Rotation-Assisted Hydrothermal Synthesis of Thermally Stable Multiwalled Titanate Nanotubes and Their Application to Selective Catalytic Reduction of NO with NH3

Titanate nanotubes are widely applied in various fields, including photocatalysts and electronic devices, but their weak thermal stability limits their application for catalyst support. Here, we found that titanate nanotubes with a thick multiwalled structure of 15 layers or more can be prepared by using rotation-assisted hydrothermal synthesis. The porous structure of conventional nanotubes synthesized without rotation collapsed easily after thermal treatment, whereas the nanotubes having a thick multiwalled structure retained their pore structure and the specific surface area (∼300 m 2 /g) even after calcination at 400 °C in air. Systematic variation of rotation speed suggested that rotation in the synthesis process accelerated the stacking of layered titanate nanosheets, which are known to be intermediates of nanotubes. Thus, the rapid assembly of titanate nanosheets facilitated by ro…