Scientists have created a system that uses solar energy to split water molecules and hydrogen-eating bacteria to produce liquid fuels. The system can convert solar energy to biomass with 10 percent efficiency, far above the 1 percent seen in the fastest-growing plants.
While the system can be used to generate usable fuels, its potential doesn’t end there, said Silver, who is also a Founding Core Member of the Wyss Institute at Harvard University. “The beauty of biology is it’s the world’s greatest chemist — biology can do chemistry we can’t do easily,” she said. “In principle, we have a platform that can make any downstream carbon-based molecule. So this has the potential to be incredibly versatile.”
Dubbed “bionic leaf 2.0,” the new system builds on previous work by Nocera, Silver and others, which — though it was capable of using solar energy to make isopropanol — faced a number of challenges. Chief among those challenges, Nocera said, was the fact that the catalyst used to produce hydrogen — a nickel-molybdenum-zinc alloy — also created reactive oxygen species, molecules that attacked and destroyed the bacteria’s DNA. To avoid that problem, researchers were forced to run the system at abnormally high voltages, resulting in reduced efficiency.
“If you think about it, photosynthesis is amazing,” he said. “It takes sunlight, water and air–and then look at a tree. That’s exactly what we did, but we do it significantly better, because we turn all that energy into a fuel.”