Research On Controllable Synthesis And Modification Of TiO₂ Particles

Among the numerous semiconductor photocatalytic materials,TiO₂ is widely studied because of its nontoxic,stable chemical properties,good photocatalytic properties and low cost,etc.However,the high band gap and low quantum efficiency restrict its large-scale application in reality seriously.In this paper,TiO₂ with different morphology were prepared by the solvothermal method.Spherical TiO₂ was selected for the Ag deposition,and Flake TiO₂ was coupled with C₃N₄.The morphology and phase structure of the samples were characterized by SEM,TEM and XRD.Degradation of methyl orange and rhodamine B solution was the method of studying photocatalytic properties.The TiO₂ particles with different morphology were prepared by using TBOT and H₂TiF₆ in n-propanol and acetonitrile.The influence of the reaction conditions such as time,temperature and the solvent ratio were investigated for preparing the TiO₂particles with the best photocatalytic performance.When the volume ratio of H₂Ti F₆to TBOT was 1:4,the TiO₂ material with the best photocatalytic performance was obtained.Moreover,the temperature and time of the reaction had a great influence on the photocatalytic performance of TiO₂.When the reaction condition was 180°C and20 h,the as-synthesized TiO₂ particles exhibited the best photocatalytic performance.The proportion of n-propanol and acetonitrile had a little effect on the photocatalytic performance of TiO₂.However,as the ratio of n-propanol and acetonitrile decreased,the surface of TiO₂ was observed to become rough,and the spherical Ti O₂ gradually turned to an irregular shape.When the volume ratio of H₂Ti F₆ to TBOT was 1:8,spherical TiO₂ particles were prepared.The influences of reaction time,temperature and the solvent ratio on the morphology of TiO₂ were investigated.It was found that the TiO₂ particles with smooth surface were prepared in the condition of 180°C and10 h.When the ratio of n-propanol and aceronitrile was less than 1,the Ti O₂particles displayed a smaller size,an incomplete morphology and the best photocatalytic performance.The Ag/Ti O₂ particles were synthesized by the photochemical reduction method.The crystalline phase and morphology of Ag/Ti O₂ were nealy the same as raw Ti O₂.As the UV-irradiation time extended,the photocatalytic performance of Ag/Ti O₂ was increased;After more than a certain time,the photocatalytic performance of Ag/Ti O₂ began to decrease.The Ag/Ti O₂ particles with the best photocatalytic performance were prepared at 2h under UV-irradiation?Flake TiO₂ particles was prepared by tetrabutyl titanate in cyclohexanol.Cotton-like C₃N₄ were synthesized by urea using pyrolysis polymerization,and C₃N₄/TiO₂ was prepared by the physical method.When the weight ratio of C₃N₄ to TiO₂ was 0.4,the synthesized C₃N₄/TiO₂ presented the best photocatalytic performance.Under visible light irradiation,rhodamine B was degraded for 95%after40 mins.