TiO2, as a typical species of semiconductor oxide, has been widely applied in photocatalysis, mesoporous membranes, solar cells, etc. Considering their large specific surface area as well as surface/ interface effects, electrospun TiO2 nanofibers possess superior performance in various fields. In 2003, Li and Xia successfully prepared electrospun TiO2 nanofibers by employing PVP/ethanol/titanium tetraisopropoxide as a precursor solution system. The diameter and the porous structure of the obtained TiO2 nanofibers can be controlled by varying diverse parameters during the electrospinning process (Fig. 3.9) (Li and Xia, 2003). Since then, various solvent systems have been used to produce TiO2 nanofibers with different kinds of structure (Madhugiri et al., 2004; Albetran et al., 2016; Ding et al., 2004). Furthermore, numerous works have been reported with regard to the applications of electrospun TiO2 nanofibers (Chuangchote et al., 2009; Hou et al., 2017; He et al., 2013a, 2016; Zhou et al., 2017; Zhao et al., 2008a; Mendoza et al., 2016; Adhikari et al., 2016). For instance, Chuangchote et al. synthesized diverse TiO2 nanofibers under different annealing temperature from 300C to 700C, and employed them as photocatalysts against hydrogen evolution. The results showed that the sample calcined at 450C exhibited the optimum catalytic activity (Chuangchote et al., 2009). Hou et al. developed a foaming-assisted electrospinning approach to synthesize N-doped TiO2 mesoporous nanofibers. Their potential applications in energy and water purification have been demonstrated by investigating the photocatalytic activity against hydrogen evolution and degradation of rhodamine B (Hou et al., 2017). He et al. prepared two types of electrospun TiO2 nanofibers by varying the solvent ratios. After sonication treatment, the properties of the obtained products as photoanodes in dyesensitized solar cells were investigated (He et al., 2013a). Similarly, Zhou et al. successfully synthesized highly nanoporous TiO2 nanofibers and studied their photovoltaic properties (Zhou et al., 2017).
TiO2 Nanofibers