Preparation and properties of sliver and nitrogen co-doped TiO2 photocatalyst

•The silver and nitrogen co-doped TiO2 photocatalysts were prepared and characterized.•The light absorption threshold wavelength of Ag–N–TiO2 is red-shifted to visible light.•The recombination of the photo-generated electrons and holes of Ag–N–TiO2 is inhibited.•The photocatalytic activity of Ag–N–TiO2 is remarkable improved.

TiO2 photocatalysts co-doped with different content of Ag and N were prepared by sol–gel method combined with microwave chemical method. The samples were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), ultraviolet–visible diffuse reflectance spectrum (UV–vis) and photo-luminescence emission spectrum (PL). The photocatalytic activity was investigated by photocatalytic degradation of methylene blue (MB) under irradiation of fluorescent lamp. The results indicate that Ag and N co-doping can restrain the increase of grain size, broaden the absorption spectrum to visible light region, and inhibit the recombination of the photo-generated electron–hole pairs. Moreover, the photocatalytic activity of Ag–N–TiO2 in MB degradation is remarkable improved. The degradation rate of the sample with Ag:TiO2 = 0.05 at%, N:TiO2 = 18.50 wt% in 5 h is 93.44%, which is much higher than that of Degussa P25 (39.40%).

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