Splitting behavior and structural transformation process of K2Ti6O13 whiskers under hydrothermal conditions

The splitting behavior and structural transformation process of K2Ti6O13 whiskers in various hydrothermal solutions were investigated by the X-ray diffraction technique, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. TiO2 (B) particle aggregates and rutile twinned crystals were produced respectively in diluted and concentrated HCl solutions via ‘‘dissolution-precipitation’’ mechanism, while no changes were observed in deionized water. In contrary to the chemical inertia of K2Ti6O13 whiskers in KOH solution, trititanate nanowires were synthesized by splitting the bulk K2Ti6O13 whiskers in NaOH solution. The driving force for the formation of nanowires originated from the intrinsic strain induced by the phase transition from K2Ti6O13 with a tunnel structure to layered trititanate.