Hydrocracking Polyolefins to Jet Fuel over a NiW/WO _<i>x</i> Catalyst

Developing non-noble metal catalysts for hydrocracking polyolefins is a promising yet formidable challenge for upcycling waste plastics in practice. Herein, we report a NiW/WO x (2 < x < 3) catalyst, which accomplishes polyolefin hydrocracking at 250 °C, yielding a liquid product of about 73 wt % and a gaseous product of about 22 wt %. The liquid fraction primarily consists of hydrocarbons in the C 4 –C 25 range, with more than 77% falling within the jet-fuel-range components (C 8 –C 16 ). The gas product is dominated by branched C 3 –C 6 hydrocarbons, characteristic of liquefied petroleum gas (LPG), with negligible carbon loss, such as methane and ethane.A sequence change from inactive to active, and back to inactive in polyolefin hydrocracking was found accompanying the reconstruction of the surface structure of the catalyst from Ni-doped WO 3 to NiW alloy nanoparticles supported on WO x (NiW/WO x ), and then to WO 2 -encapsulated NiW (NiW@WO 2 ). The coexposure of NiW alloy nanoparticles and WO x is further demonstrated to be necessary for fulfilling the bifunctionality of the catalyst in hydrogen dissociation and C–C bond cleavage in polyolefin hydrocracking, and the absence of either will deactivate the catalyst.