Perovskite-type KTaO3 Prepared by a Modified Solid-state Method at Low Temperature

Perovskite-type KTaO3 powder was synthesized by a modified solid-state method at relatively low temperature using K2CO3 and ammonium tantalum hydroxide as starting materials with the addition of KF which was then washed off with water. X-Ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis spectrometry were used to characterize the products calcined at different temperatures. The results showed that KF could inhibit the formation of pyrochlore phase and the products obtained at different temperature were agglomerations which were made up of many small grains with 10-30 nm in diameter, the band gap of samples calcined at 500, 600 and 800 degrees C were 3.68, 3.63 and 3.54 eV, respectively. The influences of other alkali halides were also investigated. The results indicated that lithium fluoride and sodium fluoride played the same role as potassium fluoride did. When using alkali chloride as additive, the major products were lithium tantalate, sodium tantaltate and pyrochlore potassium tantatate, respectively.