Green nanotechnology has emerged as a promising approach for the synthesis of metal nanoparticles using plant-based resources that are simple, cost-effective, less toxic, and environmentally benign. In this study, copper nanoparticles were biosynthesized using the aqueous leaf extract of Ocimum sanctum. Upon the addition of 1 mM copper sulfate solution to the extract, a visible color change from pale green to dark brown was observed within 30 minutes, indicating the formation of CuNPs. The effect of incubation temperature (25°C, 50°C, and 75°C) and time (0.5–6 h) was studied to optimize synthesis conditions. Maximum nanoparticle yield was observed at 75°C after 4 hours, as confirmed by a strong surface plasmon resonance peak at 580 nm in UV-Vis spectroscopy. Further characterization was carried out using Fourier Transform Infrared Spectroscopy, which revealed the presence of functional groups such as –OH, –C=O, and –C–N, indicating the role of phytochemicals in reduction and stabilization. X-ray diffraction analysis confirmed the crystalline nature of the synthesized CuNPs with distinct peaks at 2θ values of 43.3°, 50.4°, and 74.1°, corresponding to the (111), (200), and (220) planes of face-centered cubic copper. The study demonstrates that Ocimum sanctum leaf extract acts as an efficient bio-reducing and capping agent, offering a sustainable route for copper nanoparticle synthesis with potential applications in catalysis, antimicrobial formulations, and environmental remediation.
Jain et al. (Fri,) studied this question.