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/WOx (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 C4–C25 range, with more than 77% falling within the jet-fuel-range components (C8–C16). The gas product is dominated by branched C3–C6 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 WO3 to NiW alloy nanoparticles supported on WOx (NiW/WOx), and then to WO2-encapsulated NiW (NiW@WO2). The coexposure of NiW alloy nanoparticles and WOx 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.