Cobalt catalysts for simple water splitting

May 07, 2010

(PhysOrg.com) -- Researchers from UC Davis and the Massachusetts Institute of Technology are studying how a simple cobalt catalyst can split water molecules. Such inexpensive catalysts could one day be used to convert sunlight into fuel that can run domestic fuel cells.

In 2008, MIT chemists, led by Professor Dan Nocera, reported that a simple cobalt catalyst could split water at neutral pH to produce oxygen, protons and electrons. The catalyst actually seems to assemble itself over several hours as an electric current is applied, and then begins to bubble oxygen.

"This got a lot of attention from the chemistry community, but no one knew how it worked," said R. David Britt, professor of chemistry at UC Davis.

Britt's lab is working with Nocera's group to use a technique called electron paramagnetic resonance to study the chemical state of cobalt atoms in the catalyst. They found that as more water is split, the proportion of cobalt (IV) increases and the proportion of cobalt (II) decreases. The work opens the door to further studies on these catalysts, the authors write.

Ultimately, catalysts based on relatively abundant elements like cobalt, as opposed to platinum or gold, could make it economical to convert electricity from solar panels or other renewable sources into for storage or use. The protons and electrons produced from would be used in the next step of the process to make hydrogen.

Electron paramagnetic resonance is a technique similar to the used in medical imaging. Britt's lab uses it to study catalysts that split water, including both artificial catalysts and those used by plants in photosynthesis.

"Plants figured this out a couple of billion years ago," Britt said.

A paper describing the work is published online this month by the . Other authors on the paper are graduate student J. Gregory McAlpin, postdoctoral researcher Troy Stich and chemistry professor William Casey, all at UC Davis; and at MIT, graduate student Yogesh Surendranath and postdoctoral researchers Mircea Dinca and Sebastian Stoian.

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labtvonline
not rated yet May 07, 2010
I think that the need for this technology is obviously a pressing concern for the energy demands of our world. I know of a few different but similar techniques of splitting water and often the primary concern is the cost of the catalyst. I know the main substance being used currently is platinum, which is really expensive. I saw an article the other day about new compound that could do it as well, i forgot the name, but it was much cheaper like $29/ounce. I also saw a video the other day that had scientists using aluminum nano-particles as a catalyst. I'll post a link if you would like to see it for yourself. They seemed pretty high on the idea in the video. This would finally provide a safe way for the local storage of hydrogen gas.

http://www.ndep.u...dd-water
dirk_bruere
not rated yet May 07, 2010
It's important to point out that this catalyst does not split water on it own to provide "free energy". It increases the efficiency with which water is split by electricity.
Sonhouse
not rated yet May 07, 2010
It's important to point out that this catalyst does not split water on it own to provide "free energy". It increases the efficiency with which water is split by electricity.

Does anyone know the efficiency rating of this new catalyst? I remember a 9th grade experiment where we did electrolysis on brine, and it was about 3% efficient using brute force electricity. Anyone know what they are up to with these new catalysts?
Alizee
May 08, 2010
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