Abstract
Solid waste remains a global crisis in which massive amount of solid waste is disposed of in landfills and the environment yearly, leading to detrimental environmental pollution and loss of resources. However, the current downcycling technologies, such as pyrolysis and gasification, usually require extensive energy input and harsh operating conditions, posing a high possibility of causing secondary pollution. In pursuit of a sustainable future, artificial photosynthesis arises as one of the promising but arduous approaches to reform solid waste into fuels and commodity chemicals under benign conditions. Under this backdrop, this review aims to present a thorough overview of the recent advancement in solid waste transformation through photocatalysis. To begin with, the principles of solar-driven conversion pathways for solid waste are discussed under different reaction conditions. Then this review also highlights the merits of artificial photosynthesis and diverse state-of-the-art photocatalysts for solid waste valorization. Special emphasis is placed on elucidating the application of external-field-assisted photocatalysis (e.g. photothermocatalysis, photoelectrocatalysis, photobiocatalysis, and piezo-photocatalysis) for solid waste upcycling to explore the synergistic effects on performance improvement. Finally, insights on the challenges and prospects in photocatalytic solid waste conversion are presented to bridge a new exemplification towards a sustainable circular economy in the future.