Synthesis of titanate nanotube from different phases of TiO2 powders and its hydrogen absorption capacity.

Titanate nanotubes were synthesized by hydrothermal method with different NaOH concentration using various TiO2 powders (P-25, rutile, anatase, and Ni doped TiO2) at 120 degrees C for 24 hrs. At 10 M NaOH, Ni doped TiO2 powders formed the titanate nanotubes which consisted of layered structure such as A2Ti2O5.H2O, A2Ti3O7, H2TiO.H2O (A = Na and/or H) with outer and inner diameter of approximately 10 nm and 6 nm. Ni doped nanotubes absorbed a small amount of hydrogen at 6 and 10 atm, however, uptake of hydrogen was 1.2 wt% at 20 atm.

Structural characterization of titanate nanotubes for lithium storage.

Titanate nanotubes were synthesized by hydrothermal method using various TiO2 precursors as starting materials. The electrochemical properties were investigated by cyclic voltammetric methods. The microstructure and morphology of the synthesized powders were characterized by XRD, TEM. Titanate nanotubes composed of H2Ti2O5 x H2O with outer and inner diameter of approximately 10 nm and 6 nm, and the interlayer spacing was about 0.65 approximately 0.74 nm. Also, the titanate nanotubes showed a discharge capacity of 303 mAh/g and the highest cycle stability because of the open-end and rolled layers with suitable spacing. The relationships between morphology and electrochemical properties have been also discussed.

Synthesis and characterization of titanate nanotube for hydrogen storage using hydrothermal method with various alkaline treatment.

Titanate nanotubes and nanofibers were synthesized by hydrothermal method using various alkaline solutions (NaOH and KOH) in order to study the effect of synthesis condition for hydrogen storage. The microstructures of titanate nanotube and nanofibers were characterized by XRD, TEM, FE-SEM. It was found that interlayer spacing of titanate nanotubes and nanofibers depended on the alkaline solution, because some of the Ti-O-Ti bonds were broken and layered titanate nanosheet of Ti-O-A (Na+ and K+) bonds were formed. The sorption of hydrogen of the titanate nanotubes and nanofibers were studied by the conventional volumetric pressure-composition isothermal method at RT, 30 atm. The relationships between interlayer spacing, ionic radius of alkaline solution and hydrogen capacity have been discussed.