California scientists seeking to make vehicle fuel from little more than sunshine and water are getting closer to their goal after finding a way to avoid rust in the semiconductor materials they use.
The Joint Center for Artificial Photosynthesis, a federally funded lab based at the California Institute of Technology in Pasadena, said it has figured out how to use materials such as silicon and gallium arsenide in a process to split water into hydrogen and oxygen using sunlight. Avoiding corrosion in those materials, commonly used in solar panels and LEDs, is an advance that puts the lab on track to show a low-energy, carbon-free method to make solar fuel by 2015, said Nate Lewis, JCAP’s scientific director.
“For the better part of 50 years these technologically important semiconductors have all been discarded for this application because they all corrode,” Lewis said in a phone interview. “We’ve taken these materials which were thought to be of little use and are putting them back into play.”
The first target for JCAP, backed by $122 million of Energy Department funds, is a system to make large amounts of hydrogen from sunlight that can be used by fuel or chemical companies. By the 2020s, the lab aims to advance that with a system that blends hydrogen with carbon dioxide absorbed from the air, much as a plant does, to make liquid fuels for cars, heavy trucks, boats or aircraft.
The rust-reduction research was led by Caltech’s Shu Hu, a postdoctoral scholar in chemistry, the university said. Details of JCAP’s work appear in the May 30 issue of Science.
The Energy Department deemed JCAP an Energy Innovation Hub, one of four Manhattan Project-like efforts set up by the Obama administration. Others projects are trying improve nuclear power plants and make buildings more energy-efficient.
JCAP’s push to make carbon neutral fuels also combines the work of 120 scientists at Caltech; Stanford University; the University of California’s Berkeley, Irvine and San Diego campuses; and Lawrence Berkeley National Laboratory.
The process needs refinement to reduce the cost of materials and boost durability, Lewis said. The result of the research is a carbon-neutral liquid fuel source to power vehicles that aren’t ideal candidates for batteries or hydrogen, such as heavy trucks and aircraft, he said.
Ultimately, JCAP’s solar fuel generator would be a “multilayer fabric like AstroTurf,” he said.
“It wicks up sunlight and carbon dioxide from the air and vents out oxygen,” Lewis said. “You wick out your fuel product from underneath, kind of like drainage on an Astroturf-covered field.”
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