A group of scientists from Harvard University has developed a ‘bionic leaf’ that uses solar energy to split water molecules and hydrogen-eating bacteria to produce liquid fuels. This dubbed “bionic leaf 2.0” system can convert solar energy to biomass with 10% efficiency of photosynthesis far above the 1% seen in the fastest growing plants.

“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,” said Daniel Nocera, the Patterson Rockwood professor of energy at Harvard University.

“But the study shows the system can be used to generate usable fuels, its potential does not end there. In principle, we have a platform that can make any downstream carbon-based molecule. So this has the potential to be incredibly versatile,” said Pamela Silver, a professor at Harvard Medical School.

The nickel-molybdenum-zinc alloy catalyst used to produce hydrogen has created reactive oxygen species, molecules that attacked and destroyed the bacteria’s DNA, researchers said. Among the challenges, the team designed a new cobalt-phosphorous alloy catalyst which does not make reactive oxygen species. By decreasing the voltage, it led to a dramatic increase in efficiency.

The new catalyst’s chemical design allows it to “self-heal” which means it wouldn’t leach material into solution. Though there may yet be room for additional increases in efficiency and the new system is already effective enough to consider possible commercial applications Daniel Nocera said.

“In addition to increasing the efficiency, researchers were able to expand the portfolio of the system to include Isobutanol and Isopentanol. Researchers also used the system to create PHB, a bio-plastic precursor. It’s an important discovery and we can do better than photosynthesis,” Nocera said.