Net-Zero Upcycling of Mixed Polyolefins by Spatially Homogeneous Joule Heating

Mitigating plastic pollution by upcycling has been impeded by its high environmental footprint and economic costs, despite substantial potential. Here, we develop a sustainable approach to upcycle end-of-life polyolefins into H2 and graphene via spatially homogeneous Joule heating (SHJH). On-demand energy inputs enable over 99% energy savings compared to conventional thermochemical processes, with energy efficiency up to 14,700 mmol H2·kWh-1. By combining tunable temperature profiles and biomass-derived carbon-based catalysts, over 97.5% of theoretically extractable H2 is exploited through thermodynamically favorable C-H activation. Simultaneously, SHJH enables the rapid evolution of carbonaceous precursors into uniform graphene with yields up to 82 wt % via subsecond reactions. Life cycle assessment reveals that SHJH reduces energy consumption, greenhouse gas emissions, and water demand by 2 orders of magnitude, and renders the upcycling process near-zero by integrating renewable energy. Additionally, the lower net cost transforms polyolefin waste into valuable resources, incentivizing a circular economy for waste plastics.