Converting Plastic Wastes to Naphtha for Closing the Plastic Loop

To solve the serious environmental problem and huge resource waste of plastic pollution, we report a tandem catalytic conversion of low-density polyethylene (LDPE) into naphtha, the key feedstock for renewable plastic production. Using beta zeolite and silicalite-1-encapsulated Pt nanoparticles (Pt@S-1), a naphtha yield of 89.5% is obtained with 96.8% selectivity of C5-C9 hydrocarbons at 250 degrees C. The acid sites crack long-chain LDPE into olefin intermediates, which diffuse within the channels of Pt@S-1 to encounter Pt nanoparticles. The hydrogenation over confined metal matches cracking steps by selectively shipping the olefins with right size, and the rapid diffusion boosts the formation of narrow-distributed alkanes. A conceptual upgrading indicates it is suitable for closing the plastic loop, with a significant energy saving of 15% and 30% reduced greenhouse gas emissions.

Automated summary

We present a tandem catalytic conversion of LDPE into naphtha, the key feedstock for renewable plastic production, to address the serious environmental problem and resource waste of plastic pollution. The use of beta zeolite and silicalite-1-encapsulated Pt nanoparticles (Pt@S-1) enables a high naphtha yield of 89.5% and selectivity of 96.8% for C5-C9 hydrocarbons at 250 degrees C. This method utilizes acid sites to crack LDPE into olefin intermediates, which then encounter Pt nanoparticles within the channels of Pt@S-1 for hydrogenation and selective shipping of the resulting olefins, leading to the formation of narrow-distributed alkanes. Conceptually, this approach is suitable for closing the plastic loop, offering significant energy savings of 15% and a 30% reduction in greenhouse gas emissions.