Polyethylene hydrogenolysis to liquid products over bimetallic catalysts with favorable environmental footprint and economics

Establishing the sustainability of chemical recycling of plastics demands prioritizing realistic feedstocks while advancing catalyst design informed by sustainability-driven frameworks, as envisioned in the ‘Plastic-to-X’ concept. The main outcome of this work is bridging experimental and system-level approaches to explore the interplay of catalyst composition, structure, and hydrogenolysis performance using high-density polyethylene ( M _w = 100, 200 kDa) in virgin and in plastic caps form. By incorporating nickel as a modifier to the ruthenium active phase (100% gas yield), we developed titania-supported Ru-Ni alloy nanoparticles (ca. 5 nm) producing 25% of liquid (C ₆ –C ₄₅ ) products. Structure sensitivity is elucidated through experiments and simulations, disclosing that energetically favorable backbone scission is preceded by dehydrogenation and hydrogenation cycles over defective alloy sites. Integrating these findings with life cycle and technoeconomic analyses, we predict the potential for profitable processing of plastic caps using the optimal catalyst (2.5 wt% Ru and 5 wt% Ni) with significantly reduced CO ₂ emissions even when using green hydrogen. Furthermore, and within the ‘Plastic-to-X’ framework, we identify a minimal average chain length threshold of C ₁₁ for product distributions as a key metric to reconcile environmental and economic objectives.