A universal photothermal recycling strategy for post-consumer plastics using bio-derived porous carbon

Chemical recycling of plastics into monomers offers a promising strategy for addressing global plastic pollution. However, most chemical recycling methods are limited to specific polymers. Pyrolysis offers generality for universal polymer recycling; however, overheating leads to energy inefficiencies and degradation products, which limits its practicality. Herein, we report a photothermal depolymerization approach that is general to numerous polymers with high selectivity. Distinct from previous approaches, we identify a porous carbon material derived from proteins as a high-surface-area photothermal agent that does not require direct incorporation into polymer resin. Using low carbon loadings, we successfully depolymerize a wide range of polymers, including polystyrene (PS), poly(methyl methacrylate) (PMMA), poly(vinyl acetate) (PVAc), poly(vinyl alcohol) (PVA), trans-polyisoprene, poly(propylene carbonate) (PPC), poly(L-lactide) (PLLA), poly(ethylene terephthalate) (PET), and bisphenol-A polycarbonate (BPA-PC). Additionally, the porous carbon material is reusable at least five times by sequentially adding polystyrene films to the post-reacted porous carbon materials. Excitingly, this method is broadly applicable to post-consumer plastics without preprocessing and is readily scalable, demonstrating the versatility of this closed-loop chemical recycling approach. Chemical recycling of plastics into monomers can be a promising strategy for plastic pollution, but techniques such as pyrolysis can lead to energy inefficiencies and degradation products. Here the authors report a photothermal depolymerization approach that can be applied to a wide variety polymer with high selectivity.