.Hydrogen is generated spontaneously when water is added to pellets of the alloy, which is made of aluminum and a metal called gallium. The researchers have shown how hydrogen is produced when water is added to a small tank containing the pellets. Hydrogen produced in such a system could be fed directly to an engine, such as those on lawn mowers.
The key, they say, is the addition of the gallium, "because it hinders the formation of a skin normally created on aluminum's surface after oxidation." The gallium is not consumed by the process, meaning it can be reused. The aluminum, of course, oxidizes and must be recycled. While the current price of aluminum means this won't be cost-competitive with gasoline in the near term, in combination with fuel cell technology, immediate gains could be realized."