Abstract
Here we address a key mechanistic question that limits thermochemical upcycling of waste polyurethane wire: copper is not an inert background but actively redirects pyrolysis products. We propose a copper-assisted dynamic pyrolysis model in which copper reshapes the conversion-dependent energy-barrier profile through electronic-structure regulation, leading to a predictable shift in dominant reaction routes. Thermogravimetric analysis reveals a robust three-stage decomposition and a pronounced evolution of apparent barriers with conversion, consistent with a late-stage regime governed by radical reorganisation, condensation and char formation. Temperature-resolved product fingerprints provide direct chemical evidence for pathway selectivity. Reversible copper coordination and frontier-orbital interactions lower key transition barriers and stabilise intermediates, promoting radical recombination and aromatization. These results establish a cross-scale link between macroscopic pyrolysis behavior, barrier evolution and product selectivity, and offer a general framework for endogenous metal regulation, supporting cleaner processing and improved copper recovery.
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All supplementary data supporting the findings of this study are available in Zenodo at https://zenodo.org/records/18414263 (ref. 43).
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Acknowledgements
This work was financially supported by the National Key Research and Development Program of China (2022YFC3902604), National Science Foundation for Distinguished Young Scholars of China (52425004), National Natural Science Foundation of China Original Exploration Program (52554013), and Science and Technology General Project of Beijing Municipal Education Commission (KM202410005001).
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W.Z. and X.Z. completed the thermogravimetric experiment, composition distribution of pyrolysis products, data collection and data analysis. W.Z. completed the SEM-EDS analysis and picture data collection. Y.G. completed the calculation of the bond energy of the chemical bond in the polyurethane molecule. W.Z. and L.Z. completed the Infrared spectral analysis and electrostatic potential distribution on the molecular surface. R.T. and B.L. helped analyze the results of quantum chemistry calculations. All authors were involved. W.Z. wrote the paper, and all the authors revised the paper. Y.W. supervised the project.
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Communications Earth and Environment thanks Samuel Widijatmoko and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: Nandita Basu. [A peer review file is available].
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Zhang, W., Zhang, X., Geng, Y. et al. Reversible copper coordination redirects pyrolysis products in waste polyurethane enamelled copper wire. Commun Earth Environ (2026). https://doi.org/10.1038/s43247-026-03339-9
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DOI: https://doi.org/10.1038/s43247-026-03339-9
