Enhancing Hydrogen Production via Ex Situ Catalytic Fast Pyrolysis of Polypropylene with Upcycled Biochar-Supported FeAl2O4 Catalyst

• Published in: ACS sustainable chemistry & engineering Vol. 13; no. 27; pp. 10453 - 10466
• Main Authors: Li, Sijie, Wu, Yiting, Mahmood, Ayyaz, Liu, Jin, Xu, Ziqi, Lu, Kaiyang, Sheintuch, Moshe, Gao, Xi
• Format: Journal Article
• Language: English
• Published: American Chemical Society 14.07.2025
• Subjects: catalytic fast pyrolysis; tetrahedral iron; DFT; plastic upcycling; hydrogen generation
• ISSN: 2168-0485; 2168-0485
• DOI: 10.1021/acssuschemeng.5c02097

The coupling of fast pyrolysis with green catalysis offers a sustainable approach for transforming waste polypropylene (PP) plastic into valuable hydrogen and carbon materials. The intrinsic catalytic activities of biochar, Al2O3@biochar, Fe3O4@biochar, Fe2AlO4@biochar, and FeAl2O4@biochar are explored for upgrading the fast pyrolysis vapors of PP powder. The FeAl2O4@biochar catalyst with tetrahedral iron sites achieves an excellent hydrogen yield, equivalent to 86.25 H% in PP. The hydrogen yield from converting practical PP mask waste reaches 57.98 ± 1.96 mmol gplastic –1, more than 673.61 ± 7.00 mmol gFe –1. The density functional theory (DFT) calculation indicates that a closer d-band center of FeAl2O4 is more favorable for C–H bond activation and that dehydrogenation of propylene as a model compound is the primary source of hydrogen production, more readily than C–C bond cleavage, and efficiently generates H2.