A novel route for microplastic mineralization: visible-light-driven heterogeneous photocatalysis and photothermal Fenton-like reaction

Abstract

Microplastic pollution has attracted considerable attention. Here, we develop a visible-light-driven photocatalysis and photothermal Fenton-like reaction method for their removal, utilizing an α-Fe₂O₃ nanoflower on TiO₂ with a hierarchical structure of inverse opal-like layer/nanotube arrays (α-Fe₂O₃/TiO₂HNTAs film). Without external H₂O₂ dosage, nearly 100% degradation of 310 nm polystyrene (PS) spheres is obtained after 4 h at 75 °C induced by visible-light irradiation. The light initiation and photothermal effect are essential for achieving high degradation efficiency of plastics on α-Fe₂O₃. A distinctive melting phenomenon of PS under mild conditions due to the synergistic effect is observed for the first time. The catalyst system also works well for PS spheres with large particle size (2.0–2.9 μm) and real PS plastic foam. We believe that this work provides a novel strategy and new insights for removing microplastics and bulk plastics.