Chemistry Seminar: Artificial Enzymes for Energy Conversion

Artificial Enzymes for Energy Conversion

Dr. Kara Bren
Professor
Department of Chemistry
University of Rochester

Dr. Bren will present on the catalytic activity of mini-proteins and metallopeptides as electrocatalysts and in photocatalytic systems for hydrogen production.

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Abstract:
In Nature, hydrogen production is catalyzed by complex enzymes harboring multiple metallocofactors. In our group, we are developing small metalloproteins and metallopeptides as functional mimics of Nature’s hydrogenases. In this talk, the catalytic activity of mini-proteins and metallopeptides as electrocatalysts and in photocatalytic systems for hydrogen production will be described. These catalysts are notable for functioning in water near neutral pH and producing the desired products at high faradaic yields. Mechanistic studies of electrocatalysis reveal the specific roles played by water and by buffering agents in proton transfer to catalysts. Furthermore, we find that buffer pKa and sterics profoundly impact the rate and mechanism of these reactions in water. By pairing these catalysts with photosensitizers, we demonstrate their use in the storage of light energy as H2. Analysis of photocatalytic activity reveals that these artificial enzymes are robust, with system longevity primarily limited by the photosensitizer. Thus, despite their high overpotentials and fast degradation as electrocatalysts, these catalysts show high robustness and activity in photocatalytic systems for visible light-driven H2 production.

Speaker Bio:
Kara Bren was born in Minneapolis, Minnesota, USA. She earned her BA in chemistry at Carleton College in Minnesota in 1991, and her PhD at Caltech under Harry Gray’s supervision in 1996. After a postdoc at UC Davis in the lab of Gerd LaMar, she joined the faculty at the University of Rochester in 1997. In 2008, she was promoted to the rank of Professor. At Rochester, Kara is the Program Director for an NIH Chemistry-Biology Interface Predoctoral Training Program. Kara also is an American Association for the Advancement of Science Fellow, a Kavli Fellow of the National Academy of Sciences, and an Associate Editor for the Journal of the American Chemical Society.

Intended Audience:
All are welcome.
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