Stepwise hydrogen spillover–engineered synergistic sites enable near-quantitative conversion of waste PET to p-xylene

The valorization of plastic waste represents a major challenge of the 21st century due to its severe environmental impact. Here, we report a stepwise hydrogen spillover-constructed CuCo/CoO_x catalyst that enables near-quantitative conversion of waste polyethylene terephthalate to p-xylene (>99.9%), significantly outperforming the performance of various Cu- and Co-based catalysts as well as previously reported noble metal catalysts. The stepwise hydrogen spillover induces the formation of partially phase-transformed Co⁰ species and abundant oxygen-vacancy-rich Co⁰/CoO_x interfaces. The former enhances H₂ dissociation efficiency, while the latter facilitates C-O bond activation in polyethylene terephthalate and regulates substrate-product adsorption equilibria, synergistically contributing to the exceptional catalytic performance. The catalyst demonstrates broad applicability to more than 30 real-world polyester plastics. Furthermore, techno-economic analysis reveals significant reductions in CO₂ emissions and competitive processing costs. This breakthrough in near-quantitative polyethylene terephthalate conversion and stepwise hydrogen spillover-enabled active site construction offers valuable insights into plastic waste upcycling and the design of advanced heterogeneous catalysts.