Converting poly(ethylene terephthalate) waste into N-doped porous carbon as CO_(2) adsorbent and solar steam generator

Sustainable conversion of waste plastics into valuable carbon materials for diverse applications provides a promising strategy to dispose the municipal and industrial waste plastics.However,it remains a challenge to precisely control the crosslinking reaction for transforming waste polyesters into N-doped porous carbon (NPC) with well-defined microstructures.Herein,we put forwards a strategy of stepwise crosslinking using melamine and ZnCl_(2)/NaCl eutectic salts to convert poly (ethylene terephthalate)(PET) into NPC at 550℃.We prove that firstly melamine reacts with PET degradation products to form a crosslinking structure,and subsequently ZnCl_(2)/NaCl promote the dehydration and decarboxylation of the crosslinking structure to generate a more thermally stable crosslinking structure.The coordination of two tandem crosslinking reactions is critical to control the microstructure of NPC.Without activations,NPC shows large specific surface area of 1173 m~2g^(-1),abundant N dopants,and rich oxygen-containing groups.These combined features endure NPC with excellent performance in CO_(2) capture and solar steam generation,e.g.,high CO_(2) adsorption capacity of 6.47 mmol g^(-1) and evaporation rate of 1.62 kg m^(-2)h^(-1).More importantly,NPC is compared to or prevails over previous carbon-based CO_(2) adsorbents or photothermal materials.This work will advance the research on “green” reutilization of low-cost polyester wastes to prepare sustainable carbon for solar energy conversion,environmental protection,etc.