Preparation And Combination Of Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ And Bismuth Based Photocatalytic Materials

Bismuth based photocatalytic materials have the advantages of stable performance and high photocatalytic efficiency,which has a great research potential.Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ is a new optical energy storage material,and its emission wavelength is just in the response range of the bismuth based photocatalytic materials.Combination of them will be able to increase catalytic time and improve catalytic efficiency.In this paper,a series of Bi₂WO₆ and Bi₂ Mo O₆ photocatalysts were synthesized by hydrothermal method,a series of BiVO₄ photocatalysts were prepared by ultrasonic method,a series of Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ were synthesized by sol-gel method.Moreover,composite materials of Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ and bismuth based photocatalytic materials were prepared by ultrasonic-impregnation method.They were tested by XRD,SEM,EDX,FTIR,Raman,UV–vis DRS,afterglow decay,fluorescence spectra,thermoluminescence spectra,and photocatalytic performance characterization.Ion doping has the greatest impact on Bi₂WO₆ and Bi₂ Mo O₆.The sample with 0.05 mol% Er³⁺ doping has the best photocatalytic activity,and the final degradation rate was 99.41% and 93.30%,respectively.The addition of rare earth oxides has the greatest impact on BiVO₄.The sample with 30 wt% Nd₂O₃ has the best photocatalytic activity,and the final degradation rate was 43.10%.The best doping methods of Nd3+,Er³⁺ and Yb³⁺ were direct doping,Er³⁺ substituting for Eu2+ and Yb³⁺ substituting for Eu2+,respectively.Nd was the best doping element,and the sample with 30 mol% Nd3+ doping,namely Sr1.928MgSi2O7: 0.02Eu2+,0.04Dy3+,0.012Nd3+,has the best afterglow property.All the Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ samples have two excitation peaks located at 275 nm and 360 nm.Only one broadband emission peak is centered at 469 nm.This emission corresponds to the transition between the excited state and the ground state（4f65d→4f7）of Eu2+ ions.All the composite materials of Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ and bismuth based photocatalytic materials show better photocatalytic activities in dark.The composite with more Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ show better photocatalytic activities.