Crystal growth behavior interpret of co-precipitated derived nickel oxide (NiO) nanocrystals

Abstract

High crystalline nickel oxide nanoparticles (NiO NPs) were synthesized using a simple, unparalleled and unique route. Rietveld refinement analysis confirmed the formation of a 100 % pure NiO phase. X-ray diffraction (XRD) analysis revealed a strong correlation between crystallographic parameters, including crystallite size 41.2 nm, micro-strain 1.27 × 10⁻⁴ Nm⁻², lattice parameters a=b=c= 4.1791 Å, unit cell volume 72.991 ų, dislocation density 5.89 × 10⁻⁴ nm⁻², crystallinity index 2.05, specific surface area 21.41 m²/g, crystallinity percentage of 47 % and atomic packing factor 52.7 %. UV–visible absorption analysis revealed a blue shift at 325.74 nm, confirming the nanoscale distribution and an optical band gap of 3.19 eV. The zeta potential range up to 87.36 mV, indicating excellent stability and determined hydrodynamic diameter of 197.6 nm. TEM revealed uniform spherical morphology of the NiO NPs with an average particle size of 49.93 nm. HR-TEM and SAED patterns further validated the single-phase nature of NiO NPs, identifying predominant crystallographic planes (111), (200), (220), (311), (222), (400), (331), and (420). The analysis also revealed the perfection of crystal lattice by SAED and HR-TEM. EDS confirmed the purity of NiO NPs with atomic percentages of 66 % Ni and 34 % O, respectively. The catalytic degradation also explored of Methylene Blue (MB) cationic dye in presence of solar light at 85.3 % degrades nearly entirely in 300 minutes in aqueous solution.