Synthesis of belt-like bismuth-rich bismuth oxybromide hierarchical nanostructures with high photocatalytic activities

Abstract

Belt-like Bi4O5Br2 hierarchical nanostructures were synthesized through a facile one-step hydrolysis method performed at different temperatures (0–160 °C), using belt-like bismuth subsalicylate as the morphological template and bismuth source. The belt-like Bi4O5Br2 samples are found to be composed of irregular single-crystal nanosheets with highly exposed (0 1 0) facets. The photocatalytic activity of the belt-like Bi4O5Br2 was evaluated by referring to the degradation of salicylic acid and resorcinol under visible-light irradiation, and compared with those of belt-like BiOBr dominantly exposing (0 1 0) facets and plate-like Bi4O5Br2 dominantly exposing (1 0 −1) facets. The belt-like Bi4O5Br2 shows higher photocatalytic activity than belt-like BiOBr owing to the more negative conduction band potential, narrower band gap, and larger specific surface area (SBET) of the former. In addition, the belt-like Bi4O5Br2 also exhibits higher photocatalytic activity than plate-like Bi4O5Br2, mainly due to the larger SBET of the former. Interestingly, the belt-like Bi4O5Br2 obtained at room temperature (25 °C) shows the highest photocatalytic activity, because it has the largest SBET. Moreover, the as-synthesized belt-like Bi4O5Br2 exhibits excellent stability and reusability. This study provides a simple, energy-saving route for the synthesis of belt-like bismuth-rich bismuth oxyhalide hierarchical nanostructures.