Gel-hydrothermal synthesis of carbon and boron co-doped TiO2 and evaluating its photocatalytic activity.

Carbon and boron co-doped TiO(2) photocatalysts were prepared firstly by the gel-hydrothermal method, that is, synthesized through sol-gel process followed by hydrothermal in the glucose solution. The prepared photocatalysts were characterized by XRD, Raman spectra, TEM, N(2) physical adsorption, XPS, and UV-vis absorption spectra. It was found that the co-doped TiO(2) has a larger BET surface areas and a narrower band gap than undoped TiO(2). The experimental results show that the coke carbon generated on the carbon doped TiO(2) surface act as a photosensitizer and has the photosensitization effect under the visible light. Except for carbon sensitization effect, the boron and carbon co-doped TiO(2) has synergistic effect which is responsible for effective photo-degradation of 2,4-dichlorophenol in the visible light irradiation.

Wu Y ，Xing M ，Zhang J 《-》

Highly efficient visible light TiO2 photocatalyst prepared by sol-gel method at temperatures lower than 300°C.

Highly efficient visible light TiO(2) 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 TiO(2) 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 TiO(2) 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 TiO(2) is greatly higher than those of the commercial TiO(2) (P-25) and other visible photocatalysts reported in literature (such as PPy/TiO(2), P3HT/TiO(2), PANI/TiO(2), N-TiO(2) and Fe(3+)-TiO(2)) and its photocatalytic stability is excellent. The reasons for improving the visible light photocatalytic activity of the as-prepared TiO(2) can be explained by carbon self-doping and a large amount of visible photosensitive groups existing in the as-prepared TiO(2). The apparent optical thickness (τ(app)), local volumetric rate of photo absorption (LVRPA) and kinetic constant (k(T)) of the photodegradation system were calculated.

Wang D ，Xiao L ，Luo Q ，Li X ，An J ，Duan Y ... -  《-》

Synthesis and characterization of La2O3/TiO2-xFx and the visible light photocatalytic oxidation of 4-chlorophenol.

In this work, we investigated the synergetic effect of La and F on the visible light photocatalytic activity of TiO(2) catalysts. La(2)O(3)/TiO(2-x)F(x) photocatalysts were prepared by a simple sol-gel process using tetrabutyl titanate (TBT), La(NO(3))(3) and NH(4)F as precursors. XPS results revealed that La(2)O(3) accumulated on the surface of TiO(2), which enhanced the surface area of TiO(2) and inhibited the recombination of electron-hole pairs. It also showed that two kinds of fluorine species were formed and these increased the acid active sites and enhanced the oxidation potential of the photogenerated holes in the valance band. UV-vis diffuse reflection spectra of La(2)O(3)/TiO(2-x)F(x) showed that intraband gap states were present and these are probably responsible for its absorption of visible light while the intrinsic absorption band was shifted slightly to a longer wavelength. At molar ratios of La and F to Ti of 1.5:100 and 5:100 and after calcination at 500 degrees C, the degradation rate of 4-chlorophenol (4-CP) over the sample was about 1.2-3.0 times higher than that of the other doped samples and undoped TiO(2). The total organic carbon (TOC) removal rates of 4-CP showed that 4-CP was mineralized efficiently in the presence of the sample under visible light illumination.

Cao G ，Li Y ，Zhang Q ，Wang H ... -  《-》

Photocatalytic activity of TiO2 doped with boron and vanadium.

Bettinelli M ，Dallacasa V ，Falcomer D ，Fornasiero P ，Gombac V ，Montini T ，Romanò L ，Speghini A ... -  《JOURNAL OF HAZARDOUS MATERIALS》

One-step hydrothermal synthesis of N-doped TiO2/C nanocomposites with high visible light photocatalytic activity.

Wang DH ，Jia L ，Wu XL ，Lu LQ ，Xu AW ... -  《-》