Quantitative Polyethylene Upcycling to Liquid Olefins over Ru-Containing Layered Zeolites.

The direct deconstruction of polyolefins into olefins without external hydrogen source represents an ideal route for polyolefin upcycling, but it remains challenging due to the apparent trade-off between substrate conversion and product selectivity. We report herein layered MEL zeolite with confined Ru species synthesized through a ligand-assisted hydrothermal route, namely Ru@MEL, as an efficient catalyst for the quantitative upcycling of polyethylene to liquid olefins. The optimized Ru@MEL catalyst achieves >99% polyethylene conversion with 92% selectivity toward C5-C9 olefins at 270 °C within 4 h, surpassing all catalyst systems reported so far. Ru incorporation drives framework aluminum migration into the straight channels of MEL zeolite during crystallization, thereby promoting the spatial proximity of Ru species to Brønsted and Lewis acid sites toward efficient catalysis. Mechanism insights disclose a synergistic cycle involving key steps of Ru-mediated C-H activation, Brønsted acid-catalyzed β-scission, and Lewis acid-assisted hydrogen transfer. Ru@MEL catalyst exhibits high efficiency, good stability, and scalability in upcycling real-world plastic wastes, highlighting its potential for practical applications.