(638d) Nickel-Based Catalysts for Low Methane Selectivity in Polyethylene Hydrogenolysis

Catalytic hydrogenolysis has shown significant promise for deconstructing polyolefins (i.e., polyethylene and polypropylene) to lubricant, wax, and fuel-ranged alkanes at mild conditions (200-250 °C, 20-60 bar H₂). However, hydrogenolysis catalysts require expensive noble metals (i.e., Pt, Ru, Ir, etc.) to facilitate the reaction and are prone to producing low-value methane. Ni-based catalysts have been demonstrated to be earth-abundant metal alternatives to reduce the catalyst cost but they still suffer from significant methane production. Development of strategies to limit methane generation from polyethylene hydrogenolysis is a major obstacle to advancing polyolefin deconstruction. Herein, we have developed highly dispersed Ni catalysts. We demonstrate that controlled catalyst reduction is able to decrease the methane selectivity sevenfold (ca. 35% to < 5%). Catalyst characterization reveals the active site that influences the methane production and a structure-selectivity correlation. This structure-property relationship was confirmed for various catalysts.