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.

塑料废物对联合国可持续发展目标构成了日益严重的环境威胁。将塑料聚合物转化为碳纳米管等高价值化学品是一种有前途的回收方法，不会排放二氧化碳。使用两级热解催化反应器，我们在此报道了在合理设计的多相催化剂（即负载铁金属催化剂）的帮助下，将五种塑料聚合物转化为高质量的单壁碳纳米管（SWNT）由多孔氧化镁制成。由于活性组分的金属分散度高和碳溶解度大，非均相催化剂可以形成均匀的金属颗粒，从而维持高碳通量，从而合成高质量的单壁碳纳米管。更重要的是，该方法还通过塑料聚合物混合物进行了验证。这项工作有助于深入了解塑料聚合物转化为单壁碳纳米管的机制，加速可持续塑料经济的进展。