One pot synthesis of bismuth-bismuth oxybromide composites with enhanced visible-light photocatalytic activity

Bismuth/bismuth oxybromide (Bi/BiOr) composites were synthesized by a facile one-step solvothermal method with the help of dimethyl sulfoxide (DMSO). The products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XFS), N-2 sorption, UV-visible diffuse reflectance spectra (DRS) and photoluminescence spectroscopy (PL). The photocatalytic activity of the products was evaluated by the photocatalytic degradation of methyl orange (MO) under the visible-light irradiation. The results showed that Bi/BiOBr composites with the different Bi contents could be obtained by adjusting the amount of dimethyl sulfoxide (DMSO), all of which exhibited enhanced photocatalytic activity in comparison with pure BiOBr. Among them, Bi/BiOBr composites prepared with 5 ml of DMSO presented the highest photocatalytic activity. The enhanced photocatalytic activity could be attributed to an increased amount of photo-induced charge carriers and effective separation of photogenerated electron-hole pairs. The trapping experiments confirmed that the photogenerated holes and center dot O-2(-) radicals were the main active species responsible for the photodegradation of MO. (C) 2014 Elsevier Ltd. All rights reserved.