Effect of calcination temperature on the structure and visible-light photocatalytic activities of (N, S and C) co-doped TiO2 nano-materials

• Published in: Applied surface science 2015-03, Vol.332, p.172-180
• Main Authors: Lei, X.F., Xue, X.X., Yang, H., Chen, C., Li, X., Niu, M.C., Gao, X.Y., Yang, Y.T.
• Format: Article
• Language: English
• Subjects: (N, S and C) co-doping; Bonding; Calcination; Calcination temperature; Cr(VI); Photocatalysis; Photocatalytic activity; Scanning electron microscopy; Spectra; TiO2; Titanium dioxide; Visible light; X-ray photoelectron spectroscopy; X-rays
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2015.01.110

(N, S and C) co-doped TiO2 samples show good photocatalytic activity for Cr(VI) reduction under visible light irradiation. •(N, S and C) co-doping in TiO2 can preserve the anatase form to higher temperature.•(N, S and C) co-doped TiO2 samples can absorb both UV and visible light.•The band gap energy of the sample significantly reduced after (N, S and C) co-doping.•(N, S and C) co-doped TiO2 samples effective for visible light induced reduction of Cr(VI). The (N, S and C) co-doped TiO2 samples (NSC-TiO2) were synthesized by the sol–gel method combining with the high energy ball milling method calcined at the different temperature (400–700°C), employing butyl titanate as the titanium source and thiourea as the doping agent. The structures of NSC-TiO2 samples were characterized by X-ray diffraction (XRD), UV–vis diffuse reflectance spectra (DRS), X-ray photoluminescence (PL) spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetry and differential thermal analysis (TG–DTA), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), scanning electron microscopy (SEM) and nitrogen adsorption–desorption isotherms. The photocatalytic activities were checked through the photocatalytic reduction of Cr(VI) as a model compound under visible light irradiation. The results showed that the (N, S and C) co-doping and the calcination temperature played important role on the microstructure and photocatalytic activity of the samples. According to XPS spectra, sulfur was mainly attributed to the TiOS bond; nitrogen was ascribed to the TiON and TiN bonds; carbon was assigned to the TiOC bond in the NSC-TiO2 samples. (N, S and C) co-doped TiO2 samples calcinated at 500°C exhibits higher photocatalytic activity than that of the other samples under visible light irradiation, which can be attributed to the synergic effect of its enhancing crystallization of anatase and (N, S and C) co-doping.