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. (paper)