BiOBr-Ag8SnS6 heterostructured nanocomposite photocatalysts: Synthesis, characterization, and photocatalytic application

BiOBr-Ag8SnS6 heterostructured nanocomposite photocatalysts have been synthesized by chemical coprecipitation method in the presence of ethylene glycol solvent at a temperature of 100 degrees C for 4hr. The synthesized BiOBr-Ag8SnS6 heterostructured composites were characterized by X-ray diffraction, transmission electron microscopy, ultraviolet-visible near-infrared spectroscopy, photoluminescence spectroscopy, and Brunauer-Emmett-Teller surface area measurement. X-ray diffraction pattern of BiOBr-Ag8SnS6 heterostructures showed the peaks corresponding to tetragonal structure of BiOBr and orthorhombic structure of Ag8SnS6 nanoparticles, which indicated that they exist in biphasic form in the composite. Photoluminescence studies showed that the BiOBr-Ag8SnS6-1 composite possesses the lowest recombination rate of e(-)-h(+) pairs. Brunauer-Emmett-Teller surface area of BiOBr, Ag8SnS6 nanoparticles, BiOBr-Ag8SnS6-1, and BiOBr-Ag8SnS6-2 was found to be 0.05, 2.35, 1.88, and 1.0m(2)/g, respectively. BiOBr-Ag8SnS6 heterostructured nanocomposite photocatalysts exhibited robust photodegradation towards degradation of indigo carmine dye than that of single-phase BiOBr and Ag8SnS6 nanoparticles under sunlight irradiation. The enhanced photoactivity could be ascribed to heterostructure effect between BiOBr and Ag8SnS6 nanoparticles, an improved visible light absorption and the separation and easy transfer of photogenerated electrons and holes, across the interface of BiOBr-Ag8SnS6. The radical scavenger experiments showed that photogenerated holes and superoxide radicals were the main active species involved in the photodegradation process of indigo carmine.