Visible light photocatalytic activity of TiO2 with carbon-fluorine heteroatoms simultaneously introduced by CF4 plasma

CF 4 plasma treatment is performed on commercial TiO 2 to improve the photocatalytic efficiency. The CF 4 plasma treatment is a facile and fast method for simultaneous introduction of carbon and fluorine atoms onto TiO 2 . Photodegradation of rhodamine B, methyl orange, and methylene blue is carried out under solar light irradiation to determine its CF 4 plasma treatment effect. The dye removal of commercial TiO 2 to rhodamine B, methyl orange, and methylene blue is 60.0, 18.9, and 49.2%, respectively, whereas TiO 2 treated with CF 4 plasma for 50 min is 93.5, 71.0, and 88.6% for rhodamine B, methyl orange, and methylene blue, respectively. In addition, the photodegradation rate constants of TiO 2 treated with CF 4 plasma for 50 min were 0.0135, 0.0083, and 0.0129 min −1 for rhodamine B, methyl orange, and methylene blue, respectively, which are up to 7.5 times higher than that of untreated TiO 2 (0.0049, 0.0011, and 0.0039 min −1 ). This improvement is attributed to the increase in oxygen vacancies by the introduction of carbon atoms into TiO 2 using CF 4 plasma treatment. In addition, the F − ions physically adsorbed to the TiO 2 surface promote the formation of hydroxyl free radicals, enabling effective decomposition of various dyes.