Integrated capture and solar-driven utilization of CO2 from flue gas and air
Sayan Kar, Motiar Rahaman, Virgil Andrei, Subhajit Bhattacharjee, Souvik Roy, Erwin Reisner
Abstract
Integration of carbon capture with utilization technologies can lead the way to a future net-zero carbon economy. Nevertheless, direct conversion of chemically captured CO 2 remains challenging due to its thermodynamic stability. Here, we demonstrate CO 2 capture from flue gas or air and its direct conversion into syngas using solar irradiation without any externally applied voltage. The system captures CO 2 with an amine/hydroxide solution and photoelectrochemically converts it into syngas (CO:H 2 1:2 [captured from concentrated CO 2 ], 1:4 [from simulated flue gas], and 1:30 [from air]) using a perovskite-based photocathode containing an immobilized molecular Co-phthalocyanine catalyst. At the anode, plastic-derived ethylene glycol is oxidized into glycolic acid over a Cu 26 Pd 74 alloy catalyst. The overall process uses flue gas or air as carbon source, discarded plastic waste as an electron donor, and sunlight as the sole energy input. This strategy opens new avenues for future carbon-neutral or even negative solar fuel and waste upcycling technologies.