Size, Morphology and Optical Properties of Titanium-Based Colloidal Nanoparticles Prepared by Dc Electrical Arc Discharge in Different Liquids

In recent years, synthesis of nanoparticles via arc electrical discharge method get a lot of interest because this method needs low cost equipment and is environmentally friendly. In this study, synthesis of titanium-based nanoparticles carried out by direct current (DC) arc discharge in different liquids. The purpose of research is investigating the effect of liquid medium on size, crystal structure and optical properties of synthesized colloidal nanoparticles. Deionized water and three different organic liquids including ethanol, methanol and acetone were used as arc discharge medium. The arc discharge created with applying 40 A current between two pure titanium electrodes immerged in 4 cm depth of liquid. Scanning electron microscopy (SEM) and UV-visible spectroscopy were used for characterization of size and morphology and optical properties of nanoparticles respectively. However the morphology of particles is independent of liquid medium and approximately all particles are almost spherical but the average size of particles are different which among them the colloidal nanoparticles synthesized in acetone demonstrate the smallest size. According to optical transmission spectra, nanoparticles synthesized in water indicate optical characteristic of titanium oxide. Also these colloidal nanoparticles sediment after about two days. Colloidal nanoparticles synthesized in organic liquids especially acetone demonstrate high stability without any sedimentation. In addition, nanoparticles synthesized in ethanol, methanol, and acetone indicate optical characteristic of metallic nanostructure. Finally water is suitable to formation of titanium oxide nanoparticles and acetone is determined as the best medium for preparation of stable colloidal solution of titanium nanoparticles. (C) 2015 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).