Br-Doped Bi2O2CO3 exposed (001) crystal facets with enhanced photocatalytic activity

Abstract

A Br-Doped Bi₂O₂CO₃ exposed (001) crystal facet was synthesized by a one-pot hydrothermal method. The results of the total densities of states of the valence band (VB) and UV-vis diffuse-reflectance spectrum (DRS) for the Br-doped Bi₂O₂CO₃ exposed (001) crystal facet demonstrate that the doping of the Br anion can effectively narrow the band gap of Bi₂O₂CO₃ by improving the valence band position. The photocatalytic performance is evaluated by degrading methyl orange (MO) and rhodamine B (RhB) dyes in an aqueous solution. In comparison with pure Bi₂O₂CO₃, Br-doped Bi₂O₂CO₃ exhibits drastically enhanced solar-light photoactivity, which is also superior to many other reported Bi₂O₂CO₃-based photocatalysts. The highly enhanced photocatalytic performance is attributed to a combination of expanded photoresponse range caused by the doping of Br anions and effective separation of the photogenerated electron–hole pairs owing to the exposed active (001) crystal facet of Bi₂O₂CO₃. The Br-doped Bi₂O₂CO₃ exposed (001) crystal facet also shows photochemical stability, which is of special importance for its practical applications. This work demonstrates that doping enables band gap engineering and the design of high-performance photocatalysts.