Electrifying amine carbon capture with robust redox-tunable acids

Electrochemically mediated carbon capture presents an energy-efficient and cost-effective strategy to combat climate change due to its ability to utilize renewable energy and operate at ambient conditions. However, many current approaches suffer from operational instability and limited scalability potential due to a lack of reliable, low-cost redox-active absorbent materials. Here, we introduce a class of chemically robust and economical redox-tunable Brønsted acids to electrify amine carbon capture. The redox-tunable acids exhibit a reversible tunability in pKa spanning over 20 units in organic solvents in response to electrochemical potential, thereby enabling the regeneration of classic amines for CO2 separation via proton-coupled electron transfer. Remarkably, the RAs maintain their chemical integrity for over 400 h of operation in a symmetric carbon capture flow cell under 10% CO2 and 21% O2 at ambient temperature and pressure. By harnessing electrification, our approach can effectively mitigate shortcomings inherent to thermochemical carbon capture processes, facilitating a more sustainable drop-in replacement for incumbent amine scrubbing. Electrochemically mediated CO2 capture is a developing alternative to conventional temperature and pressure-swing processes but faces challenges of stability and selectivity. Here, authors develop redox-tunable Brønsted acids to enable electrochemical CO2 capture in nonvolatile organic solvents.