Effect of ultrasonic treatment and temperature on nanocrystalline TiO2

Nanocrystalline TiO2 particles were precipitated from the ethanol solution of titanium isopropoxide (Ti(O-iPr)(4)) and H2O2 by refluxing at 80 degrees C for 48 h. The obtained particles were filtered and dried at 100 degrees C for 12 h. The dried powder itself, the sample with heating at 400 degrees C, and the sample with ultrasonically treating were prepared to investigate the effects of post treatments on materials characteristics and electrochemical properties of nanocrystalline TiO2. The X-ray diffraction patterns of all of the samples were fitted well to the anatase phase. The field emission-TEM image of as-prepared sample shows a uniform spherical morphology with 5 nm particle size and the sample heated at 400 degrees C shows slightly increased particle size of about 10 nm while maintaining spherical shape. The sample treated with ultrasonic for 5 h or more at room temperature shows high aspect ratio particle shape with an average diameter of 5 nm and a length of 20 nm. According to the results of the electrochemical testing, as-prepared sample, the sample heated at 400 degrees C for 3 h, and the sample treated with ultrasonic show initial capacities of 270, 310 and 340 mAh g(-1), respectively. (c) 2006 Elsevier B.V. All rights reserved.