Preparation And Photocatalytic Properties Of Electrospun TiO₂/V₂O₅,TiO₂/SnO₂ Composite Nanofibers

TiO₂/V₂O₅,TiO₂/SnO₂ nanofibers were prepared from poly vinyl pyrrolidone (PVP)/ Ti(OiPr)4/ V(acac)3 and pyrrolidone (PVP)/ Ti(OiPr)4/SnCl4 composite were formed as a result of combining the sol–gel process with electrospinning technique,because of its large surface area-to-volume ratio, small fiber diameter, low weight and high porosity with very small pore size ability. These nanofibers could be subsequently converted into TiO₂/V₂O₅,TiO₂/SnO₂without changing their morphology via calcination in air. The structural properties of the composites were characterized by scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Raman spectroscopy, UV-vis diffuse scattering spectroscopy and X-ray-photoelectron spectroscopy (XPS). The results showed that:1. V₂O₅ was well dispersed into the TiO₂ structure, when the content of V₂O₅ was lower than 10 wt %. However, when the content of V₂O₅ content was as high as 20%, the composite nanofibers exhibited mixture phases of anatase and shcherbinaite.The resulting products exhibited homogeneous wall compositions,namely,TiO₂/V₂O₅,TiO₂/SnO₂ was uniformly dispersed into the TiO₂ framework with the loading levels of 1,5 and 10 mol% for V and 5.0mol% for Sn,respectively.The estimated size of the products ranged from 200 to 400 nm,and they showed only anatase phase although their starting solitary metal oxides exhibited suitable crystalline structures under the same preparation conditions.Raman scattering spectroscopy showed that the crystal structure of titania had a slight interference due to the incorporation of V₂O₅ or SnO₂, and UV-vis diffuse reflectance spectroscopy (DRS) showed the narrower band gap of the products compared with that of pure anatase TiO₂.2. Degradation of methylene blue (MB) dye was tested for the effectiveness of the TiO₂/V₂O₅,TiO₂/SnO₂ samples. The results showed the catalyst with the vanadium loading levels of 5mol% (T2) presented the best efficiency of photocatalysis. Moreover,the 5.0mol% of composite TiO₂/SnO₂ fibers after calcinations at 500℃showed the best efficiency of degradation of MB. and the reasons were discussed in detail.