A team of Tennessee researchers is trying to use algae to produce hydrogen that could be used as automotive fuel. Despite its energy potential, hydrogen has not taken off as an alternative fuel source because of the expensive, high-energy and sometimes climate-changing processes required to produce it. The Tennessee team - led by professor Barry Bruce of the University of Tennessee at Knoxville -- wants to use photosynthesis as a clean, efficient and sustainable source of hydrogen.
"We're looking for solutions that already exist in nature," Bruce said. "We're trying to peel back some of the barriers and make them work in the near future."
The team's research, published in Nature Nanotechnology, involves separating a tiny particle used by algae during photosynthesis and coupling it with a platinum catalyst to produce hydrogen when exposed to light.
"Compared to things like converting pharmaceuticals to drugs, this is pretty straightforward," Bruce said.
Bruce's team is not the first to use photosynthetic microorganisms as a hydrogen fuel source, but other researchers have not found a way to efficiently use the reaction at the high temperatures that would exist in a system designed to harness sunlight.
Bruce said he and his colleagues are using a strain of algae that favors warmer temperatures and could sustain reaction temperatures as high as 131 degrees Fahrenheit - roughly the temperature in deserts, where the process would be most productive.
"Having the ability to work in elevated temperatures may be important in practical future uses," Bruce said. Their system's efficiency was compared to biofuel production, a process that would similarly use photosynthesis to convert the sun's energy to alternative fuel. The verdict: The hydrogen system is about 25 times more efficient than biofuel systems.
"In cellulosic ethanol converting systems, you've got to convert cellulose into sugars, and ferment those into alcohol, which have to be distilled," Bruce said. "Our system doesn't have any of that. It's almost a just-add-water-type system."
But the process is not a cure-all. For one, it currently only exists in the laboratory. "We still face many, many problems. We're still in infancy," Bruce said. "But it's promising in that it's so simple and stable, and the efficiencies are pretty good."
A major hurdle the researchers want to overcome is the use of expensive platinum as a catalyst for the reaction. "We'd like to replace it with a more sustainable source," Bruce said.
The team would also like to eventually run the system off water. And the researchers want to make the efficiency of the system better, by coaxing the algae to absorb and use more of the solar spectrum during photosynthesis.
Bruce's team has plans to tackle all those problems with hopes of bringing the technology to mainstream use in 10 to 20 years.
[Source: Green Car Advisor]
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