Prof. Sharon Hammes–Schiffer, John Gamble Kirkwood Professor of Chemistry, Yale University, will deliver this year’s Almlöf–Gropen Lecture:
Proton-Coupled Electron Transfer in Catalysis and Energy Conversion
Professor Hammes–Schiffer’s research centres on the development and application of theoretical and computational methods for describing chemical reactions in condensed phases and at interfaces. Her research is pursued in three areas: proton-coupled electron transfer reactions, enzymatic processes, and non-Born-Oppenheimer electronic structure methods, aiming to elucidate the fundamental physical principles underlying charge transfer processes and catalysis.
Professor Hammes–Schiffer has published over 340 papers and has received numerous awards for her work, including the Dirac Medal of the International Academy of Quantum Molecular Sciences. She is a member of the American Academy of Arts and Sciences, National Academy of Sciences, and American Association for the Advancement of Science.
Abstract: Proton-Coupled Electron Transfer in Catalysis and Energy Conversion
Proton-coupled electron transfer (PCET) reactions play a vital role in a wide range of chemical and biological processes. In these reactions, an electron and a proton move in a coupled manner, often between different donors and acceptors, and could move in the same or different directions. Moreover, PCET reactions may be sequential or concerted and could involve multiple electrons and protons. A general theory has been developed to describe all of these types of PCET reactions and has been applied to PCET in solution, proteins, nanoparticles, and electrochemical systems. This general PCET theory includes the quantum mechanical effects of the active electrons and transferring proton(s), as well as the motions of the proton donor-acceptor mode and solvent or protein environment. This theory has assisted in the interpretation of experimental data and has provided experimentally testable predictions.
This talk will summarize the key elements of this PCET theory and will present a variety of applications to catalysis and energy conversion. Applications to PCET in enzymes, molecular electrocatalysts for hydrogen production and water splitting, artificial photosynthesis, metal-oxide nanocrystals, proton discharge on a metal electrode, and photoreceptor proteins will be discussed. These studies have identified the thermodynamically and kinetically favorable mechanisms, as well as the roles of proton relays, excited vibronic states, hydrogen tunneling, reorganization, and conformational motions. The resulting insights are guiding the design of more effective catalysts and energy conversion devices.