Photoreforming of Plastic Waste: Connecting the Dots for Green and Efficient Upcycling Systems within a Circular Economy

The linearity of plastics poses a threat to ecosystem stability and public health. The transition to a circular economy is essential to reintroduce waste into the value chain at the beginning, sustainably promoting the plastic carbon cycle. Among the various emerging technologies to address this challenge, photoreforming processes represent a promising approach that offers dual benefits: environmental remediation and clean energy generation by converting plastic waste into value-added chemicals and H2. However, given that this technology is still in an early stage of development, available studies show high heterogeneity in pretreatment methods, architectures, and the physicochemical properties of photocatalysts, as well as in reaction conditions. Consequently, this review synthesizes the state of the art in plastic photoreforming from 2018 to 2025, identifying patterns across fragmented evidence, connecting key concepts to establish a holistic framework, and correlating key process parameters with photocatalytic performance to guide the rational design and optimization of plastic photoreforming systems. This document covers the fundamentals of plastic photoreforming, the key operational factors that govern its performance, and the highest reported H2 production yields. It further identifies critical opportunities in polymer design, scalability, and process optimization, outlining pathways toward efficient and industrially viable photoreforming within a circular economy.