Green Synthesis of Manganese Dioxide Nanoparticles Using Clitoria ternatea Leaf Extract and Whey Milk

Green synthesis of manganese dioxide (MnO₂) nanoparticles was successfully carried out using Clitoria ternatea leaf extract (MnO₂–CT) and whey milk (MnO₂–W) as eco-friendly reducing and stabilizing agents. The synthesized nanoparticles were characterized using UV–Visible, FT-IR, XRD, FE-SEM, EDAX, and TGA analyses, confirming their nanoscale size, crystalline nature, surface functionalization, high purity, and good thermal stability. UV–Vis and FT-IR results verified nanoparticle formation and Mn–O bonding, while XRD indicated nanocrystalline structure with small crystallite size. Morphological studies revealed agglomerated, porous particles with high surface area. Thermal analysis showed that MnO₂–W exhibited higher stability, whereas MnO₂–CT displayed multistage decomposition due to phytochemical capping. Anticorrosion studies demonstrated enhanced protection, particularly in basic medium, with MnO₂–CT showing higher inhibition efficiency. Antibacterial evaluation against selected bacterial strains revealed moderate activity, with MnO₂–CT exhibiting slightly better performance due to synergistic effects of plant-derived compounds. Overall, the study highlights a sustainable and cost-effective approach for synthesizing multifunctional MnO₂ nanoparticles with promising applications in corrosion protection and antimicrobial activity.