The chemical precipitation synthesis of nanorose-shaped Bi4O5I2 with highly visible light photocatalytic performance

Abstract A facile chemical precipitation has been successfully developed to fabricate nanoflake BiOI (1.259 g) by adding 1:1 M ratio of Bi (NO3)3·5H2O and 4 mM KI into the mixture of ethylene glycol and distilled water. Interestingly, with addition of 2 mM KI, bismuth-rich oxyiodide (Bi4O5I2, 0.848 g) with nanorose-shaped structure was obtained. In addition, after the collecting the precipitation of Bi4O5I2, the extra 2 mM KI was added in solution, 0.406 g of BiOI (named as BiOI-S) was produced. The quality of the obtained Bi4O5I2 and BiOI-S with each 2 mM KI addition is similar as the one step fabrication method using 4 mM KI. The synthesized hierarchical structure Bi4O5I2 with nanorose-shaped shows higher band gap energy (1.9 eV) than that of BiOI (1.7 eV), and higher specific surface area (36.9 m2 g−1) than that of BiOI (28.1 m2 g−1). Therefore, Bi4O5I2 nanorose-shaped showed superior photo-catalytic performance and degraded 92.3% of rhodamine B, which was 4 times faster than that of the pure BiOI. Our work may provide a facile strategy for efficient photocatalytic activity application in the treatment of water pollution via controlled KI addition.