Design, Fabrication, and Modification of Cost-Effective Nanostructured TiO for Solar Energy Applications - Low-cost Nanomaterials: Toward Greener and More Efficient Energy Applications - page 21

Fig. 4 Schematic of the preparation of the TiO 2 electrodes using hybrid templates. (Reprinted
with permission from Ref. [ 78 ]). Copyright Wiley-VCH
Fig. 5 Simplified schematic of hydrothermal and solvothermal synthesis and some typical
structures prepared by both process: a nanosheets, b nanorods, c hollow microspheres and
d flower-like microspheres. (Reprinted with permission from Ref. a [ 114 ], b [ 122 ], c [ 8 ] d [ 125 ].
Copyright American Chemical Society and Wiley-VCH)
the solvents used for solvothermal synthesis are nonaqueous, while water is the
primary hydrothermal solvent [ 114 , 115 ]. Accordingly, the temperature in solvo-
thermal process can be increased much higher than that in hydrothermal method
because a variety of organic solvents with high boiling points can be adopted.
Normally, the solvothermal method possesses better control over the size, struc-
ture, size distribution, and degree of crystallinity of TiO 2 nanomaterials compared
to hydrothermal method [ 35 ].
In comparison with other methods, hydrothermal/solvothermal synthesis is a
facile route to prepare a highly crystalline oxide under moderate reaction condi-
tions, including low temperature (in general less than 250 C) and relatively short