Effect of calcination temperature on the adsorption and photocatalytic activity of hydrothermally synthesized TiO2 nanotubes

TiO2 nanotubes (TNTs) were synthesized by modified hydrothermal method and characterized by the X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), thermogravimetric (TG) analysis, BET surface area analysis and Raman spectroscopy. The effects of calcinations temperature on the morphology, textural properties, adsorption amount and photocatalytic activity of TiO2 nanotubes were investigated. The results showed that the adsorption behavior and photocatalytic activity of TiO2 nanotubes strongly depended on the calcination temperature. Photocatalytic MB degradation on TiO2 nanotubes surface followed first-order kinetics and the photocatalytic activity of TiO2 nanotube calcined at 400 °C was higher compared to other TiO2 nanotube catalysts. The higher photocatalytic activity was mainly ascribed to the adsorption amount of MB on the TiO2 nanotubes and the intrinsic rate constant, a factor of reflecting the crystalline phases and crystallinity on the photocatalytic rate of TiO2 nanotubes. In addition, the change of the total organic carbon (TOC) of MB photocatalytic-reduction was examined, it was found that nanotubes calcinated at 400 °C exhibited a good effect for the mineralization of MB.