Facile preparation of Sn-doped BiOCl photocatalyst with enhanced photocatalytic activity for benzoic acid and rhodamine B degradation

A series of Sn-doped BiOCl photocatalysts were successfully synthesized at room temperature via a facile oxidation-reduction method. The as-synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoemission spectroscopy (XPS), UV–vis diffuse reflectance spectra (DRS) and photoluminescence (PL) emission spectroscopy measurements. The results showed that the as-prepared samples exhibited tetragonal crystal structure, lamellar morphology and band gap energy of 3.12 eV and 2.91 eV for BiOCl and Sn(10%)-doped BiOCl, respectively. XPS results showed that Sn was in the form of tetra-valence. The photocatalytic activities of as-synthesized samples were evaluated by the degradation of benzoic acid (BA) and rhodamine B (RhB) in an aqueous solution. The results revealed that the Sn doping could enhance the photocatalytic performance of BiOCl and the highest photocatalytic activity was achieved by the Sn(10%)-doped BiOCl, in addition, the optimum dosage of Sn(10%)-doped BiOCl was 0.4 mg/L in degrading BA. The improved photocatalytic activity of Sn-doped BiOCl could be attributed to the narrower band gap energy (2.91 eV) than pure BiOCl. Furthermore, scavenger experimental results indicated that h+ played the pivotal role in BA photocatalytic degradation. What is more, the as-synthesized Sn(10%)-doped BiOCl photocatalyst exhibited a good stability during the photodegradation of BA and RhB, revealing its promising prospect in the practical application of the treatment of organic wastewaters.