Preparation Of Anchoring On BiFeO₃ Catalyst And Its Catalytic Performance

In this paper,pure BiFeO₃ was synthesized by coprecipitation and hydrothermal method,and then the Co₃O₄/BiFeO₃ and Bi-BiFeO₃ composite catalysts were prepared by composite method to solve the problem of low catalytic efficiency of BiFeO₃ semiconductor catalysts.The effect of reaction time on the preparation of catalyst and the change of energy band structure after semiconductor recombination were studied.The role of catalyst in photocatalysis and catalytic reduction was discussed.The main research contents and conclusions are as follows.1.Preparation and characterization of BiFeO₃ by coprecipitation hydrothermal methodIn this paper,pure BiFeO₃ was prepared by co-precipitation and hydrothermal method.The experimental results show that BiFeO₃ prepared by this method has good crystallinity and can absorb visible light.Under visible light irradiation,the photocatalytic efficiency of reducing Cr?VI?to Cr???is about 20%.2.Preparation characterization and mechanism analysis of Co₃O₄/BiFeO₃ heterojunction composite catalystIn this paper,p-n heterostructured Co₃O₄/BiFeO₃ composite catalysts were constructed by wet impregnation method.The photocatalytic activity of these composite catalysts under visible light irradiation is higher than that of pure BiFeO₃.When the loading of Co₃O₄ is 0.8wt%,the photocatalytic efficiency can reach 98%,while the photocatalytic efficiency of pure BiFeO₃under the same conditions is about 20%.At the same time,the catalytic reduction efficiency of 4-NP in the presence of NaBH₄ reached 99%within 7 minutes.After the contact of Co₃O₄ and BiFeO₃,the change of band position leads to the formation of p-n heterojunction structure at the interface between them.The improvement of catalytic performance mainly depends on this heterojunction structure,which can effectively separate photogenerated electrons and holes.3.Preparation and characterization of Bi-BiFeO₃ composite catalystBi was successfully reduced on the surface of BiFeO₃ particles by hydrothermal method.The reduced Bi particles were spherical and well dispersed.The experimental results show that the catalytic reduction efficiency of Cr?VI?reaches 70%within 100s after loading Bi.The catalytic reduction efficiency of MB reached 80%in 180s and RhB reached 60%in 180s.