Synergetic Photocatalytic Performance of Reusable Ag₂S/ZnS/Fe₃O₄ Magnetic Nanocomposite for Impressive Degradation of Methyl Orange over Visible Light

In this research, a novel ternary Ag₂S/ZnS/Fe₃O₄ magnetic nanocomposite was successfully synthesized using the facile co-precipitation method. Different characterization equipments were used to study the structure, morphology, and optical properties of the Ag₂S/ZnS and Ag₂S/ZnS/Fe₃O₄ nanocomposites, which will be used as a photocatalyst for methyl orange degradation. X-ray diffraction analyses showed that ZnS and Fe₃O₄ have a cubic crystal structure, while Ag₂S has a monoclinic structure at room temperature. TEM images revealed that the average particle size of the Ag₂S/ZnS and Ag₂S/ZnS/Fe₃O₄ nanocomposites is approximately 9 nm and 26 nm, respectively. Furthermore, the photoluminescence peak intensity of the Ag₂S/ZnS/Fe₃O₄ nanocomposite was lower than that of the Ag₂S/ZnS nanocomposite, indicating a reduction in electron-hole recombination and an enhancement in photogenerated charge carrier transitions in the ternary nanocomposite. To optimize the photocatalytic performance of the Ag₂S/ZnS/Fe₃O₄ magnetic nanocomposite for methyl orange degradation, different effective parameters such as pH, methyl orange concentration, photocatalyst dosage, and radiation type was varied. Under the optimized conditions, the Ag₂S/ZnS/Fe₃O₄ nanocomposite exhibited higher photocatalytic efficiency than Ag₂S/ZnS. Specifically, the photocatalytic degradation efficiency of the Ag₂S/ZnS/Fe₃O₄ nanocomposite was approximately 92% and 99% under visible and ultraviolet light radiation, respectively. This excellent degradation performance can be attributed to the small band gap energy and low rate of electron-hole recombination in the ternary nanocomposite. Furthermore, we found that the Ag₂S/ZnS/Fe₃O₄ photocatalyst could be easily separated with a simple magnet after the catalytic reaction. It also demonstrated a highly stable performance after recycling, indicating advanced reusability and stability. Therefore, the Ag₂S/ZnS/Fe₃O₄ magnetic nanocomposite, which is both biocompatible and reusable, can be considered an effective and high-efficiency photocatalyst for methyl orange degradation under visible light radiation.