Low cost chemical bath deposition synthesis of Zinc Oxide/Zinc sulfide composite and Zinc hydrozincite for methylene blue degradation

ZnS/ZnO (Zinc Sulfide/Zinc Oxide) composite and Zinc hydrozincite (Zn(CO3)2(OH)6), were obtained by chemical bath deposition (CBD) at room temperature in the oxygen atmosphere. Their structure, morphology, and optical properties were investigated using X-Ray diffraction, Scanning Electron Microscopy (SEM), and Spectroscopy Uv–Vis. Characteristic patterns of each material were obtained. The diffraction reflections exhibit the Hexagonal phase for the ZnS and ZnO composite, and the Hydrozincite (Zn(CO3)2(OH)6). The grain size of each material was on 6–8 nm scale. The absorption, and transmittance were analyzed to calculate the band gap (Eg) of each material. Through Energy-dispersive X-ray spectroscopy (EDS), the percentages of each compound present in each sample were determined. FTIR was performed to identify the types of compounds and bonds present in each sample and the vibrational modes detected with Raman spectroscopy. Photoluminescence measurements showed strong yellow and green emissions. The temperature required for the phase change to ZnO was determined to be approximately 426 °C through thermogravimetric analysis (TGA). The catalytic activity was investigated, and it was found that ZnS/ZnO composite degraded approximately 90% of the pollutant (methylene blue), while the mix phases of ZnS/Zn(CO3)2(OH)6 degraded about 56 % of the contaminant when illuminated with sunlight for 80 min.