Invited: Approaching Hydrogenase-like Performance with Molecular Electrocatalysts for H2 Production

Wednesday, 31 May 2017: 10:40
Durham (Hilton New Orleans Riverside)
E. S. Wiedner, C. M. Klug, A. J. Cardenas, M. O'Hagan, A. M. Appel, and M. Bullock (Pacific Northwest National Laboratory)
Hydrogenase enzymes mediate the electrochemical production of H2 at fast rates (>9,000 s–1) and low overpotentials (<100 mV). Synthetic nickel(II) complexes containing diphosphine ligands with pendant amines can catalyze the production of H2 at rates that exceed the hydrogenase enzyme, but typically exhibit much larger overpotentials. Recent efforts from our group have focused on designing new nickel catalysts that produce H2 with rates and overpotentials that are comparable to hydrogenase enzymes, which requires controlling multiple aspects of the catalyst structure and function. This talk will describe the individual and combined effects of (1) incorporating electron withdrawing groups at phosphorus, (2) preventing formation of inactive exo-pinched isomers through control of ligand structural dynamics, and (3) matching the solution pH to the basicity of the pendant amines in the catalyst.