Designing selective catalysts for low overpotential CO2 reduction

Abstract:
A critical challenge in electrocatalytic CO2 reduction to renewable fuels is product selectivity. Desirable products of CO2 reduction require proton equivalents, but key catalytic intermediates can also be competent for direct proton reduction to H2. Understanding how to manage divergent reaction pathways at these shared intermediates is essential to achieving high selectivity. Both proton reduction to hydrogen and CO2 reduction to formate generally proceed through a metal hydride intermediate. I will describe thermodynamic relationships that describe the reactivity of metal hydrides with H+ and CO2 to generate a thermodynamic product diagram, which outlines the free energy of product formation as a function of proton activity and hydricity (∆GH−), or hydride donor strength. The diagram outlines a region of metal hydricity and proton activity in which CO2 reduction is favorable and H+ reduction is suppressed. I will describe how we use thermodynamic criteria to achieve reversible CO2/HCO2− conversion catalyzed by [Pt(depe)2]2+ (depe=1,2‐bis(diethylphosphino)ethane). Direct measurement of the free energies associated with each catalytic step correctly predicts a slight bias towards CO2 reduction. I will demonstrate how the experimentally measured free energy of each step directly contributes to the <50 mV overpotential.

Education and Training:

2007-2009: Postdoctoral Fellow, Institute for Interfacial Catalysis, Pacific Northwest National Laboratory, Richland, WA. Advisor: Dr. Daniel L. DuBois

2007: Ph.D. Inorganic Chemistry, Massachusetts Institute of Technology, Cambridge, MA. Advisor: Professor Daniel G. Nocera

2001: B.S. Chemistry, University of California, Berkeley. Advisor: Professor Jeffrey Long

Research:

Jenny’s research interests include the discovery and study of inorganic electrocatalysts for the generation and utilization of chemical fuels. Current and prior research includes oxygen activation, hydrogen production and oxidation, and carbon dioxide reduction. These studies have primarily focused on the effect of bio-inspired secondary coordination sphere interactions and the effect of thermochemical properties on catalytic activity.

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