Optical and photocatalytic properties of nickel oxide nanoparticles

Abstract

This study investigates the optical and photocatalytic properties of Nickel Oxide (NiO) nanoparticles synthesized via co-precipitation at 400 °C for 6 h using nickel nitrate hexahydrate and sodium hydroxide. Characterization techniques, including X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), energy dispersive X-ray analysis (EDX), and UV–vis spectroscopy, were employed. XRD confirmed the NiO product with a face-centered cubic structure and a crystallite size of 11.32 nm. FTIR analysis identified functional groups associated with NiO formation. SEM revealed agglomerated nanoparticles of approximately 22.34 nm in size with a spherical shape. The synthesized NiO exhibited a strong UV absorption peak and an optical band gap of 4.39 eV. The synthesized NiO nanoparticles effectively degraded methylene blue under sunlight. The photocatalytic activity was optimized with catalyst dosages of 2 mg, 5 mg, and 10 mg. The 10 mg dose achieved the highest degradation efficiency of 92.32 % in 40 min, while 2 mg and 5 mg also exhibited substantial degradation, achieving rates of 87.08 % and 87.48 %, respectively. A reusability study indicated excellent stability and photocatalytic activity. These findings suggest NiO nanoparticles’ potential for wastewater treatment applications.