A professor at MIT claims to have Mother Nature beat at her own game. Dr. Daniel Nocera says his invention is ten times more efficient at photosynthesis than a real-life leaf, and could help to bring affordable alternative energy to developing countries. Described as an "advanced solar cell the size of a poker card," the device is made of silicon, electronics, and inexpensive catalysts made of nickel and cobalt. When placed in a gallon of water under direct sunlight, the catalysts break the H2O down into hydrogen and oxygen gases, which are then stored in a fuel cell -- the energy produced is apparently enough to power a single house for a day. Of course, this isn't the first time we've seen scientists try to one-up nature, in fact, we've seen solar-powered leaves before, but this thing actually looks poised for the mass market -- Nocera signed a deal with Tata in October.

As has been widely discussed, the production of oxygen from water has been the primary barrier to efficient water splitting. The Nocera group has overcome this challenge with the discovery of cobalt and nickel catalysts that duplicate the solar fuels process of photosynthesis outside of the leaf - an artificial photosynthesis. Like the oxygen evolving catalyst (OEC) of photosynthesis, the new catalysts in the Nocera labs self assemble from water to form a partial cubane structure, they are self-healing and they split water to hydrogen and oxygen using light from neutral water, at atmospheric pressure and room temperature. The catalyst operates at 100 mA/cm2 at 76% efficiency. Moreover it can operate out of any water source including the Charles River in front of MIT. Finally, the ability to split neutral water has led to the discovery on an inexpensive H2 producing catalyst that operates at 1000 mA/cm2 at 35 mV overpotential

The catalyst operates at 100 mA/cm2 at 76% efficiency. Moreover it can operate out of any water source including the Charles River in front of MIT. Finally, the ability to split neutral water has led to the discovery on an inexpensive H2 producing catalyst that operates at 1000 mA/cm2 at 35 mV overpotential

Very interesting! Surprised this hasn't gotten more responses. Can anyone help translate "1000 mA/cm2 at 35mV over potential" into something I can understand? My electrical physics is either rusty or nonexistent, so forgive me if this is a silly question. I understand amps and volts and over potential but that cm2 term is throwing me. Can the above be converted into kwh?