Study On Preparation And Activity Of Bismuth Oxide Photoelectrocatalytic Materials

In the process ofβ-Bi₂O₃ photoeletrocatalytic degradation reaction,when 1～2 V voltage is applied,it is found that the metastableβ-Bi₂O₃ electrode is unstable.Characterizations such as XRD,XPS and Raman have all proved that the photoelectric pretreatment process causes part of the Bi³⁺of theβ-Bi₂O₃ to be oxidized to Bi⁵⁺,oxygen vacancy is also introduced into the crystal structure.The ultraviolet-visible diffuse reflectance confirmed that the existence of Bi⁵⁺and oxygen vacancies made theβ-Bi2O3band gap smaller,theβ-Bi2O3 electrode undergoes a 1.8 V photoelectric pretreatment process,the light absorption band edge is red-shifted from 518 nm to 663 nm,and the light absorption intensity increased.Under visible light,whether the photocatalytic degradation activity of the 1.8 V pretreated electrode were 40.64%and 52.29%,while the photocatalytic degradation under 1 V voltage,the rates were 58.45%and 73.21%respectively.The article compares the photocatalysis and photoelectrocatalysis withβ-Bi2O3 and BiO2-x catalysts.It is found that BiO2-x has stronger photocatalytic degradation activity.For MB and MO,the photocatalytic degradation rate of BiO2-x within 120 min were48.41%and 94.95%,Bi2O3 were 15.86%and 16.47%,respectively.This can be attributed to the fact that BiO2-x contains a large number of oxygen vacancies and a relatively narrow band gap.However,in the comparison of photoelectrocatalytic degradation activity,it is found that the application of a certain voltage has a greater impact on the degradation activity of the bismuth oxide electrode.Under visible light irradiation and a 1 V bias voltage,within 180 minutes,BiO2-x andβ-Bi2O3 can photoelectrocataltic degrade MB.The photoelectrocatalytic degradation rates of BiO2-x and Bi2O3 at 8 h were 68.64%and 83.13%,respectively.In the photoelectrocatalytic degradation,β-Bi2O3 has relatively higher photoelectrocatalytic degradation activity for methylene blue and phenol.The valence transition process has a more significant effect on improving the photoelectric catalytic degradation ability ofβ-Bi₂O₃.Figure 43;Table 2;Reference 72...