Synthesis of Tio_2/Zno Core/Shell Type Nanocomposite via Sol-Gel Method

摘要

TiO_2/ZnO Nanocomposite powders with different Zn/Ti ratios were synthesized via sol-gel method. The as prepared and calcined Titania nanopowders were added to the ZnO sols. Also the as prepared and calcined ZnO nanopowders were separately added to the TiO_2 sols. However, in the latter case, the nanocomposite never formed due to the high acidity of the sols. After gelation, the powders were dried and calcined at 500°C for lh. The phase composition, structure, morphology and optoelectrical properties of the powders were characterized by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV-Vis photospectroscopy and photoluminescence spectroscopy (PL). The XRD patterns confirm the presence of TiO_2 and ZnO crystalline phases in the TiO_2 particles/ZnO sol samples. The FESEM micrographs show that TiO_2/ZnO nanocomposites heat treated at 500°C were formed with average diameter of about 250nm with 50nm ZnO particles on clusters of 40nm TiO_2 particles. It was found that the optoelectronic properties of the nanocomposites were improved according to the UV-Vis and photoluminescence spectroscopy.