Formation mechanism of the rutile phase of titanium dioxide nanorods on titanium foil substrate by g

A formation mechanism that leads to the synthesis of rutile-phase TiO2 nanorods at high temperatures on Ti foil by NaOH-based gel-oxidation method is discussed based on a series of experimental investigations. TiO2 nanostructures are prepared on Ti foil following two steps, namely gelation and oxidation. It is shown that the use of an alkali-based solution during gelation, such as NaOH, leads to the formation of tetragonal nanorods of TiO2 upon oxidation at high temperature (~ 800 oC). When an acidic solution that does not contain an alkali element, such as H2O2, is used during gelation, the shape of the nanostructures upon oxidation at high temperature does not display the tetragonal nanorod shape. The following formation mechanism is suggested: the high temperature oxidation of the Na based hydrogel (formed on the Ti surface during a 24-hour soak in NaOH solution) converts it into Na-titanate in the shape of tetragonal 100 nm 10 µm (b) (e) (d) 10 µm 1 µm (a) 10 µm 100 nm (c) (f) NaOH-treated Ti, calcinated for 1 hour at 600 oC NaOH-treated Ti, calcinated for 1 hour at 600 oC NaOH-treated Ti, calcinated for 1 hour at 800 oC NaOH-treated Ti, calcinated for 1 hour at 800 oC NaOH-treated Ti NaOH-treated Ti nanorods, which in turn convert into tetragonal nanorods of rutile-phase TiO2 when Na evaporates in the form of an oxide. For more detailed information download or read this publication here.