Phyto-fabricated Pd@Ag bimetallic nanocomposites using carica papaya leaf extract: A dual-functional platform for catalysis and antimicrobial defence

This study presents a green synthesis approach for bimetallic palladium–silver (Pd@Ag) nanocomposites using Carica papaya leaf extract, aimed at addressing urgent environmental and biomedical challenges. The synthesized Pd@Ag nanoparticles exhibited remarkable catalytic efficiency in degrading hazardous organic dyes, achieving 82% and 88% reduction of Congo Red and Methylene Blue, respectively, within minutes in the presence of NaBH 4 . This highlights their strong potential in wastewater treatment and environmental detoxification. Furthermore, the Pd@Ag nanocomposites demonstrated broad-spectrum antimicrobial activity, showing significant zones of inhibition against major bacterial pathogens including Escherichia coli and Staphylococcus aureus , as well as antifungal effects against Candida albicans and Aspergillus niger . The dual functionality—efficient catalysis and potent antimicrobial defence—establishes these green-synthesized nanoparticles as promising candidates for sustainable environmental and biomedical applications. • Green-synthesized Pd@AgNPs using Carica papaya leaf extract as a bio-reductant. • Characterization confirmed core–shell structure and nano-scale crystallinity. • Pd@AgNPs catalytically degraded Congo Red and Methylene Blue with >80% efficiency. • Exhibited strong antimicrobial activity against both gram-positive and gram-negative bacteria. • Demonstrated effective antifungal activity with significant inhibition zones.