Bioinspired Synthesis of Functional Palladium Nanoparticles from Moringa oleifera Flowers for Synergistic Antimicrobial and Photocatalytic Performance

This study reports the green synthesis of palladium nanoparticles (Pd-NPs) using Moringa oleifera flower extract, with two samples (P5 and P15) prepared using different extract volumes to evaluate the effect of phytochemical concentration. XRD analysis confirmed the formation of face-centered cubic Pd, with P15 exhibiting a smaller crystallite size than P5. TEM analysis revealed predominantly spherical nanoparticles, where P15 showed smaller and more uniformly distributed particles (5.19–16.57 nm) compared to P5 (6.78–24.78 nm). FTIR results confirmed the involvement of phenolic, amide, and carboxyl functional groups in nanoparticle reduction and stabilization. A clear enhancement in biological activity was observed for P15, which exhibited higher antibacterial activity against Escherichia coli (28 mm) compared to P5 (26 mm). Photocatalytic studies further demonstrated superior performance of P15, with a higher rate constant (0.030 min-1 vs 0.027 min-1 for Congo Red) and faster degradation of both Congo Red and Crystal Violet dyes. The improved performance of P15 is attributed to its smaller particle size, better dispersion, and higher surface area. Overall, increasing extract concentration significantly improves nanoparticle characteristics, resulting in enhanced antibacterial and photocatalytic efficiency. These findings highlight the potential of M. oleifera-mediated Pd-NPs as eco-friendly and multifunctional materials for biomedical and environmental applications.