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

Abstract

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.