Solar-Driven Photoelectrochemical Upcycling of Polyimide Plastic Waste with Safe Green Hydrogen Generation

Abstract

Arbitrary disposal of plastic waste into landfills and oceans can disturb the ecological system and even challenge human survival. Centralized plastic recycling process only works for selected types of plastics (e.g., polyethylene) with limited contribution (<10%), because of high infrastructure requirement. Comparatively, photoreforming of plastic waste for commodity and fuels production is much more facile and decentralizable, and thus holds great potential to mitigate the plastic waste challenge. To this end, a fully solar powered photoelectrochemical system is developed to selectively upgrade polyimide waste (often appears in electronic waste) into valuable commodity chemicals, including succinic acid, acetic acid, and formic acid, and cogenerating green hydrogen fuels. It is also demonstrated that one of the key monomer, pyromellitic acid, and the precious metals (in electronic waste) can be fully recycled. This proof-of-concept demonstration provides a new viewpoint for designing decentralized photoelectrochemical system for simultaneous plastic waste upcycling and renewable fuel synthesis, critical for a sustainable plastic economy. Selective cleavage of benzene ring also opens a green route for other benzene ring-containing waste upgrading.