Milling-Induced Synthesis of BiOCl1-x Brx Solid Solution and Their Adsorptive and Photocatalytic Performance.

CH3 COO(BiO) (denoted as BiOAc) is one of the most easily obtained bismuth compounds and was for the first time proposed by our group as an effective UV light photocatalyst. Herein, BiOCl1- x Brx (x refers to the feeding atomic ratio) were obtained using a facile solid state milling and subsequent water washing. More importantly, all of the as-prepared BiOCl1- x Brx possessed better visible light photocatalytic activity to the corresponding ones obtained by previously reported solution route. Especially at an optimal x value of 0.5, the solid solution showed the highest photodegradation efficiency (~100%) for rhodamine B (RhB) with a concentration of 30 mg L-1 , whereas the degradation efficiency was only 63% over that obtained by solution route. Furthermore, the as-prepared BiOCl0.5 Br0.5 also exhibited excellent photodegradation activity for malachite green (MG). The superior photocatalytic performance of the as-prepared BiOCl0.5 Br0.5 could be attributed to its thinner sheetlike structures and highly exposed (001) facets, which enable effective separation of the photogenerated electrons and holes along the [001] direction. In addition, the as-prepared BiOCl0.5 Br0.5 revealed dramatic adsorption capacity for cationic dyes like MG, RhB and methylene violet (MV), as well as anion (Cr2 O7 )2- owing to electrostatic interaction between cationic dyes and negatively charged surface of BiOCl0.5 Br0.5 , and positively charged surface in K2 Cr2 O7 solution (pH ≈ 3).