Prepatation Of Iodine Doprd Titanium And Magnetic Iodine Doprd Titanium Photocatalyst And Itsactivity In Photocatalysis

Iodine-doped titania （I-TiO₂） may greatly increase the use of visiblelight. so it is very important to study the influence to photocatalysis ofI-TiO₂preparation conditions, the photocatalytic mechanism of I-TiO₂and the photocatalysis of magnetic I-doped TiO₂photocatalyst. In thepresent work, Iodine-doped titania photocatalysts and magneticI-TiO₂/SiO₂/Fe₃O₄photocatalysts （ITSF） were synthesized andcharacterized. The photocatalytic activity of I-TiO₂and ITSF catalystswas evaluated using phenol as a model compound under visible lightirradiation.X-ray diffraction （XRD） was used to characterize the structuralproperties of iodine-doped titania photocatalysts （I-TiO₂）. Therelation-ship between the bestpreparation conditions of photocatalysts and photocatalytic activity were investigated. XRD results showed thatthe I-TiO₂catalysts were composed of anatase and rutile phase.Photocatalytic activity of I-TiO₂has been evaluated by degradation ofphenol under visible light irradiation. The results show that the I-TiO₂catalysts with20%（molar ratio） iodine,300mL water, hydrolyzed at20oC and calcinated at400oC exhibits the highest catalytic efficiency.With the aid of the introduction of various free radicals scavengers andthe decrease of dissolved oxygen, it is speculated that the photocatalyticdegradation of phenol primarily proceeded by photogeneratedh+vb/OH_ads.The photocatalytic degradation of phenol irradiated with visible lightover iodine doped TiO₂（I-TiO₂） modified with SiO₂/Fe3O4（SF）nanoparticles has been investigated in this study. A series of iodine-dopedtitanium dioxide （I-TiO₂） photocatalysts was synthesized by usingsilica-coated Fe₃O₄（SF） as the magnetic core（abbreviated here as ITSF）,in order to facilitate the efficient recovery of thesephotocatalysts.Transmission electron microscopy and X-ray diffraction resultsindicatedthat the ITSF nanoparticles had a ternary structure with a core of Fe3O4, aSiO₂mesosphere and an I-TiO₂crust with a mixture of anatase andrutilephases. Magnetic measurements with a vibrating sample magnetometershowed that the ITSF core-shell structures exhibited favorablesuperparamagnetic behaviors and the magnetic saturation value decreased after coating with the non-magnetic I-TiO₂layer. The photocatalyticactivity ofthe particles was tested by degrading an aqueous phenolsolution under visible-light illumination. The photocatalytic activity ofthe multi-functionalhybrid magnetite nanoparticles was enhanced withincreasing content of TiO₂, while the magnetism of the compositeparticles decreased. Moreover, anoptimum molar ratio of1:10I/TiO₂wasdetermined for the efficient degradationof phenol. The study showed thatthe presence of SF magnetic core would behelpful in the separation andrecovery of I-TiO₂photocatalysts.