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JCAP Special Seminar

Friday, October 18, 2013
12:00pm to 1:30pm
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Spalding Laboratory 106 (Hartley Memorial Seminar Room)
Quantum Mechanical Insights into Photoelectrochemical CO2 Reduction Processes
John A. Keith, Assistant Professor and R.K Mellon Faculty Fellow, Energy Department of Chemical and Petroleum Engineering, Swanson School of Engineering, University of Pittsburg,

Catalytic processes that efficiently and selectively reduce CO2 into chemicals and liquid fuels must be developed to ensure future energy sustainability. Two of the most promising reactions known to date are a) Re(bpy)CO3Cl catalyzed CO2 reduction to CO and b)pyridinium-catalyzed selective CO2 reduction to methanol on GaP photoelectrodes. Improvements to both processes necessitate broader and deeper understanding of their atomic scale reaction mechanisms. Recent quantum chemistry calculations provide insight that elucidate and clarify several notable issues. For a), we report a complete electrocatalytic mechanism that is fully consistent with experiment and explains the unique performance of this catalyst. By discussing how catalyst modifications influence the entire reaction process, we provide key details how to further improve this chemistry for widespread use. For b) we provide strong evidence that the active catalyst is not a solution phase pyridinyl radical as has been widely assumed, but rather a surface-bound molecular species that intriguinglyshares a similar moiety as other biological redox catalysts found ubiquitously in nature. We discuss our calculations modeling pyridine's electrochemical reactivities undervarying reaction conditions in solution and on GaP photoelectrode surfaces in the context of information gleaned from experiments. 

 

For more information, please contact Oana Luca by phone at 626-395-1570 or by email at oana.luca@caltech.edu.