Adsorption/photocatalytic performances of hierarchical flowerlike BiOBrxCl1−x nanostructures for methyl orange, Rhodamine B and methylene blue

Abstract

We synthesized hierarchical flower-like BiOBrxCl1−x (0≤x≤1) microspheres in ethylene glycol solvent and examined their fundamental properties by scanning electron microscopy (SEM), X-day diffraction (XRD), UV–visible absorption, Raman, photoluminescence spectroscopy, and BET surface area measurement. Additionally, their adsorption and photocatalytic performance were tested using methyl orange (MO), Rhodamine B (RhB), and methylene blue (MB). The adsorption performance was found to be in the order of BiOCl<BiOBrxCl1−x<BiOBr for MO under dark conditions. For the selected BiOBr0.7Cl0.3 catalyst, the adsorption ability was found to be in the order of MO⪯¡RhB<MB owing to electrostatic interactions between the catalyst and the dye. The photocatalytic dye degradation performance occurred in the order of MB<MO⪯¡RhB as a result of light absorption by the dye followed by good electron transfer from the conduction band of the dye to that of the catalyst. An indirect chemical probe method was used to examine the roles of active species in the dye-sensitized photodegradation mechanism, which were found to be in the order of OH≈O2−<h+ under visible light irradiation.