Zwitterionic carbamate interfaces unlock efficient "liquid" CO<sub>2</sub> upgrading.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 42127179.
- Also identified by DOI 10.1126/sciadv.aed8640 and PMC identifier 13170645.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Integrating carbon dioxide (CO<sub>2</sub>) capture with its direct electrochemical conversion remains a major challenge for sustainable energy technologies. Although amine scrubbing is widely used for CO<sub>2</sub> capture, its integration with electrochemical reduction is often inefficient due to poor mass transport and limited reactivity of captured CO<sub>2</sub> species. Here, we report an integrated capture-conversion platform that enables direct electrolysis of amine-captured CO<sub>2</sub> in liquid carbamate solutions. Screening structurally related amines identifies piperazine (PZ) as an effective capture agent that forms stable, highly concentrated carbamate species. When combined with a nickel-based catalyst and a designed gas-liquid-solid interface, the system enables efficient liquid-phase CO<sub>2</sub> conversion, achieving up to 60% Faradaic efficiency for carbon monoxide (CO) and providing the first quantitative verification of carbamate participation (~40%). In a scaled electrolyzer (9 cm<sup>2</sup>), rapid CO<sub>2</sub> capture and release kinetics enable CO Faradaic efficiencies of 30 to 45% and energy efficiencies of ~15 to 25% under ambient conditions, with stable operation over 150 hours.