Morphology Control Of Titania And Its Catalytic Properties

As an effective photocatalyst for degradation of organic pollutants, semiconductorhas becoming a research focus in recent years. Titanium dioxide （TiO₂） is paid moreattention than the other photocatalytic materials due to its various advantages such ashigh photocatalytic activity, chemical stability, non-toxic and low-cost et al. The objectof this study is titania, Work is divided into the following sections.Sea urchin-like anatase TiO₂nanostructure was hydrothermally synthesized underan acidic condition by using titanium potassium oxalate as the titanium source. Thecrystalline phase and morphology of the product was analyzed by X-ray diffraction（XRD） and scanning electron microscopy （SEM）. BET specific surface area of theproduct was calculated based on the N2adsorption-desorption isothermal curves and itspore size was calculated according to BJH method. The influence of the reaction timeon the morphology and size of titania was also investigated, and the growth mechanismare discussed on the basis of the morphology evolution following the reaction time. Thephotocatalytic efficiency of TiO₂samples with different crystallinity calcined underdifferent temperatures was compared for photodegradation of Rhodamine B dye.By using titanium potassium oxalate, hydrogen peroxide and ammonia as reactants,crystalline anatase TiO₂nanospindles partially enclosed by active {001} facets wassuccessfully synthesized via a facile one-step hydrothermal reaction in the absence ofany surfactant without calcination procedure. The crystalline phase and morphology ofthe product was analyzed by X-ray diffraction （XRD）, scanning electron microscopy（SEM） and transmission electron microscopy（TEM）. BET specific surface area of theproduct was calculated based on the N2adsorption-desorption isothermal curves. Underthe same conditions, the photodegradation of methyl orange, Congo red and rhodamineB were chosen as model pollutants to test the photocatalytic activity of theas-synthesized sample. For the purpose of comparison, the photocatalytic properties ofcommercial TiO₂nanopowder for degradation of the three dyes were also studied under the same conditions. The stability of the product was further investigated.The spindle-like Ag/TiO₂nanocomposite responding to visible light was preparedby applied an ultrasonic reduction method. The products were characterized by meansof X-ray diffraction （XRD）, scanning electron microscopy （SEM）, EDS analysis, XPS，fluorescence spectroscopy （PL） and UV-visible diffuse reflectance spectra. The catalyticactivity of the TiO₂nanospindles and the Ag/TiO₂nanocomposite was compared byusing Xenon lamp as light source to emit simulated sunlight.