Mechanistic Insights into Processive Polyethylene Hydrogenolysis through In Situ NMR
Date
2023-05-30
Authors
Zhao, T. Yunpu
Meirow, Max
Tennakoon, Akalanka
Wu, Xun
Paterson, Alexander L.
Qi, Long
LaPointe, Anne M.
Lamb, Jessica V.
Kobayashi, Takeshi
Delferro, Massimiliano
Major Professor
Advisor
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Iowa State University Digital Repository, Ames IA (United States)
Abstract
Chemical polymer upcycling by processive catalysts is a promising plastic waste remediation strategy, with the capability of producing selective, high-value products from waste plastics with minimal energy input. We previously designed a novel processive catalyst with a mesoporous SiO2 shell/Pt nanoparticle/SiO2 core architecture (mSiO2/Pt/SiO2) that deconstructs polyolefins within narrow pores. Here, we elucidate the mechanism of processive polyolefin hydrogenolysis using in situ magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy and coarse-grained molecular dynamics simulations. We observe that most polyethylene–Pt interactions do not lead to C–C bond cleavage but rather to the release of the polymer via a dehydrogenation–rehydrogenation cycle. The porous architecture increases the likelihood that a released polymer is later cleaved and enables the catalyst to perform multiple successive cleavages to the same polymer chain. Both experiment and simulation show that the extent of processivity is strongly correlated with the length of the pores, with longer pores leading to a higher processivity.
Series Number
Journal Issue
Is Version Of
Versions
Series
IS-J 11070
Academic or Administrative Unit
Type
article
Comments
This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in Macromolecules, copyright © 2023 American Chemical Society after peer review. To access the final edited and published work see DOI: 10.1021/acs.macromol.3c00474. Posted with permission. DOE Contract Number(s): AC-02-
07CH11358; AC-02-06CH11357.