Synthesis of nanosize zinc oxide through aqueous sol-gel route in polyol medium.

BACKGROUND: This study is aimed to synthesize nanosize zinc oxide by acid catalyzed sol-gel process using zinc nitrate hexahydrate as precursor, aqueous isopropanol as solvent and glycerin for making polyol system. The polyol mediated procedure was employed in combination with calcination induced synthesis of nanoparticles of numerous sizes obtained with the variation in calcination temperature from 500 to 900 â„ƒ. The crystal structure of the prepared samples was characterized by X-ray diffraction analysis (XRD). Infrared spectroscopy (IR) was used to identify the surface hydroxyl groups. Thermal stability was confirmed by differential scanning calorimetry-thermogravimetric analysis (DSC-TGA) whereas field emission scanning electron microscopy (FESEM) was used to study the surface morphology of nanoparticles. RESULTS: Results revealed the formation of hexagonal wurtzite structure of irregular shaped nanoparticles having size ranging from 50-100 nm. However, the particles combined to form agglomerates of 200-400 nm with the rise in calcination temperature. CONCLUSIONS: These results indicate that nanosize zinc oxide can be synthesized successfully by a simple process comprising of glycerin as a low-cost, non-toxic and eco-friendly polyol followed by calcination at ambient temperatures.

Polyol-mediated synthesis of nickel oxide nanoparticles through aqueous sol-gel route.

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.