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Solar 'Artificial Leaf' Is Unveiled by Researchers
MIT chemist Daniel Nocera has unveiled details about his long-awaited "artificial leaf" invention, a small solar cell that mimics photosynthesis and has the potential to produce low-cost electricity for individual homes - an advance that could be particularly valuable in the developing world, where many people lack electricity.
About the size of a playing card, the solar cell - which uses inexpensive and widely available materials like silicon - is able to split water into its two components, hydrogen and oxygen. Placed in a gallon of water in bright sunlight, the device could produce enough electricity to supply a house in a developing country with electricity for a day.The hydrogen and oxygen gases produced by the artificial leaf could be stored in a small fuel cell, which would use the gases to generate electricity. Nocera, who has been working on the technology for several years, released details about it during the annual meeting of the American Chemical Society in California. "Our goal is to make each home its own power station," said Nocera. While U.S. researchers had previously developed a so-called "artificial leaf," Nocera's recent discovery of inexpensive catalysts, including nickel and cobalt, has made the technology more efficient and cost-effective.
Photo by Steve Johnson/flickr/Creative Commons
Reprinted with permission from Yale Environment 360
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Photosynthesis creates carbohydrates from CO2 and water, and is truly a synthesis of new more complex compounds from smaller molecules. The new molecules carry far higher potential energy content that can be oxidized, thus storing the energy from the sun.
What this device does is hydrolyze water, reducing hydrogen back to its base state, so it can be reoxidized back into water. Much less energy storage per molecule!
Call it “photohydrolysis,” not photosynthesis!
And it is absurd to claim that a single “leaf” of such a device could power a whole house. It would take many large trees of such devices to power a house, costing a small fortune in the catalysts and storage medium for hydrogen.
Why are reporters in popular media so scientifically gullible?
Unfortunately, reduced carbon compounds (petroleum) remain the most efficient and cost effective source of energy for our modern world. Solar and hydrogen technology remain prohibitively inefficient and expensive in a real economy.
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