Tiny materials may bring about large-scale advances in a future hydrogen economy, Institute Professor Mildred S. Dresselhaus told audiences Wednesday, April 5, at MIT and at the Technion Israel Institute of Technology.
While hydrogen has advantages, it's "not a fuel. You can't mine it. We would have to make nine million tons a year, and eventually, 20 times more than that," Dresselhaus said. Because hydrogen is currently produced from fossil fuels, scientists would have to find a way to produce it from sustainable sources such as rainfall and ocean water.
"We need to develop the technology to convert hydrogen and water to free hydrogen, but we don't know how to do it cheaply and at a large scale," she said.
To make hydrogen that works as well as gasoline as an automotive fuel or to power the fuel cells that may replace internal combustion engines, researchers are depending on nanotechnology.
"By using new advanced materials now becoming available through nanoscience, scientists can take advantage of quantum phenomena that occur at this scale," she said.
Nanotechnology can help develop efficient, inexpensive catalysts for hydrogen production and storage. Several chemical species contain hydrogen in high concentrations, but the trick is to release hydrogen from its strong chemical bonds to make it usable in a system like a car that needs a steady flow of fuel.
Also see New Advances Made in Hydrogen Fuel Cells.
The best hope for bringing the hydrogen-fueled automobile to the American roadway may be a technology that is invisible to the naked eye.
The technology is in the form of tiny graphite structures that together act as a sponge to absorb and store hydrogen in the fuel system of the automobile. Onboard storage of hydrogen gas is the major obstacle impeding the progress and wide-scale commercial production of the hydrogen-powered vehicle, which many view as the next generation in energy-efficient and environmentally friendly road transportation.
The graphite structures are a product of the burgeoning field of nanotechnology. Engineers design the structures at the molecular level, working in scales as small as millimeters and nanometers. The engineers stack the fibrous platelets one atop the other, leaving the optimum gap between the wafers; then they arrange the chemistry so that hydrogen molecules are absorbed in the graphite.
The nanostructures are extremely porous, like a sponge, allowing them to absorb large capacities of hydrogen until fully saturated. Experiments demonstrate that the hydrogen storage in graphite nanofibers is safe.
Another method of hydrogen storage derived from nanotechnology involves carbon nano-tubes. With carbon nanotubes, engineers arrange carbon platelets in different configurations. Research has shown the carbon nanotubes to display strong hydrogen storage capabilities.