Simple Protocol for Generating TiO₂ Nanofibers in Organic Media

Abstract

Titania nanofibers in high yields can be accessed by treating titanium isopropoxide (Ti(OiPr)4) with acetic acid (AcOH) in heptanes when R ≥ 4.2, where R = mol of AcOH/mol of Ti(OiPr)4. Electron microscopic (SEM and TEM) images of the samples confirmed that high-aspect-ratio nanofibers with diameters in the 10−20 nm range are produced under these conditions, whereas agglomerated spherical nanoparticles are produced at R ≤ 3.8. Powder X-ray diffraction and UV-vis data confirm the anatase crystalline phase after calcination at 400 °C, with the progressive formation of the rutile phase upon heating to higher temperatures. N2 physisorption analyses showed the calcined fibers prepared at R = 5.5 have surface areas of 95 m2/g. The self-assembly pathway leading to the nanofibers was delineated by in situ attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy in tandem with electrospray ionization mass spectrometry (ESI-MS). It was found that the hexanuclear building block, Ti6O6(OAc)6(OiPr)6 (TAC1), is formed during the initial stages of the reactions, and that the axially ligated isopropoxide ligands of this complex are subsequently hydrolyzed to facilitate the one-dimensional condensation of the macromolecules at R ≥ 4.2. Incomplete hydrolysis at lower acid ratios impedes this axial growth, resulting in spherical nanoparticles.

p-Aminophenylacetic acid-mediated synthesis of monodispersed titanium oxide hybrid microspheres in ethanol solution

“…This shift to low wavenumber implies that APA was bonded to TiO 2 . The similar result was also observed in previous reports [13,14]. Additionally, in each spectrum the absorption band at 1619 cm À1 was assigned to the scissoring vibration of -NH 2 group, and the characteristic bands at 1517 and 1597 cm À1 corresponded to the C@C stretching of quinoid and benzenoid rings [15].…”

Effect of UV-light on the uniaxial tensile properties and structure of uncoated and TiO2 coated Bombyx mori silk fibers

“…5, the peak observed in the 570-670 cm À1 region with a maximum at 650 cm À1 is likely due to the vibration of Ti-O bonds. The peak at 801 cm À1 is assigned to -TiO-Ti-stretching [28]. The bands observed at 1028, 1415, and 1527 cm À1 were attributed to stretching and vibrations of the Ti-O-Ti group [29].…”

Application of Photocatalysts and LED Light Sources in Drinking Water Treatment

“…A review of literature suggested the following photocatalysts reported to have advantages such as outperforming Degussa P25 in at least one case: (a) mesoporous TiO 2 and TiO 2 nanofibers, which are reported to have large surface area [20,21]; (b) rare earths doped TiO 2 , to increases the separation efficiencies of electron and hole pairs and modifying the microstructure of the photocatalyst [22], and (c) photocatalysts with energy storage capability (WO 3 /TiO 2 and Ni(OH) 2 /TiO 2 ). The electron storage capability of WO 3 /TiO 2 extends lifetimes and as a consequence improves the interfacial transfer yield [18].…”

“…TiO 2 nanofiber, which was kindly provided by Ghosh et al [12], was prepared by the following procedure outlined by Sui et al, in which a mixture of heptane, acetic acid and titanium isopropoxide was heated to 60 °C until a gel was formed [20]. The gel was aged for 5 days, then dried at 80 °C and finally calcined at 400 °C for 2 h. A sol gel method described by Xu et al was used to prepare the Eu and Nd doped photocatalysts [22].…”