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As part of photosynthesis plants somehow very efficiently split water into hydrogen and oxygen, using relatively small amounts of energy from sunlight. Humanity can accomplish the same split by using tremendous amounts of electricity (that’s how oxygen is generated inside a nuclear submarine).  If plants had to rely on human technology they’d use up far more energy trying to do photosynthesis than they’d possibly get out of the process.  Plants have been hyper efficient in a way scientists have only been able to envy.

When I learned about this in high school I wondered if as our ability to analyze plants improves, humanity will discover how to split water as efficiently as plants do.  I pondered how this could transform how humanity generates energy.  A small amount of electricity (from a solar cell or other source), along with some water, and the right process, could split hydrogen from oxygen.  They could then be recombined to generate power, either in a fuel cell, or by exposing the hydrogen to oxygen (ie, burning it, forming water again).  All that is needed is for the day to come when human technology can split water as efficiently as the leaf of a plant.

That day may be much closer. MIT professor Daniel G. Nocera and his postdoc Matthew Kanan made an important discovery in January of 2008, and are publishing an article describing it in the August 1, 2008 edition of Science (article stub).

Prior efforts to split water efficiently tried to run electricity into water with some type of stable catalyst (a catalyst is other chemicals, that help the process along).  Photosynthesis is a violent chemical process however, and has tended to tear down catalysts.  Scientists have searched for a stable catalyst that can help make splitting water happen with small amounts of electricity.

Nocera and Kanan used an unstable catalyst instead. They dissolved an inexpensive cobalt and phosphate catalyst mixture in water, ran an electric current through an electrode, and with the additional presence of some platinum catalyst, oxygen bubbles out of the water and hydrogen forms around the electrode.  Although the cobalt and phosphate catalyst gets corroded whenever electricity is not applied, Nocera and Kanan found that it reassembles when electricty is applied.

If you are interested in more articles on this discovery, check out google news: http://news.google.com/news?hl=en&ned=us&q=%22daniel+nocera%22&ie=UTF-8&scoring=n