Visible Light Driven MnO ₂ /MnS Hybrid Nanostructures for Photocatalytic Degradation of Organic Pollutants: A Synergistic Approach for Wastewater Treatment

Abstract The environment is being threatened by rapid industrialization and water pollution. This research is focused on the synthesis of MnO 2 /MnS binary nanocomposites by using a hydrothermal process and tested as an effective photocatalyst when degrading Rhodamine B (RhB) dye in the presence of sunlight. UV–visible spectroscopy, FTIR, XRD, SEM, and EDX were used in structural and optical characterizations. The band gap was found to be 2.33 eV, and the average crystallite size was 17 nm of the nanocomposite. During photocatalytic degradation, the optimization of various factors such as catalyst dosage, oxidant dosage, pH, time, and concentration of dye was carried out. It is found that MnO 2 /MnS nanocomposite performed excellently and achieved 93% degradation of RhB after 120 min at pH 4, catalyst amount (20 mg/50 mL), and an oxidant dosage of 15 mM. Different radical scavengers were used to find the radical tappers (OH · , e − and h + ) that were effective in the degradation mechanism under sunlight. Kinetics was used, and the reaction proceeded in a first‐order model. Response surface methodology was used for identifying the interaction between various variables. It has been confirmed that MnO 2 /MnS nanocomposites can be efficiently applied in many other real‐world applications of wastewater treatment under solar irradiation.