TiO2/Fe2O3 heterostructures with enhanced photocatalytic reduction of Cr(vi) under visible light irradiation

We report a study on the synthesis of TiO2/Fe2O3 (TF) nanocomposites and their photocatalytic performance under visible-light irradiation. The characterization of structure and morphology shows that hematite Fe2O3 was deposited on anatase TiO2 nanoparticles with particle sizes in the range of 20-100 nm. In contrast to pure TiO2 and pure Fe2O3, the nanocomposites exhibited remarkable photocatalytic activity. For example, the photoreduction efficiency of TF0.5 reaches 100% for a 100 ppm Cr(vi) solution within 160 minutes. The photochemical properties were studied by various methods. Finally, we conclude that the excellent performance of the photocatalysts is mainly attributed to two aspects: the enhanced absorption of visible light and the synergistic effect of an internal electric field at the heterojunction and citric acid for promoting the separation of electron-hole pairs.