Synergistic Effects of Electricity and Light for Efficient Iron-Catalyzed Recycling of Polystyrene Waste

Due to their intensive use in every aspect of our everyday life, plastics are accumulating in the environment, hence representing a major societal challenge. The accumulation of plastic waste in the oceans is expected to reach 40 billion tons by 2050. Thus, efficient methods for chemical plastic waste recycling continue to be in high demand toward a future circular economy. Herein, we report a powerful and user-friendly strategy merging inexpensive and earth-abundant iron catalysis, light irradiation and electricity to recycle polystyrene and styrene-containing copolymers into value-added benzoyl products with up to 73% yield. The robustness of this approach using iron-electrocatalysis under light irradiation was further demonstrated using postconsumer waste, also viable on multigram scale. Cathodic formation of molecular hydrogen through the hydrogen evolution reaction (HER) offers an outstanding potential for a decentralized green hydrogen economy through a societally useful anodic oxidative transformation.