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.