Effect Of La Modification On Photocatalytic Activity Of Nano-Bi₂WO₆ And Its Characterization

To improve the solar utilization and quantum efficiency of nano-Bi₂WO₆,Bi₂WO₆photocatalyts with high-performance were exploited,which could offer high-performance photocatalytic materials for the treatment of wastewater by a photocatalytic technique.A hydrothermal method without organic solvent was successfully developed to obtain high-efficiency Bi₂WO₆ nano-photocatalyst from Bi?NO₃?₃·5H₂O and Na₂WO₄·2H₂O.The samples were characterized by XRD,TEM,XPS,DRS and other characterization measurements.When the initial concentration of Bi?NO₃?₃·5H₂O was10 mmol and Na₂WO₄·2H₂O was 5 mmol,the initial pH of the reactant solution was 7,and hydrothermal time at 160?was 12 h,and calcination temperature was 450?,and calcination time was 2 h.The photocatalytic degradation of 4-chlorophenol?4-CP?under simulated sunlight was 38.4%,which could be widely used in environmental treatment.Compared with other samples prepared at different initial pH values,when the initial pH value of the reaction solution was 7,the diffraction intensity of Bi₂WO₆photocatalyst was the best,the crystallinity was high,the visible light had good absorption.Bi₂WO₆ had a good development prospects in solar photocatalytic control of environmental pollution and other fields.La-modified Bi₂WO₆ by hydrothermal method to develop a high performance nano-photocatalyst.The effects of various factors including La-doping amount,initial pH of reactant solution,hydrothermal time,calcination temperature,and calcination time on the photocatalytic activity of La-doped Bi₂WO₆ were investigated through the photocatalytic degradation of 4-chlorophenol?4-CP?under simulated sunlight irradiation.The results showed optimal preparation conditions as follows:La-doping amount was1.5 wt%,and the initial pH value of reactant solution was 7,and hydrothermal time at160?was 12 h,and calcination temperature was 500?,and calcination time was 2 h.The photoactivity of as-prepared La-doped Bi₂WO₆ was 51%,which was much higher than that of undoped Bi₂WO₆ prepared under the same conditions?38.4%?,which could be widely used in environmental treatment.Compared with other literature reports,the La doping amount was obviously reduced,and the time of hydrothermal time was obviously shortened.The process had the characteristics of energy saving and energy saving.The samples were characterized by XRD,DRS,FL,PL,SPS,TEM,XPS and other measurements.The mechanism of La surface modification on Bi₂WO₆ enhanced photoactivity was discussed.The results showed that the presence of La was responsible for inhibiting the recombination of the photogenerated electrons and holes.La played a predominant role the crystal growth,in stabilizing the surface structure,in increasing content of surface hydroxyl,and improved the photocatalytic activity.