Enhanced Photocatalytic Performance of Anatase TiO₂ by Deposition-Precipitation Treatment

Deposition-precipitation (DP) method is commonly used to prepare the supported metal catalysts. In this study, the modification effect of the mild DP method on the photocatalytic performance of TiO₂ was investigated. The TiO₂ samples with DP treatment, as well as Au/TiO₂ prepared under the same conditions, showed enhanced photocatalytic performance of the degradation of methylene blue (MB). ·OH generated by photoexcited holes is identified as the main intermediate reactive species during the degradation reaction. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) show that TiO₂(A)-17 after DP treatment has the most amount of surface \rmOH_\rmad^- species. The presence of surface \rmOH_\rmad^- species not only changes the surface zeta potential, favoring the attraction of cationic MB; but also depresses the electron-hole recombination, favoring photodegradation of MB by hole-produced ·OH. An implication of these findings is that the modification of support properties should be taken into account while preparing supported metal catalysts using DP methods.