Ce-Promoted PtSn-Based Catalyst for Hydrocracking of Polyolefin Plastic Waste into High Yield of Gasoline-Range Products

Despite substantial efforts in recent years to address the challenges of plastic waste management, the chemical upcycling of waste plastics remains significantly hindered due to inefficiencies and instability in catalysts. In this study, we conducted plastic upgrading using PtSn-based hydrocracking catalysts promoted with cerium at different loadings under mild reaction conditions. Our results demonstrate a crucial role for cerium in enhancing the performance of PtSn catalysts, with optimal performance observed at a loading of approximately 0.5 wt %. Over 77 wt % gasoline-range products (C5–C12) can be obtained from the cracking of high-density polyethylene (HDPE) at 270 °C under 30 bar hydrogen for 2 h, representing the highest yield reported to date. Cerium incorporation into PtSn catalysts conferred several beneficial effects, including refining the size distribution of PtSn to produce smaller particles, thereby improving resistance to both metal sintering and coke formation. Furthermore, cerium doping significantly enhanced the concentration and strength of strong Brønsted acid sites (BAS) on SiO2–Al2O3 support. Finally, the introduction of cerium promoted the reducibility of platinum and mitigated the poisoning effects of tin. Our research underscores the potential of cerium-promoted PtSn catalysts in effectively degrading thermoplastic mixtures and commercial plastic-containing dyes and impurities, converting these materials into valuable gasoline-range products.