Plasmon-Enhanced Photocatalysis and Antimicrobial Activity of Green-Synthesized Ag-Decorated ZnO Nanoparticles Using Mentha pulegium Extract

Plasmonic nanomaterials have attracted considerable interest owing to their distinctive optical and electronic properties, which significantly enhance their performance in photocatalytic and biomedical applications. In this study, Ag-decorated ZnO (ZnO/Ag) nanoparticles were synthesized via a green approach using Mentha pulegium extract, resulting in spherical nanoparticles with a uniform size distribution ranging from 40 to 55 nm. The localized surface plasmon resonance (LSPR) effect of silver markedly improved light absorption and charge carrier separation, leading to a 92.6% degradation efficiency of penicillin G under optimized conditions. Moreover, the Ag-decorated ZnO nanoparticles demonstrated enhanced antibacterial activity, exhibiting a minimum inhibitory concentration (MIC) of 62.5 µg/mL against Escherichia coli and Klebsiella pneumoniae, outperforming both pristine ZnO and the plant extract. The strong plasmonic interactions further contributed to improved antioxidant performance, achieving an 84% DPPH radical scavenging efficiency. These results highlight the multifunctional potential of Ag-decorated ZnO nanoparticles and emphasize the critical role of plasmonic enhancement in advancing eco-friendly nanotechnological solutions for environmental and biomedical applications.