Study On Photocatalytic Activity Of Poly (3-Hexylthiophene)-Modified Nanoparticles Titanium Dioxide

Poly（3-hexylthiophene）（P3HT） was synthesized via chemical oxidative polymerization with anhydrous FeCl₃ as oxidant,3-hexylthiophene（3HT） as monomer, chloroform as solvent.TiO₂/P3HT nanocomposites were prepared by blending TiO₂ nanoparticles（P-25） and P3HT in chloroform solution.The resulting photocatalysts were characterized by Transmission electron microscopy（TEM）,X-ray diffractiometer（XRD）, X-ray photoelectron spectroscopy（XPS）,Fourier transform infrared spectrocopy（FTIR）, UV-vis-diffuse reflectance spectroscope（DRS） and specific surface area（SSA）.The results showed that the morphology,thecrystalline pahse and the particle diameter of TiO₂/P3HT did not change comparing TiO₂.Specific surface area reduced slightly.The absorption of TiO₂/P3HT nanocomposites increased in the visible region.The photocatalytic activities of TiO₂/P3HT nanocomposites were studied by degradation of methyl orange,rhodamine B and malachite-green.It can be concluded that the photocatalytic activities of titania were improved under the visible light,UV light and sunlight irradiation after modified by poly（3-hexylthiophene）.The photocatalytic activities of TiO₂/P3HT nanocomposites increased at first and then decreased with the increasing the proportion of P3HT.TiO₂/P3HT nanocomposites possessed the optimal photocatalytic activity when the molar ratio of TiO₂/3HT was 75:1.TiO₂/P3HT nanocomposites showed that after 10 successive cycles under the visible light irradiation,the degradation rate of MO was still 60%of that of the first cycling run,indicating that TiO₂/P3HT nanocomposites possessed excellent photocatalytic stability.The impact of hole inhibitors（EDTA） and free radical inhibitors（t-BuOH） on the photocatalytic activity of TiO₂/P3HT was also studied.Combined with the results of other studies,the mechanism of the degradation of contamination with TiO₂/P3HT was discussed.This suggested that holes were the main active species in the photodegradation process.The electron-hole pairs were separated effectively by electron transporting of the P3HT.Consequently the electron-hole recombination was reduced and the photocatalytic ability was improved remarkably.