Abstract:Anatase-type nanocrystalline titania layers were prepared by oxidizing the crystalline titanium nitride and carbon-doped titanium nitride phases prepared on a titanium plate surface. Identification of the crystalline phase was confirmed by the XRD patterns and Raman spectra of these plates. The photocatalytic activity of the plates was evaluated by observing the photocalytic degradation process of acetaldehyde gas during UV irradiation by gas chromatography. A relatively larger amount of the anatase phase was … Show more
“…The Raman spectra were fitted using the Gaussian and Lorentzian profiles in order to better understand the composition changes in the thin films. For the thin film nitrided at 600 °C, there were a series of peaks at 150, 404, 453, 512 and 643 cm −1 related to TiO 2 (anatase) in the Raman spectrum . In the Raman spectrum of the thin film nitrided at 700 °C, these peaks corresponding to anatase disappeared, instead the peaks at 100–300, 300–400 and 400–700 cm −1 were observed.…”
“…The Raman spectra were fitted using the Gaussian and Lorentzian profiles in order to better understand the composition changes in the thin films. For the thin film nitrided at 600 °C, there were a series of peaks at 150, 404, 453, 512 and 643 cm −1 related to TiO 2 (anatase) in the Raman spectrum . In the Raman spectrum of the thin film nitrided at 700 °C, these peaks corresponding to anatase disappeared, instead the peaks at 100–300, 300–400 and 400–700 cm −1 were observed.…”
“…Since the phototoxicity of TiO 2 is mediated by photochemical events such as ROS photoproduction, the photocatalytic activities of different TiO 2 nanostructures were compared. Acetaldehyde photooxidation is a commonly used indicator for photocatalytic activity, ,,, the pathway of which proceeds through radical oxidative reactions on the nano-TiO 2 surface . Figure A illustrates the decay of acetaldehyde exposed to different nano-TiO 2 at the same mass loading (10 mg) under simulated solar irradiation.…”
Nanostructured titania (nano-TiO2) is produced in diverse shapes, but it remains largely unknown how tuning the morphology of nano-TiO2 may alter its toxicity. Herein, we show that material morphology plays a critical role in regulating the phototoxicity of nano-TiO2 to bacteria. Low-dimensional nano-TiO2, including nanotubes, nanorods, and nanosheets, were synthesized hydrothermally, and their effects on the bacterial viability of Escherichia coli and Aeromonas hydrophila were compared to spherical nanostructures (anatase nanospheres and P25). Results reveal that TiO2 nanotubes and nanosheets are less phototoxic than their rod- and sphere-shape counterparts under simulated solar irradiation. None of the tested nano-TiO2 shows toxicity in the dark. In contrast to their diminished phototoxicity, however, TiO2 nanotubes and nanosheets exhibit comparable or even higher photoactivity than other nanostructures. Observations by scanning transmission electron microscopy suggest that material morphology influences nano-TiO2 phototoxicity by governing how nano-TiO2 particles align at the bacterial cell surface. Overall, when comparing materials with different morphologies and dimensionality, nano-TiO2 phototoxicity is not a simple function of photocatalytic reactivity or ROS production. Instead, we propose that the evaluation of nano-TiO2 phototoxicity encompasses a three-pronged approach, involving the intrinsic photoactivity, aggregation of nano-TiO2, and the nano-TiO2/bacteria surface interactions.
“…Raman shifts corresponding to anatase TiO 2 were observed at 144, 394, 514, and 635 cm −1 . In contrast, Raman shifts corresponding to rutile (239, 445, and 608 cm −1 ) were not detected [19, 20, 21, 22]. Fig.…”
Herein, anatase titanium dioxide (TiO
2
) nanoparticles were prepared by boiling anatase TiO
2
in water without using hydrothermal synthesis. This changed the particle diameter because boiling caused particle collision
via
convection. Substrates were then prepared by assembling anatase nanoparticles on 3-aminopropyltrimethoxysilane (APTMS)-functionalized Al surfaces. The effect of pH on the preparation of anatase nanoparticles was investigated, with results indicating that pH 3 is optimal for anatase adsorption on Al surfaces. The anatase TiO
2
suspension was thus adjusted to pH 3 using dilute HCl solution, and the Al surface selectively adsorbed anatase nanoparticles. This method enabled the adsorption of anatase TiO
2
nanoparticles at room temperature, without using a heat source. In addition to Al substrates, this method was also found to be applicable to glass surfaces.
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