Continuous carbon capture and release using an aqueous oxygen-tolerant redox electrolyte in symmetric flow cells
Year: 2026
Type: preprint
Abstract: Electrochemical CO2 capture provides a promising pathway for carbon management under ambient conditions, yet practical deployment remains limited by system complexity and energy losses associated with oxygen sensitivity, crossover, and overpotentials. Here we report a fluoflavine disulfonate (FFDS)-based symmetric flow reactor for continuous electrochemical CO2 capture. The symmetric configuration generates spatially separated alkaline catholyte and acidic anolyte through a proton-coupled electron transfer process, enabling simultaneous electrochemical regeneration of sorbent, CO2 absorption as (bi)carbonate, and CO2 release. The system demonstrates excellent stability and high oxygen tolerance under simulated flue gas conditions. Furthermore, the CO2 release rate can be regulated by varying the applied current density. Proton crossover is identified as a parasitic transport pathway that compromises energy efficiency. Its impact can be mitigated through buffer regulation and ultimately eliminated by using an industrial packed column to maximize gas–liquid contact. An isolated dual-loop cycling mode further enables simultaneous CO2 capture and release throughout charge–discharge cycling, improving electron utilization under pure-CO2 release conditions. A preliminary techno-economic analysis identifies electricity consumption as the dominant cost contributor, while the cost associated with the redox-active molecule is negligible. Overall, this work establishes a compact, modular, plug and play symmetric electrochemical platform for continuous CO2 enrichment under near-practical operating conditions.
Source: ChemRxiv
Language: English
Subfield: Filtration and Separation
Field: Chemical Engineering
Domain: Physical Sciences
Open Access status: green
Funder: National University of Singapore
Award: G4070917339
OpenAlex ID: W7214099397