Related Experiment Video
Updated: May 13, 2025
08:12
Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers
Published on: December 16, 2022
3.2K
Carbamate-bond breaking on bulk oxides realizes highly efficient polyurethane depolymerization.
Xinbang Wu1, Roland C Turnell-Ritson1, Peijie Han2
1Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
Nature Communications
|May 9, 2025
Summary
This study introduces cerium oxide (CeO2) as a highly effective heterogeneous catalyst for polyurethane chemical recycling. CeO2 efficiently converts carbamate bonds, yielding valuable anilines and polyols for sustainable material recovery.
Area of Science:
- Materials Science
- Chemical Engineering
- Catalysis
Background:
- Polyurethane (PU) is a widely used plastic in various industries.
- Chemical recycling of PU via catalytic hydrogenation offers a sustainable route to recover valuable monomers like anilines and polyols.
- A lack of practical heterogeneous catalysts hinders the industrial-scale chemical recycling of PU.
Purpose of the Study:
- To investigate heterogeneous metal-oxide catalysts for the chemical recycling of polyurethane.
- To identify efficient catalysts for the cleavage of carbamate bonds in PU.
- To propose a catalytic mechanism for PU depolymerization.
Main Methods:
- Screening of various metal-oxide catalysts for the conversion of model carbamate compounds.
- Activity testing under solvent-free hydrogenation and hydrogen-free transfer hydrogenation conditions.
- In situ Nuclear Magnetic Resonance (NMR) studies and control reactions to elucidate the reaction mechanism.
Main Results:
- Cerium oxide (CeO2) demonstrated superior catalytic activity, achieving 100% conversion and up to 92% yield of aniline products.
- A volcano correlation was observed between catalyst acidity and carbamate bond cleavage activity.
- CeO2's high performance is attributed to low oxygen vacancy formation energy and active Ce3+/Ce4+ redox pairs.
Conclusions:
- CeO2 is a highly effective heterogeneous catalyst for the chemical recycling of polyurethanes.
- The study proposes a mechanism for carbamate bond dissociation on CeO2.
- CeO2 enables both solvent-free and transfer hydrogenation methods for depolymerizing thermoplastic and thermoset polyurethanes.
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