Exploring the Role of <i>Gymnema sylvestre</i> Leaf Extract as a Green Reducing Agent in the Synthesis of Zn‐ and Ni‐Doped CuO Nanostructures with Antimicrobial Properties

Abstract In this work, we used a green synthesis technique to synthesize and analyze Zn‐ and Ni‐doped CuO nanostructures (NSs), using leaf extract from Gymnema sylvestre as a reducing and stabilizing agent. Zn(NO₃)₂·6H₂O and Ni(NO₃)₂·6H₂O were added for doping after a CuO precursor solution was prepared, and the mixture was then annealed at 700 °C. With the aid of electronic absorption spectroscopy, FTIR, SEM, XRD, and EDX analysis, the structural, morphological, and optical characteristics of the produced NSs were thoroughly investigated. Zn and Ni ions were successfully incorporated into the CuO lattice, causing a small lattice deformation, as confirmed by the XRD investigation. Nanoflower‐like nanoplatelet morphologies evolved with increasing dopant concentration, according to SEM analysis. The absorption edges redshifted with doping, according to the UV–vis spectroscopy measurements, which reflected changes in the bandgap energy. The biological activity tests revealed a significant antibacterial activity, particularly in Zn‐doped samples. These findings emphasize the prospect of eco‐friendly Zn─CuO and Ni─CuO nanostructures for applications in antimicrobial coatings and other biological uses.