Aluminum-Gallium to Make Hydrogen

Researchers from the Purdue University in Indiana have developed a method that uses an aluminum alloy to extract hydrogen from water. The hydrogen may be used for running fuel cells or internal combustion engines, which in turn could be used to replace gasoline.

One of the key issues with hydrogen fuel is that it is expensive to manufacture and is complicated to transport over long distances due to its explosive nature. With the newly developed technique hydrogen is generated on demand and only in the amount needed at the time.

The process for producing the hydrogen is remarkably simple: water is added to a liquid alloy of aluminum and gallium to produce hydrogen, which can then be fed directly to an engine. The process generates a chemical reaction which splits the oxygen and hydrogen contained in water, releasing hydrogen in the process. 

According to the scientists, the addition of gallium is critical to the process because it hinders the formation of a skin normally created on aluminum’s surface after oxidation. This skin usually acts as a barrier that prevents oxygen from reacting with aluminum. Preventing the skin’s formation allows the reaction to continue until all of the aluminum is used. 

The discovery was accidentally made by one of the scientists who was cleaning a crucible containing liquid alloys of gallium and aluminum. When the researcher added water to the alloy a violent explosion occurred (probably caused by the creation of highly explosive hydrogen in the tank).  

Currently, the biggest obstacle to this technology is cost. By recycling the aluminum it will be possible to reduce the cost in the future. This process still requires a lot of energy that must be produced in an environmentally friendly way (using wind power, solar power, or at worst nuclear power plants). If these problems will be resolved the new process will offer a way for producing cheap hydrogen which does not need to be transported across the country, eliminating the two major problems currently facing the hydrogen economy. You would simply drive into your local refueling station and fill the tank of your car with an aluminum-gallium alloy that would be mixed with water to create small quantities of hydrogen to be used as you drive along. 

In 2005 a group of scientists from the Weizmann Institute in Israel developed a very similar technology using zinc and solar energy to produce hydrogen. The problem with the Weizmann process was that zinc is heavy (and again fairly costly to recycle) and thus does not make for a very useful car fuel. Aluminum was also suggested at the time but it now appears that the Purdue University team was able to reach the target first and patent the technology for aluminum. 

More information on the new process can be found on the Purdue University website.