Synthesis and characterization of C, N-codoped TiO2 nanotubes/nanorods with visible-light activity

Visible-light response C, N-codoped TiO2 nanotubes with high aspect ratios were prepared by a two-step method. First the TiO2 nanotubes were synthesized by an ion-exchange method, and then the nanotubes were calcined at different temperatures with melamine as nitrogen and carbon source. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis diffusive reflectance spectroscopy (DRS), scanning electron microscopy (SEM), and N2 adsorption-desorption isotherms were employed to characterize the as-prepared samples. The results show that the nanotubular structure is destroyed when the calcination temperature is higher than 823 K. Further increase the temperature to 923 K, TiO2 is reduced to TiO. The photocatalytic activity of the codoped TiO2 nanotubes/nanorods was evaluated by degradation of Rhodamine B under visible-light irradiation (> 420 nm). Compared with N doped P25, these codoped TiO2 nanotubes/nanorods possess a superior photocatalytic acticity, owing to the synergistic effects of the nitrogen and carbon co-doping.