摘要
The mechanism of the conversion of titanate nanotubes into nanoribbons is of considerable interest.The details of the transformation processes involved when nanoribbons are produced from a P25 TiO 2 powder precursor by alkaline hydrothermal treatment have been investigated systematically by transmission electron microscopy.A multistep attachment model is proposed for the growth at the early stage of coarsening.The treatment duration has a strong effect on the change in product morphology from hollow nanotubes into nanoribbons,since the nanotubes cannot retain their morphology in the strong alkaline solution for extended periods of time.Most of the nanotubes were etched and dissolved,providing the nutrients for subsequent nanoribbon growth.Some stable nanotubes grew spirally internally to form nanowires or became connected together to form rafts which acted as the grains for nanoribbon growth.With increasing hydrothermal time,a large number of nanotubes and other fragments became attached to the grains which began to grow larger and eventually formed the nanoribbons,in a process in which the stepped faces and kinked faces became fused and were eliminated while the flat faces were retained in the nanoribbon morphology.
The mechanism of the conversion of titanate nanotubes into nanoribbons is of considerable interest. The details of the trans- formation processes involved when nanoribbons are produced from a P25 TiO2 powder precursor by alkaline hydrothermal treatment have been investigated systematically by transmission electron microscopy. A multistep attachment model is pro- posed for the growth at the early stage of coarsening. The treatment duration has a strong effect on the change in product mor- phology from hollow nanotubes into nanoribbons, since the nanotubes cannot retain their morphology in the strong alkaline solution for extended periods of time. Most of the nanotubes were etched and dissolved, providing the nutrients for subsequent nanoribbon growth. Some stable nanotubes grew spirally internally to form nanowires or became connected together to form rafts which acted as the grains for nanoribbon growth. With increasing hydrothermal time, a large number of nanotubes and other fragments became attached to the grains which began to grow larger and eventually formed the nanoribbons, in a process in which the stepped faces and kinked faces became fused and were eliminated while the flat faces were retained in the nanoribbon morphology.
基金
supported by the National Basic Research Program of China (2011CBA00700)
the National High Technology Research and Development Program of China (2009AA050603 and 2011AA050527)
Funds of the Chinese Academy of Sciences for Key Topics in Innovation Engineering (KGCX2-YW-326)
