, said in a telephone interview on Thursday. "It's a very simple idea but had not been done before."
On its own, aluminum will not react with water because it forms a protective skin when exposed to oxygen. Adding gallium keeps the film from forming, allowing the aluminum to react with oxygen in the water, releasing hydrogen and aluminum oxide, also known as alumina.
What is left over is aluminum oxide and gallium. In the engine, the byproduct of burning hydrogen is water.
"No toxic fumes are produced," Woodall said.
Based on current energy and raw materials prices, the cost of making the hydrogen fuel is about $3 a gallon, about the same as the average price for a gallon of gas in the United States.
Recycling the aluminum oxide byproduct and developing a lower grade of gallium could bring down costs, making the system more affordable, Woodall said.
