Complete hydrogenolysis of mixed plastic wastes

Abstract

The accumulation of plastic waste in the environment has led to a global crisis with severe consequences for wildlife and ecosystems. Upcycling offers a promising solution for reducing plastic waste by converting it into valuable chemicals and fuels. Real-life plastic waste exists as complex mixtures of different types of plastic, which poses a key challenge for efficient upcycling. Here, by using sunlight as the sole energy source, we report a thermocatalytic approach for transforming a plastic waste mixture collected from daily usage into methane and HCl using an earth-abundant Ni-based catalyst. This process successfully converted 1.03 g of a plastic waste mixture, containing five types of polyolefin, polyester and polyvinyl chloride, into 1.08 g of methane (yieldC 98%) and 0.045 g of HCl (yieldCl 91%). Catalyst deactivation caused by chlorine poisoning is prevented through the temperature-ramped process driven by the diurnal sunlight cycle, ensuring sustained catalytic activity over a period of 10 days. Real-life plastic waste exists as complex mixtures, posing a challenge for efficient upcycling. Now a sunlight-powered thermocatalytic process using a Ni-based catalyst converts a plastic mixture into CH4, H2O and HCl. Notably, chlorine poisoning is minimized through temperature modulation driven by the diurnal sunlight cycle.