Plant Assisted Synthesis of Li-doped Mn3O4 Nanoparticles Using Madhuca longifolia Leaf Extract for Enhanced Photocatalytic, Electrochemical and Antimicrobial Applications

In this study, lithium (Li) doped Mn 3 O 4 nanoparticles (NPs) were successfully synthesized via a green and eco-friendly route using Madhuca longifolia ( M. longifolia ) leaf extract as a reducing and stabilizing agent. The structural, morphological and optical properties of the synthesized nanoparticles were systematically characterized using standard analytical techniques. The formation and structural properties of the synthesized nanoparticles were confirmed by Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction analysis. In XRD analysis confirms a crystalline phase with an average crystallite size of 29.6 nm, as calculated using the scherrer equation. The Williamson-Hall (W-H) plot however, indicates a broad size of 45.26 nm. It suggests the presence of lattice strain. These are indicating successful incorporation of Li ions into the Mn 3 O 4 lattice. UV-Visible spectroscopy revealed the optical absorption behavior and band gap characteristics of the nanoparticles. This reveals the optical band gap of 3.05 eV, indicates suitable for photocatalytic applications. Transmission Electron Microscopy (TEM) analysis demonstrated nanoscale particle size with relatively uniform morphology. Energy Dispersive X-ray Analysis (EDAX) confirmed the elemental composition and purity. Electrochemical studies using cyclic voltammetry demonstrated good redox behavior with an average specific capacitance of 216.43 F/g, indicating promising energy storage performance. The biosynthesized NPs exhibited notable antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Candia albicans. Furthermore, the photocatalytic performance showed efficient degradation of both cationic and anionic dyes, achieving 77.6% degradation of methylene blue (MB) and 80.91% degradation of methyl orange (MO). The enhanced performance is attributed to Li doping which improves charge separation and reduces electron – hole recombination. Overall, this work demonstrates an eco-friendly synthesis route and highlights the multifunctional potential of Li doped Mn 3 O 4 NPs for environmental remediation, antimicrobial and energy storage applications.