Growth of ultralong potassium titanate whiskers by the KCl flux method with metallic titanium materials

Well-formed, highly crystalline potassium titanate whiskers were successfully grown by the KCl flux cooling method at a holding temperature of 800 °C using metallic titanium materials. Of primary importance were the metallic Ti spheres and potassium chloride powders that were used as the starting materials for growth of the titanate whiskers. Ultralong K ₂Ti₆O₁₃ whiskers grew radially from the center of the Ti spheres by our flux technique. Cross-sectional SEM images demonstrate that the ultralong whiskers were grown on the TiO₂ crystal layer, and the whisker spheres had a bilayer structure that was hollow in the center. When Ti powders were used as the starting material, spherical aggregation of K ₂Ti₆O₁₃ and K₂Ti₄O ₉ whiskers occurred. The product structures were different from those obtained from metallic Ti spheres. Based on SEM, EDS and XRD, the formation mechanism of the ultralong whiskers was also discussed. Furthermore, the photocatalytic activity of the whiskers was confirmed by trichloroethylene degradation under ultraviolet light irradiation.