Study On Preparation And Properties Of Titanium Dioxide Composite

TiO₂ photocatalyst is popular in degrading organic contaminants in virtue of strong oxidation power,high stability,cheapness and non-toxicity.Howbeit,the practical application of TiO₂ remains limited to poor quantum yield and wide bandgap.In order to obtain an efficient visible light-responsive photocatalyst,we composited UiO-66-FP with HPW/TiO₂ by ultrasonic method,and successfully prepared a three-component UiO-66-FP/HPW/TiO₂ composite material.UiO-66-FP and H₃PW₁₂O₄₀ were introduced to improve the photocatalytic activity of TiO₂.The problems of narrow photoresponse region and photo-generated e^--h⁺recombination of TiO₂ are solved.XRD,FT-IR,TEM,SEM-assisted EDS,XPS,N₂ adsorption-desorption and other testing methods were used to characterize the structure,morphology,composition,specific surface area and pore structure of UiO-66-FP/HPW/TiO₂.UV-Vis DRS was used to study the light absorption properties of the composite.Using dye?RhB?as a colored pollutant,the photocatalytic activity of the prepared sample was investigated,and 10 wt.%UiO-66-FP/HPW/TiO₂ was found to have the highest photocatalytic activity.After 30 min of simulated sunlight,the degradation rate of RhB molecules was 94.5%.After 80 min of visible light irradiation,the degradation rate of RhB molecules by 10 wt.%UiO-66-FP/HPW/TiO₂ was 98.6%,and the reaction rate constant was 4.68 times that of HPW/TiO₂.After 10 h of visible light irradiation,TOC decreased by 95.3%of the initial values of RhB,indicating that the pollutants had been basically converted into CO₂,H₂O,and inorganic ions.In order to eliminate the photosensitivity effect during the degradation of UiO-66-FP/HPW/TiO₂,colorless ofloxacin?OFX?was selected as the light-insensitive target pollutant for photodegradation experiments.The 10 wt.%UiO-66-FP/HPW/TiO₂ sample still has the highest photocatalytic activity.After 50min of simulated sunlight,the degradation rate of OFX molecules was 94.8%.After120 min of visible light irradiation,the degradation rate of OFX molecules by 10wt.%UiO-66-FP/HPW/TiO₂ was 97.2%,and the reaction rate constant was 4.14 times that of HPW/TiO₂.After 10 h of visible light irradiation,TOC decreased by 91.7%of the initial values of OFX,indicating that the pollutants had been basically converted into CO₂,H₂O,and inorganic ions.And the 10 wt.%UiO-66-FP/HPW/TiO₂composite still maintained high stability after four cycles of recycling.Combined with fluorescence spectrum,photoresponse current,electrochemical impedance spectroscopy,and active species capture tests,the mechanism of photodegradation of OFX by UiO-66-FP/HPW/Ti O₂ was studied;the possible charge transfer path of UiO-66-FP/HPW/TiO₂ heterostructure was speculated;it was determined that in the UiO-66-FP/HPW/TiO₂ photodegradation system·O₂^-and h_VB⁺are the main active substances attacking OFX molecules,and·OH plays an auxiliary role in the photodegradation process.