(585a) Exploring How Collective Ionic Assembly Influences Electrochemical Carbon Dioxide Upgrading

The electrochemical reduction of CO₂ to CO, CH₄, and other value-added products provides compelling avenues for closing the anthropogenic carbon cycle. However, an insufficient understanding of how molecular assembly at electrode-electrolyte interfaces contributes to catalytic activity is a major roadblock to designing industrial-scale processes. Over the last decade, ionic liquids have emerged as leading CO₂ reduction electrolytes. Despite the low overpotentials and enhanced product selectivity observed in several classes of ionic liquids, the mechanism of ionic liquid-mediated catalysis remains unclear. Here, we present our research on tuning the collective assembly of ionic liquids at the electrode-electrolyte interface to understand the reaction mechanism at silver electrodes. By changing the ionic liquid structures, concentrations, and solution environments, we reveal unexpected non-monotonic reactivity with changing ionic liquid concentration that spans ionic liquid structures. Notably, these findings point to collective assembly as a main factor that underpins structure-reactivity relationships for CO₂ electroreduction in three key concentration regimes. To highlight the impact of this concept, we will show how our findings add nuance to a mechanistic puzzle surrounding the role of carbenes in the ionic liquid electrocatalysis community and suggest new strategies for controlling the performance of CO₂ electrochemical upgrading.