Sustainable Electrochemical CO₂ Capture from Air Using Heterogenized Quinones in Aqueous Media

The urgent need to mitigate rising carbon dioxide (CO2) emissions necessitates the development of innovative and sustainable carbon capture technologies. This study introduces a dual-electrode electrochemically mediated CO2 capture system, employing the heterogenization of the redox-active polymerized benzodithiophene quinone (PBDT-Q) immobilized onto carbon nanotubes (CNTs) to form a PBDT-Q/CNT composite. The heterogenization improves the composite’s structural stability, conductivity, and enabling prolonged operation in an environmentally friendly aqueous medium. We initiated a systematic evaluation with a bulk electrolyzer, demonstrating efficient CO2 capture and release. Subsequently, we expanded the investigation to a flow-cell system tested with a simulated flue gas mixture containing 13 vol % CO2 and 3.5 vol % O2. The flow-cell system maintained stable performance over 68 cycles spanning 150 h, achieving an average capture rate of approximately 0.21 mmol CO2 per cycle. These results underscore the scalability and real-world potential of dual-electrode heterogenized quinone-based electrocatalysts, offering a sustainable pathway to advance carbon capture technologies.