Hydrothermal synthesis of potassium hexatitanates under subcritical and supercritical water conditions and its application in photocatalysis

Hydrothermal synthesis of potassium hexatitanate was carried out under vari ous subcritical and supercritical water conditions using potassium hydroxid e and titanium tetraisopropoxide as starting materials. Characterization of these hydrothermally synthesized potassium hexatitanates by XRD, SEM, TEM, and thermal analysis showed that long, felted-like fibers of potassium hex atitanates were formed and these fibers are thermally stable up to 1273 K. The use of these fibers as photocatalysts in water decomposition was invest igated using ruthenium oxide as the catalytic active phase. Photocatalytic activity in the water decomposition reaction was found to be much higher in comparison with the solid state synthesized photocatalyst. Activites of mo re than 13-fold were obtained for the photocatalysts synthesized under subc ritical water conditions and between 27- and 59-fold for those synthesized under supercritical water conditions for water decomposition.