Synergistic pore-acidity engineering of hierarchical ZSM-5 for hydrogen-free upcycling of Polyethylene to C8–C12 Methylated Aromatics
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GRAPHICAL ABSTRACT
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PUBLIC SUMMARY
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A pore-engineered ZSM-5 enables hydrogen-free conversion of polyethylene into valuable chemicals.
Optimal pore–acidity synergy boosts conversion to 98.8% and aromatics yield to 37.4% at 280 °C.
Mesopores enhance diffusion, speeding reactions and preventing over-cracking.
The catalyst shows strong stability and works well for real-world plastic waste.
Process cuts energy use and reduces emissions by over 55% vs fossil routes.
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ABSTRACT
Transforming polyethylene (PE) into high-value chemicals is often hindered by diffusion barriers. Here, we report a hydrogen-free strategy using pore-engineered hierarchical ZSM-5. By tuning desilication, we identified a critical pore–acidity synergy at an optimal Vmeso/Vmicro ratio of ~2.7 within this specific low Si/Al (25~50) framework. The optimal catalyst achieved near-complete conversion (98.8%) and an aromatic yield of 37.4% at a mild temperature of 280 °C. In-situ FTIR and molecular dynamics simulations reveal that this synergy facilitates a cascade reaction mechanism. The introduced mesoporosity enhances the effective diffusion coefficient of C10 intermediates by an order of magnitude (from 0.1 ×10−9 m2s−1 to 2.2×10−9 m2s−1), thus enabling rapid turnover and suppressing over-cracking. The hierarchical catalyst (Hier-Z5-43) demonstrated exceptional stability and versatility for real-world plastic upcycling. Techno-economic and life cycle analyses confirm substantial advantages, reducing energy consumption by 10.9 MJ/kg and decreasing global warming potential by >55% compared to conventional fossil-based routes. This study highlights the importance of synergistically optimizing pore structure and acidity to enhance catalytic performance in polyolefin upcycling.-
Keywords:
- Plastic upcycling /
- Hierarchical ZSM-5 /
- Mesoporous /
- Aromatics /
- Hydrogen-free
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Sun B., Li B., Marc M., et al. (2026). Synergistic pore-acidity engineering of hierarchical ZSM-5 for hydrogen-free upcycling of Polyethylene to C8–C12 Methylated Aromatics. The Innovation Energy 3:100155. https://doi.org/10.59717/j.xinn-energy.2026.100155
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Sun B., Li B., Marc M., et al. (2026). Synergistic pore-acidity engineering of hierarchical ZSM-5 for hydrogen-free upcycling of Polyethylene to C8–C12 Methylated Aromatics. The Innovation Energy 3:100155. https://doi.org/10.59717/j.xinn-energy.2026.100155
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Figure 1.
Structural and acidic characterization of the catalysts
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Figure 2.
(A) Screening of catalytic performance (PE conversion and product distribution) over parent ZSM-5 and the series of pore-engineered Hier-Z5 catalysts (Reaction conditions: 280 °C,3 MPa N2,1h). (B) Yield of C8–C12 aromatics as a function of desilication intensity. (C) Optimization of reaction temperature and pressure over Hier-Z5-43. (D) Carbon number distribution and (E) selectivity of liquid products compared between ZSM-5 and Hier-Z5-43. (F) 1H NMR spectra of liquid products. (G) DSC curves of post-reaction residues. (H) Comparison of C8–C12 aromatic yield and reaction temperature with literature benchmarks.
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Figure 3.
Quantitative correlation between structural properties and catalytic performance
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Figure 4.
(A) 2D correlation/contour map of in-situ IR spectra over Hier-Z5-43 (visualizing band evolution with time). (B) Time-series in-situ IR spectra over Hier-Z5-43 (0–60 min), highlighting ν(CH3) (~
2897 cm-1), aromatic skeleton ν(C=C) (~1501 cm-1), δs(CH3) (~1369 cm-1), and δop(–CH2–) (~1319 cm-1). (C) Kinetics of δs(CH3) (~1369 cm-1) intensity vs. time: comparison between ZSM-5 and Hier-Z5-43. (D) 2D correlation/contour map of in-situ IR spectra over ZSM-5. (E) Time-series in-situ IR spectra over ZSM-5 (0–60 min), assigned as in panel. (F) Kinetics of ν(CH3) (~2897 cm-1) intensity vs. time: comparison between ZSM-5 and Hier-Z5-43. -
Figure 5.
Molecular simulations reveal mesopore-enabled diffusion and a meso–micro cascade to methylated aromatics
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Figure 6.
Stability, regenerability, and real-world waste upcycling.
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Figure 7.
Techno-Economic and Environmental Assessment of H2-Free Polyethylene Upcycling.
