Upcycling plastic polymers into single-walled carbon nanotubes from a magnesia supported iron catalyst

Plastic waste has posed an ever-growing environmental threat to the United Nations' sustainable development goals. Converting plastic polymers into high value chemicals like carbon nanotubes is a promising approach for recycling without carbon dioxide emission. Using a two-stage pyrolysis-catalytic reactor, we herein report the transformation of five types of plastic polymers into high-quality single-walled carbon nanotubes (SWNTs) with the assistance of a rationally designed heterogeneous catalyst, i.e., an iron metal catalyst supported by porous magnesia. Because of the high metal dispersion and the large carbon solubility of the active component, the heterogeneous catalyst affords the formation of uniform metal particles which can sustain high carbon fluxes, resulting in the synthesis of high quality SWNTs. More importantly, the approach is also demonstrated with mixtures of plastic polymers. This work helps gain deep insights into the mechanisms of plastic polymer conversion to SWNTs, accelerating the progress toward a sustainable plastic economy.