Preparation Of Bi-Based Photocatalyst And Research On Photoelectrocatalytic Performance

Bi-based photocatalysts have been arised more and more attention due to the their characteristics of the unique lamellar structure,efficient photo-catalytic activity,good stability,non-toxic and low cost.Therefore,the study of the composition and structure of Bi-based photocatalyst materials has become an important issue in photocatalytic technology.In this paper,four kinds of Bi-based photocatalysts(Ag/Bi OCl,Ag/Ag Cl/Bi4Ti3O12,Bi PO4 Nanoparticles,Ag2O/Bi4Ti3O12)were prepared.The photocatalytic activity of organic wastewater was simulated by rhodamine B,carbamazepine and tetracycline.The structure and properties of the catalysts were characterized by XRD,DRS,XPS,SEM and TEM.The photocatalytic mechanism was also analyed.The results of the study are as follows:(1)Bi OCl with the(001)dominant crystal plane was synthesized by gentle reaction at room temperature.Oxygen vacancy and silver nanoparticles were successfully formed in the(001)crystal plane of Bi OCl nanosheets.As a result,the synergistic effect of the surface plasma of Ag on the Bi OCl(001)plane surface and the oxygen vacancy of the specific crystal planes increased the visible light induced photocatalytic performance.Compared with UV-treated Bi OCl(GBi OCl)and pure Bi OCl nanosheets(WBi OCl),Ag/Bi OCl nanosheet electrodes have high separation efficiency of photoelectron-hole pairs and charge transfer rates at the solid-liquid interface.(2)Bi4Ti3O12 nanosheets with highly exposed(001)crystal faces were successfully synthesized by hydrothermal method.The decomposition of rhodamine B,carbamazepine and tetracycline aqueous solution was analyzed under visible light irradiation.As a result,the photocatalytic activity of Ag/Ag Cl/Bi4Ti3O12 nanosheets was greatly improved compared with Bi4Ti3O12 nanosheets due to the synergistic effect of the internal electric field of Bi4Ti3O12 nanosheets and the surface plasmon resonance of Ag.The synthetic Ag/Ag Cl/Bi4Ti3O12 nanosheets also exhibit high reproducibility in photocatalytic reaction.(3)Visible light-driven Bi PO4 nanoparticles were prepared by introduce of sufficient surface oxygen deficiency using hydrothermal method and subsequentultrasonic assisted iron reduction process.The results showed that Bi PO4 has a smooth surface with a cube shape and a clear boundary and oxygen vacancy and the introduce of oxygen vacancy enhances the visible light absorption and charge separation efficiency.Moreover,the oxygen vacancy in the Bi PO4 nanoparticles can not only improve the separation efficiency of the photoelectron-hole pairs,but also enhance the visible light absorbtion by forming the mesoscopic state,which greatly enhances the degradation of Rhodamine B in in visible light irradiation.(4)Bi4Ti3O12 nanosheets with highly exposed(001)crystal planes are combined with Ag2 O to form p-n heterojunction photocatalysts,which exhibit a marked increase in visible light-driving activity.The enhancement of photocatalytic performance can be attributed to the synergistic effect of the internal electric field between the Bi4Ti3O12 nanosheets and the formation of p-n heterojunctions between the two semiconductors.The results show that 0.1 Ag2O/BTO has the best photocatalytic performance.