Were Doped Tio <sub> 2 </ Sub> Catalyst Preparation, Characterization And Properties Of Visible Light

Nano-sized TiO₂ photocatalytic technology has developed to be a kind of high efficient and environmental pollution control technologies. The current research focuses on the enhancement of photocatalytic activity and the efficiency of utilizing visible-light. Based on the current research of photocatalyst doping TiO₂ home and abroad, tri-doped TiO₂ nano-particles were synthetized in this paper. The structures and physical and chemical properties of the as-prepared samples were characterized by X-ray diffraction (XRD), nitrogen adsorption/desorption measurements (BET), Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS), Fourier transition infrared spectra (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (DRS) and surface photo-voltage spectroscopy (SPS). The photocatalytic activities of the tri-doped TiO₂ photocatalysts were evaluated through the degradation of RhB and phenol under visible-light irradiation, which were compared with the behaviors of the home-made pure TiO₂ and commercial Degussa P25TiO₂. In addition, the mechanisms of the enhancement of visible-light photocatalytic activity of the tri-doped TiO₂ nano-particles were analyzed in detailed.(1) Fe-N-S-tridoped TiO₂ photocatalyst was prepared via a sol-gel process by using ammonium ferrous sulfate as dopant. The effects of the doping dosage and calcining temperature on the structure and photocatalytic activity of the tri-doped TiO₂ photocatalysts were investigated. The results showed that the extension of light absorption edge in the range of visible-light was up to 670nm. The modified TiO₂ calcined at 350℃with 1.0 mol% ammonium ferrous sulfate content exhibited the best photocatalytic performance. Under the visible-light irradiation with 120min, the removal rate for RhB could achieve 91.5%. (2) C-N-S-tridoped TiO₂ photocatalyst was prepared through a sol-gel process by using cystine as dopant. The effects of the doping dosage and calcining temperature on the structure and photocatalytic activity of the tri-doped TiO₂ photocatalysts were also investigated. The results showed that the extension of light absorption edge in the range of visible-light was up to 800nm. The modified TiO₂ calcined at 350℃with 4.2 mol% cystine content exhibited the best photocatalytic performance. Under the visible-light irradiation with 120min, the removal rate for RhB could achieve 100%.(3) Under the 350W xenon lamp irradiation, the degradation of phenol was investigated with the as-prepared Fe-N-S-TiO₂ and C-N-S-TiO₂ photocatalysts previous. It was found that the two catalysts exhibited the excellent performance. Nevertheless, the removal rates of phenol with C-N-S-TiO₂ and Fe-N-S-TiO₂ photocatalysts were 2.5 and 2.2 times to that of home-made TiO₂, respectively. In addition, the reactions followed Langmuir-Hinshelwood (L-H) pseudo-first-order reaction kinetics model. Furthermore, C-N-S-TiO₂ presented higher photocatalytic activity than that of Fe-N-S-TiO₂, and its apparent rate constant (kAPP) and half-value period (t1/2) were 0.79h-1 and 0.88h, respectively.