Decomposition of MEK and toluene over nanolayered TiO2 photocatalyts prepared from metallic titanium chip.

The Nanolayered TiO2 photocatalysts were prepared by thermal treatment of metallic titanium chips. Photocatalytic activity for methyl ethyl ketone (MEK) and toluene was investigated using a closed circulating system. The photocatalysts were characterized by SEM and XRD. Surface of the Ti chips changed to be rough with increase of treatment temperature, and severe oxidation over 900 degrees C resulted in TiO2 powder. Uniform TiO2 nanolayer was formed as a rutile type on the metallic chip. Photocatalytic decomposition of MEK over the TiO2 photocatalysts occurred efficiently by UV-C irradiation. The maximum activity for MEK was obtained over Ti Chip treated at 700 degrees C. It was known that the prepared photocatalyts could be applied to remove various VOCs.

Visible light-responsive titanium dioxide thin film prepared by reactive sputtering.

TiO2 is a wide band-gap semiconductor (3.4 eV) and can only absorb about 5% of sun light in the ultraviolet light region, which largely limits its practical applications because of the lower utility of sun light and quantum yield. In order to move the absorption edge of TiO2 films to visible spectrum range, we have made the impurity level within a band-gap of TiO2 thin film by introduction of oxygen vacancy. Oxygen-defected TiO2 photo-catalyst have prepared by reactive sputtering with the partial pressure of Ar:O2 = 76.7:23.3 approximately 98.5:1.5 ratios. As a result, we could have the impurity level of about 2.75 eV on condition that oxygen partial pressure is 2.9%. And the photocatalytic activity was realized at 400 nm wavelength.

Photocatalytic activity of nanosized TiO2 thin film prepared by magnetron sputtering method.

Nanosized TiO2 thin film on the substrate such as stainless steel plate and slide glass film were prepared by magnetron sputtering method, and these TiO2 thin films were characterized by field emission-scanning electron microscopy (FE-SEM). Photocatalytic activity for Methyl-ethyl-ketone (MEK) and acetaldehyde were measured using a closed circulating reaction system through the various ultra violet (UV) sources. From the results of SEM images, nanosized TiO2 thin film was uniformly coated on slide glass, ranging from 360 nm to 370 nm. Photocatalytic activity of MEK over TiO2 thin film on stainless steel plate did not occur by UV-A irradiation, but was efficiently decomposed by UV-B and UV-C. Also, acetaldehyde could be decomposed than MEK. The effect of sputtering conditions on their structure and photocatalytic activities were investigated in detail.