The Synthesis Of TiO₂ Nanoparticles By Hydrothermal Method And Its Modification

The study of doped nano-titanium dioxide is a wide range of research in recent years.However,the problems of wide band gap,low light response range,low quantum yield and high photo generated recombination rate of nano-TiO₂ has not been solved well.In this paper,TiOSO4 as raw material,CoO,Fe?NO3?3·9H2O and MnSO4·H2O as dopants,Three kinds of doped nano-TiO₂ were prepared by hydrothermal method,and characterized by SEM,XRD,laser particle size distribution,infrared spectroscopy,UV spectroscopy,thermogravimetric analyzer and BET analysis.The effects of different pH,different reaction time,temperature and doping amount on the hydrothermal synthesis of doped nano-TiO₂ and photocatalytic activity were studied,At the same time,the effects of pH,light source,catalyst amount and catalyst stability on photocatalytic reaction were studied.In addition,the photocatalytic activity of Co-doped nano-TiO₂ was studied.It is intended to further study the photo-generated electron-hole separation of nano-TiO₂.In this paper,the transition metal ions are doped to improve the lifetime of photogenerated carriers.Fe,Mn and Co on the surface of nano-TiO₂ are in the form of oxides,and there is interaction with TiO₂.The binding energy of Ti 2p is in the direction of low energy level mobile.The infrared spectrum indicates that surface of nano-TiO₂ is rich of hydrated hydroxyl groups.The photocatalytic activity of the doped TiO₂ nanoparticles has been improved obviously,and the cobalt doped nano-TiO₂ has the highest photocatalytic activity compared the three dopants.The optimum conditions for hydrothermal reaction were as follows:the temperature was 200?,pH = 9,reaction time was 10 h,the doping amount was 0.5%.The influence of light source,pH value,catalyst dosage and catalyst stability on the photocatalytic reaction factors was discussed.It was found that the pH of the solution had a significant effect on the photocatalytic reaction.Finally,a device for photoelectric degrading Rhodamine B had been built by combining ultraviolet light box with Wuhan Koster CS Electrochemical Workstation.A two-electrode system was used Co-TiO₂ photocatalyst as the anode by tabletting and graphite sheet as the cathode.Under a low power ultralviolet light irradiation,photoelectrocatalytic reaction was performed at a constant potential of 1.5v for 90 min.The photoelectrocatalytic activities of the photocatalysts with different molar ratios were studied.The results show that 0.5%Co-TiO₂ sample has the highest degradation rate,is 77.25%,38.74%higher than catalyst-free,12.53%higher than pure TiO₂ sample,and 17.06%higher than 0.5%Co-TiO₂ sample without applied voltage.Similarly,the results also show that a method of preparing anodes by tab letting has improved photodedration efficiency,and has the favorable development prospect.