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摘要
Highly efficient visible light TiO2 photocatalyst was prepared by the sol–gel method at lower temperature (≤300 °C), and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), UV–vis diffuse reflectance spectroscopy (UV–vis DRS), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and differential scanning calorimetry-thermogravimetric analysis (DSC–TGA). The effects of the heat treatment temperature and time of the as-prepared TiO2 on its visible light photocatalytic activity were investigated by monitoring the degradation of methyl orange solution under visible light irradiation (wavelength ≥ 400 nm). Results show that the as-prepared TiO2 nanoparticles possess an anatase phase and mesoporous structure with carbon self-doping and visible photosensitive organic groups. The visible light photocatalytic activity of the as-prepared TiO2 is greatly higher than those of the commercial TiO2 (P-25) and other visible photocatalysts reported in literature (such as PPy/TiO2, P3HT/TiO2, PANI/TiO2, N–TiO2 and Fe3+–TiO2) and its photocatalytic stability is excellent. The reasons for improving the visible light photocatalytic activity of the as-prepared TiO2 can be explained by carbon self-doping and a large amount of visible photosensitive groups existing in the as-prepared TiO2. The apparent optical thickness (τapp), local volumetric rate of photo absorption (LVRPA) and kinetic constant (kT) of the photodegradation system were calculated.
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Highlights
► Mesoporous anatase nano-TiO2 photocatalyst was synthesized by sol–gel method at lower temperature (≤300 °C). ► Its visible light photocatalytic activity is greatly higher than that of TiO2 (P-25) and its photocatalytic stability is excellent. ► Carbon self-doping and visible photosensitive organic groups result in the improvement of the visible light photocatalytic activity.
