CeO_2 supported Zn_(1-x)Mn_xS (x: 0.025, 0.05, 0.075 and 0.10) catalyst for photoremoval of rhodamine B dye

摘要

Present work provides a detailed study of enhanced photocatalytic performance of CeO2 coupled Mn-doped ZnS nanoparticles. In a systematic study, undoped and Mn- doped (2.5, 5, 7.5 and 10 mol%) ZnS nanoparticles were synthesized using co-precipitation method. Then, using synthesized samples, heterostructure samples (ZnS/CeO2) were prepared by hydrothermal route. Successful incorporation of Mn ions in ZnS lattice was determined by X-ray diffraction, transmission electron microscopy and Fourier-transform infrared spectroscopy. Optical spectroscopies revealed the associated optical modifications because of Mn-doping and confirmed CeO2 attachment. The specific surface area calculated from N-2 sorption isotherms suggested the mesoporous structure of the samples. Rhodamine B (RhB) dye was used to understand the structural modifications of both components for the photocatalytic performance under different radiations. It was observed that hydroxyl radicals (OH center dot) were responsible for photo-oxidation of RhB molecule with excellent photostability of synthesized heterostructure sample under UV-visible illumination. To prove photocatalytic activity of catalysts under visible light, additional experiments with the use of vancomycin antibiotic, which do not absorb visible light, were performed. Though Mn doping improves the recombination rate of charge carriers of host ZnS, the attachment of CeO2 , not even reduces the optical bandgap (red shift) but contributes to better separation of the photo-excited charge carriers in heterostructure catalysts.