Boston:
A bionic leaf has been developed by the scientists which is seen as a breakthrough in bringing the next-gen biofuels closer to reality. The bionic leaf splits water molecules and hydrogen-eating bacteria using solar energy and produces liquid fuels. This process even surpasses the efficiency of photosynthesis seen in 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, professor at Harvard University in the US. According to Pamela Silver, professor at Harvard Medical School, the study shows the potential of the system is not just confined to be used for generating usable fuels.
The new system has been dubbed “bionic leaf 2.0” and it builds on previous work by Nocera, Silver and colleagues. A number of challenges were faced while creating the new system even as it was capable of using solar energy to make isopropanol.
Chief among those challenges 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, researchers said. In order to avoid that problem, researchers had to run the system at abnormally high voltages, resulting in reduced efficiency.
“We designed a new cobalt-phosphorus alloy catalyst, which we showed does not make reactive oxygen species. That allowed us to lower the voltage, and that led to a dramatic increase in efficiency,” Nocera said.
Nocera said that the system is now capable of converting solar energy to biomass with 10 per cent efficiency, far above the one per cent seen in the fastest growing plants.
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.
The new catalyst also came with another advantage - its chemical design allows it to “self-heal” - meaning it wouldn’t leech material into solution.
Though there may yet be room for additional increases in efficiency, Nocera said the system is already effective enough to consider possible commercial applications. The research was published in the journal Science.
(With inputs from PTI)
