Adaptive Brønsted Acidity From Heterolytic Dihydrogen Activation Enables Polyethylene Hydrogenolysis Over Pd-Encapsulated Na-Zeolites.

Converting polyethylene to liquid fuels requires Brønsted acidity, yet conventional acidic zeolites suffer from rapid coking and excessive gas formation. Despite Na-exchanged zeolites are well-known to resist coking in many cracking reactions, they are generally considered catalytically inert for polyethylene cracking due to absent acidity. Here, we show that encapsulated palladium nanoparticles in Na-ZSM-5 catalyze efficient polyethylene hydroconversion to C5-C9 alkanes with minimal gas yield and negligible coke formation. Mechanistic studies reveal that dihydrogen undergoes heterolytic dissociation at the confined Pd-zeolite interface, concurrently generating PdH hydrides and bridging hydroxyl groups that function as Brønsted acid sites. These dynamically created acid centers drive selective C─C bond scission via classical β-scission pathways while circumventing the deleterious side reactions. This study establishes a general paradigm for adaptive catalysis wherein active sites are created in situ within otherwise non-acidic frameworks, offering new strategies for selective bond activation.