June 9, 2004: Researchers Study Hydrogen Storage For Fuel Cells
The researchers, one group led by professor Omar Yaghi and assistant professor Adam Matzger, both of the Department of Chemistry, and the other group led by professor Ralph Yang of the Department of Chemical Engineering, will receive more than $5 million to develop new materials for storing large amounts of hydrogen at normally encountered temperatures and pressures.
According to the researchers, the Yaghi group has created materials called metal-organic frameworks (MOFs), sometimes referred to as crystal sponges. MOFs are essentially scaffolds made up of linked rods, a structure that maximizes surface area. Just one gram of a MOF is said to have the surface area of a football field. The researchers found that they can increase the material's storage capacity by modifying the rods in various ways, making it possible to store more hydrogen molecules into a small area without resorting to high pressure or low temperature.
MOFs can be made from low-cost ingredients, such as zinc oxide - a common ingredient of sunscreen - and terephthalate, which is used in plastic soda bottles, say the researchers.
"More than 500 MOFs have been synthesized and are being investigated," Yaghi said. Matzger added, "One thing we want to know is, why are these things so good at what they do, and how can they be made better."
The Yang group has been investigating the storage of hydrogen with a new type of material called carbon nanotubes (CNTs). Carbon nanotubes are tiny tubes made of carbon that are about 10,000 times smaller than human hair. These tubes are made by rolled-up sheets of graphite. Yang's group is also interested in hydrogen storage in a specific type of carbon nanotube called graphite nanofibers (GNFs). These new materials have unique adsorption properties, according to Yang, including large hydrogen storage capacities at ambient temperature. Now Yang and his coworkers will try to figure out how to maximize the storage capacity of these new materials and also to get a fundamental understanding of the reasons for this unique property.
Publication date: 06/07/2004