Background In this work, nickel oxide nanoparticles were prepared by polyol mediated aqueous route of sol–gel process using nickel nitrate hexahydrate as precursor, a mixture of isopropyl alcohol and water as solvent and glycerol for making polyol medium followed by calcination at various temperatures ranging from 500 to 900 °C. Characterization was carried out using X–ray diffractometry, infrared spectroscopy, differential scanning calorimetry-thermogravimetry and field emission scanning electron microscopy. Results The results confirmed the formation of face-cantered cubic structure of nickel oxide with its complete conversion after calcination at 900 °C; significant variation in the surface morphology was observed with the increasing calcination temperature. Conclusions The study revealed that the aqueous sol–gel route using polyol system followed by calcination at ambient temperatures lead to the successful synthesis of nickel oxide nanoparticles.

Background: In this work, nickel oxide nanoparticles were prepared by polyol mediated aqueous route of sol-gel process using nickel nitrate hexahydrate as precursor, a mixture of isopropyl alcohol and water as solvent and glycerol for making polyol medium. The synthesized nanoparticles were calcined at various temperatures ranging from 500 to 900 °C in order to investigate the effect of calcination temperature on their structure and morphology. Characterization was carried out using X-ray diffractometry, differential scanning calorimetry-thermogravimetry, infrared spectroscopy and field emission scanning electron microscopy.Results: The results confirmed the formation of face-cantered cubic structure of nickel oxide with significant variation in the surface morphology with the increasing calcination temperature.Conclusions: The study revealed that the aqueous sol-gel route can be employed successfully for the synthesis of ultrafine nickel oxide.