Normal Temperature Preparation And Characterization Of Nanosized TiO₂ Composites With Visible Light Photocatalytic Activity

Nano-TiO₂?nanosized titanium dioxide?has been regarded as a potential and environmental green nano-materials,due to lots of advantages such as a moderate bandgap,high photocatalytic efficiency,stable,non-toxic and low cost preparation features,it has been raised widespread concern in many fields like waste water treatment,air purification,self-cleaning,sensors,photoelectric conversion,antimicrobial,materials science,deodorization and pollutant degradation.In this study,nano-TiO₂ photocatalyst with visible light activity was prepared using nano-TiO₂ colloid?1%,w/w?,ferric nitrate and homemade nano-?-Fe₂O₃ as raw materials,and the application of paper coated with Fe³⁺ doped nano-TiO₂ effect is investigated.Ni²⁺,Mo⁶⁺,V⁵⁺,W⁶⁺,Co²⁺ et.al metal ion doped nano-TiO₂ photocatalyst were also prepared by in-situ composite method to assess the visible light photocatalysis at room temperature.The doped nanosized TiO₂ nanocomposites was characterized by X-ray diffraction?XRD?,X-ray electron spectroscopy?XPS?,scanning electron microscopy?SEM?and UV-Vis absorption spectra,the different dopants species and concentrations photocatalyst on the visible light photocatalytic activity were investigated,the adsorption mechanism of metal ions on the surface of nano-TiO₂ colloidal particles was proposed.The results show that the nanocrystalline TiO₂ colloid doped with Fe³⁺ at room temperature exhibits significant visible light photocatalytic activity,and the doping amount 0.25 at.% modified nano-TiO₂ obtained the optimal photocatalytic avitivity,the UV-Vis absorption spectra show that the absorption threshold wavelength red shift from 387 nm to about 443 nm,the metal ion may be chelated and adsorbed on the surface structure of TiO₂ nanoparticles.The optimum doping amount is 0.25%,while the excessive Fe³⁺ doping will hinder the photocatalysis because the distance of Fe³⁺ in the surface of nano-TiO₂ decreases,which will increase the recombination probability of electrons and holes and reduce the Fe³⁺-TiO₂ photocatalytic reactivity.In this paper,nano-?-Fe₂O₃ colloids and nano-titanium dioxide composite photocatalysts were prepared and the results showed that the complex also enhanced the visible light photocatalytic activity.Additionally,the application of iron-doped samples on paper-based has proved that the visible light photocatalyst is promising to use the indoor paper-based products with new functions of purifying air.