Orchestrating catalytic hotspots and macromolecular architectures: molecular engineering toward zero-waste polymer circularity

The pervasive accumulation of plastic waste exacerbates environmental degradation and undermines resource circularity. Selective thermal catalysis emerges as a transformative pathway for valorizing waste plastics into value-added chemicals, yet persistent challenges in catalytic activity and product selectivity demand systematic resolution. This review decodes cutting-edge advances in thermal depolymerization by converging two critical dimensions: atomic-scale active site engineering—where rational design of coordination features and interfacial architectures regulates C–C cleavage energetics and intermediate adsorption—and macromolecular-scale manipulation of polymer transient states—leveraging nanoconfinement effects, chain folding dynamics, and thermal fragmentation to accelerate conversion kinetics. We further highlight breakthroughs in operando characterization techniques that resolve time-evolving reaction coordinates across catalytic systems. By establishing multiscale structure-activity relationships linking catalyst configurations to polymer dynamics, this analysis derives design paradigms for next-generation upcycling systems. These principles enable economically viable, industrially scalable plastic valorization while charting a strategic trajectory toward carbon-circular economies. Rational design of reaction interfaces (e.g., coordination characteristics, metal-support interaction, etc ) and polymer intermediate status (e.g., folding state, entropy adjustment, etc ) with innovative methodological framework being proposed in thermal plastic waste upcycling can significantly foster circular economy and ecological restoration.