CO2 capture with catalytically upcycled polystyrene plastics

Here, we report the transition-metal-catalyzed post-functionalization of consumer polystyrene plastics using a gold-catalyzed bromination followed by a copper-catalyzed Ullmann-type C–N coupling to access self-supported solid amine CO 2 sorbents. The method enables selective control over the degree of functionalization and amine motifs, and it yields macroporous amine networks with up to 15 wt % nitrogen incorporation. The resulting materials display competitive CO 2 -capture performance under both flue gas and direct-air-capture conditions, with capacities up to 2.5 mmol g −1 at 25°C and excellent cyclability over 48 thermal swing cycles. Furthermore, the protocol was successfully demonstrated on a series of end-of-life polystyrene samples, including expanded polystyrene packaging and other single-use plastics, in order to showcase its robustness and broad applicability. We anticipate that this upcycling strategy will advance catalytic polymer amination methods and provide a sustainable route to next-generation CO 2 sorbents.