Hydrogen storage

One of the key engineering challenges to building a clean, efficient, hydrogen-powered car is how to design the fuel tank. Storing enough raw hydrogen for a reasonable driving range would require either impractically high pressures for gaseous hydrogen or extremely low temperatures for liquid hydrogen.

Now, researchers at the National Institute of Standards and Technology’s Center for Neutron Research (NCNR) have demonstrated that a novel class of materials could enable a practical hydrogen fuel tank.

A research team from NIST, the University of Maryland and the California Institute of Technology studied metal-organic frameworks (MOFs). One of several classes of materials that can bind and release hydrogen under the right conditions, they have some distinct advantages over competitors. Specifically, MOFs don’t require the high temperatures (110 to 500 C) some other materials need to release hydrogen.

In particular, the team examined MOF-74, a porous crystalline powder developed at the University of California at Los Angeles. MOF-74 resembles a series of tightly packed straws comprised of mostly carbon atoms with columns of zinc ions running down the inside walls. A gram of the substance has roughly the same surface area as two basketball courts.