نشز ی ه علند، سال هوا دوم ، شواره سوم، ابستاى ت9889 2, No.3, 2010, 40-49 . Journal of Materials Science, Vol Sol-Gel Synthesis and Photocatalytic Characterization of the Anatasenanopowder Abolghasem Nourmohammadi 1 , Mehrnaz Mehrjuee 2 , Mohammad ali Bahrevar 3 , Azarmidokht Hosseinnia 3 1- Department of Physics, Faculty of Science, University of Isfahan,Isfahan, Iran 2- Department of Materials Engineering, Islamic Azad University, Najafabad Branch, Isfahan, Iran 3- Materials and Energy Research Center, Tehran, Iran ARTICLE INFO ABSTRACT Article history: Received: 11 May 2010 Accepted: 11 Aug. 2010 Semiconductor photocatalysts are becoming more and more attractive due to their excellent potential to solve environmental problems. Among them, nanosizedanatase-phase titanium dioxide (TiO 2 ) is of great interest due to the strong oxidizing power of its holes, high photostability and redox selectivity. In this research, we have synthesized single-phase anataseTiO 2 nanoparticles and investigated their photocatalytic activity. A sol-gel route was utilized to prepare the material and demonstrate the advantages of the low-temperature preparation. In the first step, we investigated the thermal behavior of the prepared sol by simultaneous thermal analysis (STA) to determine the proper heat-treatment conditions. The as-prepared powders were subsequently characterized by X- ray diffraction (XRD), transmission electron microscopy (TEM), and BET surface area measurement technique. The mean crystallite size, for each heat-treatment conditions, was also calculated based on the Scherer equation. The photocatalytic activity of the powders was investigated using both Methylene Blue and Rhodamine B as model organic compounds under UV light irradiation. Keywords: Visible-light-active photocatalyst Titanium oxide Anatase Sol-gel