A little algae, a little platinum and -- voila! -- hydrogen fuel

Cultivating algae to produce biofuels is, like, so yesterday. How about using algae to generate clean hydrogen fuel instead?

That’s what researchers in the US hope to achieve. They say they might have identified a way to combine the photosynthesising powers of algae with a platinum catalyst to produce a steady supply of hydrogen.

Some tout hydrogen as the clean-burning fuel of the future, as its main byproducts upon reacting with oxygen are energy and water. Great in theory, but actually producing the hydrogen has up until now been the tricky bit, as most of the processes use take a lot of energy.

A team of researchers from the University of Tennessee, Knoxville, and Oak Ridge National Laboratory describe a different approach in this week’s issue of the journal Nature Nanotechnology.

We already get most of our energy from photosynthesis, albeit indirectly, notes research team leader Barry Bruce, a professor of biochemistry and cellular and molecular biology at UT Knoxville and associate director of the school’s Sustainable Energy and Education Research Centre. Fossil fuels, after all, come from energy-rich plant matter that lived millions of years ago.

“Biofuel as many people think of it now — harvesting plants and converting their woody material into sugars which get distilled into combustible liquids — probably cannot replace gasoline as a major source of fuel,” said Bruce. “We found that our process is more direct and has the potential to create a much larger quantity of fuel using much less energy, which has a wide range of benefits.”

Bruce said his team’s method cuts out two key middlemen in the process of using plants’ solar conversion abilities: one, the time required for a plant to capture solar energy, grow and reproduce, then die and eventually become fuel, and, two, the substantial amount of energy required to cultivate, harvest and process plant material into biofuel.

Other scientists have studied the possibility of using photosynthesis as a hydrogen source, but have not yet found a way to make the reaction occur efficiently at the high temperatures that would exist in a large system designed to harness sunlight.

Bruce and his colleagues found that by starting with a blue-green algae that favours warmer temperatures, they could sustain the reaction at temperatures as high as 55 degrees C, or 131 degrees F. That is roughly the temperature in arid deserts with high solar irradiation, where the process would be most productive. They also found the process was more than 10 times more efficient as the temperature increased.

“Hydrogen has the potential to be the cleanest fuel alternative to petroleum, with no greenhouse gas production, and we need new innovations that allow for hydrogen to be readily produced from non-hydrocarbon sources,” said Bruce Bursten, dean of UT Knoxville’s College of Arts and Sciences. “Professor Bruce and his team have provided a superb example of how excellence in basic research can contribute significantly to technological and societal advances.”