Characterization of Copper Nanoparticles synthesized Using the Leaf Extracts of Lawsonia inermis, Eucalyptus globulus, Psidium guajava, and Azadirachta indica

Green synthesis of nanoparticles using plant extracts is a sustainable, eco-friendly, non-toxic, and cost-efficient approach. In this study, copper nanoparticles (CuNPs) were synthesized using the mehandi Lawsonia inermis, nilgiri Eucalyptus globulus, guava Psidium guajava, or neem Azadirachta indica leaf extracts and 1mM CuSO4.5H2O salt solution in a ratio of 1:3 at 800C temperature and characterized using UV-Visible spectroscopy, Fourier Transform Infrared spectroscopy, and Field Emission Scanning Electron Microscopy analysis. All the CuNPs showed colour change with characteristic surface plasmon resonance bands. The plasmon resonance bands of L. inermis, P. guajava, and A. indica CuNPs peaked at 300nm while those of E. globulus CuNPs peaked at 400nm. The CuNPs synthesized from L. inermis, E. globulus, and P. guajava leaf extracts exhibited brown colour while those synthesized from A. indica leaf extracts showed green colour. Eleven bands were present in L. inermis and A. indica CuNPs in the range of 538.61-3649.06cm-1 and 3867.26-519.02cm-1, respectively, while ten were in the E. globulus and P. guajava CuNPs in the range of 407.25-3326.78cm-1 and 3325.93-407.07cm-1, respectively. The L. inermis, E. globulus, and A. indica CuNPs were spherical, except P. guajava CuNPs which were flaky in shape. The particle size of L. inermis CuNPs was found in the range of 8.20 to 15.94nm; E. globulus CuNPs in the range of 7.52 to 67.47nm; P. guajava CuNPs in the range of 18.90 to 73.80nm and A. indica CuNPs in the range of 9.86 to 22.05nm.