Fabrication of tunable 1D rod-like and 3D yolk-like TiO2 hierarchical architectures for efficient photocatalysis

TiO2 has attracted significant interest owning to their excellent photocatalytic properties. However, controlled preparation of TiO2 with satisfactory morphology is still an urgent challenge in this field. In this work, tunable one-dimensional (1D) rod-like and three-dimensional (3D) yolk-like N-doped TiO2 hierarchical architectures were successfully fabricated by one-step solvothermal route. A comparative study on morphological, structural and optical behavior of 1D and 3D TiO2 is conducted by SEM, TEM, BET, XPS, UV-Vis DRS, photoelectrochemical and photodegradation experiments. The resultant N-doped TiO2 with specific surface area of 190.8 m(2) g(-1) and 166.6 m(2) g(-1) for rod-like structure and yolk-like structure, respectively, exhibited excellent photocatalytic performance using rhodamine B (RhB), methylene blue (MB) and phenol as the degraded pollutants under visible-light irradiation. Benefiting from the direct electrical path, multiple internal reflections of light and high specific surface area, the rod-like N-doped TiO2 possessed higher photocatalytic efficiency. Specifically, for rod-like N-doped TiO2, the reaction rate constant of the photodegradation for RhB, MB and phenol reached 12.1, 6.9 and 76.0 times, respectively, compared with P25. In comparison with yolk-like N-doped TiO2, the rate constant raised 1.5, 1.3 and 1.3 times. In addition, the formation mechanism of such controllable-morphology structure was also analyzed. This work suggests that the proper hierarchical structure combined with a large specific surface area plays a significant role on photocatalytic performance.