Microwave-initiated catalytic deconstruction of plastic waste into hydrogen and high-value carbons

Abstract

The ubiquitous challenge of plastic waste has led to the modern descriptor plastisphere to represent the human-made plastic environment and ecosystem. Here we report a straightforward rapid method for the catalytic deconstruction of various plastic feedstocks into hydrogen and high-value carbons. We use microwaves together with abundant and inexpensive iron-based catalysts as microwave susceptors to initiate the catalytic deconstruction process. The one-step process typically takes 30–90 s to transform a sample of mechanically pulverized commercial plastic into hydrogen and (predominantly) multiwalled carbon nanotubes. A high hydrogen yield of 55.6 mmol \({\mathrm{g}}_{\mathrm{plastic}}^{ - 1}\) is achieved, with over 97% of the theoretical mass of hydrogen being extracted from the deconstructed plastic. The approach is demonstrated on widely used, real-world plastic waste. This proof-of-concept advance highlights the potential of plastic waste itself as a valuable energy feedstock for the production of hydrogen and high-value carbon materials.

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Fig. 1: Schematic diagram.
Fig. 2: Representative single cycle experiment.
Fig. 3: Microwave-initiated decomposition of HDPE.
Fig. 4: Characterization of carbon by-product.
Fig. 5: Suggested mechanism.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding authors on reasonable request.

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Acknowledgements

We thank KACST for financial support and S. Guan at Harwell XPS for conducting XPS.

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Authors

Contributions

P.E., T.X. and J.T. supervised the project. P.E., T.X., H.A. and S.A. contributed to the funding acquisition. X.J., T.X. and P.E. conceived and designed the project. X.J. designed and developed the experiments and evaluated and analysed the performance data. X.J. and W.L. designed and performed the electron microscopy measurements, and the analysis of the data. D.S. and X.J. designed and performed the modelling and analysis of the data. X.J. drafted the original manuscript. All authors, including J.D., Y.G., I.B., S.G.-C. and B.Y., contributed to the analysis, interpretation and discussion of results and the writing and revisions of the manuscript.

Corresponding authors

Correspondence to John Thomas or Tiancun Xiao or Peter Edwards.

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Supplementary Information

Supplementary Figs. 1–8, Tables 1–11 and refs. 1–9.

Supplementary Video 1

Video illustrates the rapid production of hydrogen from microwave-initiated deconstruction of HDPE.

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Jie, X., Li, W., Slocombe, D. et al. Microwave-initiated catalytic deconstruction of plastic waste into hydrogen and high-value carbons. Nat Catal (2020). https://doi.org/10.1038/s41929-020-00518-5

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