Preparation, characterization of Au (or Pt)-loaded titania nanotubes and their photocatalytic activities for degradation of methyl orange

TiO2 nanotubes were prepared by hydrothermal method and Au (or Pt) was loaded on TiO2 nanotubes by photodeposition method. The photocatalysts were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and N2 adsorption technique, respectively. The photocatalytic properties of the samples were also investigated. The results show that TiO2 nanotubes with uniform diameter were prepared, and they have specific surface areas over 400 m2/g. The specific surface areas of TiO2 nanotubes decrease with the increasing of calcining temperature, and crystalline phase of TiO2 in the wall of nanotubes was transformed from anatase into rutile phase in calcination process. The photocatalytic activities of TiO2 nanotubes are higher than that of nanosized TiO2, and the photocatalytic activities of TiO2 nanotubes were enhanced after loading Au (or Pt). After irradiation for 40 min under a 300 W of middle-pressure mercury lamp (MPML), the degradation rate of methyl orange solution using the Au/TiNT-500 (or Pt/TiNT-500) as a catalyst can reach 96.1% (or 95.1%). On the other hand, Au-loaded sample has evident adsorption peak in visible range, indicating that Au-loaded TiO2 nanotubes are hopeful to become visible light photocatalyst.