Enhanced photoelectrochemical and photocatalytic behaviors of MFe 2 O 4 (M = Ni, Co, Zn and Sr) modified TiO 2 nanorod arrays

Abstract

Modified TiO 2 nanomaterials are considered to be promising in energy conversion and ferrites modification may be one of the most efficient modifications. In this research, various ferrites, incorporated with various cations (MFe 2 O 4, M = Ni, Co, Zn, and Sr), are utilized to modify the well aligned TiO 2 nanorod arrays (NRAs), which is synthesized by hydrothermal method. It is found that all MFe 2 O 4 /TiO 2 NRAs show obvious red shift into the visible light region compared with the TiO 2 NRAs. In particular, NiFe 2 O 4 modification is demonstrated to be the best way to enhance the photoelectrochemical and photocatalytic activity of TiO 2 NRAs. Furthermore, the separation and transfer of charge carriers after MFe 2 O 4 modification are clarified by electrochemical impedance spectroscopy measurements. Finally, the underlying mechanism accounting for the enhanced photocatalytic activity of MFe 2 O 4 /TiO 2 NRAs is proposed. Through comparison among different transition metals modified TiO 2 with the same synthesis process and under the same evaluating condition, this work may provide new insight in designing modified TiO 2 nanomaterials as visible light active photocatalysts.