Selective Nonaqueous Synthesis of C-Cl-Codoped TiO2 with Visible-Light Photocatalytic Activity

We demonstrate a low-temperature, one-pot nonaqueous sol gel method for the selective synthesis of C-Cl-codoped TiO2 with different crystal phases and morphologies, including anatase nanocrystals, rutile nanorods, and a mixed phase with anatase and rutile nanocrystals. The synthetic protocol employed titanium tetrachloride as the titanium precursor and the mixture of chloroform and ethanol as the solvent. The as-prepared C-Cl-codoped TiO2 powders were characterized in detail by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution TEM, X-ray photoelectron spectroscopy, and UV-vis diffuse reflectance spectroscopy. We evaluated their photocatalytic performances by the degradation of rhodamine B (RhB) solution under visible-light irradiation. On the basis of the above measurements, the doping process and dopant origin of C-Cl-codoped TiO2 as well as the formation mechanism of different phases were analyzed. We concluded that the tuning of the chloroform volume in the reaction system could easily control the final TiO2 phase and realize the controllable C-Cl codoping. The chlorine dopant in C-Cl-codoped TiO2 might originate from TiCl4, not from the decomposition of chloroform. We also analyzed the C-Cl-codoping modes and their influence on the visible-light photocatalytic activity of the final C-Cl-codoped TiO2. This study provides a facile, nonaqueous approach to synthesize tunable C-Cl-codoped TiO2 with enhanced visible-light-driven photocatalytic activity.