Dr Simone Raugei
Pacific Northwest National Laboratory, Richland WA(USA)
Monday, September 9th, 2013 at 11:00:00 AM
Conference room Querzoli - LENS - via Nello Carrara 1 - Sesto Fiorentino (Florence)
Published on-line at 10:22:37 AM on Tuesday, September 3rd, 2013
Rational Design of Molecular Electrocatalysts for Production of H2 and Oxidation of H2
Recent advances in Ni-based bio-inspired catalysts obt ained in the Energy Frontier Research Center (EFRC) for Molecular Electrocatalysis at the Pacific
Recent advances in Ni-based bio-inspired catalysts obt ained in the Energy Frontier Research Center (EFRC) for Molecular Electrocatalysis at the Pacific Northwest National Laboratory demonstrated the possibility of cleaving H2 or generating H2 with efficiency superior to that of hydrogenase enzymes.
In these catalysts the transformation between H 2 and protons proceeds via an interplay between proton, hydride and electron transfer steps and involves the interaction of a dihydrogen molecule with both a Ni(II) center and with pendant amine bases incorporated in a six-membered ring, whi ch act as proton relays.
By using ab initio molecular dynamics ,free energy calculations and microkinetic modeling, we have carried out an exhaustive characterization of these molecular catalysts. It will be shown that the metal center and the pendant amine act as a frustrated Lewis acid/base pairs, making the heterolytic H 2 bond cleavage or formation facile processes. A detailed microkinetic modeli ng of the catalytic cycle reveals the importance of precisely controlled delivery of protons to avoid catalytically inefficient pathways. Toward the rational design of catalysts with optimal rates and overpotentials, we are devel oping linear free energy rel ationships, based on extensive ab initio thermodynamic and kinetic data, to be employed in a theoretically driven refinement of catalysts using macrokinetic analysis.
This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science,Office of Basic Energy Sciences.
For further informations, please contact Prof. Roberto Righini.
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