Catalyst-free upcycling of crosslinked polyethylene foams for CO2 capture

Recycling of crosslinked plastics is an intractable challenge due to their very limited amenability to mechanical reprocessing. While a variety of chemical recycling methods have been recently reported, these systems primarily focus on deconstructing or depolymerizing plastics to monomers and liquid fuels, which their subsequent use likely involves additional energy consumption and greenhouse gas emission. In this work, we present a simple, scalable, and catalyst-free method for directly converting crosslinked polyethylene (PE) foams into porous carbon materials. This process is enabled by sulfonation-based crosslinking, allowing the conversion of PE to become efficient carbon precursors, while retaining the high porosity feature from the foam precursors. Through two steps of sulfonation and carbonization, derived carbons contain a relatively high surface area and sulfur-doped framework. As a result, these materials can exhibit high CO 2 sorption capacity and CO 2 /N 2 selectivity. This work presents a viable pathway to address two grand-scale environmental challenges of plastic wastes and greenhouse gas emissions. Graphical abstract