Synthesis and Characterization of Sn-Doped CeO2-Fe2O3 Nanocomposite and Application in Photocatalytic Degradation of Sudan I

Photocatalysis is a promising technique to treat organic dyes as pollutants over traditional technologies. The application of organic dyes has increased lately for industries such as textile, medicines, plastics, etc. Thus, in this report, we prepared a Tin-doped CeO2-Fe2O3 photocatalyst via the thermal decomposition method to effectively degrade Sudan I under sunlight. The synthesized catalyst was explored by different studies such as powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), Brunauer-Emmett-Teller (BET), UV-vis diffuse reflectance (UV-vis DRS). The catalyst was found to have a particle size of 1-2 mu m with a high surface area. The bandgap energy of the catalyst was changed to 2.2 eV due to the Sn doping. The effect of Sn4+ doping into the CeO2 lattice was observed as the modification in the Fermi levels of the catalyst, which resulted in enhanced photocatalytic activity. The catalyst was found to have a fast degradation rate towards Sudan I under the sunlight and showed complete degradation. The result of COD removal confirmed the removal of dye from the dye solution. Further, scavenger tests confirmed the role of the active species, hydroxyl ((OH)-O-center dot) and superoxide (O-2(center dot-)) radicals, in the degradation of Sudan I by photocatalyst. High-performance liquid chromatography (HPLC) was used to confirm the complete degradation of the dye. A possible mechanism is put forward to describe the degradation process and charge transfer during the degradation.