MIT Team Develop 'Artificial Leaf' Creating Energy by Mimicking Photosynthesis

Leaves are pretty amazing, when you come to think of it. They take water and sunlight, and through the process of photosynthesis, convert them into energy. It's not directly usable by anyone but the tree, of course, but nevertheless it's amazing. (You can, of course, use the energy if you eat the tree or plant.)

For years, scientists have wondered if they could replicate the process in a lab, without a real plant. A team at MIT (News - Alert) appears to have finally done so. Led by Daniel Nocera, Ph.D., the team has created an “artificial leaf:” an advanced solar cell the size of a poker card that mimics the process of photosynthesis that allows green plants to convert sunlight and water into energy.

“A practical artificial leaf has been one of the Holy Grails of science for decades,” said Dr. Nocera to an audience at the 241st National Meeting of the American Chemical Society.

“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,” he said. “One can envision villages in India and Africa not long from now purchasing an affordable basic power system based on this technology.”

Though the device doesn't look much like a real leaf, the team used real leaves as the models for their new development. About the shape of a poker card but thinner, the device is fashioned from silicon, electronics and catalysts, substances that accelerate chemical reactions that otherwise would not occur, or would run slowly. 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, said Nocera. It does so by splitting water into its two components, hydrogen and oxygen.

The hydrogen and oxygen gases would then be stored in a fuel cell, which uses those two materials to produce electricity, located either on top of the house or beside it.

Previous efforts to develop an artificial leaf were less successful, and the end results were made of such expensive and rare materials that the devices would be unsuitable for practical use. Nocera et al.'s discovery of several powerful new, inexpensive catalysts – made of nickel and cobalt – means that the devices are capable of efficiently splitting water into hydrogen and oxygen under simple conditions.

The “leaf” is currently about 10 times more efficient at carrying out photosynthesis than a natural leaf. However, Nocera says he is optimistic that he can boost the efficiency of the artificial leaf much higher in the future.