A LEAF TO HARVEST SUN

MIT scientist announces first "practical" artificial leaf
March 28, 2011 (Nature)

"…[H]omes of the future might be powered by [artificial] leaves…designed to mimic the process by which plants draw energy from the sun…The latest breakthrough comes from [MIT chemist] Daniel Nocera…[His] prototype solar-powered device the size of a playing card…break[s] water down into hydrogen and oxygen – valuable fuels for producing electricity via fuel cells.

"Previously Nocera had developed a catalyst that could do so with the low-voltage output from a solar cell, a major breakthrough in and of itself, since normally electrolysis (the process of breaking water into hydrogen and oxygen with electricity) requires higher voltage than can easily be produced with solar cells. But Nocera's new "artificial leaf" combines the solar cell and the electrolysis unit into one piece by chemically painting the catalyst onto a solar cell and immersing it in water…"

Looks like a real life...(from Inhabitat - click thru for more info)

"The chemistry is complex but…[comparable] to the manner in which leaves generate energy from sunlight. In plants, the energy of incoming sunlight is first used to produce electrons and positive charges within the leaf. These are then used to split water into oxygen and hydrogen (the latter being trapped as carbohydrates, rather than released into the air)…"

...but it's not a real leaf. (from Inhabitat - click thru for more info)

"In his artificial leaf, a silicon chip, similar to those used in conventional solar cells, produces electrons and positively charged holes. Then catalysts on the chip use this low-voltage current to produce oxygen and hydrogen – one gas on each side of the chip…The first such device was made in 1998 by John Turner, of the U.S. National Renewable Energy Laboratory…[but Nocera’s] new device…uses abundant cheap materials…

" …[I]t's still a few years from commercialization…[but] by integrating the catalyst with the chips, it dispenses with the need for traditional solar panels…[which] will cut costs considerably, by eliminating wires, [the need for pure water,] etc... If the process works, he says, it's a good candidate for meeting the U.S. Department of Energy's 'SunShot' initiative for developing solar power at investment costs of $1 per watt or less…"