Effect of calcination temperatures on structures of TiO[subscript 2] powders prepared by hydrothermal method using Thai leucoxene mineral

Abstract

TiO[subscript 2] powders were synthesized by hydrothermal method with 10M NaOH solution al 115 degree Celsius for 24 h using natural Thai leucoxene mineral as the starting material. The effects of calcination temperatures on structures of the prepared materials were investigated. The structures of the prepared samples were characterized by X-ray diffraction (XRD) technique and scanning electron microscopy (SHM). The as-synthesized sample showed the nanotubes-nanofibers structures with (tilde)10-20 nm in diameter of nanotubes and (tilde)20-50 nm in diameter of nanofibers. The XRD result showed that the as-prepared sample before being calcined was the mixed phase of titanate and rutile. The titanate phase could transform to anatase phase at the calcination temperature higher than 500 degree Celsius As the calcination temperature increased. crystallization of anatase phase was enhanced. With further increase in the calcination temperature from 700 to 900 degree Celsius the intensity of rutile phase increased. When the calcinations temperature reached 1000 degree Celsius only rutile phase was found in the XKD pattern.