Electrospun anatase-phase TiO2 nanofibers with different morphological structures and specific surface areas

Electrospun anatase-phase TiO2 nanofibers with desired morphological structure and relatively high specific surface area are expected to outperform other nanostructures (e.g., powder and film) of TiO2 for various applications (particularly dye-sensitized solar cell and photo-catalysis). In this study, systematic investigations were carried out to prepare and characterize electrospun anatase-phase TiO2 nanofibers with different morphological structures (e.g., solid, hollow/tubular, and porous) and specific surface areas. The TiO2 nanofibers were generally prepared via electrospinning of precursor nanofibers followed by pyrolysis at 500 °C. For making hollow/tubular TiO2 nanofibers, the technique of co-axial electrospinning was utilized; while for making porous TiO2 nanofibers, the etching treatment in NaOH aqueous solution was adopted. The results indicated that the hollow/tubular TiO2 nanofibers (with diameters of ∼300–500 nm and wall-thickness in the range from tens of nanometers to ∼200 nm) had the BET specific surface area of ∼27.3 m2/g, which was approximately twice as that of the solid TiO2 nanofibers (∼15.2 m2/g) with diameters of ∼200–300 nm and lengths of at least tens of microns. Porous TiO2 nanofibers made from the precursor of Al2O3/TiO2 composite nanofibers had the BET specific surface area of ∼106.5 m2/g, whereas porous TiO2 nanofibers made from the precursor of ZnO/TiO2 composite nanofibers had the highest BET specific surface area of ∼148.6 m2/g.

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► Electrospun anatase-phase TiO2 nanofibers were prepared.
► The TiO2 nanofibers had different morphological structures and specific surface areas.
► Different morphological structures were solid, hollow/tubular, and porous.
► Porous TiO2 nanofibers were made from Al2O3/TiO2 or ZnO/TiO2 composite nanofibers.
► The BET specific surface area of porous TiO2 nanofibers was up to ∼148.6 m2/g.