Photocatalytic degradation of 1, 2-dichloroethane by V/TiO₂: The mechanism of photocatalytic reaction and byproduct

The nano-sized V/TiO₂ prepared by a sol-gel method calcined at 500°C for 3 h was characterized in this study. The synthesized photo-catalysts were used for the photo-degradation of 1, 2-dichloroethane (1, 2-DCE). From X-ray powder diffraction data, the crystal phase presents the mixture of anatase and rutile phases with anatase the dominant phase. From TEM images, the crystallites of photo-catalysts are spherical particles with a crystallite size about 10-20 nm. UV-Visible absorption spectra of V/TiO₂ show a slightly increase in absorbance in the visible light region with the increasing vanadium ion doping concentration. The X-ray photoelectron spectroscopy results indicate that the doped vanadium ions exist in the form of V (IV). The V (IV) may alleviate the surface poison phenomenon and act as both h⁺/e^- traps to reduce the recombination rate of h⁺/e^- pairs, and the optimum vanadium doping amount is 0.01 mol%. The products and byproducts of 1, 2-DCE photo-degradation include H₂O, CO, CO₂, C₂H₅Cl, CH₂Cl₂, and HCl.