Topics in Current Chemistry (2020) 378:2
1 3
and XRD spectra in Fig. 20, the intermediate phase started to transform to nanorods
after 4 h. The length of the nanorods was dependent on the time of annealing, and
after 8 h, the intermediate phase was entirely transformed to rutile nanorods of the
maximum length. Extension of the thermal treatment led to the sintering of the 1-D
structure to coarse nanoparticles.
In 2013, Tao et al. [134] demonstrated a new method for the synthesis of TiO 2
nanorods (single-crystal) from natural ilmenite. The BM pre-treated mineral was
further wet-chemistry-treated by mixing in a 2 M NaOH aqueous solution for 2 h
at 120 °C, and flower-like FeTiO 3 nanoparticles were formed, but the authors concluded that this stage is an optional one. After short and mild drying, treatment with
4 M HCl at 90 °C for 4 h took place. The proposed mechanism was based on dissolution to TiOCl 2 and FeCl 2 , hydrolysis, and precipitation. During the hydrolysis,
TiO 2 crystals started to precipitate and grow in a 1-D fashion. The finally obtained
rutile TiO 2 tetragonal nanorods (Fig. 21) had a length in the range of 50–100 nm,
width of 5–20 nm, and thickness of 2–5 nm. The nanorods have also a moderately
high specific area for this kind of nano-structure (up to 97 m
2
/g). The most interesting outcome was that they showed excellent photocatalytic capability towards
the photodegradation of oxalic acid, analogous with the one of Sigma–Aldrich’s
Degussa P25.
In 2014, Zhao et al. [135] reported the formation of spindle-like rutile TiO 2
nanorods from the dealloying in acidic conditions of an amorphous Cu 50 Ti 50 alloy.
The latter was formed by high-energy ball milling of elemental Cu and Ti in an
Fig. 21 SEM images of original ilmenite powder (a), ball-milled ilmenite powder (b), flower-like FeTiO 3
nano-structures after treatment with NaOH (c), and the obtained nanorods after treatment with HCl for
8 h (d); inset: a higher-magnification capture of the nanorods. Reprinted with permission from [134].
Copyright (2013) Wiley
60
Reprinted from the journal
1 3
and XRD spectra in Fig. 20, the intermediate phase started to transform to nanorods
after 4 h. The length of the nanorods was dependent on the time of annealing, and
after 8 h, the intermediate phase was entirely transformed to rutile nanorods of the
maximum length. Extension of the thermal treatment led to the sintering of the 1-D
structure to coarse nanoparticles.
In 2013, Tao et al. [134] demonstrated a new method for the synthesis of TiO 2
nanorods (single-crystal) from natural ilmenite. The BM pre-treated mineral was
further wet-chemistry-treated by mixing in a 2 M NaOH aqueous solution for 2 h
at 120 °C, and flower-like FeTiO 3 nanoparticles were formed, but the authors concluded that this stage is an optional one. After short and mild drying, treatment with
4 M HCl at 90 °C for 4 h took place. The proposed mechanism was based on dissolution to TiOCl 2 and FeCl 2 , hydrolysis, and precipitation. During the hydrolysis,
TiO 2 crystals started to precipitate and grow in a 1-D fashion. The finally obtained
rutile TiO 2 tetragonal nanorods (Fig. 21) had a length in the range of 50–100 nm,
width of 5–20 nm, and thickness of 2–5 nm. The nanorods have also a moderately
high specific area for this kind of nano-structure (up to 97 m
2
/g). The most interesting outcome was that they showed excellent photocatalytic capability towards
the photodegradation of oxalic acid, analogous with the one of Sigma–Aldrich’s
Degussa P25.
In 2014, Zhao et al. [135] reported the formation of spindle-like rutile TiO 2
nanorods from the dealloying in acidic conditions of an amorphous Cu 50 Ti 50 alloy.
The latter was formed by high-energy ball milling of elemental Cu and Ti in an
Fig. 21 SEM images of original ilmenite powder (a), ball-milled ilmenite powder (b), flower-like FeTiO 3
nano-structures after treatment with NaOH (c), and the obtained nanorods after treatment with HCl for
8 h (d); inset: a higher-magnification capture of the nanorods. Reprinted with permission from [134].
Copyright (2013) Wiley
60
Reprinted from the journal