Photocatalytic degradation of Reactive Black 5 with TiO2-coated magnetic nanoparticles

A core-shell TiO2-coated magnetic nanomaterial, Fe3O4@SiO2@TiO2, was prepared, characterized and tested as photocatalyst in the degradation of Reactive Black 5 (RB5) dye by a UV-photocatalytic path. For comparison, two reference materials were also evaluated as photocatalysts in the same reaction: as-prepared non-magnetic TiO2 and TiO2 from Evonik Degussa Company (P25). TEM characterization confirmed the core-shell structure of the Fe3O4@SiO2@TiO2 nanocomposite, while SEM micrographs revealed that the particles presented a spherical morphology with sizes ranging from 140 to 160 nm. FTIR and XRD data confirmed the presence of magnetite (Fe3O4) cores, silica and anatase in the magnetic nanomaterial. The Fe3O4@SiO2@TiO2 photocatalyst in combination with UV irradiation led to a RB5 degradation of 91% after 60 min, which was very similar to the values achieved with the as-prepared TiO2 (93%) and with P25 (97%). Furthermore, the magnetic nanocatalyst was efficiently separated from the reaction medium by magnetic decantation and could be reused three times with no decrease of the photocatalytic performance. (C) 2012 Elsevier B.V. All rights reserved.