Preparation Of Visible Light Photocatalyst From TiO₂ And Polybutadiene

A series of TiO2/polybutadiene nanocomposites were prepared by the solution immersion method.The bromopolybutadiene was synthesized by brominating polybutadiene on the TiO2 surface in a bromine solution.The TiO2/conjugated polymer(CP/Ti02)nanocomposites were successfully synthesized by dehydrobromination of bromopolybutadiene when TiO2/bromopolybutadiene nanocomposites were heated at higher tempereatures.The CP/TiO2 nanocomposites were characterized by transmission electron microscopy(TEM),Fourier-transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),Energy dispersive spectroscopy(EDS),Raman spectroscopy,and UV-vis diffuse reflectance spectroscopy(UV-vis DRS).The results show that the layer of conjugated polymer,absorbed on the TiO2 surface,does not change the size,crystalline structure and dispersivity of the TiO2 nanoparticles,while greatly improves the absorbancy of the CP/TiO2 nanocomposites in the whole range of visible light.The visible light absorbancy of the CP/TiO2 nanocomposites increases as the content of conjugated polymer increasing,while increases first and then decreases as the heating temperature or time during the preparation of the samples increasing.The visible light photocatalytic activity of CP/Ti02 nanocomposites were studied by evaluating the degradation of methyl orange as the the model contaminant under visible light obtained from the two fluorescent lamps with a 400 nm cutoff filter to ensure the desired irradiation light.The results show that the CP/TiO2 nanocomposites have excellent visible light photocatalytic activity.The effects of chemical composition of the nanocomposites,heating temperature and time,pH value of MO solution,scavenger of electrons or holes on the visible light photocatalytic activity of CP/TiO2 nanocomposites were investigated.As the content of conjugated polymer,heating temperature and time,photocatalyst concentration or pH value of MO solution increasing,the visible light photocatalystic activity of CP/TiO2 nanocomposites increases first and then decrases,and reaches the highest when the mass ratio of conjugated polymer and TiO2,heating temperature and time,and pH value of MO solution are 1:50,150?,2 h,and 4.8,respectively.The photodegradation rate of MO in the presence of CP/TiO2 nanocomposites is little affected by isobutyl alcohol(electron scanvenger)while significantly depressed by ethylene diamine tetraacetic acid(EDTA,hole scavenger),indicating that the photogenerated holes may be the main active species in MO degradation photocatalyzed by CP/TiO2 nanocomposites.