Boosting strong metal-support interactions between Ru and sodium titanate nanowire for hydrogenolysis of polyolefins under mild conditions

Abstract

Catalytic hydrogenolysis provides promising opportunities for the chemical recycling of polyolefins. In this study, we have successfully developed a novel catalyst consisting of ruthenium (Ru) nanoparticles supported on sodium titanate nanowires (Ru@NTO-NH) for the hydrogenolysis of low-density polyethylene (LDPE) into high-value long-chain alkanes under mild reaction conditions (180 °C, 1–2 MPa H2), achieving yields of up to 91%. Control experiments and thorough characterizations have elucidated that the exceptional catalytic performance of Ru@NTO-NH in the hydrogenolysis of polyolefins can be attributed to strong metal-support interactions (SMSI). NTO-NH exhibits stronger SMSI with Ru species than TiO2, leading to the formation of smaller Ru nanoparticles that are more positively charged and NaTiOx-overlayered. This unique configuration facilitates the adsorption and activation of H2 as well as the desorption of alkanes, thereby enhancing catalytic efficiency and selectivity towards liquid alkanes. Moreover, the Ru@NTO-NH catalyst demonstrates remarkable stability throughout recycling experiments (10 runs). Notably, apart from LDPE, high-density polyethylene (HDPE) and polypropylene (PP) can also be effectively converted into liquid alkanes through hydrogenolysis using this catalyst.