"Bionic leaf 2.0" greatly surpasses photosynthesis efficiency - 10 percent efficient converting solar energy

06/05/2016 - 16:42

Peter Reuell

The days of drilling into the ground in the search for fuel may be numbered, because if Daniel Nocera has his way, it’ll just be a matter of looking for sunny skies.

Nocera, Ph.D., the Patterson Rockwood Professor of Energy at Harvard University, and Pamela Silver, Ph.D., Core Faculty member at Harvard’s Wyss Institute for Biologically Inspired Engineering and the Elliott T. and Onie H. Adams Professor of Biochemistry and Systems Biology at Harvard Medical School, have co-created a system that uses solar energy to split water molecules and hydrogen-eating bacteria to produce liquid fuels.


Ref: Water splitting–biosynthetic system with CO2 reduction efficiencies exceeding photosynthesis. Science (3 June 2016) | DOI: 10.1126/science.aaf5039


Artificial photosynthetic systems can store solar energy and chemically reduce CO2. We developed a hybrid water splitting–biosynthetic system based on a biocompatible Earth-abundant inorganic catalyst system to split water into molecular hydrogen and oxygen (H2 and O2) at low driving voltages. When grown in contact with these catalysts, Ralstonia eutropha consumed the produced H2 to synthesize biomass and fuels or chemical products from low CO2 concentration in the presence of O2. This scalable system has a CO2 reduction energy efficiency of ~50% when producing bacterial biomass and liquid fusel alcohols, scrubbing 180 grams of CO2 per kilowatt-hour of electricity. Coupling this hybrid device to existing photovoltaic systems would yield a CO2 reduction energy efficiency of ~10%, exceeding that of natural photosynthetic systems.