A comparative study of synthesis of ZnO nano particles: Hydrothermal and modified combustion routes

Abstract

The reduction in size leads to the introduction of novel electrical, mechanical, chemical and optical properties in materials. The properties of nano ZnO are of particular interest because of its multi-dimensional applications in the fields of industries, cosmetics, electronics etc. The fact that extra care is needed for the synthesis of nano materials and that their properties vary with synthesis routes, we have picked up two important methods for the synthesis of ZnO, namely, a modified combustion synthesis and a hydrothermal synthesis route to compare the powder property. Both type of powders were characterized by XRD, FESEM, FTIR, DSC and UV–Visible Spectroscopy, etc. to analyse the crystal structure, phase, morphology, purity, thermal behavior and optical property of the powder. Homogenous and regular crystallite size distribution have been observed in both the powders which was attributed to the molecular level of mixing of the ingredients. A noticeable difference in the optical band gap has however been observed in both the powders which was attributed to the crystallite size difference. The result was correlated with the crystallite size distribution as observed from XRD and from FE-SEM. There also has been marked difference in the powder quality on the basis of carbon residues which was attributed to the reaction steps and heat take up by the powder during the thermal treatment of the powder.