Poly(ionic liquid)s for Photo-Driven CO 2 Cycloaddition: Electron Donor-Acceptor Segments Matter.

CO 2 cycloaddition with epoxides is a key catalytic procedure for CO 2 utilization. Several metal-based catalysts with cocatalysts are developed for photo-driven CO 2 cycloaddition, while facing difficulties in product purification and continuous reaction. Here, poly(ionic liquid)s are proposed as metal-free catalysts for photo-driven CO 2 cycloaddition without cocatalysts. A series of poly(ionic liquid)s with donor-acceptor segments are fabricated and their photo-driven catalytic performance (conversion rate of 83.5% for glycidyl phenyl ether) outstrips (≈4.9 times) their thermal-driven catalytic performance (17.2%) at the same temperature. Mechanism studies confirm that photo-induced charge separation is promoted by the donor-acceptor segments and can accelerate the CO 2 cycloaddition reaction. This work paves the way for the further use of poly(ionic liquid)s as catalysts in photo-driven CO 2 cycloaddition.