Daniel G. Nocera

Daniel George Nocera (born July 3, 1957) is an American chemist. He is the the Henry Dreyfus Professor of Energy and Professor of Chemistry at the Massachusetts Institute of Technology. He is best known for his and Matthew Kanan's breakthrough discovery in 2008 of a highly efficient technique for electrolysis of water using inexpensive materials. Earlier, he was well known for his studies of the basic mechanisms of energy conversion in biology and chemistry, particularly in the theory of proton coupled electron transfer. He is also the director of the Solar Revolution Project at MIT which seeks to create innovations towards the use of solar energy in large scale, mainstream applications.

Self healing electrocatalyst discovery

Hydrogen has been worked on in the past as an electrical power storage medium, but prior approaches relied on conventional electrolysis which can lose 30% to 50% of the energy, rendering the approach impractical. Nocera and Kanan's innovation is important because much less energy is lost during conversion, opening the way for inexpensive storage of energy generated from wind or photovoltaic solar cells. His discovery of an effective and inexpensive electrocatalyst has been long sought after, and Nocera used an entirely novel approach, building on his prior work in condensed matter physics. The general social problem being addressed is that while alternative energy sources such as wind, wave and solar are now economically competitive with traditional sources, most suffer from a weakness that prevents them from entirely replacing other sources. Without efficient and low cost energy storage for electricity, their intermittent nature limits their use for base load power generation. Winds die down, the sea becomes calm, night falls just as electrical demand peaks. What this discovery promises for solar and other alternatives is that excess solar power can be used to generate hydrogen and oxygen for storage instead of expensive and limitted life batteries. In a hydrogen storage scheme, when the sun goes down, a fuel cell converts the hydrogen and oxygen back into electricity. Karsten Meyer, a professor of chemistry at Friedrich Alexander University, in Germany said that for solar power, "this is probably the most important single discovery of the century."

While an important hurdle has been crossed, more work remains before the approach is commercially viable. The recent breakthrough addressed the more difficult problem of splitting oxygen away with an electrocatalyst using earth abundant materials. The hydrogen electrode used platinum, but John Turner, a principal investigator at the National Renewable Energy Laboratory stated, "Finding a cheaper catalyst for making hydrogen shouldn't be too difficult". The second area of research concerns improving the rate at which the catalyst works.

Critics of the scheme point out that due to the 40% inefficiency of fuel cells in practical operation, and losses due to storage of the gases, the round trip from electricity to hydrogen/oxygen back to electricity will result in losses of up to 3 kilowatt-hours of energy for every 4 put in. This is much worse than lithium-ion batteries which are 80% efficient. Advocates respond that the first advantage over batteries is that storage is virtually unlimited, a factor that is important for grid energy storage scenarios where energy generation might not resume for days or longer. The second advantage is that batteries wear out with a high cost of replacement whereas the process described by Nocera is self healing- a phenomenon that suggests that there are negligible replacement or maintenance costs. Lastly, for transportation applications in which hydrogen is produced as the energy carrier rather than electricity, refueling is as fast as gasoline, whereas battery recharging of plug-in hybrids can take several hours or require a cumbersome battery swapping scheme.

The process may also have desalination uses because it can be used with salt water, producing fresh water as a biproduct of the process. Because the process works at very small scales, it has applications for integration into photoelectrochemical cells that produce hydrogen rather than electricity. Regardless of the usefulness for near term applications, the overall goal of Kanan and Nocera is not simply to make electrolysis more efficient, but to perform all functions needed for artificial photosynthesis. That is, instead of the power coming from the solar panels, energy would be captured directly by a photochemical process and transferred directly to the electrocatalyst process.

Background

Nocera received his B.S. in chemistry in 1979 with highest honors from Rutgers University where he was a Rutgers scholar. He earned his PhD from the California Institute of Technology in 1984 where he worked under Professor Harry B. Gray studying the spectroscopy, electrochemistry, and photochemistry of polynuclear metal-metal bonded complexes. He began his independent career the same year at Michigan State University where he was promoted to full professor in 1990. In 1997, he joined the faculty of MIT where he holds his current position.

Awards and honors

• 1979 — American Institute of Chemists Award
• 2005 — Italgas Prize
• 2005 — Elected to the American Academy of Arts and Sciences
• 2006 — Inter-American Photochemistry Prize

Innovations

• Construction of the first S = 1/2 kagome lattice, regarded as a significant achievement in the field of condensed matter physics. His work in layered kagome lattices is useful for the study of layered ferromagnetism and antiferromagnetism.
• First microfluidic optical chemosensor
• Invention of the Molecular tagging velocimetry (MTV) technique
• First direct observation of the zwitterionic excited state DOI: 10.1126/science.265.5173.759
• Hydrogen gas production from acidic solutions using a Rhodium photocatalyst. DOI: 10.1126/science.1062965

Publications

• Wishart, James F. (1998). Photochemistry and Radiation Chemistry (Advances in Chemistry Series). American Chemical Society. ISBN 978-0841234994. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
• Over 200 research papers

See also

• MIT Chemistry Department

External links

• Nocera at the MIT Chemistry Department Website
• MIT Chemistry Department
• Nocera Group Website