Noble metal-free tandem catalysis enables efficient upcycling plastic waste into liquid fuel components

The lack of effective approaches for upcycling waste plastic has led to severe environmental pollution and squandering of carbon resources. While hydrocracking macromolecular polyolefins over typical metal-zeolite catalyst produces high quality liquid fuel components, the limited activity of base metal and restricted accessibility of acid sites within microporous zeolite renders this process still not in practical scale. A tandem catalyst comprising Ni-WO₃/Al₂O₃ and Beta zeolite was developed for consecutive hydrocracking polyolefins, achieving a yield of 86.2 % of primarily gasoline-jet ranged hydrocarbons (mainly C₅-C₁₆ and minor C₁₆₊) at 280 °C. The incorporation of tungsten species onto Ni/Al₂O₃ largely enhances the surface acidity and accelerates the primary cracking process that converts polyethylene (PE) into medium-sized intermediates, which would readily diffuse into the pore networks of Beta and undergo further cracking to yield desired liquid hydrocarbons. In addition, this tandem catalyst also promotes facile hydrocracking of consumer-grade plastic waste and maintains excellent stability over 5 recycling tests. The noble-metal-free catalyst achieves an impressive liquid formation rate of 5.74 g·g_cat.⁻¹·h⁻¹, rivaling the noble metal-based catalyst and demonstrating high application prospects.