Efficient Photocatalytic Removal of Toluene by Synergistic FeCe/TiO ₂ : Performance and Mechanism

ABSTRACT Efficient removal of volatile organic compounds (VOCs) in confined spaces is crucial for environments such as spacecraft and deep‐sea submarines. Metal modification is an effective strategy to enhance the light absorption capacity of titanium dioxide (TiO 2 ) and suppress the recombination of photogenerated charge carriers. However, the synergistic mechanisms between metal ions in modification systems remain unclear. In this study, Fe–Ce modified anatase TiO 2 (FeCe/TiO 2 ) was prepared via the sol–gel method, and its photocatalytic performance and mechanism were systematically investigated using toluene as the target pollutant. FeCe–1.5%/TiO 2 achieves 89.0% toluene removal and 85.7% mineralization within 60 min; the mineralization rate increased to 6.08 times that of unmodified TiO 2 . Its 75% visible‐light activity makes it suitable for indoor applications. Characterization by transmission electron microscopy (TEM) and other techniques shows that Fe is mainly doped into the TiO 2 lattice, introducing defect levels that extend the photo response range and inhibit charge recombination, whereas Ce is present as surface CeO x nanoclusters that serve as electron traps and boost mineralization through the Ce 3+ /Ce 4+ redox couple. The synergistic effect of Fe and Ce generated more oxygen vacancies and surface hydroxyl groups, promoting the formation of superoxide radicals (·O 2 − ) and hydroxyl radicals (·OH), thereby significantly enhancing toluene removal and mineralization. This study devises an efficient visible‐light photocatalyst for confined environments, unveils the Fe–Ce synergy, and offers novel insights for designing high‐performance VOC photocatalysts.