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 deg C for 48h. The obtained particles were filtered and dried at 100 deg C for 12h. The dried powder itself, the sample with heating at 400 deg 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 5nm particle size and the sample heated at 400 deg C shows slightly increased particle size of about 10nm while maintaining spherical shape. The sample treated with ultrasonic for 5h or more at room temperature shows high aspect ratio particle shape with an average diameter of 5nm and a length of 20nm. According to the results of the electrochemical testing, as-prepared sample, the sample heated at 400 deg C for 3h, and the sample treated with ultrasonic show initial capacities of 270, 310 and 340mAhg-1, respectively.