Hiroaki Nishijima

Preparation of TiO2 nano-particle photocatalysts by a multi-gelation method: the effect of pH change

TiO2 photocatalysts were prepared by a multi-gelation method and the effect of the changes in the pH during the pH swing times, i.e., by a controlled pH swing, on the morphology of the TiO2 particles was investigated. The photocatalytic properties of the TiO2 catalysts prepared by controlled pH swing were compared with TiO2 particles prepared without adjusting the pH during the swing times. The photocatalytic degradation reaction of these TiO2 catalysts was investigated by comparing their effectiveness in 2-propanol oxidation. The experimental results showed that the TiO2 photocatalysts prepared without adjusting the pH performed better in controlling the important parameters of the catalysts such as particle size, surface area, anatase/rutile phase ratio and pore size, as well as pore volume than the TiO2 photocatalysts prepared by a controlled pH swing method.

Preparation of Nano-Sized TiO2 Photocatalysts by a Multi-Gelation Method and Their Application to the Degradation of 2-Propanol Diluted in Water

TiO2 photocatalysts prepared by a novel multi-gelation method showed good photocatalytic activity for the degradation of 2-propanol diluted in water by the control of parameters such as particle size, surface area, crystallinity, pore-volume, pore-diameter as well as anatase and rutile phase composition by changing the number of pH swings during preparation. In particular, with this method the phase transition from anatase to rutile at higher pH swing times can be controlled and high purity and uniformity of the TiO2 particles which leads to higher photocatalytic activity of the particles can be achieved. From our experimental results, it has been observed that TiO2 catalysts prepared by this unique multi-gelation method, i.e., adopting variations in the pH swing, significantly shows higher photocatalytic activity for the degradation of 2- propanol diluted in water. It can be considered a viable alternative over existing commercial methods for the preparation of photofunctional catalysts.