Synthesis of Cu-Doped Mixed-Phase TiO sub(2) with the Assistance of Ionic Liquid by Atmospheric-Pressure Cold Plasma

An atmospheric-pressure dielectric barrier discharge (DBD) gas-liquid cold plasma was employed to synthesize Cu-doped TiO sub(2) nanoparticles in an aqueous solution with the assistance of [C sub(2)MIM]BF sub(4) ionic liquid (IL) and using air as the working gas. The influences of the discharge voltage, IL and the amount of copper nitrite were investigated. X-ray diffraction, N sub(2) adsorption-desorption measurements and UV-Vis spectroscopy were adopted to characterize the samples. The results showed that the specific surface area of TiO sub(2) was promoted with Cu-doping (from 57.6 m super(2).g super(-1) to 106.2 m super(2).g super(-1) with 3% Cu-doping), and the content of anatase was increased. Besides, the band gap energy of TiO sub(2) with Cu-doping decreased according to the UV-Vis spectroscopy test. The 3%Cu-IL-TiO sub(2) samples showed the highest efficiency in degrading methylene blue (MB) dye solutions under simulated sunlight with an apparent rate constant of 0.0223 min super(-1), which was 1.2 times higher than that of non-doped samples. According to the characterization results, the reasons for the high photocatalytic activity were discussed.