Topic: Design of Molecular Electrocatalysts for the Production and Oxidation of Hydrogen
Speaker: Professor Morris Bullock - Pacific Northwest National Laboratory
Host: Professor Tom Hamann
Date: Monday, February 11, 2019
Time: 11:20 AM
Location: 136 CEM
Solar and wind are carbon-neutral, sustainable energy sources, but because they are intermittent, reliable energy storage is needed. Catalysts that efficiently interconvert between electrical energy and chemical bonds (fuels) are needed for sustainable, secure energy. Electrocatalysts based on inexpensive, earth-abundant metals (“Cheap Metals for Noble Tasks”) are needed. Ni complexes with “P2N2” ligands have been studied in our lab; these diphosphine ligands have pendant amines that function as proton relays, facilitating proton mobility. The crucial role of controlled structural dynamics is recognized for many enzymes, but is seldom used in synthetic catalysts. Appending long alkyl chains in the outer coordination sphere of the catalyst leads to slower structural dynamics of the ligand, with the turnover frequency increasing by orders of magnitude as the conformational dynamics become slower. Controlling all of the system components reverses the trade-off normally encountered between rates and overpotentials, providing design principles for multi-electron, multi-proton reactions.