Synthesis And Characterization Of Nano-TiO₂ Composite Materials With Visible Light Response Activity

Nano-TiO2 materials have been paid a lot of attention due to their properties, such as high-efficiency, low-cost, environment-friendly and can be used recyclely. However, TiO2 is a semicoductor with widegap, which is excited only by the ultraviolet radiation that is less than 5% of the solar light. Therefore, the investigation on synthesis and characterization of nano-TiO2 composite material with visible light response activity has very significant application.In this work, Nano-TiO2 particles with corresponding visible activity have been synthesized by sol-gel technology using Fe3+ and Gd3+ as doping agents. The products were characterized by TEM, XRD, TG-DTA and UV-Vis. The doping mechanism, synthetic technology, material structure and properties have been discussed.Iron salt was added into the sol-gel process of Tetrabutyl Titanate (TBOT) in the presence of Cetyltrimethyl Ammonium Bromide (CTAB) as a surfactant. The maximum absorption of composite products was appeared in about 530nm. The composite particles showed the photocatalytical activity toward Rhodamine B. The effects of Fe3+ and CTAB on the structure and properties of composite materials were systematically studied. The results showed that the best doping amount of Fe3+ and CTAB is 2% and 5% respectively. Fe3+ iron was doped into the crystal lattice of TiO2 and the new bandwidth (Eg=1.37eV) was appeared. Because of that, the spectral response property of TiO2 composite materials was red shift into visible light range.Gd3+ ion was also used to synthesize composite materials, which showed visible light activity. The maximum absorption was appeared in about 550nm. When the doping amount of Gd3+ is 0.5%, Gd3+ can enter the TiO2 lattice, and change the energy structure. The new bandwidth (Eg=1.27ev) was appeared. Moreover, the photocatalytic activity of Gd3+ doped materials was much better than that of pure TiO2.