Fabrication of Fe3O4@graphene/TiO2 nanohybrid with enhanced photocatalytic activity for isopropanol degradation

We report on the fabrication of a Fe3O4@graphene/TiO2 (F@G/TiO2) nanohybrid using a facile two-step hydrothermal method. Compared with either the binary graphene/TiO2 (G/TiO2) or pure TiO2, the ternary F@G/TiO2 nanohybrid exhibited an apparently improved performance for photocatalytic isopropanol (IPA) degradation, and the sample F-1@G/TiO2 (0.4 wt% Fe3O4 and 0.2 wt% graphene) achieved the highest activity (262.5 mmoL/h for acetone evolution; 28.8 mmoL/h for CO2 evolution) under an AM 1.5G solar simulator irradiation. In the F@G/TiO2 nanohybrid, the magnetic field arisen from Fe3O4 and the excellent electrical conductivity of graphene were believed to facilitate the separation and transport of photoinduced electrons and holes in TiO2. As a consequence, the synergetic effect could account for the enhanced photocatalytic activity of F@G/TiO2 nanohybrid. Mechanistic study indicated that O-2(center dot-) and hole were the main reactive oxygen species for photocatalytic IPA degradation. (C) 2019 Elsevier B.V. All rights reserved.