Modification and enhanced photocatalytic activity of TiO2 following exposure to non-linear irradiation sources

On-line monitoring of laser modification of titanium dioxide using optical surface second harmonic

“…Since the SSH is sensitive to many parameters influencing the photocatalytic activity of TiO 2 (crystal structure, oxidation state, particle size), it has therefore been demonstrated to be a powerful tool for monitoring these changes when TiO 2 was exposed to laser irradiation. So far only the enhanced photocatalytic activity of heavily treated P25 has been reported [2,3]. It would be interesting to study the photocatalytic activity of the TiO 2 during the different stages of modifications.…”

“…These properties are usually determined using surface analysis methods such as XPS, XRD or TEM, which require significant sample preparation and must be operated under vacuum. Recently Lee et al reported a modification of crystal structure and oxidation state of TiO 2 powders, which also changed in colour from white to blue grey, following exposure to pulsed laser light [2,3]. Further work has shown that the laser induced alterations were dependent on the exposure parameters i.e.…”

Analyses of surface coloration on TiO2 film irradiated with excimer laser

“…Lee et al [2] observed a visible change in color from white to dark blue, when TiO 2 (Degussa, P25), a roughly 70:30 anatase/ rutile mix, was irradiated with a laser peak power over 0.8 MWat 355 nm wavelength. They also observed that the higher the laser power the darker the color change.…”

“…Phase transition from anatase to rutile and color change were observed in laser irradiated TiO 2 by some researchers [2,3]. The color change upon laser irradiation was usually attributed to partial reduction of titanium (IV) [4,5].…”

“…TiO 2 is a technologically important material, widely used as pigments, photocatalyst, optical component coatings and in other applications [1,2]. Phase transition from anatase to rutile and color change were observed in laser irradiated TiO 2 by some researchers [2,3].…”