News 
18th November 2011
Man Made "Solar Leaf"
At The Green Insurance Company, we love reading about cool eco stories from around the world. Our most recent pick of the bunch is a really cool piece of green technology, a professor at the Massachusetts Institute of Technology (MIT) has developed an artificial solar leaf which he claims can power a house in a developing country for a day.
Professor Daniel Nocera’s artificial leaf is the size of a playing card and contains a silicon based solar cell which produces electricity. The leaf requires just a gallon of water and a ready supply of sunlight.
The leaf uses silicon, cobalt and nickel that react with sunlight to electrolyze water, creating hydrogen and oxygen. Sunlight is then converted into an electric field on the silicon-cobalt surface, causing oxygen to be released from the water. The reverse side is a silicon sheet coated with a layer of a nickel-molybdenum-zinc alloy that liberates hydrogen from the water.
The oxygen and hydrogen can be captured and then passed back through a fuel cell to make electricity and the waste product is pure water. Although the round trip (from sunlight to artificial leaf, to oxygen/hydrogen, to fuel cell and finally to water) efficiency would be low, the oxygen and hydrogen can be stored meaning a battery isn’t required. Each home could potentially be fitted with artificial solar cell leaves, making their own oxygen and hydrogen for use in fuel cells that would then provide electrical power to the home.
Very cool!