In July, we told you about how a professor at MIT has developed a cheaper, easier way to split water using solar energy. Now heâ€™s on the cover of the latest issue of MIT Technology Review, and is talking about how his new discovery is going to save the world.
His name is Daniel Nocera and he is a professor of chemistry. His method uses two electrodes, one of which is immersed in a solution of dissolved cobalt and phosphates. These ions collect on the electrode surface and form a catalyst which splits water around them. When water splits, it releases oxygen gas, and sends electrons through the circuit connecting the electrodes. At the other electrode, these electrons recombine with the hydrogen atoms (protons) from the original molecule to form hydrogen gas.
The best part is that the electric current can come from a photovoltaic panel. Thus, sunlight generates electricity, electricity (with the help of the catalyst) splits water into hydrogen and oxygen, and finally the hydrogen is stored for use as a fuel.
Nocera has been talking about his discovery in terms that are unusually rash for a scientist. "With this discovery, I totally change the dialogue," he said. "All of the old arguments go out the window." He believes that he has tapped into the power of photosynthesis and that we have finally harnessed it.
He may be right, but there are many who criticize him, especially for his apparent overconfidence. First of all, there is no new technology her, per se, other than the catalyst. We already know how to split water by running a current through it. Whatâ€™s more, Noceraâ€™s device has only a fraction of the water-splitting power found in a commercial electrolyzer. Some also suspect that going from sunlight to electricity to fuel, then back to electricity is a rather inefficient series of steps.
At the end of the day, though, if solar is going to take a significant place in our electricity generation, storage for off-peak hours will be top priority. And while we are making batteries better all the time, it doesnâ€™t hurt to explore options such as these as well.
written by Matt Simmons, October 27, 2008
written by gmoke, October 28, 2008
written by Green Products, October 28, 2008
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