Enhancing Hydrogen Spillover via Crystalline-Phase Engineering of Ru/ZrO ₂ for Selective Liquid Alkane Production in Polyethylene Hydrogenolysis

The efficient conversion of polyethylene (PE) plastic waste into high-value liquid fuels is critical for mitigating environmental pollution and increasing economic benefits. However, the hydrogenolysis of PE typically produces low-value alkanes, and an effective catalyst for selectively producing liquid alkanes via this route remains lacking. Herein, we present a crystalline-phase engineering strategy to optimize Ru/ZrO 2 catalysts, achieving 64.2% selectivity toward C 7 –C 40 liquid products under mild conditions (250 °C, 3 MPa of H 2, 4 h). Systematic characterizations reveal that the Ru/ZrO 2 -600 catalyst exhibits the highest tetragonal phase content (33.2%) and the highest oxygen vacancy concentration (37.8%), which facilitates hydrogen spillover from Ru to the ZrO 2 support, thereby increasing the surface hydrogen coverage. This effect weakens the adsorption of alkane intermediates and accelerates hydrogenation kinetics, thus suppressing further cracking into light hydrocarbons (C 1 –C 6 ) and promoting the formation of long-chain liquid products. Ru/ZrO 2 -600 achieves 62.3 and 61.5% selectivity toward C 7 –C 40 liquid hydrocarbons during the hydrogenolysis of commercial PE gloves and PE film, respectively. This work provides a promising strategy for the sustainable and economically viable recycling of waste PE plastics.