Preparation of BiFeO3-overcoated TiO2 nanorod arrays for the enhanced visible-light activity

In this work, a multiferric photosensitizer BiFeO3-coupled TiO2 nanorod arrays was synthesized by loading BiFeO3 on TiO2-NRs using a two-step process. The BiFeO3 was first prepared by a sol-gel precursor method and then spin-coated onto TiO2 nanorod arrays, which were grown on an FTO substrate by the hydrothermal method. The prepared BiFeO3/TiO2 photoelectrode was photoactive under visible light illumination, which exhibited higher photocurrent and excellent photochemical stability compared with bare TiO2 nanorod arrays. The feasibility of photogenerated charge transfer in BiFeO3/TiO2 was confirmed by electrochemical-impedance-spectroscopy. The BiFeO3/TiO2 nanorod arrays exhibited an enhanced photocatalytic performance in the degradation of methylene blue aqueous solution, likely due to the loading of the BiFeO3 photosensitizer, the formation of a heterostructure between the BiFeO3 and TiO2, and the nano-array morphology of the photocatalysts.