Photocatalytic degradation of gaseous toluene over Ag-doping TiO 2 nanotube powder prepared by anodization coupled with impregnation method

Abstract

In this work, Ag-doping TiO 2 nanotubes were prepared and employed as the photocatalyst for the degradation of toluene. The TiO 2 nanotube powder was produced by the rapid-breakdown potentiostatic anodization of Ti foil in chloride-containing electrolytes, and then doped with Ag through an incipient wetness impregnation method. The samples were characterized by scanning electron microscope, high-resolution transmission electron microscopy, X-ray diffraction, surface photovoltage measurements, X-ray photoelectron spectroscopy and N 2 adsorption. The nanotubular TiO 2 photocatalysts showed an outer diameter of approximately 40 nm, fine mesoporous structure and high specific surface area. The photocatalytic activity of Ag-doping TiO 2 nanotube powder was evaluated through photooxidation of gaseous toluene. The results indicated that the degradation efficiency of toluene could get 98% after 4 h reaction using the Ag-doping TiO 2 nanotubes as the photocatalyst under UV light illumination, which was higher than that of the pure TiO 2 nanotubes, Ag-doping P25 or P25. Benzaldehyde species could be observed during the photocatalytic oxidation monitored by in situ FTIR, and the formed benzaldehyde intermediate during reaction would be partially oxidized into CO 2 and H 2O.