To ensure enough specific surface area (the proportion of volume to surface area) to be effective in micro- world, the diameter of TiO2 must be controlled under nanometer. According to the reports by Scientific American in 2002, the general crystallization of TiO2 is between 20~250nm, which is not effective.

In fact, TiO2 will work only if its diameter is under 7nm. It is because in 3-D space, the smaller the particles’ diameters are, the closer they will line, and the increase of specific surface area will cause more sensitive reaction. The average diameter of TiO2 in Nanoyo Photocatalyst is under 7nm, which could result in a rather big specific surface area, and a high effectiveness per unit.