Jochem van de Minkelis
Utrecht UniversityCatalytic Pyrolysis of Polyethylene with Microporous and Mesoporous Materials: Assessing Performance and Mechanistic Understanding
Implementing catalysts in the pyrolysis of polyethylene (PE) can enable a circular economy. However, investigating inherent catalyst activity is hindered by the low accessibility of pores due to their small size relative to the large polymer chains [1,2]. To overcome this challenge, a mesoporous catalyst of sulfated-ZrO2 on SBA-15 was composed and used to investigate intrinsic catalyst properties, including active site accessibility [3].
Melt infiltration of PE in SBA-15 showed that pore accessibility depends on molecular weight. PE degradation temperature correlates with active site density for mesoporous catalysts, but not for microporous catalysts. Pyrolysis with sulfated-ZrO2/SBA-15 shifts the product selectivity towards higher carbon number products compared to thermal pyrolysis, primarily producing alkanes/alkenes in the liquid phase and no C1–C2 products. Compared to microporous catalysts, the selectivity for aromatics and coke deposits was lower. After regeneration, the material remained structurally intact and active.
Both acid sites and Zr3+ species influence the process, and both acid- and radical-based pathways play a role using sulfated ZrO2/SBA-15, while the latter dominates.
References
[1] Socci, J. et al., Appl. Catal. A: General, 2019, 570, 218–227.
[2] Rejman, S. et al., Chem. Sci., 2023, 14, 10068–10080.
[3] van de Minkelis, J.H. et al., ChemSusChem, 2024, 17, e202401141.
Jochem van de Minkelis has been a PhD candidate since 2021 in the Inorganic Chemistry and Catalysis group at Utrecht University. His research focuses on the use of mesoporous catalyst materials in the catalytic pyrolysis of plastics, investigating their effects on the process and how they can improve the compatibility between the catalyst and the plastic material.