In situ generated g-C3N4/TiO2 hybrid over diatomite supports for enhanced photodegradation of dye pollutants

The highly efficient g-C3N4/TiO2 heterojunction was deposited over diatomite supports through an in situ deposition process. The microstructure, morphology and optical properties of the novel g-C3N4/TiO2@diatomite composite were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR) and UV-visible diffused reflectance spectroscopy (UV-vis DRS). The photocatalytic efficiency of g-C3N4/TiO2@diatomite composite was evaluated by the degradation of rhodamine B and methylene blue under visible light and simulated solar light. It is indicated that the as-synthesized g-C3N4/TiO2@diatomite composite displayed higher photocatalytic performance than pure g-C3N4 and TiO2. This enhancement should be ascribed to that diatomite can play as an excellent catalyst carrier to improve the dispersity of g-C3N4/TiO2 and increase the reactive sites for dye pollutants degradation. The CN/T@DE-10% exhibited the highest efficiency towards RhB, which was around 2.5 times under visible light and 3.5 times under solar light asmuch as that of the pure g-C3N4. In addition, the final removal rates of RhB reach to 96% within 3 h under solar light and 83% within 6 h under visible light, respectively. On the other hand, the g-C3N4/TiO2@diatomite composite can be easily separated from suspension and presents a good durability during five cycles. The outstanding properties of g-C3N4/TiO2@diatomite composite and high photocatalytic efficiency make it promising for the potential application in the dye waste water treatment. (C) 2016 Elsevier Ltd. All rights reserved.