Transition metal oxides (MnO, NiO, Co₂O₃ and CuO) 1 w % loaded on acid treated TiO₂ nanorods were successfully prepared by chemical treatment and wet impregnation method. The catalyst were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FT-IR) and UV-visible diffuse reflectance spectroscopy (UV-DRS). FT-IR results confirmed the presence of H₂O and OH groups on the surface of acid treated photocatalyst and TEM and XPS results confirmed the fine dispersion of metal and their oxide on TiO₂ nanorods. The photocatalytic activity of as-prepared, acid treated, metal oxide loaded and metal oxide loaded on acid treated nanorods were compared and rate constant values were determined from kinetics of the degradation of Orange (II) dye. Cobalt oxide 1w% loaded on 1.0 M acid treated TiO₂ nanorods exhibited the higher photocatalytic Orange (II) degradation efficiency 98.57% (within 120 min) than as-prepared and metal loaded acid treated samples under the solar irradiation. The synergistic effect of cobalt oxide 1w% loaded on 1.0 M acid treated TiO₂ nanorods over Orange (II) degradation is considered due to fine dispersion of metal oxides on the OH rich surface of acid treated TiO₂nanorods. The mechanism of enhanced photocatalytic activity and photoelectrochemical analysis of photocatalyst also studied.

Key words: TiO₂rutile nanorods; acid treatment; wet impregnation; transition metal oxides, dye degradation; synergistic effect

Acknowledgments

This research was supported by the BK21 plus and Basic Science Research Programs (2012R1A6A3A04038530) funded by the Korean National Research Foundation (NRF).