Green Synthesis and Characterization of Nickel Oxide Nanoparticles Using Plectranthus amboinicus Leaf Extract

Abstract

The aim of this study is to synthesize the nickel nanoparticles of P. amboinicus, to identify them by spectroscopic techniques. After removal of the solvent from each extract by reduced pressure, the crude extracts were yielded. Methanolic extract was used for synthesis of nickel nanoparticles (s-NiONPs). The extract dissolved in distilled water was treated with nickel oxide solution to produce the s-NiONPs. The extensive spectroscopic study enabled the identification of synthesized s-NiONPs. The slight differences between extract and NiONPs in FTIR spectrum proved the formation of s-NiONPs. In that, some functional group such as hydroxyl in the extract was oxidized while reduction of nickel ions. The average particle size of s-NiONPs was measured as 71.6 nm by scanning electron microscope (SEM). Elemental analysis displayed the nickel percentage to be 66.12 %. X-ray diffraction analysis presented the maximum absorption of s-NiONPs at 486 nm. X-ray diffraction (XRD) pattern revealed that the crystal size of NiO nanoparticles (the value at 33.5 nm) were crystalline phase formation.