Nano-TiO₂ Photocatalytic Materials Preparation And Modification

Nano-TiO₂ which was widely used that has been considered as a promising material for application because of its high chemical stability, non-toxicity, lowcost and corrosion resistant. However, the high band gap of pure TiO₂ (absorbing only the UV light) and the high rate of electron-hole recombination on TiO₂ particles result in a low eficiency of photocatalysi. TiO₂ doping is one of the most eficient methods to improve the photocatalytic eficiency of TiO₂.The incorporation of magnetic iron oxide into titania provides a way to solve the embarrassments in practical applications, separation and recovery of titania, which is traditionally difficult to control and dealThrough sol-gel method ,we synthesized pure titania and Fe³⁺-doped titania nano powder with tetrabutyl titanate, and iron nitrate as precursor, and we have synthesized magnetic (γ-Fe₂O₃@SiO₂)_n@TiO₂ core/shell hybrid nanoparticles withγ-Fe₂O₃@SiO₂ fine particles dispersing in the titania matrix. We analysed the diameters, morphologies phases,heat stability and photocatalytic ability of the powder in special instrument,such as TEM,XRD,DTA-TG thermoanalyzer,UV-Vis spectrophotometer. Photodegradation examination of the magnetic core/shell hybrid nanoparticles was carried out in methylene blue solutions illuminated under UV light in a photochemical reactor. It is shown that the (γ-Fe₂O₃@SiO₂)_n@TiO₂ functional core/shell hybrid danoparticles display good photocatalytic ability. It indicated that the Fe³⁺-doped titania powder prepared by Sol-Gel method was small and uniformity, the nanoparticles was spherical and particle size was about 15nm.Through spectrum scaning of the powder in the range of 500-190nm, we observed that the Fe³⁺enhanced the absorption intensities of titania in the range of ultraviolet and visible light.Compared with pure titania,the spectrum of Fe³⁺-doped titania had a red-shif in the range of visible light,which was responsible for the enhancement of photocatalytic ability of titania.Photodegradation examination of core/shell hybrid nanoparticles.so that thephotocatalytic ability of the as-prepared hybrid core/shell magnetic particles withγ-Fe₂O₃ core coated by silicon oxides is close to that of pure titania, while the methylene blue dose not decompose under the illumination of UV light in the absence of photocatalyst. More importantly, the core/shell hybrid nanoparticles display super-paramagnetic characteristics as the diameter of theγ-Fe₂O₃ is about 10 nm. The super-paramagnetic characteristics of the hybrid nanoparticles can completely eliminate the magnetic reunion. The incorporation of magnetic iron oxide into titania provides a way to solve the embarrassments in practical applications, separation and recovery of titania, which is traditionally difficult to control and deal with in the field of photocatalytic and biotechnological applications related to titania functional materials.