Water steam modified crystallization and microstructure of mesoporous TiO2 nanofibers

High surface area and high crystallinity structure of TiO 2 have been concentrated for the synergistic promotion of performance in the previous studies. As high temperature heat treatment can lead the opposite development of crystallinity and surface area, high surface area TiO 2 with high crystallinity at a lower temperature has been focused. In the present work, crystallized and mesoporous TiO 2 nanofibers (NFs) with a high surface area were obtained by a simple water steam treatment at the low temperature of 150 °C without any template agents. We demonstrated that water steam could promote not only the removal of organic component but also the crystallization and phase transformation of TiO 2 NFs. The mechanisms of the low-temperature phase transformation and the formation of mesoporous of TiO 2 NFs in water steam atmosphere have been analyzed. The change of the surface area and pore size distribution of the mesoporous structures with increasing temperatures were also studied. Furthermore, photocatalytic properties of the mesoporous TiO 2 NFs were characterized by the photodegradation of methyl orange. It suggested that the mesoporous TiO 2 NFs heat-treated at 550 °C exhibited the highest photocatalytic activity for the synergistic effect of the crystallinity and surface area. In the future, such a facile, scalable, cost-effective approach can be used for the fabrication of mesoporous TiO 2 NFs.