Preparation Of Titania Photocatalyst Supported On Carbon Fiber And Its Photocatalytic Activity Under Visible Light

As we all know, anatase titanium dioxide（TiO₂） as an excellent performance photocatalytic material has been widely applied wastewater treatment because of its strong photocatalytic ability, low cost and eco-friendly. However, there are three drawbacks in the practical application of TiO₂ powder. Firstly, nanoparticles TiO₂ can only excited by ultraviolet light which wavelength less than 387 nm due to its wide band-gap（Eg = 3.2 eV）, which consequently reduces the utilization of solar energy. Secondly, the recombination of electron hole pairs generated by light on the surface of TiO₂ weakens the quantum efficiency. Furthermore, the deactivation, agglomeration, separation and recovery of TiO₂ photocatalyst from the treated water are always one of the major reasons why TiO₂ cannot come into full play in industrialization. To overcome above the disadvantages, firstly, some studies have focused on loading TiO₂ onto much larger supports of porous materials to solve the difficulties of condensed and recycled, such as molecular sieve, ceramic, glass, carbon, carbon fiber, etc. The supports have good pollutant adsorption and larger specific surface area. Furthermore, the introdution of impurity in crystal lattice of TiO₂ through a variety of methodes is an effective way to improve the photocatalytic activity since the recombination of photogenerated electrons and holes can be hindered and change the crystal morphology and structure. Therefore, the photocatalytic performance and the service life of the catalyst are improved.Based on the Iron（III） nitrate nonahydrate as the source of iron, urea as nitrogen source, thiourea as the sulfur source, and the pretreated carbon fiber（CF） as the carrier, a series of composite TiO₂/CF photocatalytic materials, such as TiO₂/CF、Fe/TiO₂/CF、Fe/N/TiO₂/CF、Fe/N/S/TiO₂/CF, were prepared by sol-gel and dipping method. Then the samples were characterized by Scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, UV-Visible diffuse reflection spectrum, Fourier transform infrared spectroscopy and BET method. Finally, the degradation of rhodamine B was used to evaluate the photocatalytic activity of the obtained under the different experimental conditions.The results show that the utilization of visible light of the samples can be improved since synergistic effect of doping-ions and CF, whether Fe doped and Fe, N, S co-doped. Fe/N/TiO₂/CF has the best photocatalytic activity when the molar ratio of Fe/N/Ti was 0.1%:0.8%:1, calcined at 500℃ for 4 h, the quantity of catalyst was 0.04 g, the initial concentration of RhB was 2.0×10-5 mol ·L-1 and pH was 8.0, and the degradation ration of RhB fell slightly after repeated four times, but not by much.