Simultaneous CO₂ Capture and Conversion From Flue Gas Using Bicarbonate Electrolysis Over a Nickel Single-Atom...

Capturing CO₂ from flue gas and converting it electrochemically into valuable chemicals represents an appealing approach to mitigate CO₂ emissions and realize carbon recycling. Currently, these two processes are usually performed sequentially, which is energy-intensive and involves multiple operational steps. Here, a simultaneous route is reported for capturing and electrochemically converting CO₂ from flue gas without interruption, mediated by bicarbonate electrolysis. The electrochemical conversion of bicarbonate solution, catalyzed by a Ni single-atom catalyst, is unaffected by O₂ and residual NO and SO₂ impurities, commonly found in flue gas. This enables the simultaneous capture and conversion of CO₂ from flue gas into CO without the need to remove these gas components. Mechanistic studies reveal that CO₂ from flue gas is first captured by basified electrolyte and then electrochemically converted. The simultaneous system operates stably for at least 120 h, achieving a CO₂ capture and utilization efficiency of 60%, producing >20000 mL of syngas with a H₂/CO ratio of ≈3, and reducing energy consumption by 25% compared to the sequential route. This simultaneous route exhibits significant advantages, including simplified operation, enhanced stability, and reduced energy consumption, thereby opening a promising avenue for direct valorization of diluted CO₂ in flue gas.