Electrochemical CO₂ Fixation and Release Cycle Featuring a Trinuclear Zinc Complex for Direct Air Capture

Abstract CO 2 capture technology can mitigate greenhouse gas emissions and global warming. CO 2 capture driven by electrochemical reactions is attractive because the operation is carried out at normal temperature and pressure and involves a simple input system using electrical energy. Although promising metal complexes with high CO 2 fixation performance have been reported, there are few studies on systems that combine electrochemical reactions and metal complexes. Here, we demonstrated stable CO 2 fixation‐release cycles using an electrochemical system with trinuclear Zn(II) complex (Zn 3 L ) as the CO 2 fixative and an ionic liquid as a supporting electrolyte for the stable operation. This system showed a faster CO 2 fixation rate than that of an aqueous alkaline solution at the same concentration. Continuous release and refixation of CO 2 were achieved by decomposition and reconstruction of the complex structure induced by H + and OH − supplied from a bipolar membrane equipped in the electrolytic cell. The CO 2 fixation‐release cycle was demonstrated even for dilute CO 2 (450 ppm) in air, where the CO 2 capture rate reached approximately 46 % of CO 2 contained in the air under an air flow condition of 200 mL ⋅ min −1 . This case, combining electrochemical drive and metal complexes, will provide a new option for CO 2 capture technology.