Fast and simplified fabrication of Cu/Cu ₂ O nanocomposites for antioxidant and antibacterial activities

This study reports a fast and simplified chemical reduction method for synthesizing Cu/Cu2O nanocomposites (NCPs) using sodium borohydride and L-ascorbic acid, with chitosan or polyvinylpyrrolidone as stabilizers. Transmission electron microscopy (TEM) revealed good monodispersity and predominantly spherical morphology of both chitosan and PVP-stabilized Cu and Cu2O nanoparticles, without agglomeration. X-ray diffraction (XRD) analysis confirmed the presence of face-centred cubic Cu (fcc-Cu) and fcc-Cu2O phases. Nanoparticles stabilized by chitosan (1%) had larger sizes (53.5 nm for Cu and 26.5 nm for Cu2O) compared to those stabilized by PVP (1%) (40.8 nm for Cu and 22.7 nm for Cu2O). Characteristic absorption peaks of NCPs were observed in the UV-vis spectra at 581–586 nm for Cu and 380–400 nm for Cu2O. Both NCPs and ascorbic acid demonstrated antioxidant activity through DPPH radical scavenging. The antibacterial activity against Staphylococcus aureus and Salmonella typhi bacteria was confirmed by the zone of inhibition observed on diffusion disks.