Formation of crystallized titania nanotubes and their transformation into nanowires

Abstract

Gram quantities of titania (TiO 2) nanotubes, with a typical outside diameter about 9 nm, wall thickness of about 2.5 nm, and length of about 600 nm, were synthesized from anatase nanopowder and micropowder using the hydrothermal method. The crystallization, structure, and phase stability of the nanotubes at high temperatures were studied. A morphology change from nanotube to nanowire was observed at 650 • C. The as-prepared nanotubes were usually contaminated with sodium impurities and were poorly crystallized, but under optimized synthesis conditions the impurity phase was completely removed, resulting in highly crystallized nanotubes. The volume filling fraction of the autoclave as well as the concentration of the acid treatment were found to be particularly important for controlling the purity and crystallinity of the resulting nanotubes. The various TiO 2-derived nanotube phases (sodium titanate and hydrogen titanate) reported previously by different groups were also observed under different synthesis conditions, resolving the contradiction among the previous results.

Synthesis of TiO2 nanotubes by using combination of sonication and hydrothermal treatment and their photocatalytic activity for hydrogen evolution

“…This lowered total energy and hence TiO 2 NT was formed (Chen and Mao, 2007). Similar results have been reported by Bavykin et al, (2004), Zhao et al, (2009), andPoudel et al, (2005), but essentially contradicting with the assumptions of Kasuga et al, (1999). They revealed an acid washing treatment step following the hydrothermal process to form tri-titanate nanotubes.…”

Synthesis and Characterization of TNTs/Polyaniline Composite as Photocatalyst Degradation of Rhodamin B by Visible Light

“…TNTs that are less than the maximum growth is most likely caused by the effect of pressure during the hydrothermal process. The pressure formed during hydrothermal process in addition affected by temperature is also influenced by the percentage of filling the autoclave [9].…”

Characterization of Hydrated Titanium Oxide With Sheet-Like and Tube-Like Structures Prepared by a Hydrothermal Processing

“…The crystalline structure of the as-synthesized nanostructures prepared using a hydrothermal process is still unclear, despite extensive investigations using mainly anatase phase as precursor [3][4][5][6]. Rutile [7][8][9] as well as brookite [10] phases have been also used as precursors, but the same unclear problem about the crystalline structure was found.…”