Synthesis, characterization and photocatalytic activity of TiO2 spherical aggregates

摘要

TiO2 spherical aggregates have been synthesized by means of a simple hydrothermal method using potassium titanium oxalate as titanium source, and then calcined at different temperatures for 2 h. The as-prepared samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), nitrogen adsorption-desorption and UV-Vis diffuse reflectance spectroscopy. The photocatalytic activities of the samples were tested by the photocatalytic degradation of 4-chloronitrobenzene (4-CNB) aqueous solution. The results indicate that the TiO2 spherical aggregates, with the diameters of 300-500 nm, are composed of numerous TiO2 nanocrystals with diameter of about 6.5 nm. Photocatalytic degradation experiments show that the TiO2 spherical aggregates calcined at 500 °C exhibit the highest photocatalytic activity, which is 2 and 1.5 times higher than that of the uncalcined sample and Degussa P25, respectively.