Preparation And Characterization Of Iron-doped Nano-TiO₂ Thin Films Supported On Silica Gel By Liquid Phase Deposition

In recent years one method called Liquid Phase Deposition (LPD) was developed in Wet Chemical Processes. Other thin films were gained after SiO2 thin film was prepared. Uniform and compact thin film of oxide or hydroxide will be obtained on substrates after immersed in certain solution. Heat treatment and expensive equipments are not required during film-formation progress. Furthermore, the progress is easy to operate.Iron-doped TiO2 thin films supported on silica gel were prepared by liquid phase deposition beginning with (NH4)2TiF6 and H3BO3, and its photo-catalytic activities were also studied. The optimum processing conditions were obtained through orthogonal experiment. They are: iron content, 0.1%; the rate of raw material, 1:2; deposition temperature, 60℃; calcinations time, 4h; calcination temperature, 500℃; deposition time, 6h. Analyses on surface elements,morphology,infrared absorption,crystal modification and UV absorbance were investigated by XPS,FT-IR,SEM,XRD,UV-Vis. The XPS results show that the samples contain the elements of Ti,O,Si,Fe which proved Fe has been doped in the crystal lattice of TiO2; the formation of Ti-O-Si was found in the FT-IR spectra which indicates TiO2 and silica gel were associative closely; the films can be seen obviously on the surface of silica gel though SEM images and the particles distribution of TiO2 uniform and combined firmly; the anatase titania was confirmed by XRD analysis when calcined at 500°C ; the phenomenon of red-shift was found at UV-Vis spectrogram which indicated the photo response range extended to visible region by doping Fe3+ and the activity of catalyst was improved.Finally, the degradation of methylene blue was carried under UV-light irradiation and visible-light irradiation. The experiment results show that TiO2 films doped Fe3+ has higher photo activity than pure TiO2 films under UV-light irradiation and the photocatalyst of Fe-TiO2/silica gel has the photo activity that TiO2/silica gel do not have. The degradation rate of methylene blue attained 70.9% after 10h. All these proved that the catalyst which the experiments gained has good performance and wide application foreground and provided more academic and experimental basis for further systematic research on LPD.