摘要
The novel nitrogen doped two-dimensional CeO 2 –TiO 2 nanosheets with a thickness of less than 5 nm were synthesized by a facile impregnation method using Chinese rose petals as biological templates. The detailed characterization by field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) exhibited that the CeO 2 –TiO 2 composites exactly duplicated the microstructure of Chinese rose petal and the self-owned nitrogen was successfully doped into the CeO 2 –TiO 2 composites, which could enhance the visible light absorption efficiency. UV–Vis diffuse reflection spectroscopy (DRS), photocurrent measurement (PM), electrochemical impedance spectroscopy(EIS) and photoluminescence spectroscopy (PL) were used to analyze the electrons and holes separation efficiency, which revealed that CeO 2 and TiO 2 formed well-defined hetero junctions promoting the effective separation of photogenerated electrons and holes. The photocatalytic activity of the samples was evaluated by photocatalytic degradation of dibenzothiophene (DBT) in model oil. The amount of hydrogenperoxide (H 2 O 2 ) and photocatalysts , the molar ratios of Ce and Ti in CeO 2 –TiO 2 composites as photocatalytic reaction conditions were investigated. Results showed that the removal rate of DBT could reach 93.7% under visible light irritation for 3 h, when the molar ratio of Ce/Ti was 1/1, the mass ratio of photocatalyst/DBT was 1/2 and the molar ratio of H 2 O 2 /DBT was 2/1. The trapping experiments confirmed that the photoinduced active species (•OH radical) was responsible for the degradation of DBT. Further studies demonstrated that DBT was converted to the corresponding sulfone, which could be extracted by the polar solvent. Moreover, a plausible mechanism for the photocatalytic oxidative desulfurization of this nanocomposite was proposed.
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