Investigation of photodegradation of rhodamine B over a BiOX (X$=$Cl, Br and I) photocatalyst under white LED irradiation

[摘要] In this study, a low temperature precipitation method was applied to prepare BiOX (X$=$Cl, Br and I) nanostructures using HCl, HBr and HI as halogen sources. The as-prepared samples were characterized by various techniques such as X-ray diffraction, field emission scanning electron microscopy, energy dispersive spectroscopy, Fourier-transform infrared spectroscopy, diffuse reflectance spectroscopy and nitrogen adsorption–desorption analysis. The photoactivity of BiOX samples to degrade rhodamine B (RhB) molecules in aqueous solution was investigated under white LED irradiation. The results indicated that BiOCl exhibits a higher photodegradation performance in comparison with BiOBr and BiOI. Ninety six percent of the RhB molecules was degraded over BiOCl after 25 min light irradiation, whereas under the same conditions, the degradation efficiencies of BiOBr and BiOI samples are 62 and 24%, respectively. The enhanced photodegradation activity of BiOCl is ascribed to the higher specific surface area which increases the physical adsorption of RhB molecules on the Vphotocatalyst surface.Moreover, the photodegradation mechanism and the main radical species in the degradation reactionsover BiOCl were investigated.

[学科分类] 材料工程

[关键词] Bismuth oxyhalide;photocatalysis;rhodamine B;LED lamp.