Photocatalytic Degradation of Methyl Orange Using a TiO2/Ti Mesh Electrode with 3D Nanotube Arrays

To further improve the photocatalytic techniques for water purification and wastewater treatment, we successfully prepared a new type of TiO2/Ti mesh photoelectrode, by anodization in ethylene glycol solution. The three-dimensional arrays of nanotubes formed on Ti mesh show a significant improvement in photocatalytic activity, compared to the nanotube arrays formed on foil. This can be demonstrated by about 22 and 38% enhancement in the degradation efficiency per mass and per area, respectively, when TiO2/Ti mesh electrode was used to photocatalyze methyl orange (MO). Furthermore, the effects of different parameters on MO photodegradation were investigated, such as different photoelectrode calcination temperature, the initial pH value of MO solution, and the present of hydrogen peroxide. The superior photocatalytic activity could be achieved by the TiO2/Ti mesh photoelectrode calcinated at 550 degrees C, due to the appearance of mixed crystal phases of anatase and rutile. In strong acidic or caustic conditions, such as pH 1 or 13, a high degradation efficiency can be both obtained. The presence of H2O2 in photocatalytic reactions can promote photocatalytic degradation efficiencies. Moreover, the experimental results demonstrated the excellent stability and reliability of the TiO2/Ti mesh electrode.