Effect of CeO2 morphology and Ru impregnation method on CH4 selectivity reduction in polyethylene waste conversion to liquid fuels and lubricants

• Ru dispersion influenced by support morphology and impregnation method. • Smaller Ru particles on CeO 2 show reduced CH 4 selectivity. • Defect site on CeO 2 (oxygen vacancies) serve as hydrogen reservoir sites. • Dissociated H 2 can spillover to intra and interparticle CeO 2 . • Enhanced hydrogen reservoir boosts hydrogenolysis rate and lowers CH 4 selectivity. Hydrogenolysis of polyolefins offers a sustainable pathway by giving plastic waste a second life as valuable resources, transforming it into fuels and lubricants. Supported Ru catalysts have shown potential for depolymerizing polyolefins under mild conditions; however, depolymerization via terminal C-C bond cleavage can lead to the excessive formation of CH 4 . This study investigated the effects of CeO 2 morphology and Ru impregnation method on the suppression of CH 4 formation and increasing liquid and wax proportions (C 5 -C 41 ) in the production of liquid fuels and lubricants through polyethylene hydrogenolysis. Controlling the morphology of CeO 2 and impregnating Ru via electrostatic adsorption can enhance the formation of oxygen vacancies and strengthen the interaction between Ru and CeO 2 . The presence of defects in CeO 2 also correlated with smaller particle size of Ru and a higher hydrogen reservoir site, which effectively suppress CH 4 formation.