▎ 摘　　要

This work reports the preparation of reduced graphene-based bismuth oxybromide (G-BiOBr) nanocomposite using a facile synthesis procedure. The synthesized nanocomposite material was characterized using a powder X-ray diffractometer, transmission electron microscope, X-ray photoelectron spectroscopy and UV-vis diffuse reflectance spectroscopy. The photocatalytic efficiency of the as-prepared BiOBr and G-BiOBr nanocomposite were examined through photodegradation of rhodamine-B dye (RhB) under a visible light irradiation at 420 nm. Experimental factors (such as contact time, the dye concentration and dosage of the catalyst) were investigated using a Central Composite Design. The results revealed that G-BiOBr nanocomposite exhibits improved photocatalytic activity, approximate to 100% degradation, far above the as-prepared BiOBr material. The improvement in photocatalytic activity may be ascribed to improved light absorption and charge separation. Also, a mechanism was proposed to describe the improved photocatalytic degradation of RhB dye using G-BiOBr where the graphene plays a key role in electron transfer and in reducing the rate of electron-hole recombination. (C) 2018 Elsevier B.V. All rights reserved.