Evaluation of Structural, Optical, Morphological and Colloidal Stability of NiO Nanoparticles Synthesized Through Green Method

Abstract

NiO nanoparticles have been produced by an eco-friendly combustion method utilizing water-based extracts from several parts of the Eichhornia crassipes plant, specifically the root, stem and leaf. Nickel nitrate hexahydrate and urea (fuel) are taken as precursors while plant extracts operated as natural stabilizers and reducing agents. We used a lot of different analytical tools to make sure that the nanoparticles we made were fully characterized. These tools included zeta potential analysis, field emission scanning electron microscopy (FESEM), photoluminescence (PL), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The XRD analysis confirmed that the NiO nanoparticles have a single-phase cubic structure with higher crystalline nature. The average crystallite sizes of the samples are in the range of 13 to 17 nm. The vibrational analysis of NiO nanoparticles revealed the presence of Ni-O stretching vibrations between 400 to 600 cm-1. The optical band gap values are found to be in between 3.40 and 3.37 eV.  The photoluminescence spectra showed too much ultraviolet and violet light, which was explained by intrinsic transitions and defect states, including oxygen vacancies. FE-SEM micrographs revealed that most of the nanoparticles are spherical and coalesced together in different ways depending on the plant extract employed. Tests of zeta potential showed that the colloids were pretty stable. This was especially true for the NiO nanoparticles that came from the stem. The results reveal that extracts from Eichhornia crassipes can be utilized to generate NiO nanoparticles with optical and structural properties that can be changed. The present analysis showed that the NiO nanoparticles are useful for photocatalysis, sensors, optoelectronics and energy devices.