Highly ordered TiO2 nanotube array as recyclable catalyst for the sonophotocatalytic degradation of methylene blue

TiO2 nanotube array was prepared by the anodic oxidation method and was characterized by XRD and TEM. The inner pore diameter, wall thickness and length of TiO2 nanotube are about 60 nm, 19 nm and 1.93 μm, respectively. The porosity and specific surface area calculated are 55% and 27.4 m2 g−1, respectively. The sonophotocatalytic activity of TiO2 nanotube array was evaluated by the degradation of methylene blue. The results show that the frequency has great effect on the synergy between sonolytic and photocatalytic degradation. At 27 kHz, the synergistic effect is as high as 22.1%. The catalyst also shows good recyclability.