'Bionic' leaf that turns sunlight into liquid fuel

A team of scientists from Harvard University has co-created a unique "bionic leaf" that uses solar energy to split water molecules and hydrogen-eating bacteria to produce liquid fuels.

Dubbed "bionic leaf 2.0," the new system can convert solar energy to biomass with 10 percent efficiency -- far above the one per cent seen in the fastest growing plants.

"This is a true artificial photosynthesis system. Before this, 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.

While the study shows the system can be used to generate usable fuels, its potential doesn't 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," added co-author Pamela Silver, the Elliott T. and Onie H. Adams Professor of Biochemistry and Systems Biology.

For this paper, the team designed a new cobalt-phosphorous 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 noted in a paper published in the journal Science.

The new catalyst also came with another advantage. Its chemical design allows it to "self-heal" -- meaning it wouldn't leech material into solution.

The new system is already effective enough to consider possible commercial applications but within a different model for technology translation.

"It's an important discovery -- it says we can do better than photosynthesis," Nocera said. "But I also want to bring this technology to the developing world as well."

In many ways, the new system marks the fulfillment of the promise of his "artificial leaf" which used solar power to split water and make hydrogen fuel.

--IANS

na/dg