In a presentation at the 241st National Meeting of the American Chemical Society today in Anaheim, Dr. Daniel Nocera of MIT said that his team has developed a practical “artificial leaf”—a type of solar cell that shows promise as an inexpensive source of electricity for the poor in developing countries. (Earlier post.)
The device is an advanced solar cell the size of a poker card that mimics photosynthesis, and uses catalysts derived from earth-abundant materials (e.g., cobalt and nickel). Placed in a single gallon of water in a bright sunlight, the device could produce enough electricity to supply a house in a developing country with electricity for a day, Nocera said.
A practical artificial leaf has been one of the Holy Grails of science for decades. We believe we have done it. The artificial leaf shows particular promise as an inexpensive source of electricity for homes of the poor in developing countries. Our goal is to make each home its own power station. One can envision villages in India and Africa not long from now purchasing an affordable basic power system based on this technology.—Daniel Nocera
The first artificial leaf was developed more than a decade ago by John Turner of the US National Renewable Energy Laboratory in Boulder, Colorado. Although highly efficient at carrying out photosynthesis, Turner’s device was impractical for wider use, as it was composed of rare, expensive metals and was highly unstable, with a lifespan of barely one day.
Nocera’s new leaf overcomes these problems. It is made of inexpensive materials that are widely available, works under simple conditions and is highly stable. In laboratory studies, he showed that an artificial leaf prototype could operate continuously for at least 45 hours without a drop in activity.
The key to this breakthrough is Nocera’s recent discovery of several powerful new, inexpensive catalysts, made of nickel and cobalt, that are capable of efficiently splitting water into its two components, hydrogen and oxygen, under simple conditions. Right now, Nocera’s leaf is about 10 times more efficient at carrying out photosynthesis than a natural leaf. However, he is optimistic that he can boost the efficiency of the artificial leaf much higher in the future.
Nocera acknowledges funding from The National Science Foundation and Chesonis Family Foundation.