Noble metal-free tandem catalysis enables efficient upcycling plastic waste into liquid fuel components
Jie Sun, Changdong Wu, Yuchen Zhou, Jiuxuan Zhang, Zhengyan Qu, Feng Zeng, Zhenchen Tang, Weihong Xing, Rizhi Chen
Abstract
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-WO 3 /Al 2 O 3 and Beta zeolite was developed for consecutive hydrocracking polyolefins, achieving a yield of 86.2 % of primarily gasoline-jet ranged hydrocarbons (mainly C 5 -C 16 and minor C 16+ ) at 280 °C. The incorporation of tungsten species onto Ni/Al 2 O 3 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.