Thursday, July 31, 2008

Solar-Power Breakthrough

Continued from page 1

By Kevin Bullis

Nocera created the catalyst as part of a research program whose goal was to develop artificial photosynthesis that works more efficiently than photosynthesis and produces useful fuels, such as hydrogen. Nocera has solved one of the most challenging parts of artificial photosynthesis: generating oxygen from water. Two more steps remain. One is replacing the expensive platinum catalyst for making hydrogen from hydrogen ions with a catalyst based on a cheap and abundant metal, as Nocera has done with the oxygen catalyst.

Finding a cheaper catalyst for making hydrogen shouldn't be too difficult, says John Turner, a principal investigator at the National Renewable Energy Laboratory, in Golden, CO. Indeed, Nocera says that he has promising new materials that might work, and other researchers also have likely candidates. The second remaining step in artificial photosynthesis is developing a material that absorbs sunlight, generating the electrons needed to power the water-splitting catalysts. That will allow Nocera's catalyst to run directly on sunlight; right now, it runs on electricity taken from an outlet.

There's also still much engineering work to be done before Nocera's catalyst is incorporated into commercial devices. It will, for example, be necessary to improve the rate at which his catalyst produces oxygen. Nocera and others are confident that the engineering can be done quickly because the catalyst is easy to make, allowing a lot of researchers to start working with it without delay. "The beauty of this system is, it's so simple that many people can immediately jump on it and make it better," says Thomas Moore, a professor of chemistry and biochemistry at Arizona State University.