Promoting Amine-Activated Electrochemical CO2 Conversion with Alkali Salts

Amine-based CO2 chemisorption has been a longstanding motif under development for CO2 capture applications, but large energy penalties are required to thermally cleave the N-C bond and regenerate CO2 for subsequent storage or utilization. Instead, it is attractive to be able to directly perform electrochemical reactions on the amine solutions with loaded CO2. We recently found that such a process is viable in dimethyl sulfoxide (DMSO) if an exogenous Li-based salt is present, leading to formation of CO2-derived products through electrochemical N-C bond cleavage. However, the detailed influence of the salt on the electrochemical reactions was not understood. Here, we investigate the role of individual electrolyte salt constituents across multiple cations and anions in DMSO to gain improved insight into the salt’s role in these complex electrolytes. While the anion appears to have minor effect, the cation is found to strongly modulate the thermochemistry of the amine-CO2 through electrostatic interactions: ...