Beyond Conventional Degradation: Catalytic Solutions for Polyolefin Upcycling

Abstract

Polyolefins (POs, i.e., polyethylenes, ethylene/α-olefin copolymers, and polypropylenes) are the most ubiquitous synthetic macromolecular materials in modern life. Their widespread use and low recovery rate after extensive usage have caused significant resource waste and environmental concerns. Chemical recycling of POs provides an efficient approach to unravelling the polymer chain to various chemicals. However, conventional chemical recycling methods, including pyrolysis, hydrocracking, and oxidation, require high-energy input (typically >500 °C) and/or the use of environmentally unfriendly chemicals, leading to complex product distribution. In this minireview, based on recent representative works, we summarize and highlight catalytic strategies addressing these issues in PO recycling from two perspectives: (1) employing advanced catalysts or technique designs to overcome the challenges in conventional chemical deconstruction approaches; and (2) developing novel tandem/cascade catalytic systems for highly selective PO upcycling under relatively mild conditions. We hope that this minireview will help researchers better understand the state of the art of PO chemical recycling and inspire more innovative and efficient ideas for this fast-developing field.