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Abstract
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tCNT–TiO2nanocomposites were prepared through (i) simple mixing of as prepared CNTsand TiO2nanoparticles (NPs), (ii) simple mixing of as prepared CNTs and TiO2NPs followedby heat treatment and (iii) simple mixing of as prepared CNTs and TiO2NPs followed byUV illumination. The synthesis of CNTs and TiO2NPs were performed individually by arcdischarge in water and sol–gel methods, respectively and characterized by X-ray diffraction(XRD), ultra violet and visible spectroscopy (UV–vis), Fourier transform infrared spectroscopy(FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM).The visible-light photocatalytic performance of CNT–TiO2nanocomposites was successfullydemonstrated for the degradation of Rhodamine B (Rh. B) as a model dye at room temper-ature. It is found that CNT–TiO2nanocomposites extended the light absorption spectrumtoward the visible region and considerably improved the photocatalytic efficiency undervisible-light irradiation. The visible-light photocatalytic activities of CNT–TiO2nanocom-posites in which CNTs are produced by arc discharge in deionized (DI) water at 40, 60 and80 A arc currents and combined through three different protocols are also investigated. Itwas found that samples prepared at 80 A arc current and 5 s arc duration followed by UV illu-mination revealed best photocatalytic activity compared with the same samples preparedunder simple mixing and simple mixing followed by heat treatment. The enhancement inthe photocatalytic property of CNT–TiO2nanocomposites prepared at 80 A arc current fol-lowed by UV illumination may be ascribed to the quality of CNTs produced at this current,as was reported before.
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