The effect of H-2-CCl4 mixture plasma treatment on TiO2 photocatalytic oxidation of aromatic air contaminants under both UV and visible light was reported. X-ray diffraction (XRD), UV-Vis spectroscopy, photoluminescence (PL), Temperature-programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS) were used to characterize the prepared TiO2 nanoparticles. Carbon atoms were doped into TiO2 by replacing titanium atoms whereas chlorine located on TiO2 surface to form Ti-Cl bond via the coordination with TO sites by plasma treatment. The carbon doping amount and surface chlorine content of TiO2 under H-2-CCl4 mixture plasma treatment were obviously higher than that under single CCl4 plasma treatment. H-2-CCl4 mixture plasma treated catalyst exhibited much higher photocatalytic oxidation performances of benzene and toluene than that of single CCl4 plasma treated catalyst and P25 under both UV and visible light. Chlorine radicals formed under illumination are effective in oxidizing aromatic side groups, but ineffective in reactions with the aromatic ring, thus benzene conversions were lower than that of toluene under both UV and visible light. The possible mechanism was proposed. (C) 2013 Elsevier B.V. All rights reserved.