Photocatalytic Property of Nanostructured S Doped TiO2 Films Prepared by the Micro Plasma Method

Mesoporous titanium dioxide thin films were prepared on titanium plates within a short time by a micro-plasma oxidation method. The films were used to degrade Rhodamine B, a textile industry pollutant. To increase the photocatalytic activity, different concentrations of CH4N2S were added into an H2SO4 electrolyte solution to make the doped S enter the films. X-ray diffraction and scanning electron microscopy were used to characterize the surface morphology, the composition, the crystal structure and microstructure of the modified films. Results show that the modified films are porous with different sizes of pores. The CH4N2S concentration in the electrolyte solution has a greater influence on the micropore density and the pore size of the film. S-doping can increase micropore density and specific surface area of the film, somewhat alters its crystal lattice parameter, but affects its crystal structure only a little. The photo-catalytic activity will be enhanced effectively by S-doping, for example, when the CH4N2S concentration in the electrolyte solution is 6.0 g/L, the photocatalytic degradation of Rhodamine B with the initial concentration of 10 mg/L by TiO2 thin films reaches 98% within 120 min, showing the maximum photocatalytic degradation of TiO2 films.