Scientists at Harvard University have developed a ‘bionic leaf’ that uses artificial photosynthesis to convert sunlight into liquid energy at 10 percent efficiency—far more efficient than even the fastest growing plants. The device shows the potential of the technology to produce biofuels.
The new device created by Harvard University Professors Daniel Nocera and Pamela Silver as well as postdoctoral fellow Chong Liu and graduate student Brendan Colón splits water molecules into hydrogen and oxygen and uses ralstonia eutropha, a hydrogen-eating bacteria, to produce liquid fuels. The researchers published their work in the journal Science.
“This is a true artificial photosynthesis system,” Nocera told Harvard Gazette’s Peter Reuell. “Before, people were using artificial photosynthesis for water-splitting, but this is a true A-to-Z system, and we’ve gone well over the efficiency of photosynthesis in nature.” In nature photosynthesis is about one percent efficient at producing fuel for plant growth in the most efficient plants.
The new device is second time the researchers have produced a bionic leaf. However the previous version used a nickel-molybdenum-zinc alloy which produced reactive oxygen species molecules that destroyed the bacteria’s DNA. The new version uses a cobalt-phosphorous alloy catalyst, which doesn’t produce the same species that attacks the bacteria. “That allowed us to lower the voltage, and that led to a dramatic increase in efficiency,” Nocera explained.
The new system could be used to make other things, according to Silver. “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.”
Already they are showing the potential to produce multiple fuelswith the new device. The previous device produced isopropanol, the new device has been used to produce isobutanol and isopentanol and PHB, a bio-plastic precursor.
At 10 percent efficiency Nocera said the device is ready to be considered for commercialization. But there may be further efficiency increases to be realized. The new device, Nocera hopes can also be used in developing nations.Tweet