Effect of Conditions for Preparation of Cyclized Polyacrylonitrile Sensitized TiO_2 Nanoparticles on Visible-light Photocatalysis and Photo Absorbance Property

摘要

Cyclized polyacrylonitrile (CPAN) sensitized titanium dioxide (TiO_2) nanoparticles were prepared by dip method. Photocatalysis and photo absorbance property of TiO_2/CPAN were measured. The photocatalytic activity of the nanocom-posites was evaluated by decomposition of an ordinary dye Reactive Brilliant Red X-3B in an aqueous solution under visible light irradiation. Results show that TiO_2/CPAN nano-composites with CPAN content of 0.5% have the highest photocatalytic activity. The optimum cydized temperature is 300℃, and cydized time is 1 h. Ultraviolet-visible diffuse reflectance spectra indicate the photo absorbance property of TiO_2/CPAN nanoparticles in the range of visible light is higher than that of TiO_2 nanoparticles. Fluorescence spectra indicate that introduction of trace CPAN onto TiO_2 nanoparticles can efficiently decrease the recombination probability of photo-generated electrons and holes, so the visible light photocatalysis of TiO_2/CPAN nanocomposites is significantly improved. The morphology and microstructure of TiO_2 and TiO_2/CPAN nanocomposites were characterized by transmission electron microscopy and X-ray diffraction. Results show that the size of TiO_2/CPAN nanocomposites is similar to that of TiO_2 nanoparticles.