Facile preparation of Sn/BiOCl composite oxides and their photocatalytic performance

Abstract

ABSTRACTSn-doped BiOCl (Sn/BiOCl) photocatalysts were synthesized by a precipitation method using Bi(NO3)3 · 5H2O as a bismuth source, SnCl2 as an Sn source, imidazole hydrochloride as a chlorine source, a solvent, and a template agent. The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, surface area analysis (Brunauer, Emmett and Teller [BET]), and diffuse reflectance spectroscopy. The XRD results showed a greater increase in the peak intensity of Sn/BiOCl because of its high degree of crystallinity. The UV–Vis results indicated a redshift from 368 nm (BiOCl) to 418 nm (Sn/BiOCl), leading to the reduced band gap of BiOCl because of Sn doping in BiOCl. The Sn/BiOCl not only retained ultraviolet photocatalytic activity of BiOCl but also showed visible photocatalytic activity. The BET results showed that the surface area of Sn/BiOCl (23.35 m2 ) was bigger than that of BiOCl (13.54 m2 g). The bigger surface show higher photocatalytic activity due to more contact opportunity between reactants. Hence, the increased photocatalytic activity of Sn/BiOCl in the degradation of rhodamine B can be attributed to a higher degree of crystallinity, larger surface area, and broader range of optical absorption. The Sn/BiOCl needed only 20 min under visible light and 40 min under ultraviolet light to completely degrade rhodamine B. Moreover, the photocatalytic experiment did not require any other chemical reagent such as H2O2. The microstructures of BiOCl and Sn/BiOCl ensured that the catalyst still has high recovery rate when it is reused. The microstructures of catalyst have a little of loss.