View Full Version : A New Leaf: New Catalyst Boosts Artificial Photosynthesis as a Solar Fuel

Richard Amiel McGough
06-18-2012, 10:33 AM
From the Scientific American:

A New Leaf: New Catalyst Boosts Artificial Photosynthesis as a Solar Alternative to Fossil Fuel
This is an example of the kind of technological advances that make me very optimistic for the future. When we solve the problem of a sustainable modern civilization, there will be no reason to fight over resources.

Scientists have found a single catalyst for artificial photosynthesis that could create storable solar energy in a liquid or gaseous form for use in transportation or electric power generation. But can the fuel be made efficiently?

Sunlight can provide more than enough energy to meet our needs—in theory. In practice, the skies are sometimes covered with clouds—and whether fair or overcast, the sun daily disappears behind the horizon. To get around these limitations, scientists have worked for years on new ways of converting sunlight into chemical energy, artificial forms of photosynthesis (http://blogs.scientificamerican.com/observations/2010/03/03/shift-happens-will-artificial-photosynthesis-power-the-world/) that would store solar energy in liquid or gaseous form—a "solar fuel." For years, they have sought a chemical catalyst that can perform this complex feat of chemical processing. Now some researchers think they may have found it.

Thomas Meyer (http://www.chem.unc.edu/people/faculty/meyer/) came upon the solution almost by accident. Meyer, a chemist at University of North Carolina at Chapel Hill and director of its Energy Frontier Research Center in Solar Fuels (http://www.efrc.unc.edu/), noticed that two separate groups of researchers working on two separate parts of the photosynthetic reaction happened to be using the same class of catalyst—ones with an atom of the metal ruthenium surrounded by organic molecules. One group used this type of catalyst to split water (http://www.scientificamerican.com/topic.cfm?id=water) into hydrogen and oxygen; the other one was splitting carbon dioxide into carbon monoxide and oxygen. "Finding a single catalyst that does both was a big surprise," Meyer says.

By combining the two steps and using the same catalyst, Meyer realized that they could reproduce photosynthesis in its entirety. Whereas natural photosynthesis, after multiple reactions, converts water, carbon dioxide and sunlight into oxygen and energy-rich fuels such as sugar, Meyer's version converts water and carbon dioxide into oxygen, hydrogen and carbon monoxide—and the latter can be combined with hydrogen to eventually make a fuel such as methanol.