The development of highly active TiO2 photocatalysts anchored onto a stable substrate have been investigated using a wet or dry process. The results of this study led to the development of highly active rectangular column-structured titanium oxide photocatalysts which could be anchored onto silica sheets. These highly active photocatalysts were then applied to develop an effective air purification system. (c) 2007 Published by Elsevier B.V.