147 W 19th Ave
Columbus, OH 43210
2016 Evans Lecturer: Daniel Nocera
Thursday, October 6th, 2016
“A Complete Artificial Photosynthesis” – 4:00-5:15pm, MP1000
The artificial leaf was invented to accomplish the solar fuels process of natural photosynthesis – the splitting of water to hydrogen and oxygen using sunlight. To create the artificial leaf, four properties of the oxygen evolving complex of Photosystem II (OEC-PSII) were mimicked: An artificial catalyst was created that:
- possessed the same cubane structure of OEC-PSII;
- self-assembled from water;
- possessed the proton-electron inventory of the Kok cycle used by the OEC-PSII for water splitting;
- was self-healing.
The latter property of self-healing is a critical discovery as it allows for the facile integration of the artificial OEC catalyst, together with a hydrogen evolving catalyst (HEC), onto a silicon (Si) wafer in a buried junction configuration. The OEC | triple-junction Si | HEC configuration gives rise to the artificial leaf, which produces hydrogen and oxygen when solar light shines on neutral water, at atmospheric pressure and room temperature.
But natural photosynthesis does more than split water. Natural photosynthesis has evolved to combine the hydrogen, produced from solar-driven water splitting, with carbon dioxide to produce biomass. We have achieved an authentic and complete artificial photosynthesis. Using the tools of synthetic biology, a bio-engineered bacterium has been developed to convert carbon dioxide, along with the hydrogen produced from the artificial leaf, into biomass and liquid fuels, thus closing an entire artificial photosynthetic cycle. This hybrid microbial | artificial leaf system scrubs 180 grams of CO2 from air, equivalent to 230,000 liters of air per 1 kWh of electricity. This hybrid device, called the bionic leaf, operates at unprecedented solar-to-biomass (10.7%) and solar-to-liquid fuels (6.2%) yields, greatly exceeding the 1% yield of natural photosynthesis.
Reception and Poster Session in CBEC Lobby following lecture
Professor Nocera s the Patterson Rockwood Professor of Energy at Harvard and he is widely recognized as one of the world’s leading researchers in renewable energy. His group has pioneered studies of the basic mechanisms of energy conversion in biology and chemistry. He accomplished a solar fuels process of photosynthesis–the splitting of water to hydrogen and oxygen using sunlight and translated this science to produce the artificial leaf, which was named by Time magazine as Innovation of the Year for 2011. He has since elaborated this invention to create the bionic leaf, which performs artificial photosynthesis that is ten times more efficient than natural photosynthesis. Nocera has received numerous awards, including the Leigh Ann Conn Prize for Renewable Energy, Eni Prize, IAPS Award, Burghausen Prize, Elizabeth Wood Award, the United Nations Science and Technology Award, and a number of awards from the American Chemical Society. He is a member of the American Academy of Arts and Sciences, the U.S. National Academy of Sciences, and the Indian Academy of Sciences. He founded the energy company Sun Catalytix; its technology is now being commercialized by Lockheed Martin.