As it stands now,different morphological products have been synthesized by differ-ent researchers even if the same precursors are used and similarconditions are applied. The “mystery” of hydrothermal synthesis in turns inspires researchers to explore not only better control ofthe morphology but also to impart unique properties and excel-lent catalytic activity. For example, the hydrothermal synthesis ofwell-ordered TiO2-based nanotubes would facilitate fast electrontransfer, and open new possibilities in photocatalytic applications.In addition, there is a need for more research on the selective pho-tocatalytic oxidation by TNTs.