Engineering Microporous Zn-Functionalized Carbon Catalysts for Controllable Chain Cracking and Aromatization in Polyethylene Upcycling

Conventional metal-zeolite systems often suffer from excessive cracking, rapid deactivation, and high cost of plastic upcycling. Here this work introduces a noble-metal-free decomposition-catalysis cascade strategy that enabled the selective upcycling of polyethylene (PE) into high-value n-paraffins and light aromatics. By engineering Zn-decorated microporous carbon with abundant oxygenated groups and Brønsted acid sites, the catalyst promoted controlled β-scission and aromatization, resulting in a remarkably high liquid yield (50.50 wt %) and a carbon selectivity exceeding 75 mol %. In situ Fourier transform infrared (FTIR) analysis further uncovered a previously unrecognized carbenium ion anchoring mechanism in which PE-derived intermediates were stabilized on acid sites to steer isomerization and chain-cracking pathways with molecular precision. The ability of this cascade system to efficiently convert real-life PE waste highlighted its robustness and practical relevance, offering a scalable and controllable route for chemical upcycling of polyolefins within a circular-economy framework.