Hydrogen-generating Technology Closer Than Ever

The technology produces hydrogen by adding water to an alloy of aluminum and gallium. When water is added to the alloy, the aluminum splits water by attracting oxygen, liberating hydrogen in the process. The Purdue researchers are developing a method to create particles of the alloy that could be placed in a tank to react with water and produce hydrogen on demand.The gallium is a critical component because it hinders the formation of an aluminum oxide skin normally created on aluminum's surface after bonding with oxygen, a process called oxidation.
Since the technology was first announced in May, researchers have developed an improved form of the alloy that contains a higher concentration of aluminum.Recent findings are detailed in the first research paper about the work, which will be presented on Sept. 7 during the 2nd Energy Nanotechnology International Conference in Santa Clara, Calif. The paper was written by Woodall, Charles Allen and Jeffrey Ziebarth, both doctoral students in Purdue's School of Electrical and Computer Engineering.Because the technology could be used to generate hydrogen on demand, the method makes it unnecessary to store or transport hydrogen - two major obstacles in creating a hydrogen economy, Woodall said.
The gallium component is inert, which means it can be recovered and reused.As the alloy reacts with water, the aluminum turns into aluminum oxide, also called alumina, which can be recycled back into aluminum. The recycled aluminum would be less expensive than mining the metal, making the technology more competitive with other forms of energy production.

In recent research, the engineers rapidly cooled the molten alloy to make particles that were 28 percent aluminum by weight and 72 percent gallium by weight. The result was a "metastable solid alloy.

The U.S. Department of Energy has set a goal of developing alternative fuels that possess a "hydrogen mass density" of 6 percent by the year 2010 and 9 percent by 2015. The percent mass density of hydrogen is the mass of hydrogen contained in the fuel divided by the total mass of the fuel multiplied by 100. Assuming 50 percent of the water produced as waste is recovered and cycled back into the reaction, the new 80-20 alloy has a hydrogen mass density greater than 6 percent, which meets the DOE's 2010 goal.