(67c) Exploring How Collective Ionic Assembly Influences Electrochemical Carbon Dioxide Upgrading

Electrochemical reduction of CO₂ to CO, CH₄, and other value-added products provides compelling opportunities to realize a closed anthropogenic carbon cycle. While increasingly demonstrated in lab-scale electrolyzers, a critical roadblock facing the design of industrial processes is a poor understanding of how molecular assembly at electrode-electrolyte interfaces contributes to catalytic activity. Over the last decade, ionic liquids have emerged as promising CO₂ reduction electrolytes, since low overpotentials and enhanced product selectivity has been observed for several classes of ionic liquids. However, the mechanisms of ionic liquid-mediated catalysis remain subject to ongoing discussion. Here, we present our research on tuning the collective assembly of ionic liquids to understand the mechanism of ionic liquid-mediated CO₂ reduction at silver, copper, and carbon electrodes. By changing ionic liquid structures, concentrations, and solvent environments, we reveal unexpected non-monotonic scaling relationships between structure, concentration, and reactivity. Notably, these findings point to collective assembly as a key factor underpinning structure-reactivity relationships for CO₂ electro-reduction. To highlight the impact of this concept, we will show how our findings help resolve a mechanistic puzzle in the ionic liquids electrocatalysis community and suggest new strategies for controlling the performance of CO₂ electrochemical upgrading.