Non-aqueous alkoxide-mediated electrochemical carbon capture

Abstract

Electrochemically mediated carbon capture utilizing redox-tunable organic sorbents has emerged as a promising strategy to mitigate anthropogenic carbon dioxide emissions. However, most reported systems are sensitive to molecular oxygen, severely limiting their application under ambient air conditions. Here we demonstrate an electrochemical carbon capture concept via non-aqueous proton-coupled electron transfer, where alkoxides are employed as the active sorbent while carbon dioxide absorption and desorption are modulated reversibly by the redox-tunable Brønsted basicity of certain organic molecules. Since all species involved in the process have outstanding oxygen stability and relatively low vapour pressure, our electrochemically mediated carbon capture mechanism intrinsically minimizes parasitic reactions and evaporative losses under aerobic conditions. Flow-based prototypes are demonstrated to operate efficiently in the presence of 20% oxygen under various practically relevant carbon dioxide feed concentrations, paving a way towards effective carbon capture driven by electrochemical stimuli. Sensitivity to O2 hinders the application of some electrochemically mediated carbon capture technologies under ambient air conditions. Here the authors report electrochemical CO2 capture via non-aqueous proton-coupled electron transfer, employing alkoxides as active sorbents, in which all species involved are highly air stable.