Photoinduced Functional Properties Of Doped Bi Based Semiconductor Materials

The bulk band width of most of the Bi-based semiconductor materials is less than 3.2eV,and it has a certain range of light response in the visible light.It has a good prospect in the photocatalytic degradation of organic pollutants.And precious metals can form heterojunctions with semiconductors to promote the transfer of photogenerated electrons,which are widely studied because they are cheaper than other precious metals.The material obtained by Ag doping is beneficial to the separation of electron hole pairs,thus improving the photocatalytic efficiency.In view of the above advantages,this study uses novel sol-gel method to prepare bismuth-based semiconductor materials.This method adds nitric acid as a solvent to maintain a low ph value of the whole system,adds acetone as a stabilizer and glycerol as complexing agent.The thermal reaction of gel was studied by differential thermal analysis(DTA),and the crystal structure,surface morphology and photoresponsiveness of the samples were studied by X-ray diffraction(XRD),scanning electron microscopy(SEM),X-ray energy dispersive spectroscopy(EDS),and UV-Vis DRS.The CuBi2O4 and ZnBi2O4 samples were prepared by different sintering temperature and holding time.Then did representaion of structure and performance of samples.The reactive brilliant red K-2G was used as the simulated degradation solution.The prepared samples were photocatalyst and degraded under visible light for 2 hours.The results showed that the photocatalytic activity of CuBi2O4 and ZnBi2O4 prepared by sintering at 600? for 3h was the best,and the degradation rate was 91.5%and 95.2%at the second hour.Using Ag,a precious metal,to do the study of the modification of CuBi2O4?ZnBi2O4,it was found that Ag-CuBi2O4 was used as a columnar structure,and Ag-ZnBi2O4 was a lamellar structure through SEM.Ag was doped into Bi-based semiconductor material by using EDS.It was found that the light absorption capacity of Ag-CuBi2O4 and Ag-ZnBi2O4 was enhanced at 450?600nm.The effect of Ag doping on CuBi2O4 and ZnBi2O4 was investigated by photocatalytic degradation of reactive brilliant red.The results showed that the photocatalytic performance of 2%molAg-CuBi2O4,5mol%Ag-ZnBi2O4 was the best.At the 80th minute,its degradation rate had already reached 96.2%and 95.2%,which were the 2-hour photocatalytic degradation rate of pure CuBi2O4?ZnBi2O4.Through five cycling tests,the photocatalytic activity of 2mol%Ag-CuBi2O4 and 5mol%Ag-ZnBi2O4 was still higher than 90%and 84%,it was concluded that the prepared Bi-based semiconductor was a visible and photocatalytic catalyst with high photocatalytic performance.The heterojunction semiconductor structure was formed by combining 2wtmol%Ag-CuBi2O4 and TiO2,then using it as a photoanode to form a dye-sensitized solar cell.Trough testing on the photoelectric properties,the enhancement of the photoelectric conversion was the largest when the composite content was 2%,and the short circuit current increased from 9.54mA/cm2 to 14.04 mA/cm2,an increase of 47.2%,the conversion efficiency increased from 3.78%to 4.92%,an increase of 30.2%.