Surface-Activated\nMechano-Catalysis for Ambient Conversion\nof Plastic Waste

Improved recycling\ntechnologies can offer sustainable end-of-life\noptions for plastic waste. While polyolefins can be converted into\nsmall hydrocarbons over acid catalysts at high temperatures, we demonstrate\nan alternative mechano-catalytic strategy at ambient conditions. The\nmechanism is fundamentally different from classical acidity-driven\nhigh-temperature approaches, exploiting mechanochemically generated\nradical intermediates. Surface activation of zirconia grinding spheres\ncreates redox active surface sites directly at the point of mechanical\nenergy input. This allows control over mechano-radical reactivity,\nwhile powder catalysts are not active. Optimized milling parameters\nenable the formation of 45% C<sub>1–10</sub> hydrocarbons from\npolypropylene within 1 h at ambient temperature. While mechanochemical\nbond scission is undesired in plastic production, we show that it\ncan also be exploited for chemical recycling.