Artificial leaf could lead to better hydrogen power

Fundamentally, most of the energy we use on the earth comes from the sun -- from fossil fuels to wind and photovoltaics. Nature has been evolutionarily perfecting mechanisms to harness the sun's rays into usable chemical energy for centuries. Now, MIT researchers have produced an artificial "leaf" that mimics this process. Instead of producing the chemicals that plants use to store energy, though, this leaf uses the sun's rays to actively separate the atomic constituents of water, producing hydrogen gas as a result. The device is self contained, a solar collector sandwiched between two films, and when dropped in sunlight-illuminated water will bubble to slowly produce molecular hydrogen and oxygen. The team's device uses materials that are cheap and widely available, a significant improvement on previous devices that accomplish a similar task.