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 surface 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.

Cooperative ionic assembly governs carbon dioxide electrolysis in ionic liquid electrolytes

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.