Photocatalytic degradation of bisphenol A on BiOI nanostructured films under visible LED light irradiation

Bismuth oxyiodide (BiOI) films were prepared through the Layer-by-Layer (LbL) method for the first time using powdery BiOI microstructures previously synthesized by a solvothermal method. BiOI films and powdery samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and UV–vis diffuse reflectance spectroscopy. The chemical composition and morphology of the powdery BiOI microstructures was not affected by the deposition process. The photocatalytic activity of prepared BiOI films and powdery samples was evaluated in the degradation of bisphenol A under white LED (Light emitting diode) light irradiation. The BiOI film composed by 1 layer (BiOI-1) of BiOI flower-like microspheres exhibited the highest photocatalytic activity in comparison with BiOI as powder and BiOI films composed by 3 (BiOI-3) and 5 layers (BiOI-5). The probable reasons for the highest photocatalytic performance of BiOI-1 may be related to its larger surface area, morphological characteristics, and fractal geometry. The results obtained in this work demonstrate that the LbL method can be a suitable technique to fabricate BiOI films with photocatalytic properties for water treatment.