Study On Preparation And Photocatalytic Activity Of Doped TiO₂ Synthesized At Low Temperature

A series of iron doped TiO2 nanoparticles with different Fe content were synthesized by a facil sol-gel-waterbath method at lower temperature.Under the condition of the optimal Fe doping content,the Fe doped TiO2 with different preparation conditions was obtained by changing the conditions of water bath.The nanoparticles were characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),UV-vis diffusion reflectance spectrometry(DRS),X-ray photoelectron spectroscopy(XPS)and Raman spectroscopy(Raman).The results showed that all of the samples were composed of only an anatase TiO2 without the presence of iron oxide.The particles possessed uniform rhombus shape with the long-axis of 15 nm and the short-axis of about 3 nm.The doping of Fe did not alter the crystalline structure,particle size and dispersivity of TiO2.The nanoparticles exhibited higher visible light absorption than pure TiO2,which is beneficial for the visible light photocatalytic activity.The doping Fe existed in the form of Fe(III)and Fe-O-Ti by sbustituting for Ti4+ cations in the TiO2 lattices,and so more oxygen vacancies generated.This is also favorable to the photocatalytic activity of TiO2.The visible-light photocatalytic activities of the as-prepared samples were evaluated by the degradation of methyl orange(MO)in an aqueous solution under visible light irradiation.The results revealed that the as-prepared Fe-doped TiO2 nanoparticles exhibited excellent visible light photocatalytic activity.The effects of doping-Fe content and water-bath treating conditions(such as temperatue and pH value of water-bath)on the visible light photocatalytic activity of Fe-TiO2 nanoparticles were investigated.With the Fe dopant content increasing from 0 to 5.0%,the visible light photocatalytic activity of the as-prepared Fe-TiO2 increased at first,and then decreased,the optimal doping content was determined as ca.0.5%.With the water-bath temperature increasing,the visible light photocatalytic activity of Fe-TiO2 increased first and then decreased,the optimal temperature was ca.70 ?,The Fe-TiO2,prepared under acidic conditions,possessed higher visible light photocatalytic activity.A novel photocatalyst with core-shell structure was prepared by immersing TiO2 nanoparticles in Fe(NO3)3 solution.The as-prepared nanocomposites showed much higher visible light photocatalytic activity than pure TiO2.