Synthesis of Clean Hydrogen Gas from Waste Plastic at Zero Net Cost.

Hydrogen gas (H ) is the primary storable fuel for pollution-free energy production, with over 90 million tonnes used globally per year. More than 95% of H is synthesized through metal-catalyzed steam methane reforming that produces 11 tonnes of carbon dioxide (CO ) per tonne H . "Green H " from water electrolysis using renewable energy evolves no CO , but costs 2-3× more, making it presently economically unviable. Here catalyst-free conversion of waste plastic into clean H along with high purity graphene is reported. The scalable procedure evolves no CO when deconstructing polyolefins and produces H in purities up to 94% at high mass yields. The sale of graphene byproduct at just 5% of its current value yields H production at a negative cost. Life-cycle assessment demonstrates a 39-84% reduction in emissions compared to other H production methods, suggesting the flash H process to be an economically viable, clean H production route.