Photocatalytic degradation of Methyl Red dye using highly efficient ZnO/CdS hierarchical heterostructures under white LED

This study reports the photocatalytic degradation of Methyl Red dye at various pH values under white LED light using highly efficient ZnO/CdS Hierarchical Heterostructures grown by a two-step ultrasonicated hydrothermal route. The ZnO/CdS heterostructures were synthesized using a two-step ultrasonicated hydrothermal route and characterized by morphological, structural, and optical studies. The samples were then applied for photocatalytic degradation of Methyl Red dye with pH variation studies. The X-ray diffractogram peaks show mixed hexagonal structures with decreased particle size with increasing CdS content. It was found that the samples exhibited mixed hexagonal structures with reduced particle size and increased CdS content. The average size of ZnO and ZnO/CdS doped nanocomposites was about 30, 29, 19, and 17 nm, respectively. FESEM and TEM micrographs of ZnO/CdS heterostructures exhibit hexagonal arrangements with increased CdS content. Photoluminescence spectra show excellent luminescence in the visible region. Using the visible light spectrum, excellent photocatalytic behavior is reported to degrade Methyl Red dye at different photoluminescence pH values. The photoluminescence studies of pigments after degradation shows that the OH* radical formation is more at pH9 than pH4. As a result, 95% degradation of dyes was observed in the primary region, at pH 9, with ZnO/CdS catalyst under the visible light source. This research indicates that ZnO/CdS heterostructures can be a promising photocatalyst for degrading organic pollutants in wastewater treatment.