Abstract:

Electrochemical reduction of CO₂ and CO can generate multicarbon products such as ethylene and ethanol, which are attractive as fuels and as synthetic precursors. However, the carbon–carbon bond-forming step that produces multicarbon products competes with pathways that terminate at single-carbon products. Water governs much of this competition through roles that extend well beyond that of an inert solvent. It solvates ions and thereby influences their adsorption at the electrode, hydrogen bonds to reaction intermediates, modulates access to active sites, and supplies protons or oxygen through its own dissociation. Despite considerable progress in electrolyte design, the relationship between the structure and properties of interfacial water and electrocatalytic reactivity remains largely empirical. This seminar will explore how deliberate manipulation of interfacial water, achieved by varying water activity and by using supporting ions to reorganize the structure of interfacial water, controls carbon–carbon coupling during CO₂ and CO electroreduction.