Conversion of Polyolefin Waste to Liquid Alkanes with Ru-Based Catalysts under Mild Conditions

Julie Rorrer, Gregg Beckham, Yuriy Roman-Leshkov

Research output: Contribution to journalArticlepeer-review

194 Scopus Citations

Abstract

Chemical upcycling of waste polyolefins via hydrogenolysis offers unique opportunities for selective depolymerization compared to high temperature thermal deconstruction. Here, we demonstrate the hydrogenolysis of polyethylene into liquid alkanes under mild conditions using ruthenium nanoparticles supported on carbon (Ru/C). Reactivity studies on a model n-octadecane substrate showed that Ru/C catalysts are highly active and selective for the hydrogenolysis of C(sp3)-C(sp3) bonds at temperatures ranging from 200 to 250 °C. Under optimal conditions of 200 °C in 20 bar H2, polyethylene (average Mw∼4000 Da) was converted into liquid n-alkanes with yields of up to 45% by mass after 16 h using a 5 wt % Ru/C catalyst with the remaining products comprising light alkane gases (C1-C6). At 250 °C, nearly stoichiometric yields of CH4were obtained from polyethylene over the catalyst. The hydrogenolysis of long chain, low-density polyethylene (LDPE) and a postconsumer LDPE plastic bottle to produce C7-C45alkanes was also achieved over Ru/C, demonstrating the feasibility of this reaction for the valorization of realistic postconsumer plastic waste. By identifying Ru-based catalysts as a class of active materials for the hydrogenolysis of polyethylene, this study elucidates promising avenues for the valorization of plastic waste under mild conditions.

Original languageAmerican English
Pages (from-to)8-12
Number of pages5
JournalJACS Au
Volume1
Issue number1
DOIs
StatePublished - 25 Jan 2021

Bibliographical note

Publisher Copyright:
© 2021 American Chemical Society. All rights reserved.

NREL Publication Number

  • NREL/JA-2A00-78170

Keywords

  • alkanes
  • depolymerization
  • heterogeneous catalysis
  • hydrogenolysis
  • plastic upcycling
  • polyethylene
  • polyolefins
  • ruthenium

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