Visible-light photocatalytic activity and mechanism of novel AgBr/BiOBr prepared by deposition-precipitation

A new composite photocatalyst AgBr/BiOBr was prepared by loading AgBr on a BiOBr substrate via deposition-precipitation and characterized by X-ray diffraction,scanning electron microscopy,high-resolution transmission electron microscopy and UV-vis diffuse reflectance spectroscopy.The as-prepared AgBr/BiOBr comprised face-centered cubic AgBr and tetragonal BiOBr particles.The average crystalline sizes of AgBr in the AgBr/BiOBr composites were less than 28.5 nm.The absorption edges of AgBr/BiOBr in visible-light region had a red shift with increasing AgBr content.Photocatalytic degradation of methyl orange results show that the AgBr/BiOBr composites could degrade methyl orange efficiently under visible-light irradiation (λ>420 nm).The optimal molar percentage of AgBr was 50 mol% with corresponding maximum k app of 0.00619 min -1.Active ·O 2- played a major role for methyl orange degradation while h + and ·OH had little effect on the photocatalytic process.The enhancement of photocatalytic activity of AgBr/BiOBr is mainly ascribed to the heterojunction effect between AgBr and BiOBr.