Solar-driven conversions of plastic waste to valuable chemicals with green hydrogen production

Abstract

The conversion of plastic waste into renewable fuels through photocatalytic processes represents a promising pathway toward addressing both environmental pollution and energy demands. This review presents a detailed examination of solar-driven plastic photoreforming, a strategy that leverages water and sunlight to generate H₂ and other value-added compounds from discarded polymers. We begin by outlining the fundamental mechanisms of this technology, emphasizing how charge carriers and reactive species mediate concurrent plastic oxidation and H₂ evolution or CO₂ reduction. Key mechanistic insights are discussed, particularly those related to oxidative degradation pathways and the roles of reactive oxygen species. Then, recent advances in photocatalyst development and system integration using various semiconductors, with attention to catalyst design parameters, system configuration, and coupling with secondary processes. While this approach offers significant potential, practical deployment remains constrained by challenges such as low catalytic efficiency, carbon management inefficiencies, pretreatment needs, and scale-up limitations. To address these, we provide a roadmap for future development, including recommendations for material innovation, mechanistic exploration, and system-level optimization. This review aims to serve as a comprehensive guide for researchers seeking to advance the field of solar-assisted plastic valorization and contribute to the establishment of a circular, carbon-neutral economy.