Catalytic upcycling of waste plastics over nanocellulose derived biochar catalyst for the coupling harvest of hydrogen and liquid fuels

A powerful simple biochar catalyst derived from nanocellulose was applied to the catalytic upcycling of waste plastics into H2 and liquid fuels for the first time. For the results from model low-density polyethylene (LDPE) pyrolysis, the C8-C16 aliphatics and monocyclic aromatics were dominant constitutes of the liquid product with the yields ranging from 22 to 68 wt%. At the temperature of 500 °C and biochar to LDPE ratio surpassing 3, the LDPE could be completely degraded into liquid and gas without wax production. A wax yield of 16 wt% was observed at the temperature of 450 °C and biochar to LDPE ratio of 4, which was dramatically lower than that (77 wt%) from the absence of biochar at the temperature of 500 °C. Up to 92 vol% of H2 was detected in the gaseous product with a yield of 36 wt%. The lower temperatures and higher biochar to LDPE ratios favored increasing the generation of H2 at the expense of light gas CnHm especially CH4. Moreover, this biochar catalyst was tested effectively to convert the real waste plastics including grocery bags and packaging tray into valuable liquid and H2-enriched gas. [Display omitted] •A simple novel nanocellulose derived biochar (NCB) catalyst was developed.•The waste plastics catalytic upcycling over NCB was performed for the first time.•The NCB significantly lowered the temperature required to completely degrade LDPE.•Enhanced generation of hydrogen and valuable constitutes in liquid was achieved.