Green-synthesized silver nanoparticles as plasmonic redox catalysts: Linking charge transfer to antibacterial and dye degradation activities

Biogenic nanocatalysts synthesized via green routes offer unique opportunities to couple redox activity with environmental remediation. Here, silver nanoparticles (AgNPs) were synthesized using Pleurotus sajor-caju (PSC) extract, in which the phytochemicals served as both reducing and stabilizing agents. Structural characterization confirmed the formation of crystalline, face-centered cubic AgNPs with surface functional groups that mediate electron transfer during synthesis and catalysis. The PSC-AgNPs exhibited potent antibacterial activity and radical-scavenging capacity, attributed to efficient electron donation from mushroom-derived biomolecules and subsequent redox cycling at the nanoparticle surface. Under solar irradiation, PSC-AgNPs achieved 93.5% degradation of methylene blue within 6 h, demonstrating their photoactive catalytic activity. The enhanced photocatalytic activity is attributed to surface plasmon resonance-induced charge separation in AgNPs, which facilitates the generation of reactive oxygen species that drive the degradation of the dye. This study highlights the mechanistic interplay among biogenic surface chemistry, electron-transfer dynamics, and plasmon-driven charge activation in PSC-AgNPs, establishing them as sustainable redox-active nanocatalysts for antibacterial, antioxidant, and photocatalytic applications.