Scientists and engineers around the world are working to find a way to power the planet using solar-powered fuel cells.
Such green systems would split water during daylight hours, generating hydrogen (H2) that could then be stored and used later to produce water and electricity. But robust catalysts are needed to drive the water-splitting reaction. Platinum catalysts are quite good at this, but platinum is too rare and expensive to scale up for use worldwide. Several cobalt and nickel catalysts have been suggested as cheaper alternatives, but there is still plenty of room for improvement. And no one has been able to determine definitively the mechanism by which the cobalt catalysts work, making it difficult to methodically design and construct improved catalysts.
Now chemists at the California Institute of Technology (Caltech) have determined the dominant mechanism for these cobalt catalysts. Their findings illuminate the road to the development of better catalysts -- even suggesting a route to the development of catalysts based on iron, an element that is plentiful and cheap and could offer part of the answer to our energy woes.
"We've worked out this mechanism, and now we know what to do to make a really great catalyst out of something that's really cheap as dirt," says Harry Gray, the Arnold O. Beckman Professor of Chemistry at Caltech and senior author of a paper that describes the findings in the current issue of the Proceedings of the National Academy of Sciences (PNAS). "This work has completely changed our thinking about which catalyst designs to pursue."
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