Daniel Nocera - Highly efficient oxygen catalyst found
New catalyst, made of inexpensive and
abundant materials, could prove useful in
rechargeable batteries and hydrogen-fuel
David L. Chandler, MIT News Office
October 28, 2011
A team of researchers at MIT has found one of the
most effective catalysts ever discovered for splitting
oxygen atoms from water molecules — a key
reaction for advanced energy-storage systems,
including electrolyzers, to produce hydrogen fuel and
rechargeable batteries. This new catalyst liberates
oxygen at more than 10 times the rate of the best
previously known catalyst of its type.
The new compound, composed of cobalt, iron and
oxygen with other metals, splits oxygen from water
(called the Oxygen Evolution Reaction, or OER) at a
rate at least an order of magnitude higher than the compound currently considered the gold standard for such
reactions, the team says. The compound’s high level of activity was predicted from a systematic experimental
study that looked at the catalytic activity of 10 known compounds.
The team, which includes materials science and engineering graduate student Jin Suntivich, mechanical
engineering graduate student Kevin J. May and professor Yang Shao-Horn, published their results in Science on
The scientists found that reactivity depended on a specific characteristic: the configuration of the outermost
electron of transition metal ions. They were able to use this information to predict the high reactivity of the new
compound — which they then confirmed in lab tests.
“We not only identified a fundamental principle” that governs the OER activity of different compounds, “but also
we actually found this new compound” based on that principle, says Shao-Horn, the Gail E. Kendall (1978)
Associate Professor of Mechanical Engineering and Materials Science and Engineering.
Many other groups have been searching for more efficient catalysts to speed the splitting of water into hydrogen
and oxygen. This reaction is key to the production of hydrogen as a fuel to be used in cars; the operation of some
rechargeable batteries, including zinc-air batteries; and to generate electricity in devices called fuel cells. Two
catalysts are needed for such a reaction — one that liberates the hydrogen atoms, and another for the oxygen
atoms — but the oxygen reaction has been the limiting factor in such systems.
Other groups, including one led by MIT’s Daniel Nocera, have focused on similar catalysts that can operate — in
a so-called “artificial leaf” — at low cost in ordinary water. But such reactions can occur with higher efficiency in
alkaline solutions, which are required for the best previously known catalyst, iridium oxide, as well as for this new
Shao-Horn and her collaborators are now working with Nocera, integrating their catalyst with his artificial leaf to
produce a self-contained system to generate hydrogen and oxygen when placed in an alkaline solution. They will
also be exploring different configurations of the catalyst material to better understand the mechanisms involved.
Their initial tests used a powder form of the catalyst; now they plan to try thin films to better understand the reactions.
In addition, even though they have already found the highest rate of activity yet seen, they plan to continue
searching for even more efficient catalyst materials. “It’s our belief that there may be others with even higher
activity,” Shao-Horn says.
Jens Norskov, a professor of chemical engineering at Stanford University and director of the Suncat Center for
Interface Science and Catalysis there, who was not involved in this work, says, “I find this an extremely
interesting ‘rational design’ approach to finding new catalysts for a very important and demanding problem.”
The research, which was done in collaboration with visiting professor Hubert A. Gasteiger (currently a professor
at the Technische Universität München in Germany) and professor John B. Goodenough from the University of
Texas at Austin, was supported by the U.S. Department of Energy’s Hydrogen Initiative, the National Science
Foundation, the Toyota Motor Corporation and the Chesonis Foundation.