Catalytic Activation of Polyethylene Model Compounds Over Metal‐Exchanged Beta Zeolites
Jacob H. Miller, Anne K. Starace, Daniel A. Ruddy
Abstract
Abstract Decomposition of polymers by heterogeneous catalysts presents a promising approach for reuse of waste plastics. We demonstrated non‐hydrogenative decomposition of model polyolefins over proton‐form and metal (Cu, Ni) ion‐exchanged beta (BEA) zeolites at moderate temperatures (around 300 °C). Near complete polyolefin decomposition was observed in batch reactions monitored by thermogravimetric analysis, while decomposition at partial conversion was studied in flow reactions. Ni‐exchanged zeolites produced H 2 at substantially higher rates (>10x) than other catalysts while also uniquely resisting deactivation over time. Application of the delplot formalism offered insights into the reaction network for polyolefin decomposition over Ni/BEA most notably that H 2 is solely a primary product. We deduce that H 2 production is catalyzed by activation of C−H bonds at ionic Ni sites, and H 2 prevents buildup of polyaromatic coke species in Ni‐exchanged zeolites that deactivate Cu‐exchanged and protonic zeolites.